TA1纯钛表面镍基喷焊层的组织和磨损性能

Microstructures and Wear Behavior of Ni-based Spray-welding Coating on Pure Titanium TA1 Substrate

利用等离子喷焊技术在TA1纯钛表面制备了镍基耐磨喷焊层,研究了喷焊层结构、显微组织和显微硬度以及摩擦磨损性能。结果表明:喷焊层由过渡层和强化层组成,焊层与基体间形成了基于原子扩散的冶金结合界面及以树枝晶为主的过渡层。喷焊层的组织主要由γ-Ni固溶体,γ-Ni(Ti)固溶体以及TiC、Cr_7C_3、Ni_3B和TiB_2等硬质相组成。强化层为韧Ni基体+硬质相耐磨组织,硬度(HV_(0.5))在8300~9070 MPa之间,较基体高出7000 MPa。喷焊层主要合金元素的扩散、显微组织变化及显微硬度沿层深方向的分布具有连续性和渐变性。与基材TA1对比试验表明,喷焊镍基合金后摩擦系数降低,耐磨性明显提高,喷焊层磨损面呈轻微的磨粒磨损特征。

The Ni-based wear resistance coating on pure titanium TA1 substrate was prepared by plasma spray-welding process. The interface morphology, the microstructure, the microhardness of the coating and its tribological behavior were studied. The results show that the coating is composed of transition layer and strengthening layer, and a metallurgical bonding interface based on atomic diffusion and a transition layer mainly composed of dentrite are formed between the coating and substrate. The phases of the coating are mainly composed of γ-Ni and γ-Ni（Ti） and hard particles such as TiC , Cr7C3, Ni3B and TiB2. Strengthening layer is characterized by a wear resistance microstructure composed of a tough Ni matrix and hard particles. The surficial micro-hardness is between 8300~9070 MPa, which is 7000 MPa higher than that of the substrate. The element distribution, the microstructure, and the micro-hardness of the spray-welding coating in the cross section change continuously and gradually along depth direction. Compared with TA1 substrate, the friction coefficient of Ni-based spray-welding coating is decreased, the wear resistance is obviously enhanced and spray-welding coating presents a slightly abrasive wear characteristics.