A WEAR-RESISTANT COMPOSITE COATING

It has been found that there is a critical load in the sliding wear of electroless co-deposited Ni-P-SiC coatings. If the load exceeded the critical value, the wear volume increased greatly. Further research fo und this critical point related to the wear state in which the heat of friction changes the wear from lubricated wear to dry wear. For a Ni- (8.73 percent P)-SiC coating, if the load is increased continuously, a second critical point of load will appear, indicated by an accumulati on of phosphorus on the wear surface in the form of a glazy layer. The temperature range studied comprised three parts-low, medium and high. In the low temperature range, wear volume decreased with rise of heat treating temperature and the hardness of the coating controlled the w ear. In the medium temperature range, wear volume decreased with incre ased temperature, but the toughness of the coating controlled the wear . In the high temperature range, wear volume increased with increased temperature, but the wear was again controlled by the hardness of the coating.