Influence of laser treatment on the structure and wear resistance of Co-Cr coatings obtained by cold spraying
摘要
In this study, the influence of laser treatment on the structure and tribological properties of Co-Cr coatings obtained by cold spraying was investigated. A powder mixture consisting of cobalt and chromium at a ratio of 40:60 wt. % was sprayed onto a stainless steel substrate. The content of chromium in the resulting coating was about 30 wt. %. The laser treatment of the coating was performed at a scanning rate of 45 mm/s and power of 1 kW in order to minimize the amount of defects (e.g., pores, cracks, discontinuities). The structure and phase composition of the resulting coatings were studied by scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction analysis. It was shown that the phase composition of the initial coatings is represented by cobalt and chromium, whereas the laser treated coatings only contain cobalt-based solid solution. Changes in the structure and phase composition after the laser treatment of the coatings resulted in a 2-fold increase in the wear resistance, with the specific wear rate under the dry friction conditions measuring 3.99×10−5 mm3/(N×m). The wear surface analysis has shown that as a result of the laser treatment, the wear mechanism changed from abrasive-oxidative to oxidative.