HVAF喷涂不同碳化物含量的NiCr-Cr_3C_2涂层研究

The Study of HVAF Sprayed NiCr-Cr_--------3C----_2 Coatings with Different Carbide Contents

本文利用HVAF技术在CrZrCu基体上喷涂制备了NiCr-30%Cr_3C_2涂层和NiCr-50%Cr_3C_2涂层。采用X射线衍射仪和扫描电镜表征涂层物相组成和截面形貌;使用拉伸试验机、维氏硬度计、销盘磨损试验机测量了涂层的结合强度、硬度和摩擦磨损性能。结果显示:含有50%Cr_3C_2的涂层具有更高的硬度和耐磨性,但是由于碳化物含量较多使得涂层内部孔隙率增加,同时结合强度变差。而30%Cr_3C_2涂层具有较低的孔隙率和较高的结合强度。两种喷涂层均以机械结合为主,磨损机制主要为黏着磨损和轻微的氧化磨损。

NiCr-30%Cr3C2and NiCr-50%Cr3C2coatings were deposited on CrZrCu substrate by High Velocity Air-fuel Spraying technique.X-ray diffraction tester and scan electron microscope were used to detect the composition and cross-section morphologies of sprayed coatings.The bond strength,hardness and wear performance of coatings were tested by Tensile tester,Vickers hardness tester and Pin-on-disk tester.The results showed that the coating with50%Cr3C2performs better in hardness and wear resistance but not in porosity and bond strength.This mainly relate to the higher carbide contents caused poor binding state inside the coating.The coating with30%Cr3C2has relatively lower porosity and higher bond strength.But the bonding mechanism of both coatings still kept as mechanical lock and the wear mechanism was composed by adhesive wear and slightly oxidation wear.