Solid Solubility of Aluminum and Boron in Silicon Carbide

Solid solubility of aluminum in silicon carbide was studied by the powder X‐ray diffraction technique (Debye‐Scherrer method). At 2200° C the solubility limit was 1.0 wt%. Measurements of the lattice parameter of Al‐saturated samples as a function of temperature gave a heat of solution of 147 kJ/mol. The change in the lattice parameter indicates that Al substitutes for Si. Literature data are interpreted as indicating that B replaces both Si and C.