SiO_2微球负载BTA缓蚀剂型自修复耐蚀涂层的制备及性能研究

Preparation and Properties of SiO_2 Microspheres Loading with BTA Inhibitor Type Self-healing Corrosion-resistant Coating

目的研究由负载缓蚀剂多孔Si O2微球和7537聚氨酯(PU)所制备的自修复涂层的耐蚀性能和防腐机理。方法利用负压-浸渍法将苯并三氮唑(BTA)负载到Si O2微球中,利用X射线衍射(XRD)、扫描电子显微镜(SEM)、热重分析(TGA)分别对Si O2的形貌与BTA负载含量进行分析检测,并利用划痕浸泡试验、电化学极化曲线及交流阻抗技术,研究Si O2、BTA以及负载有BTA的多孔Si O2微球(Si O2/BTA)对涂层耐蚀性能的影响。结果 SEM图像分析表明Si O2微球粒径约为1μm,热重分析试验表明BTA的负载含量为32.38%(质量分数)。划痕试验表明在浸泡过程中除了PU+Si O2/BTA coating试样外,其他试样的划痕处都出现了宏观腐蚀现象。电化学极化曲线和交流阻抗结果表明PU+Si O2/BTA coating试样始终具有最低的电流密度和较高的阻抗值。结论涂层中的多孔Si O2一方面可以储存BTA,当该涂层产生缺陷时,Si O2中的BTA被释放出来并在基体的缺陷处吸附成膜,从而使该涂层对微观缺陷具有一定的自修复功能;另一方面提高了涂层的致密性;两方面协同作用使PU+Si O2/BTA coating试样具有最好的耐蚀性能和一定的自修复功能。

Objective In order to study the corrosion resistance and anti-corrosion mechanism of the self-healing coating prepared by adding corrosion inhibitors loaded mesoporous Si O2 microspheres into 7537 polyurethane. Methods The benzotriazole（ BTA） was loaded into Si O2 microspheres by negative pressure-impregnation method. The morphology and crystal structure of Si O2 microspheres and loading content of BTA were characterized by scanning electron microscopy（ SEM）,X-ray diffraction（ XRD）and thermogravimetric analysis（ TGA）. The effects of Si O2,BTA,Si O2-BTA addition on the corrosion resistance of the coatings were studied by potentiodynamic polarization curve measurement and electrochemical impedance spectroscopy（ EIS）. Results SEM images showed the size of Si O2 was approximately 1 μm. TGA showed the loading content of BTA was 32. 38 wt%. According to immersion test,corrosion occurred on all kinds of coatings in the progress of immersion except for the PU Si O2/ BTA coating samples. The electrochemical polarization curve and EIS results showed that PU ＋ Si O2/ BTA coating samples always had the lowest current density and relatively high impedance values. Conclusion Porous Si O2 microspheres could store the BTA. When the coatings were damaged,BTA could release,diffuse and absorb on the defect regions,granting this coating a certain self-healing function. In addition,Si O2 microspheres could improve the coating density. Therefore,the addition of BTA loaded porous Si O2 microspheres led to coating with the best corrosion resistance and a certain self-healing function.