Ultra Low Thermal Expansion Ceramics
Abstract : Further exploration in the (NZP) - family was carried on-in that the systematic crystal chemistry investigation of M1Zr2P3O12 (M1 = Li, Na, K, Rb and Cs) and M11Zr4P6O24 (M11 = Mg, Ca, Sr, Ba) was completed and few more new compositions were synthesized and characterized. An effort was made to grow single crystals of Na, Sr and Ca zirconium phosphates using B2O3 as flux in order to obtain more data to confirm the results obtained on powdered samples. NaGe2P3O12 was studied as a potential candidate for the development of glass- ceramic due to its low melting behavior. It has been established that sol-gel process is superior to powder method for synthesizing (NZP)-compounds and therefore most of the compositions were prepared by this route. Dielectric measurements made on CaZr4P6O24 showed that in general, (NZP)-materials have low dielectric constant with relatively low loss. New families such as diborides and A12O3-GeO2 were investigated in order to search any new low thermal expansion composition with high dielectric constant. (JES)