Wetting of Hot-Pressed Aluminum Borides and Borocarbides by Molten Aluminum and Copper

The sessile drop method has been used to determine the temperature dependence of the wetting of boride and borocarbide phases by molten aluminum and copper. Hot-pressed substrates have been used made of aluminum boride and borocarbides, which are well wetted by aluminum above 1000°C. Aluminum borocarbide phases are not wetted by copper under these conditions. The temperature dependence is derived for the synthesis of finely divided aluminum 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 borides) but by metallation (alumination) of the boron lattice.[PUBLICATION ABSTRACT]