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摘要本文以镁合金 AZ31 为实验对象，采用环保型只有水的水热法对其进行处理。利用数码相机、扫描电子显微镜、 X射线衍射仪、能谱仪、接触角测量仪等一系列设备测定 AZ31镁合金在120℃下水热处理2、4、6 小时后的表面颜色、形貌、成分和润湿性的变化。采用电化学工作站分别测量不同时间处理后的 AZ31 镁合金在 0.144molNaCl 和 0.2molPBS溶液中的极化曲线和交流阻抗，进而确定其耐腐蚀性能的改变。结果表明： 经过不同时间的水热处理后， AZ31 镁合金的表面会表现出不同色彩，可以得到绿色、红色及黄铜色等颜色。XRD 和 EDS 的结果表明 AZ31 镁合金经水热处理后表面生成了Mg(OH)2。表面润湿性的结果表明，水热处理后镁合金的亲水性减弱，并且当水热时间为4h时，接触角最大，为 94.75°，呈现疏水特性。极化曲线表明，由于合金表面 Mg(OH)2生成以及溶液中PO43-、Cl-离子的存在，使得镁合金表面的腐蚀变得复杂。交流阻抗结果表明，水热处理能在一定程度上增强镁合金 AZ31 的耐腐蚀性。 48676
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毕业论文关键词 AZ31 镁合金 水热法 形貌 润湿性 耐腐蚀性
Title Morphology and corrosion resistance of magnesium alloy after hydrothermal treatment
Abstract In this paper, we used AZ31 magnesium alloy as experimental subjects, using the only-water hydrothermal treatment for its surface, using digital cameras, scanning electron microscopy, X-ray diffraction and energy dispersive to study the surface morphology changes of AZ31 magnesium alloy after immersed in ultrapure water at 120℃ for different time. Wetting angles were measured by contact angle measuring instrument and Electrochemical Workstation measuring AZ31 magnesium alloy in polarization curves and AC impedance in 0.144mol NaCl and 0.2mol PBS solution after hydrothermal treatment, and then determine the changes of its corrosion resistance. The main results are as follow: The results showed that after the hydrothermal treatment at different times, the surface of AZ31 magnesium alloy can exhibit different colors, such as green, red, brass and other colors. XPS results showed that the surface compositions of AZ31 magnesium alloy after hydrothermal process were mainly Mg(OH)2. The wettability results showed that after 4h hydrothermal treatment, its contact angle of AZ31 magnesium alloy can reach 94.75°, and showed the hydrophobicity. The results of polarization curves showed that since the existence of Mg(OH)2 ,PO43-and Cl- , such corrosion of magnesium alloy surface became complicated. AC impedance results indicated that hydrothermal treatment of magnesium alloy AZ31 can improve its corrosion resistance to some extent.
Keywords AZ31 magnesium alloy hydrothermal method morphology wettability corrosion resistance
目次
1引言1
1.1镁合金的研究进展1
1.1.1镁合金的优点1
1.1.2镁合金的缺点1
1.1.3镁合金的应用2
1.1.4AZ31镁合金3
1.2镁合金的腐蚀特性及防护3
1.2.1镁合金的腐蚀3
1.2.2镁合金的防腐4
1.3镁合金表面微纳结构的构建4
1.3.1刻蚀法4
1.3.2微弧氧化法5
1.3.3电镀法5
1.3.4溶胶凝胶法5
1.3.5水热法5
1.3.6其他方法6
2实验7
2.1实验材料及试剂7
2.2实验主要仪器和设备7
2.3实验方法——只用水的水热法7
2.4实验步骤8
2.5表征方法8
2.5.1形貌表征——SEM8
2.5.2成分检测——XRD、EDS9