Hot press assisted synthesis and thermophysical properties of iridium intermetallic compounds

The simple hot press assisted synthesis of iridium-based intermetallics, MIr3±x, (M = Hf, Ta) from the powder mixtures of corresponding carbides and iridium, and the powder mixtures of the metal and iridium was proposed. The application of pressure provides the formation of dense intermetallic MIr3±x phase as the main constituent. The coefficient of thermal expansion (CTE) of the TaIr3 phase was determined by means of high-temperature X-ray diffraction analysis. The CTE was evaluated to be equal to 5.2∙10−6 K−1. A set of thermophysical properties, such as spectral emissivity, linear expansion of the sample, heat capacity, thermal diffusivity, and thermal conductivity of the TaIr3-based intermetallic material were determined using the original laser-flash technique up to 2200 K. The effect of porosity and composition on the thermal conductivity of the TaIr3-based material is discussed. The results can be of interest for the evaluation of the behavior of the TaIr3-based intermetallic material at ultra-high temperatures.