CMZP — A New High Temperature Thermal Barrier Material
New (Ca1-x,Mgx)Zr4(PO4)6 ceramics in the ultra low expansion NZP family not only have near zero thermal expansion but also have thermal conductivities lower than those of conventional thermal barrier materials such as ZrO2. In addition, CMZP is less dense than ZrO2 with a theoretical density of approximately 3.2 gm/cm3 versus 5.8 gm/cm3. Techniques have been developed to fabricate lightweight ceramics with both open and closed pore structures with relative densities ranging from 0.2 to 0.8. The tensile, compressive, and flexure strengths are shown to compare favorably with those of ZrO2. Furthermore, no strength loss following air quenching from temperatures up to 1500°C was observed indicative of good thermal shock resistance.
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