Studies on the thermal stability of nanosized powder of WC1-x-based product prepared by plasma dynamic method, compaction feasibility of the powder and preparation of composite with aluminium

Obtaining ceramics and composites based on cubic tungsten carbide WC1-x requires knowledge of its thermal behavior, which is poorly studied now. The paper presents the results of a thermal analysis of the nanosized WC1-x-based product with the stoichiometry of WC0.72-0.74 synthesized by a plasma dynamic method. Taking into account the known literature data on the structure of WC1-x products, an investigation of synthesized nanoparticles allows us to conclude that WC1-x cannot exist without a crystalline graphite shell and/or an amorphous carbon matrix. Similarly, the destruction of both carbon shells and a matrix leads to either quick oxidation of WC1-x to WO3 when heated in air or the phase transition WC1-x → WC when heated in vacuum. The thermal analysis shows WC1-x is stable up to 550 °C in air and up to 1200 °C in vacuum and argon. The obtained data made it possible to formulate recommendations for preserving WC1-x material in bulk specimens when compacting from the dispersed powder. The preparation of binderless ceramics from the WC1-x-based product by the SPS method seems to be impossible due to carbon diffusion during the sintering process, while the use of WC1-x-based products as a reinforcing additive to a metal (Al) matrix seems to be the only way to preserve this crystalline phase in a bulk form at the present time.