Research On Thermal Barrier Coatings TGO Growth Mechanism And Coatings Failure Mechanism

This article describes some as international advanced Air plasma spray (APS) facility, internal pioneered High Velocity Oxy-fuel facility and SSPB for preparing thermal Barrier coatings. SEM, XRD and EDS test procedure system are adopted based on the protocol of high-temperature oxidation test and heat circulates experiments by aeronautical standard so as to analyze growth process of Thermal Barrier coatings failure mechanism deeply and perfectly. This definitely indicates TGO growth mechanism. At meantime, Thermal Barrier coatings failure process is analyzed particularly with the combination of effective factors for which TGO growth process and mechanism research lead to Thermal Barrier coatings failure. This put steady basis for deeply investigating thermal grown oxide and coatings failure under factual serviced conditions of Thermal barrier coatings.Thermal grown oxide composed of double deck structure is developed with bond coating oxide under double function of interface reaction mechanism and element diffusion mechanism. Oxidation initial stage is controlled by interface reaction to form blend oxide which is constituted of Al₂O₃,NiO and Spinel oxide. However, at post- oxidation stage, Al slowly diffuses by interface oxidation to form single Al₂O₃ coatings and a paper-thin poor AL band come into being under the bond coating..It improved appearance of bond coating on thermal Barrier coatings effectively to adopt High Velocity Oxy-fuel and SSPB, which prevents nocuous oxide developing and decrease disfigurement during process on original form and actual application.With Entire failure process of microcrack from development, growth, propagation and coalescence to divestment on thermal barrier coatings, interface appearance, interface elements diffusion and microcrack by stress effect for hole resulted as Al₂O₃ phase change shrinkage and hard brittle spinel oxide can lead to be final failure factor under thermal barrier coatings environments.