This work is devoted to the study of microstructure, corrosion behavior, and deposition formation of ERNiCrMo-13 and NiCrBSi coatings in simulated coal-fired boiler environments. It was found that these coatings applied to TP347 boiler steel by means of arc spraying were comprised of Cr_1.12Ni_2.88 compound. The hot corrosion tests were performed in simulated flue gases and synthetic fly ashes at 900 °C. The composition (wt%) of synthetic ashes was 75 fly ash + (25 − x) Na₂SO₄ + x NaCl with varying levels of Na₂SO₄ and NaCl (x = 0, 3.25, 7.99, and 25). The experimental results showed that NiCrBSi coatings had better corrosion resistance than ERNiCrMo-13 coatings. The corrosion kinetic of the coatings was composed of two stages including a rapid mass gain and a reduction of the mass gain rate due to selective oxidation (stage I) and a mass loss or a larger mass gain rate due to dissolving of oxide scales or deposition of fly ashes (stage II). The high level of NaCl in the fly ashes was responsible for the non-parabolic rate law of the corrosion kinetics, the accelerated corrosion of the coatings, and the internal oxidation of the substrates. The severe corrosion of ERNiCrMo-13 and NiCrBSi coatings occurred in the condition with a high content of NaCl. During corrosion tests, the different compounds such as NiO, Cr₂O₃, CrO₂, NiSi₂, and Fe₃Cr₂Si₃O₁₂ were formed on the coating surfaces. The protective Cr₂O₃ and/or CrO₂ scales formed due to the selective oxidation acted as a corrosion barrier in the initial stage, and will lose the protection when the reaction between chromium oxides and NaCl occurs. The oxides and salts were found to be covered on the coatings due to the deposition of the fly ashes. The mechanisms of deposition formation, Cl-induced corrosion, and internal oxidation under the simulated coal-fired boiler conditions are discussed.

这项工作致力于研究模拟燃煤锅炉环境中ERNiCrMo-13和NiCrBSi涂层的微观结构，腐蚀行为以及沉积形成。发现通过电弧喷涂施加到TP347锅炉钢上的这些涂层由Cr _1.12 Ni _2.88化合物组成。热腐蚀测试是在900°C的模拟烟气和合成粉煤灰中进行的。合成灰分的组成（wt％）为75粉煤灰+（25-  x）Na ₂ SO ₄  +  x NaCl，Na ₂ SO ₄和NaCl（x = 0、3.25、7.99和25）。实验结果表明，NiCrBSi涂层比ERNiCrMo-13涂层具有更好的耐腐蚀性。涂层的腐蚀动力学包括两个阶段，包括快速的质量增加和由于选择性氧化而导致的质量增加率的降低（阶段I），以及由于氧化物垢的溶解或沉积而导致的质量损失或更大的质量增加率飞灰（第二阶段）。飞灰中高含量的氯化钠是腐蚀动力学，涂层加速腐蚀以及基材内部氧化的非抛物线速率定律。在NaCl含量高的条件下，发生了ERNiCrMo-13和NiCrBSi涂层的严重腐蚀。在腐蚀测试中，各种化合物（例如NiO，Cr ₂ O _3）在涂层表面上形成CrO ₂，NiSi ₂和Fe ₃ Cr ₂ Si ₃ O ₁₂。由于选择性氧化而形成的保护性Cr ₂ O ₃和/或CrO ₂垢在初始阶段起腐蚀屏障的作用，并且在氧化铬与NaCl之间发生反应时会失去保护作用。发现由于飞灰的沉积，氧化物和盐被覆盖在涂层上。讨论了在模拟燃煤锅炉条件下的沉积形成，Cl诱导的腐蚀和内部氧化的机理。