332 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Metallography, etc. 



The Silver-zinc Equilibrium.* — H. C. H. Carpenter and W. 

 Whiteley, accepting the accuracy of the liquidus of the silver-zinc system 

 as determined by Heycock and Neville, have determined the l)oundaries 

 of the solid phases by taking heating and cooling curves, and by micro- 

 scopically examining specimens, maintained at a given temperature for 

 a period sufficiently long for the attainment of equilibrium, and either 

 quenched or slowly cooled. From to 60 atomic p.c. of zinc the 

 diagram is astonishingly similar to that of the copper-zinc system, and 

 the a, p and y constituents have microscopic characteristics similar to 

 those of the corresponding phases in the copper-zinc system. On cooling, 

 P undergoes a eutectoid inversion at 264° C. to a + y. Alloys in the 

 a range were satisfactorily etched with 25 p.c. aqueous ammonia, to 

 which a few drops of hydrogen peroxide had been added immediately 

 before use. 



In an appendix, H. C. H. Carpenter emphasizes the close relationship 

 between the copper-zinc, silver-zinc, and silver-cadmium equilibria, and 

 discusses its theoretical bearing. 



Antimony in Copper. f—F. Johnson describes the structure of speci- 

 mens of copper containing antimony and oxygen together, in different 

 amounts. The oxygen occurs in combination with that part of the anti- 

 mony which is not in solid solution in the copper, as " oxidules," while 

 oxygen present in excess of that combined with antimony, exists as cup- 

 rous oxide, which forms a ternary eutectic with the solid solution and 

 the antimonial " oxidules." 



Ternary Alloys of Magnesium, Zinc, and Cadmium. if — G. Bruni 

 and C. Sandonnini have studied microscopically the numerous alloys 

 used in the thermal investigation of this ternary system, and give 

 detailed descriptions, illustrated with photomicrographs, of the micro- 

 structures of both binary and ternary alloys. Nitric acid in amyl- 

 alcohol was found to be a useful etching reagent. 



Copper-zinc-nickel Alloys. §—L. Guillet shows that the partial 

 replacement of zinc by nickel in copper- zinc alloys has an effect on 

 microstructure and properties indicated by a " coefficient of equivalence " 

 of nickel of -1*1 to -1*4. The effect is much the same as in 

 partially replacing the zinc by copper. 



Annealing of Coinage Alloys. || — T. K. Rose has studied the effect 

 upon scleroscope hardness and microstructure, of annealing cold-rolled 

 specimens of gold, silver, copper, nickel, zinc, and several alloys, at 

 different temperatures for various lengths of time. AVhen the change 

 from the hard to the soft state takes place, re-crystallization occurs 

 almost if not quite simultaneously. 



* Int. Zeitschr. Metallographie, iii. (1912) pp. 145-75 (21 figs.). 

 t Journ. Inst. Metals, viii. (1912, 2) pp. 192-221 (12 figs.). 

 X Zeitschr. Anorg. Chem., Ixxviii. (1912) pp. 273-97 (52 figs.). 

 § Comptes Keudus, civ. (1912) pp. 1512-14 (4 figs.). 

 li Journ. Inst. Metals, viii. (1912, 2) pp. 86-125 (17 figs.). 



