Investigation of the microstructure and tribological properties of laser cladding 5%Ti3SiC2 reinforced Co-based composite coatings under different loads over the wide temperature range

Abstract

In order to improve the mechanical properties of SUS 304 in practical engineering application, Co-5%Ti3SiC2 coating was successfully prepared on SUS 304 by laser technology. The microstructure of Co-5%Ti3SiC2 coating was characterized by scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and X-ray diffractometer (XRD) to evaluate the tribological properties in detail. The relevant wear mechanism of the substrate and Co-5%Ti3SiC2 coating under different loads (2, 5 and 8 N) in isothermal tribological experiments (25 and 600 °C) were systematically explored. The results show that the Co-5%Ti3SiC2 coating is mainly composed of continuous matrix γ-Co solid solution, ceramic Fe2C, Cr7C3 and TiC, and lubricating phase Ti3SiC2. The average micro-hardness of Co-5%Ti3SiC2 coating is 358.61 HV0.5, which is significantly higher than that of SUS 304 (239.32 HV0.5). In all isothermal tribological experiments, the wear rate of Co-5%Ti3SiC2 coating decreases with the increase of load, and its coefficient of friction (COF) also decreases with the increase of load.

Keywords

• laser cladding
• Ti3SiC2
• Wide temperature range
• Mechanical properties