富镍导电涂层在模拟海水中的耐蚀性能研究

Anti-corrosion Performance of Nickel-rich Conductive Coatings in Simulated Seawater

在高黏度的丙烯酸树脂中加入镍粉、消泡剂及其它助剂制备出具有导电功能的防腐涂料并涂覆在作为船舶材料的20#碳钢上。通过测试涂层的表面接触电阻来表征涂层的导电性,研究发现镍粉含量越高,涂层的导电性越好。用电化学阻抗谱研究了不同镍粉含量的导电涂层在模拟海水中的耐蚀性,并用扫描电镜(SEM)观察了浸泡90 d后涂层的表面形貌。结果表明,随浸泡时间的延长,镍粉的含量越高,涂层的容抗弧、阻抗、相位角、|Z|0.05越小;且下降的越快;从Tafel极化曲线可知,镍粉含量越高,涂层的腐蚀电流越大;从涂层表面的SEM像可知,镍粉含量越高,涂层表面腐蚀越严重。在所研究的体系中,镍粉的含量约在20%(质量分数)时,具有较好的导电性能和耐蚀性能。

Conductive anticorrosion coatings were prepared with high viscosity acrylic resin as ma- trix, Ni- powder and defoamer etc. as additives, and then applied on 20# carbon steel. The electrical con- ductivity and the anti-corrosion performance in simulated seawater of the coatings with different Ni-pow- der content were characterized by means of surface contact resistance measurement, electrochemical impedance spectroscopy, and scanning electron microscopy respectively. Results show that with the in- creasing amount of Ni-powder, the electrical conductivity of the coatings increased. While, as the longer of the immersion time and the higher amount of the Ni-powder are, the lower of the capacitive reactance arc, the impedance, the phase angle and ｜Z｜0.05 of the coatings are. For a desired immersion time, the higher amount of the Ni-powder is, the faster decline of the capacitive reactance arc, the impedance, the phase angle and the ｜Z｜0.05 of the coatings is. According to Tafel polarization result, the higher amount of the Ni-powder is, the greater of the corrosion current of coatings is. It is concluded that with the higher amount of Ni-powder, the coatings exhibit better electrical conductivity, but the lower of the viscosity and worse corrosion resistance. A coating with about 20% Ni-powder possesses a comprehensive perfor- mance with better electrical conductivity and corrosion resistance.