硫氯含量对TC4渗铝涂层高温腐蚀性能的影响

Effect of Sulfur and Chlorine Content on High-Temperature Corrosion Performance of TC4 Aluminized Coating

摘要:

针对垃圾焚烧炉受热面的高温腐蚀，分析了硫/氯协同作用对涂层高温腐蚀性能的影响，以期为未来涂层服役性能的提升提供理论指导，促进垃圾焚烧发电的发展。在实验室模拟气氛（体积分数95%）+O₂（体积分数5%）条件下，对涂有Na₂SO₄盐、NaCl盐及NaCl+Na₂SO₄混合盐的TC4渗铝样品进行600 ℃的高温腐蚀实验，并利用扫描电镜（SEM）、能量色散光谱仪（EDS）和X射线衍射（XRD）等手段对试样进行了分析。结果表明：当喷涂Na₂SO₄溶液时，涂层表面发生微弱的腐蚀；当喷涂NaCl+ Na₂SO₄（质量分数比1:2）混合盐溶液时，在涂层表面生成了多层结构的腐蚀氧化层；当喷涂NaCl溶液时，涂层表面发生了严重的腐蚀，腐蚀产物主要是富含Al、Ti的氧化物和氯化物。在腐蚀过程中，氯化钠在高温下形成Cl^-1，其穿透初期形成的氧化膜，随后生成的金属氯化物在高温下汽化，向外扩散到达表面氧分压较高的区域时又被氧化为金属氧化物，此过程连续循环，使表面的多层氧化膜不断被腐蚀，随着Cl^-1浓度的增加样品的腐蚀更加严重，但S和Cl的协同作用可以降低涂层的腐蚀速率。

Abstract:

Aiming at the high-temperature corrosion of the heating surface of the waste incinerator， this paper is devoted to analyzing the effect of sulfur/chlorine synergy on the high-temperature corrosion performance of the coating， in order to provide theoretical guidance for improving the service performance of the coating in the future， and promote the development of waste incineration power generation. The high-temperature corrosion experiments of aluminized TC4 samples coated with Na₂SO₄ salt， NaCl salt， and NaCl+Na₂SO₄ mixed salt were carried out under the condition of a laboratory simulated atmosphere （95%N₂+5%O₂）. The experimental samples were analyzed using a scanning electron microscope （SEM）， energy dispersion spectrometer （EDS）， and X-ray diffraction （XRD）. The results show that weak corrosion occurs on the surface of the coating when Na₂SO₄ solution is sprayed， and a multi-layered corrosion oxide layer is formed when spraying NaCl+Na₂SO₄ （1∶2wt.%） mixed salt solution. When the NaCl solution was sprayed， serious corrosion damage appears on the surface of the coating， and the corrosion products are mainly oxides and chlorides rich in Al and Ti. With the increase of Cl ion concentration， the corrosion damage of the sample is more serious， and the synergistic effect of S and Cl can reduce the corrosion rate of the coating.