LDH型MoO_4^(2-)缓蚀剂的合成及防腐性能

Synthesis of Molybdate Inhibitor Based on Intercalated Layered Double Hydroxide(LDH) and Its Anticorrosive Properties

采用共沉淀法制备了镁铝氢氧化物为层板、MoO24-柱撑的LDH型MoO24-缓蚀剂(记为MoO24-LDH),利用XRD和Raman光谱对样品进行表征。通过缓释实验,讨论了LDH型缓蚀剂的释放能力以及缓蚀剂的缓蚀机理。SEM-EDS、ICP、N2吸附脱附和极化曲线测试结果表明,合成的LDH型MoO24-缓蚀剂具有很好的离子交换和吸附Cl-的性能,释放出MoO24-缓蚀剂进入电解液,24 h内对镁合金的腐蚀电流保持在9.129μA/cm2,减缓了镁合金腐蚀。添加质量分数20%MoO24-LDH颜料的环氧涂层在质量分数3.5%NaCl溶液中的EIS测试体现出较好的耐蚀作用,耐盐雾腐蚀187 h以上。

Mg-Al layered double hydroxide （LDH） loaded with molybdate anions were synthesized via coprecipitation method. The resulting compounds were characterized respectively by means of X-ray diffraction（ XRD ） and Raman spectra. The properties of the release of inhibitor and the inhibition mechanism were observed and analyzed by slow-release experiment. The SEM - EDS, ICP and N2 adsorption-desorption measurements demonstrated the excellent anion-exchange and adsorption capabilities for chloride ion. Polarization curves measurements showed that the filtrate as electrolyte exhibited a lower corrosion current density value due to the presence of MoO42-. The results indicate that the released inhibitor can provide adequate corrosion protection, maintaining a corrosion current density at approximately 9. 129 μA/cm2 for magnesium alloy within 24 h. The coatings containing 20% MOO24-LDH pigment keep excellent corrosion resistance by electrochemical impedance spectroscopy （EIS） during immersion in 3.5% NaCl solution with more than 187 hours of exposure to salt spray test.