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采用同轴送粉等离子熔覆工艺在Q235基体上制备了多层65%Ni60A-35%WC体积梯度涂层。采用OM、SEM、EDS、XRD等研究了涂层与基体、涂层与涂层的界面及组织特征,测量了涂层的硬度(HRC)。结果表明:涂层与基体界面处元素Cr、Ni由涂层向基体扩散;靠近界面约223μm范围内基体内的晶粒尺寸约长大了1.75倍;梯度涂层内部界面上层与层枝晶交错生长,形成联生结晶;梯度涂层由下至上的组织特征为:粗大树枝晶逐渐过渡为细小杂乱无方向性的致密组织;WC颗粒周围的Ni与基体Fe互熔,形成冶金结合;梯度涂层物相成分主要由Cr2Ni3、FeCr0.29Ni0.16C0.06、Fe3Ni2、CrFe7C0.45、BNi2、WC等组成;梯度涂层内硬度(HRC)值与65%Ni60A-35%WC体积分数成正相关关系。
Multi-layer 65% Ni60A-35% WC volume gradient coating was prepared on Q235 substrate by coaxial powder feeding plasma cladding process. The interface and microstructure of the coating, matrix, coating and coating were investigated by OM, SEM, EDS and XRD. The hardness (HRC) of the coating was measured. The results show that the elements Cr and Ni at the interface between the coating and the matrix diffuse from the coating to the matrix. The grain size in the matrix near the interface is about 1.75 times larger than that at the interface of about 223μm. The morphology of the gradient coating from the bottom to the top is characterized by the following: the coarse dendrites gradually transition to small, disorderly and non-directional dense structures; the Ni around the WC particles interpenetrates with the matrix Fe to form a metallurgical bond; the gradient coating The composition of interlaminar phase mainly consisted of Cr2Ni3, FeCr0.29Ni0.16C0.06, Fe3Ni2, CrFe7C0.45, BNi2, WC and so on. The hardness (HRC) of graded coating was positively correlated with the volume fraction of 65% Ni60A-35% WC .