Thermal-Mechanical Properties of Mullite and Mullite-Zirconia Substrates

Mullite and mullite-zirconia substrates were prepared by tape casting a mixture of kaolin and alumina (and zirconia for the composite) with an organic binder . The thermal- mechanical properties of the sintered substrates were studied as a function of sintering temperature and time. The mullitization reaction was more sensitive to sintering temperature than time. The mullite zirconia substrates could be sintered to a higher relative density than the mullite substrates . About 50% of the zirconia remained in the tetragonal form. The strengthtoughness and thermal shock resistance of the mullite-zirconia substrates were significantly greater than the mullite substrates .