Structure-Property Correlation in Ir Transparent Zinc Sulphide (Zns) Ceramics Under Chemical Vapour Deposited & Hot Iso-Statically Pressed Conditions

Abstract

M Buchi Suresh and Roy Johnson

IR Transparent ZnS ceramics processed through chemical vapour deposition were subjected to Hot Isostatic pressing and the samples in both the conditions were characterized by XRD, microstructure and high temperature impedance spectroscopic studies for the dielectric and electrical properties. Both the samples have shown cubic sphalerite phase with enhanced orientation along (111) plane as a result of hot isostatic pressing as revealed by XRD.HIP treatment to ZnS facilitated the enhancement of the homogeneity of microstructure and enhancement in the grain size from 10μm to 50μm. The electrical behavior of both the samples was investigated by AC impedance spectroscopy in the frequency range 1Hz to 1MHz from RT to 500°C in dry air. HIP has resulted in a significant increase in the dielectric constant, which can be attributed to the increase in homogeneity and the grain size. Further, the complex impedance plots exhibited two impedance semicircles identified in the frequency range is explained by the grain and grain boundary effects. An equivalent-circuit analysis of AC impedance spectra based on the brick-layer model was performed. Activation energies obtained from the conductivity plots indicates an Arrhenius type thermally activated process.

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