WC硬质合金表面涂层摩擦磨损特性及其铣削性能研究

Study on Friction and Wear Characteristics of Coating on Surface of WC Cemented Carbide and Its Milling Performance

为了研究WC硬质合金表面氮化物涂层的摩擦磨损特性及其对刀具铣削性能的影响,采用物理气相沉积法(PVD)在WC硬质合金表面分别沉积了TiN、CrN和TiAlN 3种氮化物涂层。利用扫描电镜(SEM)、X射线衍射仪(XRD)、摩擦磨损试验机分析了WC硬质合金及3种氮化物涂层的组织和摩擦磨损性能。以45钢为被铣削材料,研究了WC硬质合金及3种氮化物涂层刀具的铣削性能。结果表明:氮化物涂层能有效提高WC硬质合金的表面硬度和耐磨性能,3种氮化物涂层中,TiAlN涂层的硬度最高,相比WC基体提高了26.5%,TiAlN涂层能显著提高WC硬质合金的耐磨性能,其磨损特征为较小的磨粒磨损和轻微氧化磨损。TiAlN涂层的高硬度和高耐磨性能更有利于铣削45钢,铣削过程中产生的氧化膜易覆盖在刀尖表面,起到保护刀具表面的作用,进而显著提高刀具的铣削性能。同时相比其他涂层,TiAlN涂层刀具后刀面的磨屑的黏附少,表现出较强的排屑能力,这对于提高刀具的铣削性能具有重要意义。

In order to investigate the friction and wear characteristics of nitride coatings on surface of WC cemented carbide and their effect on tool milling performance,TiN,CrN and TiAlN nitride coatings were deposited on surface of WC cemented carbide by physical vapor deposition(PVD).The microstructure and friction and wear properties of WC cemented carbide substrate and three nitride coatings were analyzed by means of scanning electron microscope(SEM),X-ray diffraction(XRD)and friction and wear tester.The milling performance of WC cemen-ted carbide and three nitride coated cutting tools was studied by using 45 steel as the milling material.Results showed that the nitride coating could effectively improve the surface hardness and wear resistance of WC cemented carbide substrate.Among the three nitride coatings,TiAlN coating had the highest hardness,which was 26.5%higher than that of WC substrate,and significantly improved the wear resistance of WC ce-mented carbide.The wear characteristics of TiAlN coating were small abrasive wear and slight oxidation wear.The high hardness and high wear resistance of TiAlN coating were more conducive to milling 45 steel.The oxide film generated in the milling process was easy to cover the sur-face of the tool tip,playing a significant role in protecting the tool surface and further improving the milling performance of the tool.Compared with other coatings,TiAlN coated tools had less chip adhesion on the back face of the tool,and showed strong chip removal ability,which was of great significance to improve the milling performance of the tool.