热处理对纯Mg表面纳米TiO_2涂层耐蚀性的影响

摘要

Nanometer TiO2,prepared by sol-gel technique using titanium tetrachloride and ammonia water as raw materials,was coated on pure magnesium by the method of dip-coating,followed by heat treatment at 100,300,500℃ for 2h,respectively.The phases and microstructure of the coated-TiO2 magnesium at different heat treatment temperatures were characterized using XRD,TG/DSC,FT-IR,FE-SEM.Electrochemical polarization tests were performed to investigate the effect of heat treatment temperature on the corrosion resistance of coated-TiO2 pure magnesium.The results show that TiO2 coating can improve the corrosion resistance of pure magnesium,that 100℃-treated TiO2 coating with the corrosion current density of 4.5×10-3mA/cm2,compared with a much higher 3.256mA/cm2 of pure magnesium,has the optimal anti-corrosion among the experiment coated-TiO2 samples,and that the corrosion resistance decreases with the increased heat treatment temperatures.Also,the anti-corrosion mechanism of TiO2 coating was discussed.%以四氯化钛为原料,制备纳米TiO2溶胶,再采用浸渍-提拉法在纯Mg表面制得TiO2薄膜,随后涂有TiO2的纯Mg分别在100、300、500℃下热处理2h。采用XRD、DSC/TG、FT-IR、FE-SEM表征不同热处理条件下试样的组成和结构;通过动电位极化表征试样的耐蚀性,考察温度对TiO2涂层纯Mg试样耐蚀性的影响。结果表明TiO2涂层可提高纯Mg的耐蚀性;100℃热处理试样具有最优的耐蚀性,其腐蚀电流密度为4.5×10-3 mA/cm2,较纯Mg的3.256mA/cm2明显下降;随着温度的升高,试样