含碳化钨硬相镍基涂层耐磨粒磨损性能研究

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

为了改善沙漠地区用汽车发动机缸套／活塞环系统的抗磨粒磨损性能，延长发动机的使用寿命，对３种含不等量硬质相ＷＣ颗粒的镍基复合涂层的摩擦磨损性能进行了试验研究，并且利用扫描电子显微镜对复合涂层表面进行了观察，在此基础上又对其抗磨粒磨损作用机理进行了分析与讨论，Ｆａｌｅｘ试验结果表明，含ＷＣ硬质相的镍基复合涂层的抗磨粒磨损性能明显地比常用缸套／活塞环材料磷铸铁的好，适用于磨粒磨损十分严重的沙漠地区车辆汽缸／活塞环系统，激光重熔可使Ｍｉ６０＋６０％ＷＣ喷涂涂层形成均匀而致密的金相结构，并有含钨、镍、铬和硅等元素的复合碳化物新相生成，因而能够进一步改善涂层的抗磨粒磨损性能。这类含ＷＣ硬质相的复合涂层抗磨粒磨损性能良好的主要原因有：涂层整体硬度的提高，均匀而致密的金相结构的形成和比较高的硬相。基体结合强度，以及由多种硬相共存构成的良好承载系统。镍基碳化钨复合涂层的摩擦性能与传统材料的没有很明显的差别。

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.