Synthesis, processing and microstructural characterization of CaSnO3 and SrSnO3 ceramics

Abstract

A thorough study of CaSnO3 and SrSnO3 with respect to their synthesis, processing and microstructural characterization has been made. In order to establish a standard methodology for mass manufacturing with identical and beneficial microstructure and reproducible electrical characteristics, different synthesis routes were adopted. Evolution of micro structure which is intimately related to the envisaged properties in the ceramics, was closely and systematically followed in terms of sintering over a wide range of temperatures and soak time. By using an alternative precursor (nitrate instead of carbonate) with favorable decomposition kinetics, the temperature of compound formation by solid-state route was lowered by a significant margin of 200°. In the case of the self-heat-sustained (SHS) method, the final compound was found to have formed via two-step reaction between molten tin and metal nitrate. In CaSnO3, a dense micro structure with near zero porosity and uniform grain size could be developed by sintering at 1200°C up to 48 h, while the solid-state derived SrSnO3 could be sintered to about 85-90% density relative to that of the green compact at 1350°C/24 h. In the case of SHS technique, small grain size and a narrower particle size distribution was an interesting feature of the sintered samples. Sintering at 1350°C for soak-time 48