Microstructure-properties relationships in samarium modified lead titanate piezoceramics .1. Quantitative study of the microstructure

Samarium modified lead titanate piezoceramics prepared from hydrothermally synthesized powder are microstructurally characterized. The evolution of the ceramic microstructure of the ceramics during sintering and Hot Isostatic Pressing (HIP) as a post-sintering treatment is studied by a combination of optical and scanning electron microscopies with computerized image analysis. The obtained grain size and pore area distributions are studied through the use of probability plots. The analysis of the grain size distributions indicates that a process of normal grain growth takes place during sintering. The pore area distributions of some of the studied ceramics are bimodal, revealing a degradation of the microstructure, with the appearance of large area pores as sintering time or temperature increases. The post-sintering HIP process reduces drastically the ceramic porosity and acts mainly on the pores of large area, thus restoring the degraded microstructures.