TiC–diamond composite disk-heater cell assembly to generate temperature of 2000 °C in a large-volume belt-type high-pressure apparatus at 10 GPa

Abstract

A TiC–diamond composite was prepared for the heater of a large-volume belt type high-pressure apparatus. Graphite has conventionally been used for the heater in high-pressure studies, but it cannot be used at pressure higher than 10 GPa and above 1500 °C because of the problem associated with the graphite-to-diamond phase transformation. New TiC–diamond heater overcomes this problem and achieves stable temperature generation by using a belt-type high-pressure apparatus. The composite was fabricated by heat-treatment of a mixture of diamond and TiC0.8 with nonstoichiometric composition at ambient pressure. By optimizing the preparation conditions, we obtained TiC–diamond composites that exhibited mechanical and electrical properties suitable for a heater material without any volatile component such as resin. Since reported conventional TiC–diamond composite heaters include epoxy resin as binder, volatile components arise from decomposition of the resin at high temperature preventing stable high-pressure/high-temperature experiment above 2000 °C. Attainment of reproducible temperature-generation efficiency in the present heater makes it possible to perform stable experiments at high temperature and pressure, i.e., in the region of 2000 °C and 10 GPa.