THE SYNTHESIS, SINTERING, AND THERMAL-PROPERTIES OF (CA1-X,MGX)ZR4(PO4)6 (CMZP) CERAMICS

(Ca1-x, Mg(x))Zr4(PO4)6 (CMZP) ceramics have been made by sol-gel and solid state reaction methods. Single phase (Ca1-x, Mg(x))Zr4(PO4)6 (x less-than-or-equal-to 0.4) has been obtained. The densification of CMZ P depends on the powder synthesis method. Near theoretical density can be achieved by cold pressing and sintering with the addition of a sin tering aid. Bulk thermal expansion of CMZP is shown to depend on the p hase composition, grain size, and presence of microcracks. By choosing different sintering temperatures and times, the thermal expansion of CMZP can be controlled. CMZP (x = 0.4) ceramics exhibit near zero bulk thermal expansion, low thermal expansion anisotropy, low thermal cond uctivity, and thermal stability up to 1500-degrees-C.