Wetting of hot-pressed aluminum borides and borocarbides by molten aluminum and copper

The sessile drop method has been used to determine the temperature dependen ce of the wetting of boride and borocarbide phases by molten aluminum and c opper. Hot-pressed substrates have been used made of aluminum boride and bo rocarbides, which are well wetted by aluminum above 1000 degreesC. Aluminum borocarbide phases are not wetted by copper under these conditions. The te mperature dependence is derived for the synthesis of finely divided aluminu m boride and borocarbide powders from simple substances. Details are given of the nucleation and formation of an aluminum phase containing boron. The aluminum borides and borocarbides are formed not as a result of boration of the metal lattice (which occurs in the synthesis of transition-metal borid es) but by metallation (alumination) of the boron lattice.