Preparation of Mullite–TiC–ZrC-Ceramic Materials by a Plasma-ARC Method and Their Properties

Abstract

The phase composition for synthesized titanium carbide TiC and zirconium carbide ZrC powders is provided, and development of the crystal phases, microstructure, relative density, open porosity, true shrinkage, hardness, strength in compression of mullite–TiC–ZrC-specimens with a different ratio of TiC and ZrC sintered by a plasma-arc method in the range 1200 – 1500°C is demonstrated. Synthesized TiC and ZrC powders have intense crystallization of TiC and ZrC phases, and sintered specimens with a different ratio of TiC and ZrC have different mullitization in the range 1200 – 1500°C and degree of TiC and ZrC phase development at up to 1500°C. Above 1500°C there is development of TiC or ZrC phases in relation to the ratio of TiC and ZrC within sintered materials. Specimens with a higher TiC concentration have a denser sintered microstructure compared with specimens containing a greater amount of ZrC. This facilitates an increase in relative density, linear shrinkage and a reduction an open porosity, formation of harder specimens with uniform indentation impression without damage formation around it, and with the best strength indices in compression.