High temperature wear resistance of laser cladding NiCrBSi and NiCrBSi/WC-Ni composite coatings

NiCrBSi coating and NiCrBSi/WC-Ni composite coating were produced on stainless steel by laser cladding. The friction and wear behavior of the laser cladding coatings sliding against Si3N4 ball at an elevated temperature of 500 degrees C was evaluated. The morphologies of the worn surfaces and wear debris were analyzed by means of scanning electron microscopy and three-dimensional non-contact surface mapping. Moreover, the elemental composition of the wear debris was determined by means of energy dispersive spectrometry. It has been found that the microhardness and wear resistance of the laser cladding coatings are excellent than that of stainless steel substrate. In particular, laser cladding NiCrBSi/WC-Ni composite coating shows better high temperature wear resistance than NiCrBSi coating, which is due to the formation of hard WC phase in the composite coating. Stainless steel substrate sliding against Si3N4 counterpart ball at an elevated temperature is dominated by adhesion wear, abrasive wear and severe plastic deformation and cutting; while both laser cladding coatings, involving only mild abrasive and fatigue wear when sliding against the ceramic counterpart, are able to prevent them from severe adhesion and abrasive wear. (C) 2011 Elsevier B.V. All rights reserved.