石墨粉对低锌含量水性环氧富锌漆阴极保护性能的影响

Effect of graphite powder on cathodic protection performance of water-based epoxy zinc-rich paint with low zinc content

配制了颜料体积浓度(PVC)与临界颜料体积浓度(CPVC)之比为0.9的低锌含量水性环氧富锌漆,加入占锌粉质量1%、2%和3%的石墨粉,研究了石墨粉对水性环氧富锌涂层阴极保护性能的影响。涂层的阴极保护性能评价采用传统的开路电位(OCP)测试法与自行开发设计的恒电流溶解法。OCP测试结果表明,添加石墨后的涂层有更长的阴极保护时间,石墨粉添加量越大,阴极保护时间越长。恒电流溶解法测试结果表明,加入石墨粉之后涂层的活性溶解时间变长,石墨粉添加量越高,活性溶解时间越长。导电胶和涂层电极在3.5%NaCl溶液中的电化学阻抗谱测试结果表明,随着石墨粉含量的增加,涂层阻抗降低,阴极保护作用增强。

The water-based epoxy zinc-rich paint with a ratio of pigment volume concentration （PVC） to critical pigment volume concentration （CPVC） equal to 0.9 and low zinc content was prepared. The effect of graphite powder on the cathodic protective performance of water-based epoxy zinc-rich coating was researched by adding graphite powders with a mass fraction of 1%, 2% and 3% （relative to the zinc powders）, respectively. The cathodic protection property of the coating was evaluated using traditional open circuit potential （OCP） and a self-designed galvanostatic dissolution method. The OCP test results indicated that the coating with graphite powders has longer cathodic protective time, and the higher the graphite content is, the longer the cathodic protection time will be. The results of galvanostatic dissolution measurement showed that the active dissolution time of the coating containing graphite powder is prolonged, and the higher the content of graphite powder is, the longer the active dissolution time is. Analysis results of electrochemical impedance spectroscopy （EIS） for the conductive adhesive and coated electrode in 3.5% NaC1 solution showed that the impedance of the coating is decreased with increasing content of graphite powder, improving the cathodic protection performance.