High-Temperature Corrosion of Be-Ta Protective Coatings on Stainless Steel

Research into the application of protective beryllide coatings in thermonuclear devices and high-temperature structures is currently of great interest. In thermonuclear devices, beryllides serve as an alternative to pure beryllium. Because beryllides exhibit high corrosion resistance and thermal stability, it was proposed to explore the possibility of using tantalum beryllide as protective coatings for high-temperature structural components. Such structures are used, among other things, in nuclear and thermonuclear facilities. Magnetron tests of tantalum beryllide coatings on stainless steel were conducted under high-temperature oxidation conditions. This article presents new experimental results on the high-temperature corrosion resistance of tantalum beryllide coatings. Coatings subjected to high-temperature oxidation were investigated using gravimetry, RBS analysis, X-ray diffractometry, and high-resolution scanning electron microscopy. The data obtained from the various methods are consistent, enabling a well-founded assessment of the coatings’ durability. It has been determined that, following the tests, the coating thickness decreases by more than a factor of two. A maximum Be diffusion depth of 400 nm into the substrate is achieved at a test temperature of 900 °C. The test results showed relatively low coating resistance under high-temperature oxidation conditions. However, under the test conditions, they contributed to a reduction in corrosion damage to the substrate surface. This makes it possible to classify tantalum beryllide as a promising protective coating for high-temperature materials.