The oxidation reaction of heat-resistant coating is studied in order to improve the efficiency of turbine engines

Some parts of an aircraft's aero-gas turbine engine typically reach temperatures above 1200 degrees Celsius. Any material used in such a harsh environment must be durable and competent for the job.
ceramic-based composites made from silicon carbide (SiC) have become a promising candidate for gas turbine engines

. However, these materials require a heat-resistant coating to prevent the oxidation of the SiC and evaporation of SiO 2, a process that results in a decrease in the volume of the material, resulting in such as large cracks or coating peeling, as well as damage to the structure at the top.
, the existing coating does not completely stop the oxidation process of SiO 2, as oxygen can penetrate through subtle cracks in these layers or through simple diffusion.
To solve this problem, some scientists have focused on using Yb-Si as a coating material because Yb-Si can reach high melting points, and their oxides are mainly Yb-silicates, which remain attached as oxide layers without evaporating easily. However, little is known about how these materials will change at high temperatures.in a recent study published in the journal Intermetallic Compounds,
was made up of a team of scientists, including Akihito Ishiguro, a junior associate professor at Tokyo University of Science and Technology, Associate Professor Hirohito Akihito and Professor Kangxiong, and Aoki Toya, a senior researcher at the Japan Aerospace Exploration Agency (JAXA), to learn about oxidation in Yb-Si. They conducted various experiments to understand the oxidation behavior and degradation reactions of different Yb-Si coatings at high temperatures under three types of atmosphere (air, water vapor, and a mixture of both).
X-ray diffraction analysis, energy dispersion spectrum, and scanning electron microscopes, scientists were able to accurately visualize and quantify the shape and composition of Yb-Si samples before and after thermal exposure tests. One of the main findings is that Yb/Si is the main factor determining the oxidation behavior of the material, and Yb5Si3 oxidation is higher than Yb3Si5 due to Yb's priority oxidation in silica. In addition, in atmospheres with high water vapor content, the amount of oxides is significantly reduced.
, the researchers explored the rationale by which the content of the content affects the formation of SiO 2. "After the thermal exposure of the two silicates of steam, we found that SiO 2 was oxidized into SiO3, and silicon actually still exists in Si2O5, " said Ishido, who led the study. "Our analysis shows that SiO2 growth in Yb3Si5 is inhibited because SiO2 is involved in the formation of the Yb silicate reaction and is a limiting factor in that reaction," he added. Although the exact intermediate reactions that led to the formation of various Yb-silicates were not fully understood, the team suggested two highly likely response pathways. This may be clarified by the use of more detailed charactering techniques in future studies.
, this study provides meaningful insights into what happens during Yb-Si's oxidation process, which will help develop protective coatings for gas turbine engines. "If coatings can be achieved in harsh environments, engine parts will become more heat-resistant and naturally improve engine efficiency," Dr. Ishii said. We
further development of coating technology will reduce air transport costs and fuel consumption, making safe flight less costly and less harmful to the environment.
About Tokyo University of Science
Tokyo University of Science (TUS) is a well-known and respected university and japan's largest private research university specializing in science, with four campuses in central Tokyo and its suburbs and Hokkaido. Founded in 1881, the university has made a continuous contribution to the development of science in Japan by instilling a love of science among researchers, technicians and educators.
mission of TUS is to "create science and technology for the harmonious development of nature, human beings and society", and has carried out extensive research from basic science to applied science. TUS has embraced interdisciplinary research methods and has conducted in-depth research in some of today's most important areas. TUS is an elite country where the best science is recognized and nurtured. It is the only private university in Japan that has won a Nobel Prize, and the only private university in Asia that has produced a Nobel Prize winner in the field of natural sciences.
, associate professor at Tokyo University of Science and
Technology, received his Ph.D. in 2014 from the University of Tokyo, Japan, where he served as a project researcher for one year. He joined Tokyo University of Science and Technology in 2015 as an Assistant Professor in the Department of Materials Science and Technology. He now serves as a junior associate professor in the Department of Mechanical Engineering at The Wells Laboratory, where he is responsible for the development and research of composite materials for automotive, aircraft and research. He has published more than 30 peer-reviewed articles and is a member of the Japan Ceramic Society and the Japan Society of Mechanical Engineers.
。