摘要
镁合金表面溶胶凝胶涂层存在易析出氢气、涂层缺陷多及防腐性能提升不明显等问题。为改善这些问题利用Ce(NO_3)_3催化制得SiO_2-ZrO_2溶胶并旋涂3层于AZ91D镁合金表面,并与HCl催化制得的镁合金表面SiO_2-ZrO_2溶胶涂层进行对比分析。采用扫描电镜和傅里叶红外光谱等分析涂层微观形貌和化学成分;通过接触角测试涂层亲疏水性;利用极化曲线和电化学阻抗谱对比研究不同催化剂加入的溶胶凝胶层在3.5%NaCl溶液中的耐腐蚀性能。结果显示:与HCl催化制得的镁合金表面SiO_2-ZrO_2溶胶涂层相比,Ce(NO_3)_3催化制得的涂层表面微观缺陷少;接触角由84.2°增大到93.5°;同镁合金基体自腐蚀电流密度1.480×10^(-4) A/cm^2相比,HCl催化和Ce(NO_3)_3催化涂层的自腐蚀电流密度分别为2.562×10^(-6) A/cm^2和7.821×10^(-7) A/cm^2,其耐蚀性提升明显;HCl和Ce(NO_3)_3催化涂层阻抗极化电阻值由镁合金基材的224.9Ω分别增大至4 401Ω和53 888Ω,HCl催化涂层的失效时间为1 d,Ce(NO_3)_3催化涂层失效时间延长为3 d。可见,两种催化剂制备的涂层,Ce(NO_3)_3催化涂层防护更持久,耐蚀性更好。
The sol-gel layers on magnesium alloy can easily evolute a great amount of hydrogen, produce much film defects and perform poor corrosion resistance. In order to solve the problems, SiO2-ZrO2 sol-gel was catalyzed by Ce（NO3）3 and spined on the surface of AZ91D magnesium alloy with three layers and compared with the layers catalyzed by HCl. The surface morphology, functional group were studied by scanning electron microscope （SEM） and Fourier transform infrared spectroscopy （FT-IR）, respectively. Hydrophilicity of layers were analyzed by contact angle （CA）. The protective performance of layers with different catalysts in 3.5% NaCl solution was investigated by polarization curves and electrochemical impedance spectroscopy. The results show that the layers catalyzed by Ce（NO3）3 have less micro defects than the layers catalyzed by HCl, and the contact angel of the layers catalyzed by Ce（NO3）3 （93.5°） is higher than the layers catalyzed by HCl （84.2°）. Compared with the corrosion current density of magnesium alloy （1.480×10-4 A/cm2）, the layers catalyzed by HCl （2.562×10-6 A/cm2） and Ce（NO3）3 （7.821×10-7 A/cm2） perform better corrosion resistance. The layers catalyzed by HCl and Ce（NO3）3 have electrochemical impedance modulus of 4 401 Ω and 53 888 Ω, respectively, which is higher than that of magnesium alloy （224.9 Ω）. The failure time of the layers catalyzed by Ce（NO3）3 and HCl is 3 d and 1 d, respectively. Therefore, the layers catalyzed by Ce（NO3）3 perform better corrosion behavior and have more durable failure time than the layers catalyzed by HCl.
作者
郭亚鑫
华帅
陶庆爽
范爱兰
唐宾
GUO Ya-xin HUA Shuai TAO Qing-shuang FAN Ai-lan TANG Bin(School of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 03002)
出处
《中国表面工程》
EI
CAS
CSCD
北大核心
2016年第6期99-106,共8页
China Surface Engineering
基金
国家自然科学基金(51671140
51474154)
山西省研究生教育改革项目(2015JG42)
