Abstract:Yb2Si2O7 and high entropy double silicate powders (Yb0.25Y0.25Lu0.25Er0.25)2Si2O7, (Yb0.2Y0.2Lu0.2Er0.2Sc0.2)2Si2O7, and (Yb0.2Y0.2Lu0.2Er0.2Ho0.2)2Si2O7 were prepared through solid-state reaction. The phase composition, thermal expansion coefficient, thermal conductivity, and elastic modulus of their ceramic blocks and insulation treatment were studied. The results show that due to the addition of rare earth elements Y, Lu, and Er, the thermal expansion coefficient and thermal conductivity of high entropy (Yb0.25Y0.25Lu0.25Er0.25)2Si2O7 are similar to those of Yb2Si2O7, but the elastic modulus decreases the least, at 10.28%; Due to the addition of Scelements, high entropy (Yb0.2Y0.2Lu0.2Er0.2Sc0.2)2Si2O7 has lower thermal expansion coefficient and thermal conductivity compared to (Yb0.25Y0.25Lu0.25Er0.25)2Si2O7, and the elastic modulus is reduced by 18.74%; Compared with (Yb0.25Y0.25Lu0.25Er0.25)2Si2O7, the high entropy (Yb0.2Y0.2Lu0.2Er0.2Ho0.2)2Si2O7 doped with Ho element has a higher thermal expansion coefficient and lower thermal conductivity, but its elastic modulus decreases the most, reaching 24.78%. After insulation at 1200 ℃ and 1300 ℃ for 10, 30, and 50 hours, Yb2Si2O7, (Yb0.25Y0.25Lu0.25Er0.25)2Si2O7, (Yb0.2Y0.2Lu0.2Er0.2Sc0.2)2Si2O7, and (Yb0.2Y0.2Lu0.2Er0.2Ho0.2)2Si2O7 all exhibited good high-temperature stability, and their elastic modulus increased with the increase of insulation time, while their thermal expansion coefficient gradually decreased. After high entropy double silicate insulation treatment, it still exhibits good high-temperature phase stability and has a similar coefficient of thermal expansion to the substrate, indicating that the prepared high entropy double silicate is suitable for thermal environment barrier coating materials of high thrust weight ratio aviation engines.