Invited Speaker
Assoc. Res. Bo Cheng
Lanzhou University of Technology
E-mail: chengbo_o@126.com
Title: Formation Mechanisms of Columnar/Dense Structure for Gd2Zr2O7 Ceramics Coatings with Superior CMAS Corrosion Resistance
Profile:
Cheng Bo, Doctor of Engineering, Associate Researcher, Master's Degree Supervisor, Gansu Outstanding Youth Fund Recipient, Director of the Council of Gansu Materials Society, Member of the Youth Work Committee of Surface Engineering Branch of Chinese Mechanical Engineering Society, and Red Willow Outstanding Youth of Lanzhou University of Science and Technology. He graduated from Xi'an Jiaotong University with a Ph.D. degree in June 2018 in Materials Science and Engineering. He is mainly engaged in surface engineering research in the direction of thermal barrier coating structure design, high-precision magnetic grinding of metal surfaces, multifunctional powder modification, and chalcocite thin film technology, etc. He has presided over the National Natural Science Youth Fund, regional funds, tasks of the National Key Research and Development Program of China, the State Key Laboratory of Strength of Metallic Materials open project, the University of Science and Technology of Beijing outsourcing project, and the ‘Red Willow Outstanding Young Talent Support Program’ of Lanzhou University of Science and Technology. He has participated in many projects such as Gansu Provincial Science and Technology Major Project and Gansu Provincial Higher School Industry Support Program as the first participant. He was awarded the first prize of Gansu Provincial Scientific and Technological Progress (2021), the second prize (2022), and the first prize of Gansu Provincial Materials Science and Technology (2020). He has published more than 60 SCI/EI papers and 9 patents. Including: Matter, Materials Today, Journal of Advanced Ceramics, Materials & Design, Journal of the European Ceramic Society, Surface & coatings technology, Ceramics International, Journal of the American Ceramic Society and others.
Abstract:
Corrosion failure induced by calcium-magnesium-alumina-silicate (CMAS) deposits is a predominant degradation factor in advanced thermal barrier coating (TBCs) systems. This study systematically investigates the surface laser modification strategy for reconstructing the microstructure near GZO (Gd2Zr2O7) coatings surface prepared by air plasma spraying (APS), with aims to enhance TBCs CMAS corrosion resistance. Numerical simulations revealed that laser power thresholds govern microstructural transformations, a fully dense layer forms near GZO surface at 4 W, while micro columnar crystallization (honeycomb crystals first form at the bottom of the bath, growing from the bottom to the top of the bath with a slight bias towards the laser scanning direction, and then forming columnar dendritic crystals in the middle and upper part of the bath) initiates at 12 W. A parameter set of 14 W power, 100 mm/s scan speed, 0.02 mm line spacing and 0.5 mm spot diameter is filtered to form a hybrid textured like surface, vertically-aligned microcolumns (10 μm) overlying a dense sublayer (15 μm). Superior CMAS corrosion resistance was achieved through the low wettability combine infiltrating (columnar micro-nanostructures increase the apparent contact angle, resulting in super-hydrophobic properties) to CMAS of this composite structure. The synergistic effects of surface texturing and subsurface structural engineering provide new insights into designing corrosion-resistant TBCs through laser-induced phase-selective recrystallization.