Mullite and ZrO2-mullite ceramics have been prepared by tape casting mixtures of Al2O3, quartz, and ZrO2 powders and subsequent reaction sintering. Tape casting leads to homogeneous, high-density green materials with good sinterability. The design of a thermal cycle which favors densification with respect to mullitization allows the preparation of nearly dense, nearly fully reacted materials at sintering temperatures below 1600-degrees-C. ZrO2 additions limit grain growth, but the ZrO2 content must not be too high when a high tetragonal:monoclinic ratio is required.
