Damage Behavior of SiC/SiC Composites with BSAS-based EBC in Wet Oxygen Atmosphere at 1300℃
To meet the demand for long and stable service of new-generation high-performance aero-engines with higher turbine inlet temperatures,continuous SiC fiber reinforced and toughened SiC ceramic matrix(SiC/SiC)composites with environmental barrier coatings(EBC)are gradually being applied to hot-end components.For the service behavior of SiC/SiC composites with EBC in simulated gas environments,the oxidation and corrosion experiment of SiC/SiC composites with BSAS-based EBC in wet oxygen atmosphere at 1300℃was carried out in this paper.The microstructure evolution,internal defects characteristic,weight change rate and mechanical properties evolution law were studied to reveal its damage mechanism.Cracks in the EBC acted as channels for wet oxygen atmosphere diffusion into the internal part,which reached the Si bonding layer and prompted corrosion pores to appear on its upper surface,thus cutting down the barrier protection life of the EBC.It was found that the oxidation of SiC/SiC composites with barium strontium aluminosilicate(BSAS)EBC in wet oxygen atmosphere at 1300℃obeyed diffusion control.SiC/SiC composites under the protection of the EBC did not suffer from significant oxidation and corrosion damage.The load-bearing capacity of SiC fibers at the near surface and the center of the SiC/SiC substrate was increased after a certain time of assessment service according to the result of micromechanical analysis.Therefore,the mechanical properties of SiC/SiC substrates protected by EBC were improved after 300h of oxidation and corrosion.
SiC/SiC compositesEBCwet oxygen atmosphereoxidation and corrosion damagemechanical properties
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