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By changing the molecular weight and concentration of dispersant, PH value of dispersion solution and treat process, this paper focuses on the optimization parameters of the TiCp-reinforced ß-sialon nanocomposites suspensions. Zeta potentials, sedimentation tests have been carried out to prepare a well reagglomerated and uniform suspensions. The optimum molecular weight of PEG is 1540 for Al2O3 powder and 4000 for others, while the concentration is 0.5wt% to 0.8wt% with the pH values range from 9.5 to 10. After addition of dispersant, PEG (polyethylene glycol), the surfaces of the TiC particles and Sialon contents were selectively covered with long organic molecular chains by soaking within solution. The resulting powders not only resisted reagglomeration, but were also readily dispersible within the mixed solution. Optimum dispersion conditions, i.e. the surfactant molecular weight and the concentration, the PH value of the suspens ions and the soaking time were determined.

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Machine parts made of nickel-based alloys usually work in high-temperature service environments such as aircraft turbines. The mechanical properties and antioxidant properties of materials tend to be reduced at high temperatures. Therefore, it is of great practical significance to reveal the wear mechanisms of materials at different temperatures. In the present investigation, the tribological behaviour of an Inconel 718 superalloy at different temperatures was investigated. First, the coefficient of friction curves obtained under different test conditions were analysed in detail to illustrate the dynamic change process of friction at high temperature. Next, the morphology of the wear surface, surface morphology of friction pairs and material transfer during friction were analysed via scanning electron microscopy 3D morphology and energy dispersive spectroscopy measurements to reveal the wear mechanisms of materials in a high-temperature environment. Finally, the microstructure of the cross section of the wear tracks was analysed by using optical microscopy electron back-scattered diffraction etc., to clarify the mechanisms of crack initiation and material removal. The results show that the friction properties of the Inconel 718 superalloy have differences at different test temperatures. Although increasing the test temperature does not necessarily aggravate the wear of the material, the oxidation of the wear surface during the friction process significantly increases. In addition, when the contact load increases, the thickness of the oxide layer and wear of the material simultaneously increase.