Phase evolution and microstructural development in sol-gel derived MSnO3 (M = Ca, Sr and Ba)

Alkaline-earth stannates having the general chemical formula MSnO3 (M = Ca, Sr and Ba) have been projected as potential electronic ceramics. In view o f the information gaps in the reported research, a vigorous and systematic investigation on these exotic materials has been carried out. In this commu nication, the synthesis of CaSnO3, SrSnO3 and BaSnO3 via sol-gel technique is reported. Infrared spectroscopy and X-ray analyses of various gel sample s with different thermal history helped in identifying the reaction pathway s and the stage where amorphous gel to crystalline phase transition occurre d. Grains of submicron size with narrow size distribution and spherical mor phology, were the most noticeable characteristics of sintered calcium metas tannate derived by sol-gel method. In the case of barium analogue, a fascin ating 'sugar cube' structure (akin to that observed in solid-state reaction and the self-heat-sustained reaction derived samples) having improved dens ity characteristics evolved at low sintering temperatures. This gradually t ransformed into a more familiar spherical granular motif with improved dens ity characteristics as the sintering profiles were varied from 1200 degrees C/24 h to 1500 degrees C/2 h. This seems to be an inherent feature of this system, irrespective of the method of synthesis. (C) 2000 Kluwer Academic Publishers.