搪瓷封孔处理对45CT涂层热腐蚀行为的影响  

Effect of enamel sealing treatment on hot corrosion behavior of 45CT coating

作　　者：占阜元 熊义 罗钦 刘光明[2] 任亚飞 毛晓飞 董猛 ZHAN Fuyuan;XIONG Yi;LUO Qin;LIU Guangming;REN Yafei;MAO Xiaofei;DONG Meng(CHN Energy Fengcheng Power Generation Co.,Ltd.,Fengcheng 331100,China)

机构地区：[1]国家能源集团丰城发电有限公司,江西丰城331100 [2]南昌航空大学材料科学与工程学院,江西南昌330063 [3]国电科学技术研究院有限公司,湖北武汉430066 [4]东方锅炉股份有限公司材料研究所,四川自贡643001

出　　处：《电镀与涂饰》2020年第16期1066-1073,共8页Electroplating & Finishing

基　　金：国家自然科学基金(51961028)。

摘　　要：采用超音速电弧喷涂在Super304H不锈钢表面制备了45CT涂层,然后用含SiO2和硅酸盐的搪瓷粉对其进行封孔,研究了有无封孔的涂层表面涂覆75%(质量分数)Na2SO4+25%(质量分数)NaCl盐膜后在700°C下的热腐蚀行为。通过X射线衍射仪、扫描电镜和能谱仪分析了高温腐蚀产物的成分、结构和形貌。结果发现45CT涂层在腐蚀过程中出现明显质量损失,表面生成了以富铁氧化物为外层,富铬氧化物为内层的双层氧化膜,腐蚀产物剥落严重。涂层/基体界面有明显裂纹,基体一侧发生了晶间腐蚀。搪瓷封孔层具有较高的热稳定性和较低的腐蚀速率,因此在熔盐中仅发生了轻微溶解,有效地提高了45CT涂层的抗热腐蚀性。A 45CT coating was prepared on the surface of Super304H stainless steel by supersonic arc spraying,and then sealed with an enamel powder comprising SiO2 and silicate.The hot corrosion behavior of the coatings with and without being sealed beneath a film of mixture of 75wt.%Na2SO4+25wt.%NaCl at 700°C was studied.The composition,structure,and morphology of the high-temperature corrosion products were analyzed by X-ray diffractometry,scanning electron microscopy,and energy-dispersive spectroscopy.The 45CT coating exhibited obvious mass loss during the corrosion process.A Fe-rich oxide outer layer and a Cr-rich oxide inner layer was formed on its surface,and serious spallation of corrosion products took place.Cracks were observed at the 45CT coating/substrate interface.Intergranular corrosion occurred on the side of Super304H substrate.The enamel sealing layer was slightly dissolved in the molten salt due to its high thermal stability and low corrosion rate,which effectively improved the hot corrosion resistance of 45CT coating.

关 键 词：不锈钢 镍-铬-钛系电弧喷涂涂层 搪瓷 封孔 熔盐 热腐蚀 

分 类 号：TG174[金属学及工艺—金属表面处理]