Variations of Microstructure and Mechanical Properties of Si-B-O-N Ceramics with Sintering Temperatures

Junbao ZHANG, Guangwu WEN, Tingquan LEI, Dechang JIA and Jiancun RAOSchool of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China

摘 要：<正>Si-B-O-N powder without B-O bonds synthesized by polymeric precursor were hot-pressed into ceramics at different tempera-tures. The variations of microstructure and mechanical properties of Si-B-O-N ceramics have been investigated. Crystallization of Si-B-O-N ceramics occurred at about 1400. Density, elastic modulus, and flexural strength of the ceramics increased with the increasing sintering temperatures, and reached to their maximum values at 1600. By contrast, hardness and frac-ture toughness of the ceramics monotonically changed with increasing sintering temperatures. Hardness decreased, while the fracture toughness increased. The principal toughening mechanisms including crack deflection, crack bridging and plate grain pulling-out effects are discussed

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