Materials Science Forum, Vol.473-474, 135-140, 2005
Some experiences of tribological, microstructural and mechanical investigation of post heat treated SiAlON ceramics
Tribological performance of technical ceramics is influenced by various factors. Among the others the material properties, loading conditions, residual stresses as well as chemical reactions and interaction between contacting parts effect the damage process. The current paper focuses on the material features, investigating the possibility of modifying the wearing characteristics of a Si3N4 based technical ceramics by post-heat treatment. The microstructure, the mechanical properties and the wearing characteristics were studied on HIP-sintered SiAlON samples, post heat-treated in oxidizing atmosphere at different temperatures. Wearing performance was characterized by pin-on disc tests. The wear rate varied with the temperature of heat treatment. From tribological point of view especially treatment at 1200degreesC proved to be advantageous Microstructural investigations by TEM and X-ray diffraction studies revealed some explanations of these changes. The above studies were completed by mechanical tests. Microhardness, E-modulus, four point bending strength and indentation fracture toughness have been determined in order to study the correlation between the tribological and mechanical properties. Based on our results, the post heat treatment may be useful to improve the wearing performance of SiAlON ceramics.
Keywords:Si3N4 based ceramics;post heat-treatment;wear;pin-on-disc test;mechanical properties;microstructure;TEM;X-ray diffraction