Preparation and corrosion resistance of electroless Ni-P/SiC functionally gradient coatings on AZ91D magnesium alloy
Preparation and corrosion resistance of electroless Ni-P/SiC functionally gradient coatings on AZ91D magnesium alloy
复制标题
AZ91D镁合金化学镀Ni-P/SiC功能梯度涂层的制备及其耐蚀性能
DOI：
10.1016/j.apsusc.2013.09.079
复制
发表时间：
2013-12-01
影响因子：
6.7
通讯作者：
Jiang, Wen-Feng
中科院分区：
文献类型：
--
作者：
Wang, Hui-Long;Liu, Ling-Yun;Jiang, Wen-Feng
本文在AZ91D镁合金基体上成功制备了化学镀Ni-P/SiC梯度保护涂层。对所制备的Ni-P/SiC梯度涂层的微观结构、形貌、显微硬度和对基体的附着力进行了表征。研究了沉积反应动力学，并建立了 AZ91D 镁合金化学镀 Ni-P/SiC 的经验速率方程。通过动电位极化和电化学阻抗谱 (EIS) 研究评估了 Ni-P/SiC 梯度涂层在 3.5 wt.% NaCl 溶液中的防腐性能。动电位极化测量表明，镀液中的 SiC 浓度和热处理会影响化学镀 Ni-P/SiC 梯度涂层的防腐性能。 EIS 研究表明，与 Ni-P 涂层相比，Ni-P/SiC 梯度涂层具有更高的电荷转移电阻和略低的电容值。随着腐蚀性介质中浸泡时间的持续增加，Ni-P/SiC梯度涂层的耐腐蚀性能先增加后降低。与Ni-P涂层相比，化学镀Ni-P/SiC梯度涂层能够为镁合金基体提供更好的腐蚀防护。 (C) 2013 Elsevier B.V. 保留所有权利。
In this paper, the protective electroless Ni-P/SiC gradient coatings on AZ91D magnesium alloy substrate were successfully prepared. The prepared Ni-P/SiC gradient coatings were characterized for its microstructure, morphology, microhardness and adhesion to the substrate. The deposition reaction kinetics was investigated and an empirical rate equation for electroless Ni-P/SiC plating on AZ91D magnesium alloy was developed. The anticorrosion properties of the Ni-P/SiC gradient coatings in 3.5 wt.% NaCl solution were evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) studies. The potentiodynamic polarization measurements revealed that the SiC concentration in the bath and heat treatment can influence the corrosion protection performance of electroless deposited Ni-P/SiC gradient coatings. EIS studies indicated that higher charge transfer resistance and slightly lower capacitance values were obtained for Ni-P/SiC gradient coatings compared to Ni-P coatings. The corrosion resistance of the Ni-P/SiC gradient coatings increases initially and decreases afterwards with the sustained increasing of immersion time in the aggressive medium. The electroless Ni-P/SiC gradient coatings can afford better corrosion protection for magnesium alloy substrate compared with Ni-P coatings. (C) 2013 Elsevier B.V. All rights reserved.