表面机械研磨法制备Ni+WC复合涂层的耐磨性研究

Wear Resistance of Ni+WC Composite Coatings Prepared by SMAT

为强化TA1钛合金的组织结构并提高其耐磨损性能,采用行星式机械球磨装置,在Ni与WC 2种粉末配比分别为1∶1、2∶1、3∶1、4∶1及5∶1的5种混合型增强介质下对TA1合金进行表面机械复合强化处理,在0.05 MPa氮气气氛下,设定转速为350 r/min,时间为8 h,对TA1钛合金进行表面机械变形+固相涂层复合强化处理,这种一步法表面复合强化技术具有工艺简单、能耗少、涂层选材灵活等优势。结果显示:TA1钛合金表面形成由Ni+WC涂层+形变细晶区组成的复合强化层,涂层区厚度在40μm以上,其中Ni∶WC为3∶1时所得复合涂层内部缺陷最少,且连续均匀。在5 N、10 N载荷下Ni∶WC为3∶1摩擦系数相较于其他比例低,摩擦区间更加稳定且持续时间更长。2种载荷下磨损量均较TA1原样少,其中Ni∶WC为3∶1的强化样磨痕深度、磨损量均优异于其他4种配比,因此减摩效果最为优异。此种Ni、WC混合增强介质下表层机械复合强化工艺可大幅提升TA1钛合金表层耐磨损性。混合增强颗粒涂层具有较强的减摩效果,其磨损机制主要是磨粒磨损与氧化磨损。

To enhance the microstructure and improve the wear resistance of TA1 titanium alloy,a planetary mechanical ball milling device was used to perform surface mechanical composite reinforcement treatment on TA1 alloy using five types of mixed reinforcing media with Ni and WC powder ratios of 1∶1,2∶1,3∶1,4∶1,and 5∶1,respectively.The treatment was carried out at the nitrogen atmosphere of 0.05 MPa,and the rotating speed was set at 350 r/min for 8 h.The one-step surface composite strengthening technology of surface mechanical deformation and solid-state coating composite strengthening treatment on TA1 titanium alloy had advantages such as simple process,low energy consumption and flexibility in coating material selection.Results showed that a composite reinforcement layer consisting of Ni+WC coating and a deformation fine-grained zone was formed on the surface of the TA1 titanium alloy.The thickness of the coating zone was approximately 40μm or more.The composite coating,obtained when the Ni∶WC ratio was 3∶1,was observed to exhibit the fewest internal defects and was continuous and uniform.Under the applied loads of 5 N and 10 N,the friction coefficient for the Ni∶WC ratio of 3∶1 was lower.The friction range was more stable and the duration was longer.The reinforced samples exhibited a lower wear amount under both load conditions compared to the original TA1 sample.Specifically,the strengthened samples with a Ni∶WC ratio of 3∶1 demonstrated superior wear depth and wear amount compared to the other four ratios,hence exhibiting the most outstanding wear reduction effect.The surface mechanical composite strengthening process under this Ni and WC mixed reinforcement medium significantly enhanced the wear resistance of the TA1 titanium alloy surface.The mixed reinforced particle coating exhibited a strong friction-reducing effect,with its wear mechanism primarily being abrasive wear and oxidative wear.