为探究NiCoCrAlY/AlSiY复合涂层在高低温交替海洋环境中的腐蚀损伤和退化机理，通过设计高-低温氧化交替和高温氧化-酸性盐雾交替试验，对NiCoCrAlY/AlSiY复合涂层腐蚀损伤开展研究。试验结果表明，经750℃高-低温交替氧化50次循环后，涂层在氧化试验中发生氧化侵蚀，但表面结构完整性并未受到破坏。试验结束后合金质量仅增加了3.87 mg/cm2,表明涂层有效抑制了氧气向内部发生扩散，避免了基体遭受氧化侵蚀。在50次高温氧化-酸性盐雾交替循环过程中，NiCoCrAlY/AlSiY复合涂层发生了严重的腐蚀降解，试验结束后合金质量高达13.52 mg/cm2。氧化层结构因长期的盐雾侵蚀导致表面松动，萌生腐蚀孔洞甚至发生脱落。随着高温氧化-酸性盐雾交替循环次数的增加，引起涂层损伤的临界反应由氧化侵蚀转变为热腐蚀。混合盐共晶反应生成的氯气作为催化载体，加速了氧化产物的生长，证明NiCoCrAlY/AlSiY复合涂层在高温氧化-酸性盐雾交替环境下的抗腐蚀性能较弱。
朱荣涛, 张亮, 汪永宏, 陈世露, 季星红, 池汕, 许金亮, 郭春江, 段龙汉, 燕峰, 解志文
. 高低温交替海洋环境下NiCoCrAlY/AlSiY复合涂层的腐蚀失效机理[J]. 材料保护, 2024
, 57(4)
: 1
-10
.
DOI: 10.16577/j.issn.1001-1560.2024.0072
To investigate the corrosion damage and degradation mechanism of NiCoCrAlY/AlSiY composite coatings in alternating high and low temperature marine environments, the corrosion damage behavior of NiCoCrAlY/AlSiY composite coatings was studied by designing the alternating high and low temperature oxidation and high temperature oxidation-acidic salt spray alternating tests. Results showed that after 50 cycles of alternating high and low temperature oxidation at 750 ℃, the coating underwent oxidative erosion in the oxidation test, but the integrity of the surface structure was not damaged. After the experiment, the weight of the alloy increased by only 3.87 mg/cm2, indicating that the coating effectively inhibited the diffusion of oxygen into the interior and prevented the substrate from oxidative attack. During the 50 cycles of alternating high temperature oxidation and acidic salt spray tests, the NiCoCrAlY/AlSiY composite coating experienced severe corrosion degradation, and the alloy weight increased to as high as 13.52 mg/cm2 by the end of the test. Due to long-term salt spray erosion, the oxide layer structure weakened, leading to surface loosening, the formation of corrosion pits, and even peeling. As the number of alternating cycles of high temperature oxidation-acidic salt spray increased, the critical reaction causing coating damage shifted from oxidative erosion to thermal corrosion. The chlorine, generated from the eutectic reaction of the mixed salt, acted as a catalytic carrier and accelerated the growth of oxidation products, demonstrating that the NiCoCrAlY/AlSiY composite coatings had weak corrosion resistance under alternating high temperature oxidation-acidic salt spray environments.
