HIGH-TEMPERATURE REACTION OF ALUMINUM-OXIDE WITH BORON IN VACUUM

The reaction of aluminum oxide with boron in vacuum was studied over a wide range of temperatures. Analysis of the reaction products was car ried out by chemical, x-ray diffraction, optical, and metallographic m ethods. The temperature dependence of the reaction was determined. A h igh boron phase of the composition AIB(18-31) is produced by the borot hermic reduction of aluminum oxide. The crystalline phase possesses a hexagonal structure with the elementary cell parameters a = 1.097, c = 2.378 nn. Aluminum dodecaboride and diboride phases were not detected in the reaction products.