Research Progress of La2Zr2O7 Material Modification Based on Thermal Barrier Coating
With the continuous development of aero engines in the direction of high thrust-to-weight ratio and high performance,traditional and single thermal barrier coatings(TBCs)have been unable to meet the harsh service requirements of hot-end components.Lanthanum zirconate(La2Zr2O7)has the advantages of high melting point,structural stability at high temperatures,low thermal conductivity and excellent thermal insulation performance,making it an excellent candidate material for the next generation of TBCs.However,there are still two key issues in practical applications,namely low thermal expansion coefficient and poor fracture toughness.Consequently,La2Zr2O7 materials during service may experience localized thermal stress concentration due to thermal mismatch,leading to premature peeling and failure of the coating and seriously affecting the service life of the coating.Domestic and foreign researches have shown that modification of La2Zr2O7 materials can effec-tively solve the above problems.Therefore,this article systematically analyzed the researches on the modification of La2Zr2O7 materials,and summarized them into four categories:second-phase composite,rare earth doping,nanoization and high-entropy.The article focused on the impact and toughening mechanism of the four different modification methods on the thermal conductivity and thermal expansion coefficient of La2Zr2O7 materials.Furthermore,the research works on La2Zr2O7 material modification were summarized and prospected,which could provide the theoretical support for the application of La2Zr2O7 material in the field of thermal barrier coatings.
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