Sol–gel synthesis and coating of nanocrystalline Lu2Si2O7 on Si3N4 substrate

In this present work, we report sol–gel synthesis of nanocrystalline α-Lu2Si2O7, a candidate rare-earth disilicate phase being used recently as environmental barrier coating (EBC) layer for Si3N4 ceramics in high temperature water vapor corrosion environment. The method consists of the reaction of Lu(NO3)3 and TEOS in the adequate molar ratio to form a complex gel composed by the two cations, Si and Lu, which yields the stoichiometric Lu2Si2O7 after calcining. Thermal history and phase identification of the synthesized phase were examined using TG–DTA and XRD analyses, respectively. High dense coating layer is obtained by pressureless sintering at relatively low temperature.