Oxidation and thermal shock resistant properties of Al-modified environmental barrier coating on SiCf/SiC composites

Significance 

The efficiency of a turbine engine is directly proportional to the lightness and heat-endurance ability of its heat section components. Presently, turbine engine heat-components made from Ni-based super-alloys have reached their upper limit in terms of temperature capabilities. To this note, the need to develop new heat-capable turbine engine component parts has attracted much attention. As of now, silicon carbide-based ceramic matrix composites have been envisioned as potential capable alternative materials for the next generation of turbine engine heat-components. To this note, the higher performance of this material has contributed to it being heavily utilized in the heat-sections of gas turbines. Unfortunately, the ceramic matrix composites have a punitive drawback in that their surface has been seen to recede in case of exposure to heat corrosion.

To this effect, a team of researchers led by Professor Kesong Zhou from Guangdong Institute of New Materials developed a new alternative environmental barrier coating. The purpose of this coating was to offer the much desired protection to the silicon carbide based ceramic matrix composites. Furthermore, they hoped to characterize the microstructure evolution of oxidation in both original and the aluminum-modified silicon carbide-based ceramic matrix composites and observe the thermal shock resistance of aluminum-modified silicon carbide-based ceramic matrix composite. Their work is now published in the research journal, Ceramics International.

Briefly, the research method commenced by the deposition of an aluminum film on the surface of the silicon carbide based ceramic matrix composites which was then followed by heat treatment in a vacuum. The researchers then proceeded to fabricate a dense alumina overlay on the surface of the ceramic matrix composites. Eventually, the professors and their colleagues analyzed the microstructure evolution of silicon carbide based ceramic matrix composites and characterized the oxidation and thermal shock resistance of the same.

The authors observed that the aluminum-modified silicon carbide based ceramic matrix composites had a better oxidation resistance than the original silicon carbide based ceramic matrix composites. Additionally, they noted that the water-quenching tests showed that the aluminum-modified silicon carbide based ceramic matrix composites had a good thermal shock resistance due to the reactants of silicon oxide and mullite which had the potential to act as a mixture transition layer to release the mismatch between the dense aluminum oxide overlay and silicon carbide based ceramic matrix composites.

The Dr. Xiaofeng Zhang and colleagues study successfully presented an alternative environmental barrier coating design that helps improve the oxidation resistance of silicon carbide based ceramic matrix composites. This novel mechanism has been thoroughly investigated and the results obtained have matched well with the anticipated expectations. To this end, the proposed environmental barrier coating design is available for adoption and application for protective coating purposes of the silicon carbide-based ceramic matrix composites.

Al-modified environmental barrier coating on SiCf/SiC composites-Advances in Engineering

About the author

Dr. Xiaofeng Zhang is currently an engineer at National Engineering Laboratory of Modern Materials Surface Engineering Technology, Guangdong Institute of New Materials, china. He received his bachelor degree in Materials Physics from Jingdezhen Ceramic Institute, China, in 2009. And He received his Ph.D. degree in Materials Processing Engineering from South China University of Technology in 2016.

His research has been mainly focused on function coating such as Environmental Barrier Coating (EBC), Thermal Barrier Coating (TBC) through thermal spraying, vapor deposition, etc. Now, he has published more than 70 peer-reviewed papers in relevant field. And his has got more than 8 patents. He proposed a novel method Al-modification for functional coating improvement. Through Al-modification, the SiC/SiC ceramic composite material has a better oxidation resistance. Besides, this method has been applied in YSZ TBC. By means of in-situ synthesis of Al and ZrO2, the YSZ TBC has better performances including particle erosion, thermal cycle, CMAS corrosion, etc. Additionally, regarding the new thermal spray technique (plasma spray-physical vapor deposition, PS-PVD), he has presented a deposition mechanism creatively and corresponding paper has been cited many times.

Based on his above research, he has received numerous award, including the 2017 Best Paper Award of Chinese Youth Surface Engineering Conference, the 2015 Best Paper Award of Asian Thermal Spray Conference, and the 2014 Best Paper Award of Chinese Materials Conference. Besides, Dr. Zhang has served a number of important appointments, such as working committee of Chinese Advanced Ceramic Society, the fellow of Chinese Materials Research Society, and the reviewer of lots of journals in relevant field.

About the author

Professor Kesong Zhou receive his bachelor degree from Tsinghua University, China in 1965. He was a visiting researcher at State University of New York, U.S.A from 1980 to 1982. He has been faculty member of Guangzhou Research Institute of Nonferrous Metals from 1971 to 2015. Since 2016, he has served in Guangdong Academy of Sciences.

His research filed focuses on surface engineering involves thermal spray, vapor deposition, laser processing. Due to more than 40 years of research, his lots of investigation has been applied in aviation, steel, nuclear energy, etc. Based on numerous achievements, he was named Academician of the Chinese Academy of Engineering in 2009.

Reference

X.F. Zhang, K.S. Zhou, M. Liu, C.M. Deng, C.G. Deng, S.P. Niu, S.M. Xu. Oxidation and thermal shock resistant properties of Al-modified environmental barrier coating on SiCf/SiC composites. Ceramics International, volume 43 (2017) page 13075–13082

 

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