122 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Alloys of Iron with Chromium.* — W. Treitschke and G. Tammann 

 have investigated the equilibrium diagram. Owing to the high viscosity 

 of molten chromium at 1(>0<>° C, it was found necessary to heat the 

 alloys to 170<> C. in magnesia tubes in order to secure complete mixing 

 of the fluid metals. With more than 1(1 p.c. chromium the cooling 

 curves no longer indicated the transformation points of iron. The 

 peculiarities of the freezing point curve are explained in the same way 

 as for the iron-molybdenum alloys, by the existence of a compound x 

 with a relatively slow rate of formation. The system thus becomes a 

 ternary system. The diagram, and the microstructure of the alloys, 

 are discussed in detail. 



Alloys of Potassium with other Metals.j — D. P. Smith has deter- 

 mined the equilibrium diagrams of the binary alloys of potassium with 

 aluminium, magnesium, zinc, cadmium, bismuth, tin, and lead, and 

 gives a table summarising his results. Potassium is not miscible in the 

 liquid state with aluminium and magnesium, and only partially miscible 

 with zinc, cadmium, and lead. Compounds were found in each series 

 except the potassium-aluminium and potassium-magnesium systems. 

 Owing to the rapidity with which the alloys oxidised, microscopic 

 examination was difficult. Some sections were cut and examined under 

 paraffin oil. 



Metallography of Cast Iron.} — E. Heyn and 0. Bauer have sought 

 to determine the range of temperature in which graphite is formed, in two 

 series of alloys, the first containing about 4 p.c. silicon, 3 p.c. carbon, the 

 second about 1"5 p.c. silicon, :-5 # 2 p.c. carbon. The samples were slowly 

 cooled from a temperature well above the melting point, and quenched 

 at different temperatures. One sample of each series was slowly cooled 

 to atmospheric temperature, the cooling curve being taken. Graphite 

 was estimated in each sample, and sections were microscopically ex- 

 amined ; total carbon and silicon were also determined. The results 

 indicate that iron alloys containing 1*2-4 "25 p.c. silicon and 2 • 7— 

 3 - 12 p.c. total carbon solidify as white iron, and that nearly the whole 

 of the graphite is formed in the temperature interval of 40° C. below 

 the end of solidification. E Heyn discusses the literature of the 

 subject. P. Goerens§ and E. Heyn || deal with the formation of kish. 



Crystallisation and Structure of Steel.1T — A. Bajkow has made 

 analyses and microscopic examination of octahedral crystals found 

 in blow-holes in steel castings. In three specimens the carbon was 

 • 54-0* 98 p.c, manganese 0' 78-1* 06 p.c. All the crystals contained 

 inclusions of slag in crystalline form. 



Osmondite.** — H. M. Howe gives an account of the experimental 

 results from which Heyn and Bauer deduced the existence of this new 



* Zeitschr. Anorg. Chem., lv. (1<J07) pp. 402-11 (9 figs.), 

 t Op. cit., lvi. (1907) pp. 109-42 (9 figs.). 



% Stahl und Eisen, xxvii. (1907) pp. 1565-71, 1621-5 (33 figs.). 

 § Torn, cit., pp. 1776-7. '|| Tom. cit., p. 1778. 



^f Journ. Soc. Chem. Ind., xxvi. (1907) p. 1139. Abstract from Journ. Russ. 

 Phvs.-Chem. Ges., xxxix. (1907) pp. 399-410. 



** Electrochem. and Met. Ind., v. (1907) pp. 347-50 (2 figs.). 



