蓖麻油对AZ91镁合金环氧有机涂层防腐性能的提升作用研究

Influence of castor oil on the corrosion resistance of epoxy coating on AZ91 magnesium alloy

以环氧树脂为胶粘剂,以聚酰胺为固化剂,采用化学浸渍法在AZ91镁合金表面制备了环氧有机涂层,在制备过程中添加不同含量的蓖麻油,采用扫描电子显微镜(SEM)、X射线衍射仪(XRD)和红外光谱(FT-IR)等手段表征了复合有机涂层的组成及微观结构,并用电化学极化曲线及电化学阻抗谱考察了蓖麻油的添加对环氧有机涂层防腐性能的影响。结果表明:环氧有机涂层具有一定的抗腐蚀性能,在制备有机涂层前,对镁合金基底进行磷酸盐转化,可以提高有机涂层与基底的结合力;适量蓖麻油的添加可大大提高复合涂层的防腐能力,当蓖麻油加入量为3%时,得到的复合涂层防腐性能最佳,其腐蚀电位可以达到-0.823V,比未添加时提升了374mV。

The epoxy organic coating was prepared by chemical immersion method on the surface of AZ91 magnesium alloy with the epoxy resin as adhesive and polyamide as curing agent.And the different concentration castor oil was added in the preparation process.The microstructure and composition of complex organic coating were characterized using scanning electron microscopy（SEM）,X-ray diffraction（XRD）and infrared spectroscopy（FT-IR）,and the influence of castor oil on the performance of coating was investigated by the electrochemical polarization curve and the electrochemical impedance spectroscopy.The results showed that the coating had the corrosion resistance and the conversion of phosphate before the preparation of organic coating can improve the adhesion of coating and the magnesium alloy substrate.A certain amount of castor oil can greatly improve the corrosion resistance of coating and the best corrosion resistance appeared when the amount of castor oil was 3%,the corrosion potential can reach-0.823 V,the increasing was 374 mV more than that without castor oil.