摘要
[目的]对比分析火力发电设备中常用的热喷涂NiCr/Cr_(3)C_(2)涂层和45CT涂层对基体材料的保护性。[方法]将未喷涂与热喷涂两种涂层的P12钢表面涂覆15%NaCl+15%Na_(2)SO_(4)+70%K_(2)SO_(4)混合盐膜后分别置于650、700和750℃下腐蚀36 h。采用能谱仪(EDS)分析试样表面腐蚀产物的成分,采用扫描电镜(SEM)和X射线衍射仪(XRD)分析腐蚀后涂层的微观结构和相变。[结果]热喷涂两种涂层的P12钢在上述熔盐中腐蚀36 h后的质量损失相近,均为未喷涂时质量损失的1/2左右,其中45CT涂层试样的质量损失在腐蚀12 h后明显趋缓。NiCr/Cr_(3)C_(2)涂层在腐蚀过程中受S元素影响,与基体的结合力较45CT涂层差,出现开裂现象。[结论]45CT涂层在长时间服役时会表现出更好的耐蚀性。在高氯环境下,含铬量较高的NiCr/Cr_(3)C_(2)涂层因结合力受到影响,故对基体的保护性能稍差于45CT涂层。
[Objective]The protective properties of two common thermally sprayed coatings i.e.NiCr/Cr_(3)C_(2)and 45CT for the materials used in thermal power generation equipment were compared.[Method]The uncoated,NiCr/Cr_(3)C_(2)-coated,and 45CT-coated P12 steel specimens were coated with a mixture of 15%NaCl+15%Na_(2)SO_(4)+70%K_(2)SO_(4),and then subjected to a 36-hour corrosion at temperature 650℃,700℃,and 750℃,respectively.The elemental compositions of the corrosion products formed on the specimens were analyzed by energy-dispersive spectroscopy(EDS).The microstructure and phase transformation of the coatings after corrosion were characterized by scanning electron microscopy(SEM)and X-ray diffraction(XRD).[Result]The mass loss of P12 steel sprayed with the two types of coatings after 36 hours of corrosion in molten salts was similar,and was approximately half that of the uncoated substrate.The weight loss of the 45CT-coated specimen significantly slowed down after 12 hours of corrosion.The NiCr/Cr_(3)C_(2)coating was affected by sulfur element during the corrosion process,resulting in weaker adhesion to the substrate than the 45CT coating,and cracking occurred.[Conclusion]The 45CT coating is expected to exhibit superior corrosion resistance during long-term services.In high-chloride-content environments,the NiCr/Cr_(3)C_(2)coating with a higher chromium content has reduced adhesion due to the influence of sulfur,and therefore provides slightly inferior protection to the substrate compared to the 45CT coating.
作者
黄世福
刘宣义
刘帅岐
毛晓飞
汪飞
徐星
徐媛媛
刘光明
HUANG Shifu;LIU Xuanyi;LIU Shuaiqi;MAO Xiaofei;WANG Fei;XU Xing;XU Yuanyuan;LIU Guangming(Wuhan Branch of National Energy Group Science and Technology Research Institute Co.,Ltd.,Wuhan 430070,China;School of Material Science and Engineering,Nanchang Hangkong University,Nanchang 330063,China)
出处
《电镀与涂饰》
北大核心
2025年第1期9-15,共7页
Electroplating & Finishing
基金
国家自然科学基金(51961028)。
关键词
低合金耐热钢
热喷涂
高温熔盐
氯离子
腐蚀
low-alloy heat-resistant steel
thermal spray coating
high-temperature molten salt
chloride ion
corrosion
