不同腐蚀试验的电化学阻抗谱评价

Comparison of Different Accelerated Corrosion Test Methods by Electrochemical Impedance Spectroscopy

采用电化学阻抗谱分析了环氧涂层的介质浸泡、ASTM-B117盐雾试验、PROHESION循环试验的性能变化。实验结果表明:介质浸泡更侧重考察涂层的屏蔽作用,对环氧-聚酰胺体系酸性电解质更容易导致涂层失效;而盐雾试验更容易导致涂层吸收水分,干湿交替增加了有机涂层吸水能力;划痕试验表明样板在ASTM-B117和PRO-HESION遵循不同的腐蚀机理。

by using epoxy iron oxide red primer, the influence of immersion in seawater, immersion in 0.05%NaCl ＋0.35% （NH4）2SO4, ASTM- B117 and PROHESION salt spray test on coatings have been studied by electrochemical impedance spectroscopy （EIS） , also the corrosion mechanism of coating with artificial scratch has been discussed. The results revealed that comparing with salt spray, immersion in electro- lyte favored examing the barrier effect, but salt spray test led to coating absorbing more water. For epoxy - polyamide system, acidic electrolyte will lead the coating failure more quickly. Cyclic wet -dry condition will cause the coating with more water uptake. Salt spray tests with scratch indicated that there were different corrosion mechanism between ASTM -B117 and ASTM- 5894 salt spray test.