镍/碳化钨钎涂层界面行为与力学性能分析

Wang Xingxing1, Li Yang1, Wu Shengjin1, Du Quanbin2, Jia Lianhui3, Li Shuai1, Chen Xiaoming4(1.Henan International Joint Laboratory of High-efficiency Special Green Welding, North China University of Water Resources and Electric Power, Zhengzhou 450045, China)

摘要:

具有高耐磨、抗腐蚀、高硬度的镍/碳化钨复合涂层，在盾构部件、航空航天等领域广泛应用。为提高水力机械过流部件服役寿命，文中以WC颗粒和镍基粉状钎料为原材料，采用真空钎涂在201不锈钢表面制备镍/碳化钨复合钎涂层，借助扫描电镜、金相显微镜、洛氏硬度计对钎涂层界面微观组织和力学行为进行研究。研究表明，涂层与基体之间元素扩散主要表现为钢基体中Fe、Cr和Mn元素向涂层组织中溶解扩散，在界面处偏析沉淀；含有25 wt.%WC钎涂层显微硬度分布均匀，是钢基体的4.6倍；钎涂层耐磨性随WC含量增加而提高，添加15～35 wt.%WC可显著提高基体表面耐磨性，复合钎涂层耐磨性是钢基体的8.4～15.7倍；钎涂层表面未发生明显变化，裂纹开口平整，呈脆性断裂。

Abstract:

Ni/WC composite coating with high wear resistance, corrosion resistance and high hardness characteristics, it is widely used in shield components, raerospace and other fields. In order to improve the service life of hydraulic machinery overflow components, the paper simulated the material of hydraulic turbine blades, WC particles and Ni-based powder brazing filler metals were used to prepare Ni/WC composite brazing coating on the surface of 201 stainless steel by vacuum brazing process. The interface microstructure and mechanical behavior of the brazing coating were resolved with scanning electron microscope, metallographic microscope and rockwell hardness tester. The results show that the diffusion behavior of elements between the coating and substrate are main dissolution of elements Fe, Cr and Mn from the stainless steel into the coating microstructure, and the interface appears segregation precipitation phenomenon. 25wt.% WC coating occurs a uniform hardness distribution, 4.6 times more than steel substrate. The wear resistance of coating increased with the increase of WC content. 15~35 wt.% WC addition can significantly improve the wear resistance of the steel surface. The wear resistance of the coating is 8.4~15.7times that of the steel, the surface of the coating don’t change significantly, and the crack opening is flat and brittle fracture.