Bonding strength and thermal conductivity of novel nanostructured Lu₂Si₂O₇/Lu₂SiO₅ environmental barrier coating

As is known to all, environmental barrier coating requires high bonding strength and low thermal conductivity to extend the service life of ceramic matrix composite (CMC) components. In this work, a novel nanostructured Lu2Si2O7/Lu2SiO5 environmental barrier coating was deposited successfully using as-synthetized Lu2Si2O7 feedstocks and Lu2SiO5 feedstocks. Meanwhile, the microstructure, bonding strength and thermal conductivity of Lu2Si2O7/Lu2SiO5 coating were analysed systematically. Results indicate that the nanostructured Lu2Si2O7/Lu2SiO5 environmental barrier coating processes a bi-model microstructure. The Lu2Si2O7/Lu2SiO5 coating is relatively dense and the Lu2Si2O7 layer and Lu2SiO5 layer achieve the mechanical interlocking. The bonding strength of Lu2Si2O7/Lu2SiO5 coating is 14.9 MPa. In addition, the thermal conductivity of Lu2Si2O7/Lu2SiO5 coating is 0.59 Wm(-1)K-1-1.24 Wm(-1)K-1 from 25 degrees C to 1200 degrees C, which is visibly lower than that of Lu2SiO5 coating.