Crystallization of Zirconium Nitride in Silicon Nitride Ceramics with Nitrogen Pressures and Sintering Additives
We investigated grain boundary crystallization of gas-pressure-sintered silicon nitride with zirconia and magnesia as sintering aids. Cation compositions were mostly uniform throughout the specimen however, ZrO2 was crystallized in the surface region, while ZrN in the inside. When the specimen was heat-treated at 1 atm nitrogen atmosphere, ZrO2 in the surface region transformed to ZrN. The transformation, however, was suppressed when alumina was incorporated as an additional sintering aid. Based on these results, we propose a model describing the reaction among Si3N4, SiO2, ZrO2, ZrN and N2. Observed microstructures and measured mechanical properties were consistent with the model.
Hai-Doo Kim, Hua-Tay Lin and Michael J. Hoffmann
S.M. Lee et al., "Crystallization of Zirconium Nitride in Silicon Nitride Ceramics with Nitrogen Pressures and Sintering Additives ", Key Engineering Materials, Vol. 287, pp. 253-258, 2005