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DEVELOPMENT OF ZIRCONIA RESISTANT TO THERMAL SHOCK*
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References
1947
Year
Materials ScienceHigh Temperature MaterialsEngineeringThermal ProtectionPure ZirconiaComplete StabilizationCeramic MaterialCeramics MaterialsThermal AnalysisThermodynamicsChemistryCeramic PowdersCrystal StabilizationThermal EngineeringCeramic Technology
A bstract The effects on the crystal stabilization and other properties of pure zirconia were determined for additions of CaO, MgO, BeO, ThO 2 , and CeO 2 in binary and ternary combinations. Complete stabilization was attained with the following compositions (in mol. %): 10 to 20 CaO, 14 MgO, 26 CeO 2 , 10 CaO + 5 ThO 2 , 10 CaO + 5 BeO, or 2 to 7 CaO + 4 to 6 to MgO. Cerium oxide produced partial stabilization, but BeO and ThO 2 used alone were ineffective at 1927°C. Some strong, dense bodies were found which had good resistance to thermal shock, namely, those containing (mol. %) 8 to 12 CaO, 6.7 CaO + 3.7 MgO, or 2.3 CaO + 6.4 MgO; all of these compositions still had a small amount of inversion present. This small inversion may be necessary for high resistance to thermal shock in ZrO 2 ware because ( a ) the over‐all thermal expansion is then small and gradual and ( b ) with complete elimination of inversion, the expansion is large since the expansion curve is a straight line and the coefficient of expansion is rather high, 11 to 12 × 10 ‐6 .