Microstructure and Corrosion Resistance of Ni60 Alloy Overlay Deposited by PTA Method on Water Guide Bearing
DENG De-wei1,2,3, NIU Ting-ting1, TIAN Xin2, LIU Hai-ying1, SUN Qi2, ZHANG Lin2
1. School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, Liaoning, China;
2. R&D Division of Shenyang Blower Works Group Corporation, Shenyang 110869, China;
3. Key Laboratory of Solidification Control and Digital Preparation Technology (Liaoning Province), Dalian 116024, Liaoning, China
Abstract：The Ni60 overlay was deposited on Z2CN18-10 stainless steel substrate by plasma transferred arc (PTA) method, and the microstructure, hardness and corrosion resistance of Ni60 overlay were investigated. The results show that the overlay mainly consists of Ni-rich γ solid solution (γ-Ni), borides and carbides, and γ-Ni and borides eutectic structure. The overlay from the top to bottom shows different phase fractions, and the amount of chrysanthemum-like structure in the middle is large. The hardness of Ni60 overlay is around 500HV, which is higher than that of Z2CN18-10 stainless steel. The hardness increase is attributed to the chrysanthemum-like eutectic structure. In the borate, Ni60 exhibits higher passivation ability than that in seawater, and the corrosion potential of Ni60 alloy is similar to Z2CN18-10 stainless steel. In simulated seawater, the corrosion resistance of overlay in the middle is more superior than that in the bottom and top. Due to the large difference of corrosion potential in seawater, the galvanic corrosion is prone to occur between Ni60 overlay and Z2CN18-10 stainless steel.
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