Synthesis and Sintering of KTP Family Compounds NaSbOSiO₄, KSbOGeO_4, RbSbOGeO₄ Orthorhombic

Abstract

A series of NaSbOSiO₄(NSS), ICSbOGeO₄(KSG), RbSbOGeO₄(RSG) compounds have been prepared by mechanochemical mixing (MM) route, which is a kind of technique of solid state reaction, or via a sol-gel route. They crystallize in the orthorhombic system, space group Pna 2, , Z=8. The framework structure, built up from SiO₄[Ge0₄] tetrahedra and Sb06octahedra, is isotypic with that of KTiOPO4. For both routes, preparation conditions have been optimized by studying the influence of various parameters such as calcination temperature, sintering temperature, sintering time.
According to the difference of topoch emical reactivity between MM and SG routes, the crystal phases deposited by the calcination are variant. Fine powders prepared by the SG route improve the sinterability. Within the group of alkali metal ion, K⁺ ion favours the progress of high polymerization during the hydrolysis. The microstructure of sintered bodies are very variant by the kind of compounds. The grain growth of KSG and RSG is cornparativery small with subsequent production of high dence pellets, while the sintering of NSS is very difficult.