High thermal conductivity ceramic body of aluminum nitride

Abstract

A process for producing an aluminum nitride ceramic body having a composition defined and encompassed by polygon P1N1KJ but not including lines KJ and P1J of FIG. 4, and a thermal conductivity greater than 1.00 W/cm.multidot.K at 25.degree. C. which comprises forming a mixture comprised of aluminum nitride powder containing oxygen, yttrium oxide, and free carbon, shaping said mixture into a compact, said mixture and said compact having a composition wherein the equivalent % of yttrium and aluminum ranges between points K and P1 of FIG. 4, said compact having an equivalent % composition of Y, Al, O and N outside the composition defined and encompassed by polygon P1N1KJ of FIG. 4, heating said compact up to a temperature at which its pores remain open reacting said free carbon with oxygen contained in said aluminum nitride producing a deoxidized compact, said deoxidized compact having a composition wherein the equivalent % of Al, Y, O and N is defined and encompassed by polygon P1N1KJ but not including lines KJ and P1J of FIG. 4, and sintering said deoxidized compact at a temperature of at least about 1860.degree. C. producing said ceramic body.