缓蚀剂对镁合金在氯化钠溶液中腐蚀行为影响研究

发布时间：2018-01-18 14:09

本文关键词：缓蚀剂对镁合金在氯化钠溶液中腐蚀行为影响研究　出处：《太原理工大学》2017年硕士论文　论文类型：学位论文

更多相关文章： AZ31B镁合金 缓蚀剂 腐蚀 电化学测试

【摘要】：镁合金由于其质量轻、比强度/比刚度高、良好的压铸性等优点而得到广泛应用,现已成为一种重要的工程结构材料。但是,镁合金高的化学活性和差的耐蚀性,严重制约其优势在工业领域的发挥。在众多的抑制镁合金腐蚀的措施中,缓蚀剂防腐蚀技术是一种非常经济、有效的方法。因此,本文采用电化学测试、浸泡失重测试及扫描电子显微镜、傅里叶变换红外光谱等表面分析技术,研究了所选单组份缓蚀剂及复配型缓蚀剂对AZ31B镁合金在3.5 wt.%NaCl溶液中的缓蚀行为及缓蚀机理,主要研究结果如下:(1)单独使用二乙基二硫代氨基甲酸钠(SDDTC)、乙酸钠(NaAc)和磷酸氢二钠(Na_2HPO_4)时,均可有效延缓AZ31B镁合金在NaCl溶液中的腐蚀速度。随着缓蚀剂浓度的增加,缓蚀效率均呈现先增大后减小的趋势,它们单独使用时达到的最佳缓蚀效率及添加的浓度分别为:添加5.0×10~(-3)mol L~(-1) SDDTC时,缓蚀效率为69%;添加0.20mol L~(-1) NaAc时,缓蚀效率为80%;添加3.0×10~(-3)mol L~(-1) Na_2HPO_4时,缓蚀效率为92.9%。(2)当SDDTC与NaAc复配使用时,在特定的浓度下,二者会产生协同作用;当浓度为10.0×10~(-3)mol L~(-1) SDDTC+0.15mol L~(-1) NaAc时,缓蚀效率最高为90.4%。SDDTC与NaAc均符合Langmuir吸附模型,均在镁合金表面发生物理吸附,形成了一层致密的保护性混合膜:SDDTC-Mg+NaAcMg+Mg(OH)_2。(3)SDDTC与Na_2HPO_4共同使用时,缓蚀效率明显增大,当浓度为2.0×10~(-3)mol L~(-1) Na_2HPO_4+10.0×10~(-3)mol L~(-1) SDDTC时,缓蚀效率最高,达到了94%。两种缓蚀剂复配时,在镁合金表面形成一层非常致密的保护膜,提高了缓蚀效率,明显抑制了镁合金的腐蚀。
[Abstract]:Magnesium alloy has been widely used because of its light weight, high specific strength / specific stiffness, good die-casting properties, and has become an important engineering structural material. Magnesium alloys have high chemical activity and poor corrosion resistance, which seriously restrict their advantages in the industrial field. Corrosion inhibitor corrosion prevention technology is very economical among many measures to inhibit magnesium alloy corrosion. Therefore, surface analysis techniques such as electrochemical test, immersion weightlessness test, scanning electron microscope and Fourier transform infrared spectroscopy were used in this paper. The corrosion inhibition behavior and corrosion inhibition mechanism of AZ31B magnesium alloy in 3.5 wt.%NaCl solution were studied. The main results are as follows: (1) when the sodium diethyldithiocarbamate (SDDTCX), sodium acetate (NAAC) and disodium hydrogen phosphate (Na2HPO4) are used alone. The corrosion rate of AZ31B magnesium alloy in NaCl solution can be effectively delayed. With the increase of inhibitor concentration, the corrosion inhibition efficiency increases first and then decreases. The optimum corrosion inhibition efficiency and the added concentration are: 5.0 脳 10 ~ (-3) mol / L ~ (-1) SDDTC. The corrosion inhibition efficiency was 80 when 0.20mol / L ~ (-1) NaAc was added. When 3.0 脳 10 ~ (-3) mol / L ~ (-1) Na_2HPO_4 was added, the corrosion inhibition efficiency was 92.9%.) when SDDTC was combined with NaAc, the corrosion inhibition efficiency was 92.9%. At certain concentration, the two have synergistic effect. When the concentration was 10.0 脳 10 ~ (-1) mol / L ~ (-1) SDDTC, 0.15mol / L ~ (-1) NaAc. The highest corrosion inhibition efficiency is 90.4. SDDTC and NaAc accord with the Langmuir adsorption model, and physical adsorption occurs on the surface of magnesium alloy. A dense protective mixture membrane: SDDTC-Mg NaAcMg Mg(OH)_2.(3)SDDTC was formed when it was used together with Na_2HPO_4. The corrosion inhibition efficiency is obviously increased. When the concentration was 2.0 脳 10 ~ (-3) mol / L ~ (-1) Na_2HPO_4, the concentration was 10.0 脳 10 ~ (-3) mol / L ~ (-1) SDDTC. When the two inhibitors are mixed, a very dense protective film is formed on the surface of magnesium alloy, which improves the corrosion inhibition efficiency and obviously inhibits the corrosion of magnesium alloy.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG174.42

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