Study on Abrasive Resistance of Ni-Based Coatings Containing WC Hard Phase

To improve the wear resistance of piston ring and cylinder liner,and extend the servicelife of the engine for the automobiles in desert area applications,friction and wear performanceshave been tested for three Ni-based composite coatings containing varied contents of WC particles ashard phase.Scanning electron microscope(SEM)has been used for observing the surfaces of thecomposite coatings,and wear mechanisms of the coatings have been discussed on the basis of theobservation.The results obtained from Falex test showed that the composite coatings with WC hardphase have improved abrasive wear resistance in comparison with current ring/cylinder materlals.The laser remelting processing, applied to the Ni60+60%WC sprayed coatings,was provedbeneficial to produce an uniform and dense metallographic structure,form a new complex carbidephase containing various elements such as W,Ni,Cr,Si,etc.,and lead to a further improvementin abrasive wear resistance. The excellent abrasive resistance of the composite coatings with WCparticles were found related to three major factors:enhanced bulk hardness,compact metallographicstru cture a nd strong bon d between matrix and ha rd phase,as well as a load supportin g systemconstru cted by hard phase structure.As for as the friction coefficient is concerned,no significantdifferen ces are found betwee n traditional materials and Ni-based WC compooite coatings.