Composite Fretting Wear Behavior of HVOF Sprayed WC-CoCr Coatings

High Velocity Oxy-Fuel spraying technique was used to achieve the WC-CoCr coatings on 35^# steel surface. The composite fretting wear behavior of the coatings was tested using a SLP-20 electro-hydraulic servo micro testing machine. The wear surface morphology was observed by scanning electron microscopy, and the wear mechanism was investigated. The results show that the F-D curves changed from quasi-trapezoidal loop to elliptical loop under a 40 μm fretting amplitude, while the fretting changed from slip regime to micro-slip regime. With the increase of fretting amplitude, the range of slip regime was slightly enlarged. The fretting scars showed a unsymmetrical ring-shaped morphology with the intermediate adhesion and edge wear, the composite fretting wear mechanisms of WC-CoCr coatings in slip regime were adhesive wear and delamination, while in the micro-slip regime were mainly fatigue wear.