Wear behaviors of HVOF-sprayed NiSiCrFeB, WC-Co/NiSiCrFeB and WC-Co coatings evaluated using a pin-on-disc tester with C45 steel pins

Abstract

This research aimed to study the mechanical properties and wear behaviors of high velocity oxygen fuel (HVOF) sprayed NiSiCrFeB, WC-Co/NiSiCrFeB and WC-Co coatings on AISI 1095 steel for some interesting applications, in which coatings would be subjected to cumulative wear due to repeated contact against relatively soft sliding steel parts. According to hardness and roughness measurements, the NiSiCrFeB coating displayed the lowest average hardness of 670 H V while the WC-Co coating exhibited the highest hardness of 1,350 H V when the surface roughness value tended to be inversely related to the hardness value of these coatings. The wear performances of HVOF coatings were evaluated using a pin-on-disc method with C45 steel counter pins having a moderate hardness of 745 H V. From the wear test results, the mean friction coefficients of WC-Co/NiSiCrFeB and WC-Co coatings tested for 60 min were similarly lower than that of NiSiCrFeB coating. The mean wear rates of NiSiCrFeB coatings were relatively high compared with the other two coatings while the wear rates of WC-Co/NiSiCrFeB and WC-Co coatings were not significantly different. Therefore, WC-Co/NiSiCrFeB and WC-Co coatings were more appropriate for moderately hard counter work materials such as medium to high carbon steels than NiSiCrFeB coating. Related wear mechanisms were analyzed and discussed.