Reaction sintered multiphase ceramic

Claim 1

A reaction sintered multiphase ceramic body consisting essentially of a fine-grained, homogeneous, intimate interdispersion of: (a) 5-95 mole percent of nitride phase or phases having a maximum grain size substantially not greater than 10 μm and being nitride of one or both of Al and Si, and (b) 5-95 mole percent of second phase or phases having a maximum grain size substantially not greater than 10 μm and being boride, carbide, silicide, sulfide or combination thereof of one or more of the elements of Groups 3b including lanthanide and actinide series elements, 4b, 5b and 6b; which body contains 0 to 4 weight percent oxygen and is prepared by the process comprising: (c) admixing particulate reactants of maximum particle size substantially not greater than 150 μm and being elements, compounds, intermetallic compounds, alloys or combination thereof in stoichiometric proportions to substantially form the nitride and second phases, and (d) shaping and heating the admixture to form the reaction sintered body, the heating being done in atmosphere that is nonreactive with the admixture and at temperature at which the reaction and sintering occurs between the reactants to substantially form the nitride and second phases.