Physico-chemical investigation of components interaction of the Si-Al-O-N-Ti system in the region Si{sub}3N{sub}4-AlN-Al{sub}2O{sub}3-SiO{sub}2-TiN-TiO{sub}2. I. The subsystems Si{sub}3N{sub}4-Al{sub}2O{sub}3, Si{sub}3N{sub}4-TiN, and Al{sub}2O{sub}3

摘要

Using the methods of differential thermal analysis and X-ray diffraction, the interaction of components in the Si-Al-O-N-Ti system was investigated, in particular, for the subsystem Si{sub}3N{sub}-Al{sub}2O{sub}3, Si{sub}3N{sub}4-TiN and Al{sub}2O{sub}3-TiN, under conditions approximated to conditions of hot pressuring of composites. It is established, that during interaction of Si{sub}3N{sub}4 with Al{sub}2O{sub}3 the β-sialon, SiO{sub}2, AlN and products of intermediate reaction (mullite and X-phase) result. During interaction of Si{sub}3N{sub}4 with TiN, owing to decomposition of Si{sub}3N{sub}4 at the temperatures 1650-1900°C, titanium disilicide forms. The titanium disilicide with free silicon and the rest of TiN forms eutectics' at 1320 and 1280°C, respectively Interaction of Al{sub}2O{sub}3 with TiN also brought to formation of eutectic of Al{sub}2O{sub}3 and spinel at 1850°C. Presence of eutectic liquidus in the specimens after their sintering promoted the natural compaction of material and thus, the improvement of some their mechanical characteristics.