Synthesis/sintering of dense carbides-, borides- and perovskites-based materials by SPS

The one-step synthesis and consolidation by Spark Plasma Sintering (SPS) of metalceramic (WC-Co) and ceramic-ceramic (TiC-TiB2) composite materials starting from commercial powders is investigated. In addition, we report the results related to the Self-propagating High-temperature Synthesis (SUS) of perovskitic oxides, specifically BaTiO3, and their subsequent densification by SPS. A systematic study of the influence of the most important operating parameters (i.e. current intensity, temperature, processing time, etc.) on product characteristics and process dynamics was performed. Specifically, the investigation of the effect of the time during which the electric current is applied allows us to identify the experimental conditions for the obtainment of optimal products in terms of purity and density, as well as the intermediate phases formed during the synthesis process of the two composites by SPS. Moreover, for the case of WC-Co, it is found that synthesis and densification stages occur simultaneously, i.e. a full dense pure product is formed immediately after reaction completion. On the other hand, during the synthesis of TiC-TiB2, a satisfactory densification degree is reached only by maintaining the application of the electric current once the full reaction conversion is obtained. Finally, with the aim of obtaining dense nanostructured perovskite materials, products formed by Self-propagating High-temperature Synthesis (SHS) are mechanically treated before the SPS densification stage. For the case of BaTiO3, the effect of the sintering time on crystallite size, and relative density of the obtained products is systematically studied