镁合金表面陶化膜的制备及耐蚀性研究  

Preparation of Ceramic Conversion Coatings on AZ80 Magnesium Alloy and Its Corrosion Resistance

作　　者：杨天园 宋影伟[1] 董凯辉 陈荣石[1] 韩恩厚[1] YANG Tian-yuan;SONG Ying-wei;DONG Kai-hui;CHEN Rong-shi;HAN En-hou(Key Laboratory for Nuclear Materials and Safety Evaluation,Institute of Metals Research,Chinese Academy of Sciences,Shenyang 110016,China;College of Materials Science and Engineering,University of Science and Technology of China,Hefei 230026,China)

机构地区：[1]中国科学院金属研究所核用材料与安全评价重点实验室,沈阳110016 [2]中国科学技术大学材料科学与工程学院,合肥230026

出　　处：《表面技术》2021年第8期318-326,共9页Surface Technology

基　　金：国家重点研发计划(2016YFB0301105);国家自然科学基金项目(51671199)。

摘　　要：目的通过在Zr-Ti基础成膜液中添加适宜的氧化剂,获得均匀致密的陶化膜,提高膜层对AZ80镁合金的保护性。方法通过盐雾试验和SEM观察的结果,筛选出最佳的成膜液体系。通过测试陶化膜在3.5%NaCl溶液中的极化曲线,选出最佳的成膜液pH和成膜时间。利用XRD和XPS对膜层物相组成进行分析。通过盐雾和电化学试验对膜层的耐蚀性进行表征。结果当基础成膜液中添加氧化剂KMnO_(4)和NH_(4)VO_(3)的质量浓度比为3∶1、转化液pH为2.5、成膜时间为3.5 min时,制备出的陶化膜均匀、致密,膜层主要由ZrO_(2)、TiO_(2)、MgO、MgF_(2)、V_(2)O_(3)组成。氧化剂的添加抑制了析出相上过快析氢反应对成膜的不良影响,实现了膜层的均匀沉积。陶化膜将AZ80镁合金的耐中性盐雾时间从4 h提高到48 h。结论添加适宜氧化剂的Zr-Ti系陶化膜可以显著提高AZ80镁合金的耐蚀性。This work aims to obtain a uniform and dense ceramic conversion coating by adding a suitable oxidant to the Zr-Ti basic coating-forming solution and improve the corrosion resistance of AZ80 magnesium alloy.The optimal bath solution was obtained based on the results of salt spray tests and SEM observation;the optimal pH and treatment time were selected according to the polarization curves of the ceramic conversion coating in 3.5%NaCl solution;XRD and XPS were used to analyze the chemical composition of the coating;the corrosion resistance was characterized by salt spray and electrochemical tests.When the mass concentration ratio of the oxidants of KMnO_(4) and NH_(4)VO_(3) in the basic bath solution was 3∶1,the pH of the bath solution was 2.5,the treatment time was 3.5 min,and the coating was uniform and dense,which was mainly composed of ZrO_(2),TiO_(2),MgO,MgF_(2) and V_(2)O_(3).The addition of the oxidants can suppress the adverse effect of the excessively fast hydrogen evolution reaction on the precipitation phases during the coating formation process,and realize the uniform deposition of the coating.The ceramic conversion coating increasess the salt spray resistance time of AZ80 magnesium alloy from 4 h to 48 h.The Zr-Ti ceramic conversion coating with suitable oxidants can significantly improve the corrosion resistance of AZ80 magnesium alloy.

关 键 词：镁合金 陶化膜 氧化剂 耐蚀性 锆/钛酸 

分 类 号：TG174.4[金属学及工艺—金属表面处理]