Preliminary study on sintering of Y ₂O ₃/ZrO ₂ composite ceramic foam

Y ₂O ₃/ZrO ₂ two-layer and Y ₂O ₃/Y ₂ O ₃-ZrO ₂/ZrO ₂ three-layer composite ceramic foams, as well as the single phase Y ₂O ₃ and ZrO ₂ samples, were prepared by polymeric sponge replication. The combinations between ceramic layers of the composite ceramic foams were analyzed. Microstructures of each layer sintered at different temperatures were investigated and compared with Y ₂O ₃ and ZrO ₂ single layer sample. A gap was observed between layers of the two-layer sample, resulting from the asynchronous sintering of Y ₂O ₃ and ZrO ₂. The Y ₂O ₃-ZrO ₂ middle layer in the three-layer sample decreased the interlaminar stress caused by asynchronous sintering, which led to the improvement of combination between layers and significant reduction of macroscopic cracks on the surface. The sintering degree of the inner ZrO ₂ layer in both composite samples was lower than that of single phase ZrO ₂, mainly because the outer Y ₂O ₃ layer sintered earlier than the inner ZrO ₂ layer, which was detrimental to the excretion of inner gas and hindered the sintering of ZrO ₂.