METALLURGICAL A B S T R A C T S
(G E N E R A L A N D N O N -F E R R O U S )
Volume 2 JUNE 1935 Part 6
I.— PR O PER TIES OF METALS
(Continued from pp. 197-212.)
*The Annealing of Pure Aluminium and Its Possible Utilization as a Criterion of the Purity of this Metal. J . Calvet (Light Metals Research, 1935, 3, 368- 370).—Translated from Compt. rend., 1935, 200, 66-68. See Met. Ahs., th is volume, p. 137.—J . C. C.
*On the Plasticity of Crystals. [Torsion Tests on Polycrystalline Copper and Single Crystals of Copper.] Pol Duwez (Phtjs. Rev., 1935, [ii], 47, 494-501).—
A theory of plastic distortion is developed by assuming the existence of the secondary structure postulated by Zu icky. • {Note by Abstractor: th e criticisms of the theory of Zwicky by Buerger and T aylor should be read in this connection.] Gliding in crystals is assumed to take place on th e 7r planes which characterize th e secondary lattice a t shearing stresses m uch sm aller th an those derived from th e theory of ideal lattices. This is illustrated by a mechanical model consisting of springs (representing elastic forces) connected by flat plates which glide over one another. The stress-strain curve is obtained as an exponential law involving th e torsional modulus, the elastic lim it, and th e m axim um stress th a t can be applied w ithout producing rupture. The equations are confirmed by th e results of torsion experiments on polycrystalline copper, an d also on a single crystal.—W. H .-R.
*The Creep Fracture and Fracture of Lead and Lead Alloys. H erb ert F.
Moore, B ernard B. B etty , an d Curtis W. Dollins (U niv. Illinois B ull. No.
2 7 2 ,1935, 9 47).—The m aterials used in th is investigation were : commercially pure lead ( A ) ; an d alloys thereof w ith 2% tin (B ); 0-75% antim ony (C ); and 0-04% calcium (D ). I n no case is there a n absolute lim iting tensile stress below which no creep o ccu rs; a t room tem perature under a stress of 180 lb ./
in .2 creep occurs a t a ra te varying from 0-3% per annum for D to 0-6% per annum for A, and a t 65° C. the corresponding figures are 0-6 and 1*4%. E x tra polated from the results of te sts over 1000 hrs. th e approxim ate creep a t room tem perature under 1 y ear of steady tensile stress is as follows : 200 lb./in.2, (A) 0-7, (B) 0-6, (C) 0-4, (D) 0 -3% ; 300 lb ./in .2, (A) 1-6, (B) 1-1, (C) 0-7, (D ) 0-4% ; 400 lb ./in .2, (.4) 3-9, (B) 1-9, (C) 1 0 , (D) 0 -6% ; 500 lb ./in .2, (A) 5-0, (B) 3-2, (C) 1-4, (D) 0-8% . These figures show th a t th e addition of calcium and antim ony has a very m arked effect in reducing the creep of lead a t high stresses. The lowest stress under which fracture occurs under long continued load is 600 lb ./in .2 for A , B, an d C and 1000 lb ./in .2 for D, the corre
sponding tim es to fracture being ab o u t 36,148, 262, an d 333 days, respectively.
U nder reversed flexural stresses of 200 lb ./in .2 ab o u t 108 cycles are necessary to produce fracture of (A), the w eakest of th e m etals tested. Microscopic exam ination of lead an d its alloys after subjection to long-continued steady loads indicates th a t there is d isto rtio n by ro ta tio n of a t least th e surface crystals, whereas in short tim e tests d istortion occurs by slip w ithin the crystal grains, large-grained m etal appearing to resist creep b etter th a n fine-grained m etal. I n creep tests on single crystals d istortion occurs along certain definite atom ic planes and there appears to be a lim iting resolved shearing stress along these planes below which creep is very slow, b u t above w hich it occurs rapidly.
—A. R . P.
* Denotes a paper describing the results of original research, f Denotes a first-class critical review.
274 M etallurgical Abstracts
Vo l. 2Properties and Uses oi Lithium. J . Staes (Rev. Univ. M ines, 1934, [viii],
10, 635-637).—S. G. , _ _ ... , , v „
*Absorption and Adsorption o£ Hydrogen by Nickel. J . S m ittenberg ( e . trav. chim ., 1934, 53,1065-1083).—The absorption an d adsorption of hydrogen by nickel a t low pressures was studied w ith a long th in nickel wjre * i n e absorption or solution of hydrogen in solid nickel is proportional to the square ro o t of th e pressure, an d increases a t co n stan t pressure w ith increasing tem p erature, obeying th e equation : log a — A — B / T . The h eat of absorption am ounts to — 2-62 kg.-cal. per grm. mol. of hydrogen.—C. It. H .
♦The Atomic Heat of Nickel at Liquid Helium Temperatures. W. H. Kecsom an d C. W. Clark (Physica, 1935, 2, 230).— [In English.] I n th is prelim inary note, K . an d C. sta te th a t th ey have m easured th e atom ic h eat, C, of nickel from 1-1° to 20° abs. I t appears th a t as a lim iting law a t liquid helium tem perature, T (1° — 4° abs.), C = T X const. The contribution to the atom ic h e a t a ttrib u ta b le to a v ariatio n of m agnetization w ith tem perature is, theoretically, proportional to I '3''2. The experim ental values are largely in excess of th is am ount, an d follow another law. The atom ic heats of nickel are m any tim es larger th a n th e values deduced from Somm erfeld’s form ula based on th e existence of free electrons. These larger values m ay be associated w ith an abnorm ally sm all value of th e lim iting electronic energy.
—J . S. G. T.
*A New Method for Determining Thermionic Work-Function of Metals, and Its Application to Nickel. G erald W . Fox an d R o b ert M. Bowie (Proc. Iowa Acad. Sci., 1933, 4 0 ,154).—See J . In st. Metals, 1933, 53, 690.—S. G.
♦Platinum-Helium Compound Probably as Large as Colloidal Particles.
H oracio D am ianovich (Anales soc. d ent. Santa Fe, 1934, 6, 17-19; C. Abs., 1935, 29, 2814).—Failure to o b tain photom icrographs of individual particles of th e p latinum -helium com pound leads to th e belief th a t th e y m ay be of colloidal size. Calculations indicate th a t P t 6H e is th e first com pound of the series of possibilities likely to give molecules of colloidal size.—S. G.
* Microstructure of Platinum Subjected to the Action of Helium, Oxygen, and Hydrogen under the Influence of the Electric Discharge. H oracio D am iano
vich (Anales soc. d ent. Santa Fe, 1934, 6, 20—22; C. Abs., 1935, 29, 2814).——
Photom icrographs of platinum surfaces subjected to electric discharges in atm ospheres of hydrogen an d helium are reproduced. V ery curiously different protuberances appear in each case. These phenom ena will be investigated in different conditions.—S. G.
The Thermal Expansion of Silver, Quartz, and Bismuth by X-Ray Measure
ments. A. H . J a y (Z. K rist., 1934, 89, 282-285).—A sum m ary of w ork pu b lished elsewhere (cf. J a y , Proc. Roy. Soc., 1933, [A], 142, 237; and 1934, [A], 143, 465 (Met. Abs., 1934,1, 113)).—W . H .-R.
♦The Thermionic Properties of Tantalum. A lvin B. Cardwell (Phys. Rev., 1935, [ii], 47, 628-630).—Prolonged outgassing of ta n ta lu m a t 2200° K . pro
duced a n app aren tly stable condition (cf. Cardwell, ibid., 1931, [ii], 38, 2041), an d a final stable condition was only obtained a t 2500° K . F o r the final condition, th e constants of th e R ichardson equation are b = 47,560° K ., h = 4-10 v., A = 37-2 am p./cm .2 degree2. Com parison w ith previous results shows th a t th e value of th e photoelectric w ork-function determ ined by Fow ler’s m ethod agrees w ith th e value of th e therm ionic w ork-function of the same surface, regardless of w hether th e surface is com pletely outgassed or n o t.—W. H .-R .
♦Electrical Resistances and Volume Changes up to 20,000 Kg./cm .2 [Tel
lurium, Lithium, Sodium, Potassium]. P . W. B ridgm an (Proc. N at. Acad.
S ci., 1935, 21, 109-113).—The resistance of tellurium , an d the p ressu re- v o lum e-tem perature relations of lithium , sodium , an d potassium have been studied a t pressures u p to 20,000 kg./cm .2. M easurem ents of th e volum e
1935
I . — Properties o f Metals 275
changes of these alkali m etals revealed a serious error in the results previously published. On increasing the pressure from 2000 to 20,000 kg./cm .2, the mean coeffs. of linear expansion (0°—95°) of lithium , sodium, and potassium decreased from 0 0000515 to 0 0000273, 0 0000622 to 0-0000233 and 0-0000670 to 0-0000125, respectively.—C. E . H . ’
*The Elastic Properties of Single and Multiple Tin Crystals. W. Boas (Helv P h ys.A cta , 1934, 7, 878-883; Set. Abs., 1935, [A], 38, 236).— [In German.]
ih e dependence on orientation of the m oduli of elasticity an d torsion of the crystal of tin is described. The m ethod employed was th a t given by H uber and Schmid (Met. Abs., this volume, p. 208). B y sum m ation of average values over the whole region of orientation the moduli of th e quasi-isotropic m ultiple crystal are calculated, an d comparison is m ade w ith experim ent. S. G.
*New Method of Preparing Pure Vanadium. André M orette (Compt. rend., 1935, 200, 1110-1112).—V anadium tetrachloride, obtained by th e action of chlorine a t 500 —600° C. on cast vanadium and free from oxychlorides, is passed w ith a current of pure hydrogen over pure magnesium filings in a magnesia boat, the tem perature being increased progressively in 2 ] hrs. to 700° C On cooling, a grey pow der containing 99-3% of vanadium is obtained. A lter
natively, vanadium dichloride, obtained by the action of hydrogen on the tetrachloride a t 750°-800° C., is reduced by magnesium (2 p a rts of dichloride to 1 of magnesium filings) by heating in a magnesium b o at in vacuo, in argon, no (Win'S?/ kyd r°gei? a t 700° C. for 1-2 ] hrs. A grey powder containing 98-9-99-5 /0 of vanadium results after cooling, washing, and cold-drying the product. The m etal th u s prepared burns w ith brilliant sparks when throw n into a Bunsen burner flame. I t reacts violently w ith concentrated nitric acid, giving, after dessication, a substance possessing the characteristics of vanadium anhydride ; i t is soluble in hydrofluoric acid and is u n attack ed by hydrochloric acid.—J . H . W.
* Work in the Charlottenburg Cryoscopic Laboratory on Superconductivity and on the Hydrogen Isotope [Vanadium ; Molybdenum]. W. Meissner (Helv.
Phys. Acta, 1933, 6, 414—418; C. Abs., 1935, 29, 2413).—V anadium and molybdenum become superconducting a t 4-3° and 1-1° K ., respectively.
Arsem c-lead alloys become superconducting a t th e transition point of lead.
g Q
*The Exact Measurement of the Specific Heats of Solid Substances at High Temperatures. VI.—The Specific Heats of Vanadium, Niobium, Tantalum and Molybdenum. F . M. Jaeger and W. A. V eenstra (Rec. trav. chim., ] 9,34*
53, 677-687). See also Met. Abs., 1934, 1, 227. The specific heats of these 4 m etals were determ ined a t various tem peratures u p to ab o u t 1550° C by the m ethod previously described (ibid., 1932, 51, 2). The exactness and repro
ducibility of the m easurem ents proved to be 0 1 -0 -2 % of the values indicated, krom the results, equations connecting specific an d atom ic heats w ith te m perature were developed for the various metals, and thus values were cal
culated for tem peratures from 0° to 1600° C., a t 100° C. intervals. I n th e case of niobium, specific heats a t constant volum e were also calculated.—C E H
*Mosaic Zinc Crystals. E. P. T. Tyndall and H . K . Schilling (Proc. Iowa Acad. Sci., 1933, 40, 156; C. Abs., 1935, 29, 2415).—Crystals of a d istinctly mosaic type (th a t is, a group of polycrystals w ith alm ost identical orientations) were grown w ith great frequency during 1931 an d 1932.— S. G.
, 3 ? " ^ of Mosaic Zinc Crystals. W. J . Poppy (Proc. Iowa Acad. Sci., 1933, 40, 156 ; C. Abs., 1935, 29, 2415).—See also Met. Abs., th is volum e, pp.
5 and 46. Zinc mosaics d ep art from th e resistiv ity -o rien tatio n relation ch ar
acteristic of a tru e single crystal. They show m arked increases in resistivity after strain w ith a decline to th e original, or lower values, on annealing. S. G.
Elasticity of Zinc Crystals. A. W . H anson (Proc. Iowa Acad. Sci., 1933, 40, 156 ; C. Abs., 1935, 29, 2415).—See also J . In st. Metals, 1933, 53, 692 and
276 Metallurgical Abstracts
Vo l. 2Met. Abs., 1934, 1, 228. The ap p aratu s for th e determ ination of elastic con
sta n ts was im proved. Incom plete tests seem to show th a t crystals w ith d istin ct mosaic stru ctu re differ only slightly, if a t all, in elastic properties from tru e single crystals.—S. G.
*0n the Effect of Slight Impurities on the Elastic Constants, Particularly the Compressibility of Zinc. P . W. B ridgm an (Phys. Rev., 1935, [ii], 47, 393-397).
—Cf. following ab stract. Single crystals of zinc were prepared from 3 sources of exceedingly pure m etal, an d th e ir linear com pressibilities for different orientations m easured by B .’s m ethod (Proc. Airier. Acad. Sci., 1923, 58, 166).
No difference w ithin th e experim ental error could be correlated w ith the source of th e m etal. T his is in m arked co n trast to th e conclusions of H anson [Phys.
Rev., 1934, [ii], 45, 324) who calculated th e elastic co n stan ts an d compressi
bilities from the results of bending an d torsion experim ents. Some of B.’s specimens were m ade from th e sam e blocks of m etal used by H anson, and it is concluded th a t th e differences found by th e la tte r are due to in tern al strains.
The following im proved values are found for th e com pressibility of z in c : 90° orientation, — Al/l0 = 1-57 X 10~7 p — 0-75 X 10“12 p 2, 0° orientation,
— Alll0 = 13-50 X 10-7 p — 7-68 X 10~12 p 2, volum e compression, — A F /F 0=
16-64 X 10~7 p — 9-62 X 10-12 p 2, a t 30° C., p in kg./cm .2.—W . H .-R .
*Note on the Probable Values of the Elastic Constants of the Zinc Crystal.
E . P . T. T yndall {Phys. Rev., 1935, [ii], 47, (5), 398-399).—The w ork of Bridg
m an (preceding ab stract) is accepted as disproving th e conclusion of Hanson [Phys. Rev., 1934, [ii], 45, 324) th a t th e elastic constants an d compressibilities of zinc crystals are m arkedly affected b y m inute traces of im purities. One set of H anson’s m easurem ents is, however, n o t only self-consistent, b u t also in good agreem ent w ith B ridgm an’s com pressibility d a ta , an d th e following values for th e elastic constants are considered to be th e m ost p ro b ab le:
au = 7-70, s12 = 0-83, sn = - 6-93, s33 = 27-66, s41 = 24-40, all x 1 0 13 cm .2/dyne.—W. H .-R .
Factors Influencing Creep. R . W. Carson (M achinist (Eur. Edn.), 1935, 79, 261-263).—The various factors influencing creep are reviewed, and it is suggested th a t creep a t norm al tem p eratu re is closely related to high-tem- peratu re creep, although th e controlling factors are different. Copper alloys have m ore creep th a n nickel or Monel m etal, b u t age-hardening alloys are an im p o rtan t exception to th is generalization.—J . H . W.
* Transparency of Thin Metallic Films in the Ultraviolet. H . H arold H artz- ler (./. Opt. Soc. A m er., 1934, 24, 339-341).—M easurem ent of transm ission of lig h t of different w ave-lengths was m ade on m etallic films of varying thicknesses by m eans of th e vacuum prism spectrograph (Cario an d Schm idt-O tt). The m etals copper, silver, gold, magnesium , tin , lead, arsenic, antim ony, and bis
m u th were deposited on th in films of celluloid b y ev ap o ratio n in a vacuum tube. The individual num erical results are given. Zinc an d cadm ium failed to give suitable film s; the films were porous an d fern-like in stru ctu re. Poor films were also given by the alkaline e a rth m etals an d those of th e iron group.
—R . G.
* Action of Nitrogen on the Metals. Electrical Discharges at Low Pressures.
G. B erraz [Anales soc. d en t. Santa Fe, 1933, 5 ,5 4 -5 6 ; G. Abs., 1935, 29, 2861).
—C athodic sp u tterin g of silver in nitrogen a t reduced pressure resulted in fixation of very little nitrogen, an d i t is doubtful w hether an y N Ag3 was form ed. Sim ilar results were obtained w ith gold. L ead gave a n easily pulverizable deposit which gave N H 3 in m oist a i r : i t is probably N 2P b 3, w hich reacts as follows : N 2P b 3 + 3H 20 = 2 N H 3 + 3PbO .— S. G.
Anodic Passivation [of Metals]. W . J . S h u tt [Trans. Faraday Soc., 1935, 31, 636-637).—A reply to A rm strong an d B u tler’s criticism of S h u tt and W alton’s conclusions on th e m echanism of th e passivation of gold in chloride solutions (cf. M et. A bs., th is volum e, p. 3).—A. R . P.
1935
I . — Properties o f Metals 277
The Effect of Slow Electrons on Metal Surfaces. J . B. Philipson (Proc.
Iowa Acad. Sci., 1933, 40, 150-151; C. Abs., 1935, 29, 2452).—The im pact of electrons on a m etal surface alters th e chemical properties of th e surface in such a way th a t certain subsequent chemical treatm en ts will m ake the exposed portions visibly different from the unexposed portions.—S. G.
*The Influence of Cold-Work on the Thermal Conductivity of Metals. G. Tam- mann and W. Boehme (A nn. PhysiJc, 1935, [v], 22, 500-506).—The therm al conductivity of m etal wires draw n to 98% reduction is less th a n th a t of sim ilar wires in the annealed state by the following am ounts : silver 5-8, copper T6, iron 3-2, nickel 5-4, alum inium 0, 77 : 23 silver-zinc alloy 22, 72 : 28 brass 22% . These values correspond alm ost exactly w ith the increase in electrical resistance, and th e curves showing change in electrical and therm al resistance w ith annealing tem perature are also similar. The therm al conductivity of rolled sheets of iron, nickel, silver, copper, an d alum inium shows no anisotropy.—v. G.
*Asymmetric [Electrical] Conductivity of an Electrode System comprising Metal-Salt Layer-Adsorbed Alkali Metal. J . H . de Boer and W. Ch. van Geel (Physica, 1935, 2, 309-320).— [In German.] A silver-calcium fluoride- caesium rectifier is investigated.—J . S. G. T.
* Asymmetric [Electrical] Conductivity of the Combination Metal-Blocking Layer-Salt Layer-Adsorbed Alkali Metal. W. Ch. van Geel and J . H . de Boer (Physica, 1935, 2, 321-327).— [In German.] See also preceding abstract.
—J . S. G. T.
*Thermo[electric] Force and [Electrical] Resistance. L. N ordheim and C. J . G orter (Physica, 1935, 2, 383-390).— [In German.] A ny p ertu rb atio n in tro duced into th e atom ic system of a m etal will give rise to an increased electrical resistance an d to a change in its therm oelectric power. I n certain conditions a parallelism betw een such changes is to be anticipated. Theoretical formulae relating to these two physical quantities are reviewed briefly and the effects of perturbations as shown by solid solutions, ferrom agnetic m aterials, cold- worked metals, and liquid m etals are briefly discussed both theoretically and w ith reference to experim ental results. Parallelism betw een th e two pheno
mena apparently exists in some cases, b u t the observations require consider
able amplification. Such d a ta when available prom ise to extend very con
siderably our knowledge of th e m etallic sta te .—J . S. G. T.
*The Superconductivity of Thin Films. E . F. B urton, J . O. W ilhelm , and A. D. Misener (Trans. Boy. Soc. Canada, 1934, [iii], 28, Sect. I l l , 65-79).—•
Experim ents were carried o u t on th in films of tin , deposited on wires of a non-superconducting m etal. I t was found th a t th e superconducting p o in t was approxim ately th e same w hether th e tin was deposited on C onstantan, nickel, steel, phosphor-bronze, or manganese. The m ethod of application of the tin (wiping, hot-dipping, or electrodeposition) was also w ith o u t im p o rtan t effect. W ith decreasing thickness of th e tin layer, th e films become super
conducting a t lower tem peratures, an d are more sensitive to cu rren t strength.
W hen the film of tin is covered by an electrodeposited layer of copper or nickel, the superconducting p o in t is depressed considerably. I t appears th a t a definite thickness of m etal and a free surface are necessary for super
conductivity.—C. E . H .
*Effective Permeability of Superconductors. F. G. A. T a rr and J . O. W il
helm (Trans. Roy. Soc. Canada, 1934, [iii], 28, Sect. I l l , 61-63).—Describes an experim ent on a block tin tube, verifying th e findings of W . Meissner and R . Ochsenfeld (see Met. Abs., 1934, 1, 289), th a t on lowering th e tem perature of a superconductor, its perm eability becomes zero below the tran sitio n point.
—C. E . H .
*The Course of the Penetration of a Transverse Magnetic Field into a Super
conductor. W . J . de H aas an d J . M. Casim ir-Jonker (Physica, 1934, 1, 291- 296; Comm. K . Onnes Lab. Leiden, No. 229d).— [In G erman.] B ism uth a t
278 Metallurgical Abstracts
Vo l. 2liquid helium tem peratures shows m arked resistance changes in a m agnetic fie ld ; it was used as indicator for th e field stren g th inside a tin single crystal a t or near th e superconducting transition point. A cylindrical single-crystal tin wire (7 mm. in diam eter, 8 mm. long) w as provided w ith 3 p arallel glass capillaries, one in th e axis, 2 others 1 mm . under th e skin of th e wire. Inside th e capillaries bism uth wires, 1-2 cm. long, w ith copper p o ten tial an d current leads were introduced. The tin cylinder was cooled below th e transition point w ithout m agnetic field, a transverse field was th e n applied an d increased in stren g th u n til th e superconductivity of the tin was again destroyed. During the la tte r period th e bism uth resistance was m easured repeatedly. U p to a threshold value for th e external field th e bism uth resistance did n o t change;
the threshold value was higher for th e central wire th a n for th e outside ones.
The curve of bism uth resistance (changing w ith local field strength) versus the external field strength for the enclosed wires is entirely different from th e normal one for bism uth. The sudden increase above th e threshold value extends to a value above th e norm al curve an d is followed b y a grad u al approach of the la tte r. I t is concluded th a t th e external m agnetic field induces persistent currents which com pensate the field stren g th inside th e superconductor. From a certain field stren g th on th e surface superconductivity is destroyed, the persistent currents disappear and tliis destruction g radually penetrates into th e tin m etal w ith increasing field stren g th , the in terv al between th e initial an d to ta l destruction being 3 gauss. Above 32 gauss, th e value for complete destruction, th e bism uth resistance retu rn s to norm al. F o r a longitudinal field th e resistance changes o f th e 3 bism uth wires are a ll identical and simul
tan eo u s; th e curve has the sam e character as above. On cooling a tin wire in a co n stan t field i t w as observed th a t th e field disappears from the superconductor n ear th e o u ter bism uth wires, th e central bism uth wire showed a field increase a t th e tran sitio n point.—S. G.
♦Superconduction and Diamagnetism. F . and H . London (Physica, 1935, 2» 341—354). [In G erman.] C ontrary to th e usual conception th a t an electric cu rren t in a superconductor cannot ex ist w ith o u t the coexistence of a magnetic field, th e super-current is here conceived as a k in d of diam agnetic volume c u rren t, an d is m aintained by a m agnetic field which can be generated by the cu rren t itself. The m athem atical analysis of th e phenom enon is developed along these lines an d is extended to the case where b o th superconducting and norm al electrons are p resent.—J . S. G. T.
c tE lectrom c Structure of Metals. J . C. Slater (Rev. M odem Physics, 1934, b, 203-280).—The first usable electronic model of th e electron was th a t of Lorentz. I t conceived a m etal as consisting of em pty space containing h a rd spherical atom s, betw een w hich th e electrons moved subject to 2 forces only, viz. any external applied electric fields an d forces of elastic collision with atom s. I his model, characterized by a beautiful sim plicity, requires modi
fication in the light of present-day knowledge of atom ic stru ctu re, and Lorentz’s theory of th e m etal sta te has been superseded by th e extrem ely com plicated present-day theories. H ere, the m odern m athem atical theory of th e metallic sta te is presented. The subjects discussed com prise (1) F erm i statistics and tree electrons, and (2) the wave m echanical theory. The tre a tm e n t throughout is m athem atical. A bibliography of 118 references is appended. J . S. G. T.
Quantitative Calculation of the Proper Functions of Electrons in Metals.
n l f w 5' a\ 1934, 7’ SuPPt - n > 18-23; C. A bs., 1935, 29, 2833).— Only q ualitative explanations of the energy levels of m etal electrons and physical properties of m etals can be given by theory. T his is because of the rigid requirem ents m ade by eith er a free-electron th eo ry or by an atom ic proper function (valency force) theory. Free electrons in the alkali metals, the cohesion of m etals and the absorption of light by m etals are discussed.
—S. G.
1935
I I . — Properties o f Alloys 279
The Limits of the Elementary Theory of Electrons in Metals. L. Nordheim (Helv. Phys. Acta, 1934, 7, Suppt. I I , 3-17 ; C. Abs., 1935, 29, 2834).—A general discussion of the hypothesis of free electrons and of free paths of electrons in metals.—S. G.
The Statistical Basis of the Electron Theory of Metals. R. Peierls (Helv.
Phys. Acta, 1934, 7, Suppt. I I , 24-30 ; C. Abs., 1935, 29, 2834).—Assumptions m ust be m ade in the statistical treatm en t of the electron theory of m etals which are n o t fulfilled for m etals a t high tem peratures. This case can be treated by using other simplifications which give good results.—S. G.
Basis of the Electron Theory of Metals and the Method of the Self-Con
sistent Field. Léon Brillouin (Helv. Phys. Acta, 1934, 7, Suppt. I I , 33 46 ; C. Abs., 1935, 29, 2835).—Methods employing hypothetical assum ptions of free electrons and periodic potential are compared w ith self-consistent field methods. A table is given showing the results of several theories.—S. G.
Surface Waves in the Electron Theory of Metals. A. W. Maue (Helv. Phys.
Acta, 1934, 7, Suppt. I I , 68-71).—See M et. Abs., this volume, p. 94.—S. G.
Application of the Electron Theory of Metals to the Study of Alloys. H.
Jones (Helv. Phys. Acta, 1934, 7, Suppt. II , 84-87 ; C. Abs., 1935, 29, 2835).—
The physical properties of bism uth and its alloys are considered from the point of view of Brillouin zones. The magnetic susceptibilities are calculated and compared w ith experim ental values.—S. G.
*The Liquid State. W. H . Rodebush (Phys. Rev., 1935, [ii], 47, 513).—A note. Analogies betw een the electrons in a m etal and the molecules in a liquid are pointed out. Superheating of a solid above its melting p o in t does not occur because th e h e a t of activation for fusion is small, and presum ably no greater th a n the h e a t of fusion, b u t w ith tran sitio n points superheating is possible, because a h eat of activation essentially equal to the h eat of vaporiza
tion is required.—W. H .-R .
*Hall Coefficients of Alkali Metals [Electron Theory of Metals]. Clarence Zener (Phys. Rev., 1935, [ii], 47, (8), 636).—A note. R ecent values for the H all coeff. show good agreem ent w ith theory for sodium, fair agreem ent for potassium and cæsium, and a poor agreem ent for lithium . The theoretical implications are discussed.—W . H .-R .
II.— PROPERTIES OF ALLOYS
(Continued from pp. 212-219.)
Contraction of Aluminium and Its Alloys on Solidification.—I. L. Losana (Allum inio, 1934, 3 , 321-327 ; C. Abs., 1935, 2 9 ,2133).—The changes in volume of alum inium and some of its alloys have been m easured by th e hy d ro static balance m ethod (cf. Oazz. chim. ital., 1923, 53, 89-94). The contraction in volume on solidification, w hich is 6% for pure alum inium , is reduced to 5-95 and 5-6%, respectively, by the addition of 1 an d 2% iron. Sim ilarly, additions of 0-7, 1-4, and 1-6% silicon reduce the contraction to 5-8, 5-2, an d 4-6%. F u rth er addition reduces the contraction in proportion, up to 20%
silicon, th e lim it studied. A ddition of 1, 2, 5, an d 7% copper reduces the contraction to 5-8, 5-4, 4-3, and 3-6% , respectively. F u rth e r ad d itio n of copper produces very little change.—S. G.
*Transformations in Iron-Aluminium Alloys. C. Sykes and H . E vans (Iron Steel Inst. Advance Copy, 1935, 1-23).—In conditions of slow cooling, atom ic rearrangem ent (“ ordering ” ) occurs in alloys of th e approxim ate com position Fe3Al (13-9% of alum inium ). The h eat evolution due to th is process sta rts a t ab o u t 560° C. an d continues over a considerable range of tem perature, probably down to 200°-250° C., depending on th e ra te of cooling. The critical tem perature can be obtained from th e m easurem ent of th e resistivity of samples quenched from various tem peratures and, so obtained, is in good
280 M etallurgical Abstracts
Vo l. 2agreem ent w ith th e results of therm al m ethods. The m agnetic change points of alloys containing 11-17% of alum inium were determ ined, from w hich it appears th a t the ordering process can in certain cases affect the m ag n etizatio n - tem perature curve.—J . H . W.
*On the Low Temperature Diffusion of Solid Aluminium into Iron. Leo G.
H all (Phys. Rev., 1935, [ii], 47, 418 -419).—A note. A lum inium will diffuse into steel or cast iro n a t 300° C. provided th a t b o th surfaces are clean, and sufficient pressure exists to ensure full contact of th e surfaces. P enetration w ithout su b stan tial pressure has n o t been observed below th e m elting point of alum inium . The ra te of diffusion is a direct function of th e pressure, whilst th e pressure necessary to produce a given ra te of p en etratio n decreases with increase of tem perature. W hen a b a r of iron is im m ersed in m olten aluminium, th e alum inium diffuses upw ard a t th e ra te of 1-2 cm ./day, an d some iron dissolves in th e alum inium . Some properties of iro n im pregnated w ith alum inium are described briefly.—W . H .-R .
*The Alloys Formed by the Aluminium-Magnésium Solid Solution. G.
Chaudron an d R . D andres (Com.pt. rend., 1935, 200, 1324-1326).—The varia
tio n of th e m echanical properties of th e alum inium -m agnesium alloys (con
taining up to 15% of magnesium) in sheet form , as a function of the magnesium content, has been investigated. The breaking load increases regularly, but th e elongation decreases rap id ly from 55 to 32% a t 2% of magnesium , and th ereafter rem ains approxim ately co n stan t or slightly increases u p to the lim it of th e solid solution. C ertain im purities have th e same effect as small q u an tities of m agnesium in considerably m odifying th e deform ability of pure alum inium . F or instance, 0-15% of silicon largely increases th e resistance an d dim inishes th e elongation, an d sim ilar effects are caused by 0-45 and 0-1%
of m anganese. The sum of th e breaking load an d the elongation of these alloys is practically co n stan t for the same magnesium content. The mechanical properties of th e solid solution are n o t altered b y 1% of zinc or cadm ium , which crystallize in th e sam e system as magnesium . A nnealing experim ents showed th a t th e Al3Mg2 crystals cause a considerable dim inution of th e elongation w ith o u t appreciably raising th e breaking load. M etallographically, th e pre
cip itatio n of the (3-crystals is seen a t first betw een th e grains, and then within them . These alloys have, a fte r annealing, a m ore electro-negative notential th a n th e (3-erystals.—J . H . W.
*The Variation of the Mechanical Properties of an Aluminium-Magnésium Alloy as a Function of the Purity. H enri F ou rn ier (Compt. rend., 1935, 200, 1398-1400).—The effect on th e m echanical properties of cast alum inium - m agnesium alloys of various refining fluxes an d gases used in m elting has been investigated. Chlorine was elim inated b y th e a d d itio n of fluorides.
I he alloys, of commercial p u rity , were tre a te d as follows : (1) addition of salt fluxes ; (a) sodium fluosilicate, (b) m ixtures of fluxes, as th a t of the chloride an d cryolite ty p e : BaCl2 35, KC1 23, NaCl 18, CaCl2 17, an d A lN a,F 8 7 % ; (2 chlorides of m etals susceptible to reduction by alloying; (a) manganese chloride, (b) m olybdenum chloride, (c) tita n iu m chloride ; (3) gas treatm ents, (a) d ry nitrogen, (b) nitrogen followed by chlorine an d nitrogen ; (4) addition of m etals m ore electro-positive th a n alum inium -sodium . The treatm ents were given a t a tem p eratu re of 750° C., an d the alloy cast a t 730°-750° C into hrr!ifr>f ?rr,Sant! ' 0r ^ i “ °.1Jlds- ,T h® breaking load, a p p aren t elastic lim it, lim it of proportional elasticity, and the modulus of elasticity were measured!
The properties w ith these alloys were inferior to those of alloys m ade w ith pure metals, an d were m axim um in sand castings a fte r using a flux such as cryolite or tita n iu m chloride. In the case of several m elts, lower values were found for the lim it of proportional elasticity an d th e m odulus of elasticitv th a n have been elsewhere recorded, b u t in o th er cases, norm al values were obtained. F u rth e r experim ents are necessary to explain th is fact. J . H W
1935
I I . — Properties o f Alloys 281
*The Aluminium-Rich Alloys oi the Ternary System Aluminium Tin- Manganese. A. Schiick (Light Metals Research, 1935, 3, 384-401).—^Trans
lated from Z. Metallkunde, 1935, 27, 11-18; see Met. Ahs., th is volume, pp.
50, 147.—J. C. C.
•¡'The Fatigue-Strength of Cast Light Metals. W . Linicus and E . Scheuer (Light Metals Research, 1935, 3, 365-367).—T ranslated from Metallwirtschaft, 1934, 13, 829-836, 849-855. See Met. Ahs., th is volume, p. 95.—J . C. C.
Aluminium Alloys. W. C. D evereux (Machinery (Lond.), 1935, 46, 7-11, 140 143).—R ead before the Scottish Local Section of th e In s titu te of Metals and th e Coventry B ranch of the R oyal A eronautical Society. Comparative tests on various alloys cast in “ R .R .” and B.S.I. type moulds illustrate th a t the feeding m ethods employed affect the properties of different alloys in dif
ferent ways. The im portance of investigating methods of feeding, running, and chilling for each individual casting is emphasized. H eat-treatm en t is n o t recommended for in tricate and large castings. F o r im pact-testing cast levers, a machine is described w hich delivers a series of blows, th e tu p being raised between each u n til fracture occurs. B y th is means, the advantage of low modulus of elasticity in absorbing shock is tak en into account, and m aterial w ith high elastic lim it shows up th e best. Over-fluxing light alloys m ay give large grain-size. Defects arising in w rought m aterial, particularly those due to the grow th of large crystals, are discussed, and reference m ade to the effect of heat-treatm ent after cold-working.—J . C. C.
•¡"Advances and Researches in the Field of Light Metals. --- (Metallwirt- schaft, 1935, 14, 192-194).—A review of the literatu re.—v. G.
*The Hall Effect and Some Other Physical Constants of Alloys. IV.—The Bismuth-Cadmium Series of Alloys. S. Gabe an d E . J . E vans (Phil. Mag., 1935, [vii], 19, 773-787).—The electrical resistivity a t 0° C., and its tem pera
ture coeff. over the range 0°-100° C., th e density, therm oelectric power relative to copper, H all effect, and th e specific heats of carefully annealed alloys (18) of the bism uth-cadm ium series have been determ ined over th e complete range of compositions. The density (d), specific h e a t (s), resistivity (p), and thermoelectric pow er (P ), of an alloy containing * % of bism uth are given by the following equations : d = 8-64 -f- 1-16/10 2; s = 0 0559—2-58/10 4;
p = 6-83 + 0-168* + 0-00270*2 + 56-2*«10-12 ; P = 1-701 - 0-130* - 0-00380*2 — 15-1*71 0 14. The resistivities decrease on annealing th e alloys, the change being g reatest for th e alloy containing 14-9% by w eight of bism uth.
The bism uth-cadm ium alloys exhibit no reversal of sign over th e range of m agnetic field strengths 3096-8424 oerstedt, contrary to w h at is found to occur in the b ism u th -tin and b ism uth-lead series of alloys. The H all coeff.
of all the bism uth-cadm ium alloys exam ined are negative, an d dim inish as the m agnetic field stren g th is increased. A large negative value of th e H all coeff. corresponds w ith a high resistivity. The therm oelectric pow er- composition curve follows th e general tre n d of the H all coeff. com position curve.—J . S. G. T.
Cadmium-Silver Bearing Metal on New Pontiacs [Motor Cars]. (Amer.
Metal Market, 1935, 42, (28), 2).— A short note. The engine bearings are m ade of a silver-copper-cadm ium alloy (cadm ium 87-5, silver 2-25, copper 0-25%) having a m elting p o in t of 610° F. (321° C.) and a Brinell hardness of 40 a t room tem perature an d 16-5 a t 310° F . (154° C.). A chill-cast section, \ in.
thick, w ithstands 135° cold bend w ithout cracking an d a t 400° F . (204° C.) can be b en t flat on itself w ith o u t cracking. The tensile stren g th is approxi
m ately 22,000 lb ./in .2. The alloy shows low frictional characteristics com parable to tin-base B a b b itt an d is non-scoring to steel shafts. Owing to its higher m elting p o in t an d g reater hardness a t operating tem peratures, the life of bearings of th is alloy is several tim es th a t of tin-base B a b b itt bearings.
—I. M.
282 Metallurgical Abstracts
V o l. 2*The Beta Transformation in Copper Alloys. I. O binata (K inzoku, 1934, 4, 289-291, 333-335).— [In Japanese.] In th e b inary system s oopper-zinc, eopper-tin, an d copper-alum inium there is a [3 —>- fi t transform ation, an d in the [3-phase there is a eutectic transform ation resembling th e A j transform ation in steel. D uring th is transform ation, a m etastable interm ediate phase is form ed. In th e case of th e copper-zinc system th e (3-phase is stable a t room tem perature an d there is no eutectic tra n sfo rm a tio n ; below room tem perature, however, th is eutectic transform ation m ay take place.—S. G.
*The Ternary System Copper-Silver-Cadmium. L. Losana a n d C. G oria (Industria chimica, 1934, 9, 1603-1615; C. Abs., 1935, 29, 2061).—The com position an d cooling curves of th e system copper-silver-cadm ium were studied completely, an d th e results of studies of several of th e b in ary system s were combined. The equilibrium diagram is very complex. Several useful alloys are indicated : (a) cadm ium 81, silver 12, copper 7% , m elting a t 490°-505° C .;
(b) cadm ium 57, silver 6-5, copper 36-5%, m elting a t 535°-550° C .; (c) cad
m ium 39, silver 40-5, copper 20-5% , m elting a t 670° C. These alloys are resistan t to oxidation, b u t are fragile, especially (c). They are useful for fusible safety plugs, &c.— S. G.
*High-Tin Bronze. C. H . Tonam y (K inzoku, 1934, 4, 4 0 1 ^ 0 2 ).— [In Japanese.] E v en in h e at-treated gun-m etal a tensile stren g th of 20 tons /in .2 is o b tain ab le; when high-strength copper alloys are required, therefore, heat- tre a te d hig h -tin bronze is recom m ended in place of m anganese-brass and alum inium -bronze.” Three specimens, containing 20, 22, an d 24% tin, respectively, held a t 650° C. for 1 hr. an d th e n quenched in w ater, h ad the following tensile stren g th s an d elongations, respectively: 26-21 to n s/in .2 12-5% ; 26-80 to n s/in .2, 3-0% ; 25-00 to n s/in .2, 2-0% .—S. G.
tStudies on Cast Red Brass for the Establishment of a Basic Classification of Non-Ferrous Ingot Metals for Specification Purposes. C. M. Saeger, J r . (Proc.
Inst. B rit. Found,., 1933-1934, 27, 268-304; discussion, 304-317).—American Exchange P aper. See M et. Abs., 1934, 1, 382, 491.—S. G.
Non-Metalhc Inclusions in Ferro Alloys. B. M atuschka (Iron Steel Inst.
Advance Copy, 1935, 1-8).-—T he stru ctu re an d physico-chem ical behaviour of the slag inclusions in liquid an d solid steel are considered in general terms an d the nature, occurrence, an d behaviour of non-m etallic inclusions in ferro- alloys w ith tungsten, chrom ium , nickel, m olybdenum , cobalt, vanadium , m anganese, silicon, alum inium , an d copper are described. J . H . W.
fLead Bearing Metals ; Present Position of Their Technique and the Know
ledge of Their Applications. F r. W itte (Z .V .d .L , 1935, 79, 98-100).—The characteristic properties of lead-base bearing m etals are described and their fu tu re developm ent is discussed w ith especial reference to the a tte m p ts which are being m ade to im prove th e ir stab ility by addition of heavy m etals.—K . S.
Melts at Temperature of 116° F. (Am er. M etal Market, ru-JO, u , (88), 5).—A brief note. T he discovery of a new low -m elting point alloy is announced by Professor S. J . F rench of Colgate U niversity, U.S.A • its com position is n o t given. Since its m elting p o in t is only slightly above moulds —I Mm an y ’ 11 m ay find USG in m aking finger p rin t an d surgical in, Mature the Diffusion of Mercury on Tin. T. A ltv an d A R Clark (Trans Faraday Soc., 1935, 31, 6 4 8 -6 5 9 ).-T h e diffusion of m ercury’in tin consists of a rap id surface diffusion accom panied by a m uch slower volume diffusion. A detailed stu d y of th e surface process shows it to be a true diffusion in th a t it obeys an o rdinary diffusion equation. The v ariatio n of adsorh^d°film^ffusion w ith th e tem p eratu re obeys th e sam e law as th a t of an adsorbed film, an d th e energy of activ atio n of th e mobile atom s on a pure tin surface is 1920 grm -cal./grm .-atom . The ra te of diffusion in w ater is greater and th a t in oil slower th a n in a i r ; a t 60° C. the ra te in w ater 7s 1 08l!
1935
I I . — Properties of Alloys 283
and a t 15-3° C. 1-076 tim es th a t in air, w hilst a t 60° C. the rate in light liquid petroleum is 0-77 tim es th a t in air. The diffusion of m ercury on a surface of a tin am algam containing 8 atom ic-% m ercury decreases w ith rise in tem perature, and the energy of activation of the mobile atom s on the amalgam surface is — 328 grm .-cal./grm .-atom .—A. R . P.
♦X-Ray and Hardness Tests on Nickel-Rich Nickel-Tin Alloys. E ric R . J e tte and E rich F etz (Metallwirtschaft, 1935, 14, 165-168).—The alloys w ith 0-33% tin were m elted in a vacuum furnace, th en homogenized, powdered, annealed a t various tem peratures, quenched, and exam ined by X -rays. The results gave th e following values for the solubility of tin in nickel : 500° C.
1-9; 700° C. 8-8 ; 900° C. 17-7; an d 1100° C. 19-8%. Consequently these alloys are capable of being precipitation-hardened, th e 10% alloy to a Brinell hardness of 290 and the 20% alloy to a hardness of 490.—v. G.
♦On a Further Investigation of the Equilibrium Diagram of the Nickel-Zinc System. K anzi T am ura an d A tom i Ôsawa (Sci. Rep. Tohôlcu Im p . Univ., 1935, [i], 2 3 ,794—815).— [In English.] See Met. Abs., th is volume, p. 216.— S. G.
♦On the Glow-Electric Effect of Palladium-Silver Alloys Saturated with Hydrogen. J . Schniederm ann (A nn. Physilc, 1935, [v], 22, 425-442).—
Adsorption of hydrogen increases the electron emission of all p alladium - silver alloys, th e effect being a t a m inim um a t 40% silver as is the case w ith all other properties.—v. G.
♦Solidification Diagrams of Alloys Formed by Two Alkali Metals : The Potas
sium-Rubidium Alloys. E . R inck (Compt. rend., 1935, 200, 1205-1206).—A continuation of th e w ork done on th e alloys of sodium w ith potassium , rubidium , an d cæsium (see Met. Abs., th is volume, p. 54). Potassium and rubidium are completely miscible in the solid state. The liquidus and solidus are very close, an d show a flat m inim um a t 32-8° C., corresponding exactly to K + 2 R b. M icroexam ination showed th a t these 2 m etals form a single series of solid solutions.—J . H . W.
Are Not Liquid Sodium Amalgams Colloidal? R. M. Joshi (In d ia n J . Research, 1934, 9, 153-159; C. Abs., 1935 29, 2814).—The probability th a t colloidal system is present is greater th a n B ent (J. In st. Metals, 1933, 53, 493) adm its.—S. G.
♦Magnetoresistance of Liquid Sodium-Potassium Alloy. J . E . Arm strong (Rhys. Rev., 1935, [ii], 47, 391-392).—Cf. Met. Abs., th is volume, p. 218.
The effect of a m agnetic field on th e resistance of a liquid sodium -potassium alloy containing approxim ately 35% of sodium has been studied for field- strengths up to 16,000 gauss. A definite magnetoresistance effect exists a p a rt from any secondary effects due to m otions in th e liquid. A longitudinal m agnetic field produces a larger effect th a n a transverse field, although, in non-ferrom agnetic crystalline solids, the converse is true. Above 2000 gauss there is a linear relation betw een the m agnetoresistance (d R / R ) an d the field- strength.—W . H .-R .
tAlloys— Old and New. (Sir) H . C. H . C arpenter (Iron Steel In st. Advance Copy, 1935, 1-19).—P residential Address. The various meanings of th e term
“ alloy ” are explained, an d th e history of the developm ent of alloys from the earliest tim es is briefly set out. I n relating the properties of an alloy w ith its previous tre a tm e n t, it is necessary to consider (1) its composition, (2) its constitution, (3) its stru ctu re, an d (4) its condition. These factors, as well as the properties an d tre a tm e n t, are so inter-related th a t th ey cannot be con
sidered entirely independently. Composition varies greatly in im portance w ith the properties, an d is determ ined chiefly b y th e electric, m agnetic, and chemical properties required of the alloy. The constitution an d structure are determ ined m ore by th e m echanical properties desired, an d th e ir stu d y is based on th e equilibrium diagram , the 4 principal types of w hich are here classified, an d th e stru ctu re characteristic of each is described. The tra n s
284 Metalliirgical A bstracłs
Vo l. 2form ations in solid alloys are explained w ith examples of th e gold-copper, alum inium -iron, an d m agnesium -silicon system s, an d th e hypotheses p u t forw ard to account for age-hardening are critically reviewed.—J . H . W.
♦On the Rate of Precipitation-Hardening [of Alloys]. E rich Sohnchen (Metallwirtschaft, 1935,1 4 ,205-208).—The effect of ad d itio n of o th er elem ents, of variations in grain-size an d degree of deform ation, an d of m agnetic fields on the ra te of precipitation-hardening of various alloys has been determ ined, and the results are discussed w ith reference to th e literatu re. M agnetic fields have no influence on alum inium or m agnesium alloys.—v. G.
Progress in Metals. A lbert J . D o rn b la tt (Heat-Treating and Forging, 1935, 21, 129-131).—The com position of a num ber of alloys fo r various appli
cations in tra n sp o rta tio n equipm ent and the specific properties required in each case are ta b u lated .—J . H . W.
“ Iso-Elastic.” A New Alloy for Springs. --- {Amer. M etal Market, 1934, 41, (225), 5).—A brief note. The alloy is in ten d ed for use in m easuring ap p aratu s, an d conforms to H ooke’s law und er w idely varying conditions.
I t is a m odification of E linvar, b u t th e com position is n o t given. I. M.
On Ferromagnetic Alloys and Their Conformity to Laws. A. K ussm ann (Chem.-Zeit., 1935, 59, 285—287).— R ecent w ork on th e relatio n betw een con
stitu tio n an d m agnetic properties is review ed w ith special reference to the stress theory of th e m agnetization curve an d to th e developm ent an d uses of new m agnetic alloys w ith high nickel o r cobalt contents.—A. R . P .
♦Curves of Fusion of Solid Solutions Accompanied by the Formation of a Chemical Combination. A. Mlodziejowski (Physica, 1935, 2, 159-168).— [In French.] M. has already derived a n expression for th e radius of curvature of a curve of fusion of a b inary system a t th e m elting p o in t, for th e case of binary system s form ing a single liquid phase w hich on solidifying yields only crystals n o t containing th e com ponents in solid solution (Arch. Neer., 1931, I I I , A, 196). H ere th e analysis is extended to th e case where a solid solution is form ed.—J . S. G. T.
III.— STRUCTURE
(M etallography; M acrography; C rystal S tructure.)
(Continued from pp. 220-22G.)
♦Metallographic Films. E . 0 . B ern h ard t an d H . I. W iester (Z. V .d .I., 1935,
’<’9, 7-11). The ap p aratu s, technique, uses, and results of filming th e changes w hich tak e place in th e stru ctu re of m etals a t high tem peratures, e.q. the process of recrystallization, are described.— K S
^ A lu m in iu m and Its Alloys. H . N ishim ura (Kinzoku, 1934, 4, 17J-184, 321-326).— [In Japanese.] The m icrostructures of the alum im um -copper, alum inium -silieon, alum inium -m agnesium , alum inium - zinc-copper, an d alum inium -silicon-copper alloys were investigated. A new equilibrium diagram is p u t forw ard for the alum inium -copper system .—S. G.
i /i ,J ,!n the Hume-Rothery Phases. U . D ehlinger (Metallwirtschaft, 1935, 14, 140-149).—The principles of the H um e-R othery rule for th e form ation of intercrystalline phases are discussed on therm odynam ical considerations.
The Structure of Metallic Coatings, Films, and Surfaces. Introductory Paper. Cecil H . Desch (Faraday Soc. Advance Copy, 1935, M ar 2 tin ) — A brief outline of recent work on th e stu d y of m etal surfaces is followed by a brief survey of th e field covered by th e papers presented a t th e general dis- a b stra c ts ^ —A SR Up Ure ° f metaUic coatings> m m s> an d surfaces (see following
1935
I I I . — Structure 285
♦Factors Influencing the Formation and Structure of Hot-Dipped Tin Coat
ings. Edw ard J . Daniels (Faraday Soc. Advance Copy, 1935, Mar., 5 p p .; and Tech. Publ. Internat. T in Res. Development Council, 1935, [A], (17), 1-10).—
Theories of th e mechanism of the form ation of hot-dipped coatings are reviewed and i t is suggested th a t the prim e factor in w etting is the a ttra c tio n between the solid and liquid metals, the affinity betw een the two m etals resulting generally in th e form ation of an interm etallic compound or solid solution a t the interface; m any examples of these phenomena are discussed, and in the case of tin coatings on copper and iron the effects of additions of various metals on th e n atu re of the interm ediate layer are described. The action of fluxes in prom oting union of th e liquid and solid m etals is briefly outlined, and it is shown th a t hydrogen can act as a tru e flux in the tinning of copper since it reduces the oxides of both m etals below 300° C. an d th u s provides clean surfaces. Steel cleaned w ith em ery can also be tin n ed by im mersion in m olten tin containing only 0-05% phosphorus w ithout th e use of any flux.
A ddition of 0-04% cobalt or 0-1% of nickel to tin entirely prevents rippling of the coating on steel, and addition of m ore th a n 3-7% silver or 1 1 % copper to tin has the same effect on coatings on co p p er; it is suggested th a t deposi
tion of tin y crystals of a n interm etallic compound, e.g. N i3Sn2, Cu6Sn5, or AggSn, evenly over the surface of th e coated m etal, acts as a “ g r i t 11 in the m olten m etal, preventing the movem ents which, when unim peded, produce ripples. If th e tinning tem perature is too low th e “ g rit ’* crystals become too large and the coating is pim ply, b u t if the tem perature is too high rippling occurs since th e “ g rit ” is dissolved in th e h o t m etal. Bright, unrippled coatings can also be obtained by a suitable quenching operation.
—A. R . P.
♦Determination of the Phase Structure of Metallic Protective Coatings by Anodic Dissolution. A. Glazunov (Faraday Soc. Advance Copy, 1935, Mar., 3 pp.).—The thickness of zinc coatings and of th e various interm ediate layers on galvanized iron m ay be determ ined b y anodic dissolution of th e coating in a satu rate d solution of zinc sulphate. If d is th e thickness of th e layer, e th e electrochemical equivalent, I the cu rren t intensity, t the tim e, r; th e sp.
gr. of th e m etal, an d s th e area, th en d — e . I . t/t] . s. If the voltage of the cell is plotted against th e tim e a graph will be obtained consisting of one or more horizontal sections connected by sloping lines. Since each phase of constant composition has its own p o ten tial w hich rem ains constant during its dissolution, an d since th e p otential changes regularly during th e dissolution of a solid solution, from the lengths of th e individual p o ten tial values (horizontal positions in the graph) an d of th e intervals betw een them th e thickness of the various layers an d th eir com position can be determ ined w ith the a id of the above equation if th e course of th e p o ten tial curves of the binary system in question is known. T hus galvanized coatings have been shown to contain Zn3Pe an d probably also Z nFe3.—A. R . P .
■¡The Determination of the Structure of Electrodeposits by Metallurgical Methods. D. J . M acnaughtan an d A. W. H othersall (Faraday Soc. Advance Copy, 1935, Mar., 6 pp.).—R ecent w ork on th e determ ination of th e stru ctu re of electrodeposits of nickel, chrom ium , an d other m etals by m icrographic m ethods an d by physical tests, especially hardness determ inations, is described an d critically reviewed, photom icrographs of nickel deposits m ade under various conditions are shown an d discussed an d the effect of annealing on the crystal stru ctu re is briefly outlined.—A. R . P .
¡ The Effects of Film Formation on the Structure of Electrodeposited Metallic Coatings. E . Liebreich (Faraday Soc. Advance Copy, 1935, Mar., 3 pp.).—•
Modern theories of th e m echanism of th e electrodeposition of m etals, w ith especial reference to th e effect of film form ation on th e stru ctu re of chrom ium deposits are reviewed.—A. R . P .
286 M etallurgical Abstracts
Vo l. 2Contribution to the Experimental Study of the Influence of the Support or Cathode on the Structure of Electrolytic Deposits Obtained in Aqueous Solution.
A lbert M. P ortevin an d Michel Cymboliste (Faraday Soc. Advance Copy, 1935, M ar., 7 pp.).—F rom experim ents on nickel- an d chrom ium -plating an d from a review of th e published results of o th er investigators i t is concluded th a t th e stru ctu re of electrodeposits m ay be influenced by th e cry stal stru ctu re of th e cathode b u t also depends on the ra te of form ation (N c) of cry stal nuclei and on th eir rate of grow th ( Vc) w hich are functions of th e concentration of the electrolyte in co n tac t w ith th e cathode, th e c u rren t density, and the tem perature. Crystalline co ntinuity betw een th e deposit an d th e cathode requires th e absence of surface films on th e cathode an d of th e hardened am orphous layer produced by polishing. If N c is large, e.g. in fine-grained deposits, com pared w ith th e num ber (n ) of crystals per u n it area of cathode th e effect of th e surface of th e la tte r is sm all since n is negligible com pared w ith N c, w hereas if N c is v ery sm all the n a tu re of th e cathode surface d eter
mines th e grain-size of th e deposits. I n general th e grain-size decreases w ith increase in N e and increases w ith increase of Vc. The effect of various con
ditions on th e n atu re of nickel an d chrom ium plates is shown in a series of 23 photom icrographs.—A. R . P .
♦Influence of the Basis Metal on the Structure of Electrodeposits A W H othersaU (Faraday Soc. Advance Copy, 1935, Mar., 5 pp.).—E xam ination ot th e stru ctu re of deposits of copper on cold-rolled copper, annealed silver an d nickel, an d cast 98 : 2, 90 : 10, 70 : 30, 60 : 40, and 54 : 46 brasses, of tin on cast tin , cast 1% a n tim o n y -tin alloy, and annealed copper, an d of nickel on amnealed nickel an d iron, an d filed electrodeposits of nickel (micrographs of all are reproduced) shows th a t co ntinuation of a basis m etal stru ctu re in a n electrodeposit is possible when bo th belong to th e sam e cry stal system and the lattice param eters v ary by from , e.g., - 2-4 to + 12-5%, and when both belong to different system s. T hus tetrag o n al tin continues th e m icrostructure ot face-centred cubic copper, an d copper continues th e stru ctu re of body-centred cubic brass. D istortion of th e lattice by cold-work or by th e in troduction of a n elem ent in solid solution does n o t re stric t continuation of m icrostructure during electrodeposition of an o th er m etal. I t is unlikely, therefore th a t co-deposition of hydrogen in solid solution has an y effect on th e grain-size of electrodeposits. The high degree of adhesion obtainable w ith electro
deposited coatings is probably associated w ith th e ir a b ility to continue the CTi n , 1,attj ce of th e .basls m etal even if only to a lim ited thickness.—A. R . P.
t Electrode Potentials and the Form of Electrodeposited Metals. Samuel Gladstone (Faraday Soc. Advance Copy, 1935, Mar., 3 pp.).—F rom a critical analysis of recent w ork on the deposition of silver from cyanide baths, and of
“ nc an d nlckel from sulphate baths, it is concluded th a t there m u st be some connection betw een th e form of an electrodeposited m etal an d the potential a t the cathode during deposition, b u t th a t th e relation is difficult to determ ine exactly owing to the effect of num erous o th er factors, some of which work in
opposite directions.—A. R . P . worK m
S T v (Ci ° rSi A fff C tin f t h e ®t r u c h r e and Grain-Size of Electrodeposited Cadmium.
S. W ernick (Faraday Soc. Advance Copy, 1935, Mar., 4 pp.).—In n eu tral potassium cadm icyam de b ath s th e grain-size of th e deposits becomes finer as the cadm ium co n ten t is increased from 8 to 40 g rin ./litre b u t owing to the absence of free cyanide the anode tends to darken an d become “ foul ” A d d f tio n of free cyanide to a b a th w ith 30 grm ./litre of cadm ium gradually im p ro v es the n atu re of th e deposit u n til w ith 100% excess cyanide a w hite com pact a n d v ery fine-grained deposit is o b tain ed ; w ith a larger excess o fT a n T d e c o n sid e ra te gassing occurs a t th e cathode. The presence of “- 2 ° / M free alkali hydroxide in the b a th increases the conductivity, has a restraining influence on the anode dissolution, and m aterially assists in m a L t e £ g i h l
1935
I I I . — Structure 287
colour and uniform ity of the deposit. I n a b a th containing cadm ium 30 grm ./
litre, free cyanide 100%, and caustic soda 15 grm ./litre increase in cu rren t density from 10 to 15 am p ./ft.2 causes the original w hite deposit to become greyer and more crystalline, while a t 30 am p ./ft.2 th e deposits are “ bu rn t, and a t 40 am p ./ft.2 dark, nodular, and large-grained, all of these defects being, however, overcome by stirring the electrolyte. Increase in tem perature above 30°-35° C. increases th e crystal size of th e deposits an d makes them loose, granular, and poorly adherent. In sulphate electrolytes the deposit is finer the higher the pu up to ab o u t 6-6, good fine-grained plates being obtained from Jli-cadmium sulphate solutions buffered to pa 5-5-6-6 by addition of boric acid 30, and sodium chloride 5-85 grm ./litre, and operated a t 35-40 am p./
ft.2 w ith s tirrin g ; the plates are, however, n o t so fine-grained as those obtained from cyanide baths, although they can readily be huffed to a good colour.
Increase in tem perature from 22° to 50° C. reduces th e crystal size b u t darkens the deposit, b u t a fu rth er increase to 80° C. makes th e deposit more crystalline, b u t w hiter. A ddition of 0-04% dextrin, or b e tte r 0T -0 -2 % gelatin, reduces the grain-size to th a t obtainable in cyanide baths.—A. R . P.
*Structure and Properties of Nickel Deposited at High Current Densities.
William Blum and Charles K asper (Faraday Soc. Advance Copy, 1935, M ar., 5 pp.).—The tensile strength, elongation, hardness, an d structure of nickel deposits obtained a t 100° C. w ith cu rren t densities of 22-45 am p ./d m .2 in 42V-nickel solutions of p K 1-2 have been determ ined, and the results are shown in a table and in a series of photom icrographs. Deposits from chloride solu
tions have a fine-grained stru ctu re and are relatively sm ooth, strong, hard, and brittle, whereas those from sulphate solutions under the same conditions are rough, coarse-grained, soft, an d ductile. I n m ixed solutions in w hich a t least 25% of the nickel is present as chloride th e deposits are sim ilar to those obtained from pure chloride solutions. Change in p a from 1 to 2 has no effect in chloride solutions, b u t in sulphate solutions a n increase in p n increases the hardness and reduces th e ductility. Boric acid additions slightly soften deposits made from sulphate b ath s b u t have no effect on those m ade from chloride baths. The cathode efficiency is higher in chloride th a n in sulphate baths, especially a t the higher c u rren t densities.—A. R . P .
♦The Crystallization of Thin Metallic Films. E . N. da C. A ndrade (Faraday Soc. Advance Copy, 1935, Mar., 4 pp.).—The n atu re of th in gold and silver films produced by cathodic sp u tterin g has been investigated and th e ir be
haviour on heating in vacuo exam ined by optical m ethods w ith light- and dark-field illum ination an d w ith polarized light. I n films ab o u t 50 atom s thick silver begins to crystallize a t 250°-280° C. and gold a t about 400° C .;
a t these tem peratures the eye can d etect no change, b u t under the microscope spherulitic crystals of ab o u t 1 p. can be distinguished. As th e tem perature is increased th e num ber an d size of th e spherulites increases, an d eventually they coalesce to tru e crystals of th e ordinary form. The n atu re of th e original sputtered films cannot be definitely established by microscopic exam ination, b u t if they are crystalline th e size of the crystals is beyond th e resolving pow er of the microscope. W hilst i t is possible th a t th e spherulites are the end products of a process of gathering together of m inute sub-microscopic crystals and n o t the result of an association of un-ordered atom s, i t appears to be more likely th a t the original film is am orphous an d th e spherulites are form ed by the m otion of th e surface layer to the d ep th of a few atom s w ith the p ro duction of a spherulitic aggregate which la te r grows in size and crystallizes.
—A. R . P.
♦Optical Research on Evaporated Metal Layers. L. S. O rnstein (Faraday Soc. Advance Copy, 1935, Mar., 10 pp.).—O ptical research on m etallic films produced by evaporation from tu n g sten filam ents in vacuo gives valuable inform ation on th e stru ctu re of th e m etal in th in layers an d on th e effect of
