Abstract
Abstract Ytterbium disilicate (Yb 2 Si 2 O 7 ) is promising material for multilayered environmental barrier coatings (EBCs) on SiC fiber reinforced SiC matrix composites (SiC/SiC), because of its excellent volatilization resistance in a water vapor environment and the conformity of its coefficient of thermal expansion to SiC/SiC. A Yb 2 Si 2 O 7 layer was formed on a mullite substrate, of which the combination was applied to the multilayered EBCs, via electron beam physical vapor deposition (EB-PVD) with dual electron guns using Yb 2 O 3 and SiO 2 ingots as vapor sources, simultaneously heating on the substrate at 1523 K. The resulting layer consisted of a single-phase of Yb 2 Si 2 O 7 , with the (1 1 0) oriented structure. The layer had a highly dense columnar structure extending in the direction of thickness, but not the feather-like structure typical of layers synthesized via conventional EB-PVD techniques. It is expected that the application of dual EB-PVD during heating is useful for the construction of EBCs with excellent gas barrier performance.
Published Version
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