Effect of Chemical Regimes on Oxide Laye

Nowadays most commonly used materials in power engineering are stainless steels. Temperatures and pressures in systems are currently increased to achieve higher efficiency. In some plants, supercritical values are applied. This paper focuses on the improvement of corrosion protection possibilities. Besides new materials like titanium and nickel superalloys, various types of surface treatments or layers are utilized to mitigate corrosion issues. If a passive film is formed on a treated surface, such as nitrided surfaces, differences in properties may emerge. Oxidic layers are prevalent; however, issues like exfoliation, increased porosity, or variability in passive layers occur during the operation of water-steam cycles in power plants. This leads to higher corrosion rates, resulting in material degradation and equipment failure. In the experimental section, oxidic layers were created under laboratory conditions, and the behavior of materials used in power industry was monitored. Subsequently, their properties and compositions were evaluated, allowing for the analysis of the optimal conditions for specific materials. Samples were subjected to autoclave exposure under various cycle chemistries and analyzed using ESCA, X-ray diffraction, and metallography.