镀锌钢表面硅烷掺杂电泳漆涂层的腐蚀电化学行为研究

将γ-(2,3环氧丙氧) 丙基三甲氧基硅烷 (GPTMS) 掺杂到不含颜料的水性环氧树脂中,通过一步电泳法在镀锌钢表面构建得到硅烷掺杂的电泳漆涂层。采用电化学阻抗谱和扫描电化学显微镜技术研究了涂层体系的防护性能,并结合其它手段开展了机理研究。结果表明,有机硅烷的加入能够显著提高环氧电泳漆涂层在腐蚀介质中的防护性能,硅烷掺杂抑制环氧涂层的吸水和溶胀。提出了硅烷掺杂电泳漆涂层的如下防护机理：一方面,GPTMS的掺杂增加了涂层的交联程度;另一方面,电泳过程中促进GPTMS组分在金属与涂层界面的优先沉积形成富集层,从而提高了基体与涂层间的结合力。

Electrochemical Investigation of Corrosion Performance of Electrophoretic Hybrid Epoxy-silane Coatings on Galvanized Steel

γ-glycidoxypropyltrimethoxysilane (GPTMS) was doped into pigment-free waterborne epoxy to prepare silane-incorporated coatings on galvanized steel by electrophoresis. The corrosion performance of the prepared coatings was then studied by means of electrochemical impedance spectroscopy and scanning electrchemical microscopy. Results showed that the addition of organosilane significantly improves the corrosion performance of electrophoretic epoxy coatings in corrosive medium. Silane incorporation suppresses the water absorption and inhibits the swelling of epoxy coating. The corrosion protection mechanism was proposed. On one hand, the addition of GPTMS improves the cross-linking degree of the coating; and on the other hand, GPTMS-enriched layer which was preferentially formed at the metal/coating interface during the electrophoresis process results in better adhesion between the substrate and the coating.