Gas turbine reliability is a crucial requirement for passenger safety in aviation and a secure energy supply. Hence, corrosive degradation of combustor parts, vanes, and blades in gas turbines must be prevented. One of the most severe forms of corrosion is alkali-sulfate-induced hot corrosion, which is associated with internal sulfidation of components and is usually anticipated to fade in importance in the absence of sulfur. However, the literature suggests that hot corrosion might still occur in low-sulfur combustion gases. In this study, established thermodynamic modeling methods are used to analyze the low-sulfur hot corrosion regime. Liquid sodium chromate is found to be stable in these conditions. A comparison of calculation results and engine findings suggests that high alkali levels can negatively impact thermal barrier coating life even if sulfur is absent in the fuel. Laboratory tests are carried out to validate the chromate formation on MCrAlY-coated specimens. It is shown that molten sodium chromate can alter the oxidation behavior of MCrAlY, promoting the formation of voluminous spinel. This represents a new and different form of hot corrosion compared to type I hot corrosion.

中文翻译：

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低硫燃料燃烧时 TBC 涂层部件的热腐蚀

燃气轮机的可靠性是航空乘客安全和安全能源供应的关键要求。因此，必须防止燃气轮机中的燃烧器部件、叶片和叶片的腐蚀退化。最严重的腐蚀形式之一是碱金属硫酸盐引起的热腐蚀，它与部件的内部硫化有关，通常预计在没有硫的情况下其重要性会减弱。然而，文献表明在低硫燃烧气体中仍可能发生热腐蚀。在这项研究中，已建立的热力学建模方法用于分析低硫热腐蚀状态。发现液体铬酸钠在这些条件下是稳定的。计算结果和发动机结果的比较表明，即使燃料中不含硫，高碱水平也会对热障涂层寿命产生负面影响。进行实验室测试以验证 MCrAlY 涂层试样上的铬酸盐形成。结果表明，熔融铬酸钠可以改变 MCrAlY 的氧化行为，促进大量尖晶石的形成。与 I 型热腐蚀相比，这代表了一种新的不同形式的热腐蚀。