Combustion Synthesis and Spark Plasma Sintering of Sialon Composites

摘要

Spark-plasma sintering (SPS) of composite ceramics in the β-Si_5AlON_7- system (SiC, TiN, BN) was studied. An effective mechanism of intensification of sintering processes was revealed due to the introduction of h-BN, having a scaly structure and playing the role of a solid lubricant, which improves the compressibility of the sintered powder mixtures under load. According to XRD results, the raw powders of β-Si_5AlON_7, h-BN, and TiN did not contain impurity phases while β-SiC had trace amounts of Si_3N_4. According to SEM results, all as-synthesized powders appeared largely as agglomerates. The achieved level of physical-mechanical properties and functional characteristics of the obtained samples of composite ceramics (flexural strength, electrical conductivity, linear thermal expansion coefficient, thermal shock, wear resistance) confirms that productive and energy efficient methods of SHS and SPS can be successfully applied in the development of promising ceramic materials and products based on sialons for use in extreme conditions.