CRYSTAL-CHEMISTRY AND THERMAL-EXPANSION OF CD0.5ZR2(PO4)(3) AND CD0.25SR0.25ZR2(PO4)(3) CERAMICS

Cd0.5Zr2(PO4)(3) (CdZP) and the partially substituted phase Cd0.25Sr0. 25Zr2(PO4)(3), prepared by the sol-gel route, belong to the NZP family . The structure of CdZP (S.G.R (3) over bar) has been established by t he Rietveld method. The thermal behavior of CdZP, investigated by X-ra y powder diffraction, is anisotropic, i.e., the structure expands alon g c axis and contracts along a axis. Dilatometric measurements and SEM micrographs of ceramics, sintered with 5% ZnO, show that CdSrZP prese nts the advantage to decrease microcracking, and then anisotropy,occur ring during the heating cycle. The thermal expansion coefficient a(bul k) of the ceramic CdSrZP is very small (0.6 x 10(-6)degrees C-1).