Sintering Mechanism for High-Density NZP Ceramics

We have studied the shrinkage kinetics and mechanism of NaZr2(PO4)3 containing inorganic additives. The sintering of NaZr2( PO4)(3) containing ZnO microadditives is shown to follow a liquid-phase mechanism. Effective sintering aids include oxides of metals in the oxidation states 2+ and 3+ that are capable of reacting with sodium zirconium phosphate to form solid solutions. Ceramics having a relative density of 96-99% and isostructural with NaZr2(PO4)(3) can be prepared by adding 0.75-2.0 wt % ZnO as a sintering aid capable of influencing the structure of grain boundaries in ceramic materials, pressing green bodies at 200-300 MPa, and sintering them at 1000-1100 degrees C for 7-15 h.