发动机气缸电喷镀镍磷合金镀层及耐腐蚀性能  

Anti-corrosion properties of Ni-P alloy coated on engine cylinder prepared from jet electrodeposion

作　　者：王颖[1] 康敏[1,2] 傅秀清[1] 王兴盛[1] 

机构地区：[1]南京农业大学工学院,南京210031 [2]江苏省智能化农业装备重点实验室,南京210031

出　　处：《农业工程学报》2014年第15期54-61,共8页Transactions of the Chinese Society of Agricultural Engineering

基　　金：江苏省普通高校研究生科研创新计划资助项目(CXZZ12_0271);南京农业大学工学院引进人才科研启动基金项目(Rcqd11-05)

摘　　要：为提高发动机气缸的耐久性,该文采用喷射电沉积法在发动机气缸上制备Ni-P合金镀层,并用电化学极化曲线方法和交流阻抗技术对比研究镀有Ni-P合金的发动机气缸在50 g/L的NaCl溶液中不同时刻的腐蚀规律和腐蚀机理。结果表明,随着浸泡时间的增加,原始氧化膜减薄,膜层下的Ni-P合金暴露在溶液中产生活性溶解,随后电极表面有腐蚀产物聚集,阻碍腐蚀的进行;腐蚀过程由活化控制转变为镀层和腐蚀产物内的扩散控制;电喷镀所得Ni-P镀层在NaCl溶液中的耐腐蚀性能约是传统电沉积的5倍左右,发动机气缸电喷镀Ni-P合金镀层后具有良好的耐蚀性。研究结果可为进一步提高镍磷镀层的耐腐蚀性能提供参考。Cylinder is the important part of tractor engine, which service life and the production cost are directly affected by anti-corrosion of the component. With the excellent wear resistance, corrosion resistance and higher hardness, Ni-P alloy deposited layer plays an important role for enhance the service life and reliability of cylinder, and the capability and quality of the tractor engine can be improved. Because of severe working environment of cylinder and piston such as high temperature, high load, high-velocity motion, poor lubrication, difficult cooling, especially weak acid for work environment, it is advisable to study the anti-corrosion properties of Ni-P alloy coated on engine cylinder. However, with the advancement of social economy, the conventional method for electrodeposited Ni-P alloy fails to meet the requirements of the development due to lower depositing rate and lower production efficiency. The jet electrodeposition is developed in recent years, which can significant increase the production efficiency because jet electrolyte can accelerate transfer process of the electrodeposition material and augment limiting current density. So the jet electrodeposition is a kind of high-velocity, selective electrodeposition technique with high deposition current density. In this paper, the engine cylinder coated with Ni-P alloy with jet electrodeposition was taken as research object. The surface appearance of deposited layer was observed by 6XB-PC reflective optical microscope. The corrosion behavior of Ni-P alloy coated on cylinder in 50 g/L NaCl solutions at different moment was studied by electrochemical impedance spectroscopy and potentiodynamic polarization method. The results show that the coating surface appearance is dense and smooth. Electrochemical impedance spectroscopy is composed of high and low frequency arcs when the layer immersed in 50 g/L NaCl solutions with 0.5, 1, 6, 12 and 24 h. The high frequency arcs have relation with original oxidation film, and the low frequency arcs have relation wit

关 键 词：发动机 耐腐蚀性 交流阻抗谱 极化曲线 电喷镀 

分 类 号：S232[农业科学—农业机械化工程] TQ153.2[农业科学—农业工程]