Synthesis and characterization of single-phase X2-Lu2SiO5 nanostructured feedstocks for advanced plasma-sprayed environmental barrier coatings

Abstract

The objective of this work is to synthesize the single-phase X2-Lu2SiO5 nanostructured feedstocks for plasma-sprayed environmental barrier coatings (EBCs). Generally speaking, high-performance feedstocks are a prerequisite for obtaining high-performance coatings. The single-phase X2-Lu2SiO5 nanostructured feedstocks were fabricated by a nanopowder reconstitution method for the first time. The morphology and phase structure of X2-Lu2SiO5 nanostructured feedstocks were examined. The physical properties of X2-Lu2SiO5 feedstocks were evaluated. In addition, the thermal conductivity of nanostructured X2-Lu2SiO5 coatings was measured. Results show that the single-phase X2-Lu2SiO5 nanostructured feedstocks are successfully synthesized when the mole ratio of Lu2O3 and SiO2 nanopowder is 1:1.1 and the agglomerated powders are sintered at 1300 °C for 2 h. The nanocrystalline size of the X2-Lu2SiO5 feedstocks ranges from 40 to 70 nm. Moreover, the d10, d50 and d90 of X2-Lu2SiO5 feedstocks are 24.69 μm, 37.78 μm and 54.75 μm, respectively. The apparent density and tap density of X2-Lu2SiO5 feedstocks are 1.76 g/cm3 and 2.09 g/cm3, respectively. The thermal conductivity of as-deposited Lu2SiO5 coating is 0.78–1.20 W m−1 K−1 (30–1200 °C). Overall, the single-phase X2-Lu2SiO5 nanostructured feedstocks are the most promising feedstocks for advanced EBCs system in the future.