826 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Selenium-antimony System.* — H. IV-hhon has examined micro- 

 scopically numerous selenium-antimony alloys, and concludes that the 

 only compound obtainable by direct fusion of the elements is Sb.,Se 3 . 

 Within certain limits of composition, the alloys, in the molten state, con- 

 sist of two phases, of nearly the same density. Measurements of electrical 

 resistance of the alloys were consistent with the existence of Sb 2 Se 3 . 



Alloys of Noble Metals. \—W. Geibel has determined the electrical 

 resistance and its temperature co-efficient, the thermoelectric power 

 against platinum, and the tensile strength, of palladium-silver, palladium- 

 platinum, platinum-indium, platinum-gold, and platinum-silver alloy.-. 

 Palladium and platinum appear to form a continuous series of solid 

 solutions, as also do palladium and silver. 



Iron-carbon System.; — R. Ruer and N. Iljin prepared a pure cast- 

 iron containing 4 to 4 • 5 p.c. carbon, nearly all in the graphitic state. 

 Small specimens were heated for 6 hours at different temperatures in the 

 range G00°-1120° C. and quenched. The percentage of combined carbon 

 then found in the specimen is held to indicate the lower limit of solu- 

 bility of elementary carbon in iron at the temperature to which the 

 specimen had been heated. The solubility curve is parallel to that of 

 cementite, reaching a maximum of 1*25 p.c. at 1120°. By allowing 

 specimens to cool from 1100" C. and quenching at different tempera- 

 tures, it was shown that temper-carbon does not separate above 800 c C, 

 but that the length of time of heating above 800° C. influences the 

 amount of temper-carbon separating below 800° C. It is suggested that 

 " centres of crystallization " form at temperatures above 800° C. 



Growth of Cast-irons after Repeated Heatings.§ — H. C. H. Car- 

 penter has continued his investigation of this phenomenon. Phos- 

 phorus, sulphur, and manganese tend to diminish growth. Dissolved 

 gases have no influence when more than 3 p.c. silicon is present : their 

 influence is most potent when silicon does not exceed 1 p.c. : they may 

 then cause a growth of 10 p.c. A table is given showing how growth 

 increases with increase of silicon content. An alloy containing 2 " 6 p.c. 

 carbon, - 6p.c. silicon, and 1*6 p.c. manganese, showed no signs of 

 growth after 150 heats ; it appears to be a suitable material for anneal- 

 ing ovens and other objects in which growth on repeated heating is 

 objectionable. 



Iron-silicon-carbon Alloys. || — W. Gontermann explains the equili- 

 brium diagram for the range Fe-Fe 3 C-FeSi of this ternary system. 

 The diagram has been derived from the thermal analysis of numerous 

 alloys. The two chief types of crystal separating from the melt are — 



(1) mixed crystals of iron, silicon, and carbon, termed silico-austenite ; 



(2) mixed crystals of the compounds Fe s C and FeSi, termed silico- 

 cementite. View T s of the three-dimensional model of the ternary system 



are given. 



* Coniptes Kendus, clii. (1911) pp. 1302-5 ; cliii. (1911) pp. 343-6. 



t Zeitschr. Anorg. Chern., lxx. (1911) pp. 240-54 (9 figs.). 



[ Metallurgie, viii. (1911) pp. 97-101 (3 figs.). 



§ Journ. Iron and Steel Inst., lxxxiii. (1911) pp. 196-248 (17 figs.). 



j Journ. Iron and Steel Inst., lxxxiii. (1911) pp. 421-75 (20 figs.). 



