锅炉受热面复合陶瓷涂层抗高温SO_2腐蚀性能

SO_2 corrosion resistance of composite ceramic coating for boiler heating surface

针对燃煤锅炉受热面存在的高温腐蚀问题,采用料浆法在20G钢材表面制备复合陶瓷涂层,烧结后的复合陶瓷涂层表面较为致密,涂层与基材具有良好的结合状态。对喷涂及未喷涂陶瓷涂层钢片在SO_2腐蚀气氛环境下的抗高温腐蚀性能进行试验,并采用热分析动力学方法对试验数据进行处理,结果表明,在400~500℃温度范围内,两种试样的腐蚀过程均符合一维扩散反应动力学模式,计算求得喷涂涂层钢片腐蚀反应活化能低于未喷涂涂层钢片,涂层具有较好的抗高温腐蚀性能。对腐蚀试验后试样的形貌、成分和物相分析结果显示,涂层在SO_2气氛下腐蚀后,表面生成K_2SO_4晶粒,但由于涂层较为致密,阻止了S的扩散,内部基本没有检测到K2SO4的存在。

To address high-temperature corrosion at heating surface of coal-fired boilers,a composite ceramic coating on surface of 20G steel sheet was prepared by slurry method.After sintering,the composite ceramic coating had a relatively dense surface and good bonding to the substrate.Both uncoated and ceramic-coated steel sheets were studied for high-temperature corrosion resistance in sulfur dioxide（SO2） by thermal kinetic analysis method.The results show that corrosion of the coated and uncoated steel sheets adheres to one dimensional diffusion reaction kinetic model at 400—500℃.Although activation energy of coated steel corrosion was lower than the uncoated one,the coating provided preferable high-temperature corrosion resistance.After exposure to SO2,the appearance,element contents and phase structure of the sheets were characterized.Potassium sulfate（K2SO4） crystal grains were found to form on the coating surface.However,K2SO4 was not detected inside coating because relatively dense coating blocked sulfur diffusion.