Aluminum nitride, aluminum nitride containing solid solutions and aluminum nitride composites prepared by combustion synthesis and sintered bodies prepared therefrom

A sintered AlN body formed by sintering, an aluminum nitride powder prepared by a method comprising,

• a) igniting, in the presence of gaseous nitrogen at a pressure of from 0.75 to 30 atmospheres (0.075 to 3 MPa), a particulate material that is a metal selected from aluminum and aluminum alloys, optionally in admixture with an inert solid diluent, the particulate material having a bulk density and an aluminum metal content sufficient to establish and maintain a self-propagating combustion wave that passes through the admixture and
• b) allowing the combustion wave to pass through substantially all of the admixture to convert the aluminum in the particulate material to aluminum nitride powder,
• in an inert atmosphere at a temperature and pressure sufficient to densify the aluminum nitride powder to form the AlN sintered body, said body having a density of at least about 98% of theoretical, thermal conductivity of at least about 100 W/m-K and metal impurity concentration of at least about 200 ppm to at most about 20,000 ppm by weight, wherein the metal impurity is in the form of a metal silicide, a metal boride, or a metal boron silicide.