预处理对阴极等离子电解沉积制备Al_2O_3涂层性能的影响  

Effects of Pretreatment on Properties of Al_2O_3 Coating by Cathode Plasma Electrolytic Deposition

作　　者：王林秀 王德仁[1] 李文超 李文凯 WANG Lin-xiu;WANG De-ren;LI Wen-chao;LI Wen-kai(Beijing Key Laboratory for Corrosion-Erosion and Surface Technology, University of Science and Technology Beijing, Beijing 100083;Ford Motor Research ＆ Engineering （Nanjing） Co., Ltd., Nanjing 211106)

机构地区：[1]北京科技大学北京市腐蚀磨蚀与表面技术重点实验室,北京100083 [2]福特汽车工程研究(南京)有限公司,南京211106

出　　处：《中国表面工程》2017年第6期75-83,共9页China Surface Engineering

摘　　要：采用阴极等离子电解沉积法在镍基高温合金K418上制备Al_2O_3陶瓷层,为降低沉积过程中的电流密度,研究了950℃预处理对涂层微观组织、物相组成、力学性能及沉积过程中电流密度-电压曲线的影响。结果表明:预处理对涂层的表面、截面形貌和物相组成没有明显影响。当预处理时间延长至300 min,涂层抗超声振荡性能和抗热冲击性能分别提高了106.36%和90.13%。拉伸法测定涂层结合强度结果显示,经950℃预处理30 min的试样结合力可由未经预处理时的24.60 MPa提高至37.32 MPa。这些特性主要归因于预制氧化膜使合金基体表面导电性下降,有效地将电流密度-电压曲线第一个峰值由未经预处理的1.84 A/cm^2降至0.26 A/cm^2,同时氧化膜的存在为后续等离子放弧均匀化提供基础,从而提高了涂层与基体之间的结合力。The Al2O3 coatings were prepared by cathode plasma electrolytic deposition （CPED） on cast nickel-based superalloy K418. In order to reduce the current density in the deposition process, the effects of pretreatment at 950 % on the coating structure, phase, properties and the current density-voltage curves were studied. The results show that pretreatment has no obvious effects on the surface, cross section morphologies or phase structure of the coating. When the pretreatment time is prolonged to 300 minutes, the anti-ultrasonic and anti-thermal shock properties of the coating are improved by 106.36% and 90.13%, respectively. The tensile strength of the Al2O3 coating sample increases from 24.60 to 37.32 MPa after pretreatment at 950℃ for 30 minutes. The beneficial property improvement can be attributed to the decrease of the surface conductivity of the sample. The existence of the film can provide the basis for the subsequent uniform plasma discharge, which has reduced the first peak data of the current density-voltage curve from 1.84 A/cm~ to 0.26 A/cm~.

关 键 词：阴极等离子电解沉积 氧化铝涂层 预处理 结合强度 

分 类 号：TG174.444[金属学及工艺—金属表面处理]