Mean grain size evaluation of tungsten- and boron-carbide composites sintered at various temperatures by ultrasonic methods

Abstract

In this study, the mean grain size of different ceramic-metal composites made from tungsten carbide and boron carbide have been determined with the ultrasonic velocity technique. In addition, the electroless coating method was used to coat the tungsten carbide samples. The prepared samples were sintered at different temperatures ranging from 1200°C to 1400°C in an argon atmosphere. Powders were placed in a 30 mm diameter mold and pressed using a hydraulic press at a pressure of 200 bar. The results were compared to the mean grain size obtained from Scanning Electron Microscopy (SEM). This study shows a clear dependence of ultrasonic velocity on grain size in composites of boron carbide and tungsten carbide. Especially the temperature dependence of mean grain size for tungsten carbide composites can be seen very clearly.