Phase equilibria in the system Cr2O3-Al2O3

Abstract

A dilute solution of Cr2 3 in A12 3 has long been known as the ruby. More concentrated solutions do not possess the desirable color of the ruby, but are of interest because of their refractory properties. 1 reported that on heating mixtures of Cr2 and. A12 3 3 Duboin to a "red white" heat, from 15 to 16 per cent Cr2 3 united with the A12 3 . Passerini 2 made an examination by X rays of mixtures which had been heated to 600° C. and found that limited solution in the solid state occurred at this temperature.