Preparation and characterization of Si{sub}3N{sub}4/TiN nanocomposites ceramic tool materials

摘要

Si{sub}3N{sub}4/TiN nanocomposites ceramic tool materials were sintered under 30MPa at 1650℃for 40min. The effects of nano-scale TiN on the mechanical properties and microstructure were investigated. The strengthening and toughening mechanisms of Si{sub}3N{sub}4/TiN nanocomposites were studied by observing the fracture surfaces, samples for TEM and cracks. The oxidation resistance of Si{sub}3N{sub}4/TiN nanocomposites was also discussed based on the observation of microstructure. The results showed that the elongated Si{sub}3N{sub}4 grains which were pulled out from the fracture surfaces were reduced with the increase of the addition of nano-scale TiN, and many intragranular TiN grains were observed in Si{sub}3N{sub}4/TiN nanocomposites. The greater crack deflection and microcrack provided the contributions to the strengthening and toughening mechanisms for Si{sub}3N{sub}4/1 vol% TiN nanocomposite. However, Si{sub}3N{sub}4/TiN nanocomposites were oxidized strongly at higher temperature.