送粉方式对WC增强复合涂层组织的影响
Influence of powder-feeding mode on microstructure of WC reinforced composite coating
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摘要: 在同步送粉和后送粉两种不同的WC送粉方式下,通过等离子堆焊技术制备了WC增强镍基合金复合涂层.利用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、能谱仪(EDS)对涂层的显微组织,相结构和成分特征进行观察和测试.结果表明,复合涂层显微组织为未溶WC颗粒、结晶碳化物(WC,W2C)分布于亚共晶组织基体之上.相对于同步送粉,后送粉时WC颗粒溶解较少;复合涂层中初生WC,W2C数量较少、组织较细,含钨共晶组织较少;WC与基体界面元素浓度梯度较大.Abstract: WC reinforced Ni-based composite coating was prepared by using plasma surfacing process with two different power-feeding modes of synchronous feeding and back feeding.The microstructure,phase structure and chemical compositions were analyzed by scanning electron microscopy(SEM),X-ray diffractometer(XRD) and energy dispersive spectrometer(EDS).Results showed that the microstructure consists of WC particles embedded in hypoeutectic matrix.Compared with synchronous feeding,less dissolution of WC,less primary phases WC,W2C with finer microstructure and greater concentration gradient of elements were observed in the composite coating with back-feeding process.
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