Articles
  • Designing lutetium silicate environmental barrier coatings for silicon nitride and its recession behavior in steam jets 
  • Shunkichi Ueno*, Tatsuki Ohji and Hua-Tay Lina
  • Advanced Manufacturing Research Institute, National Institute of Advanced Industrial Science and Technology, 2266-98 Shimo-Shidami, Moriyama-ku, Nagoya 463-8560, Japan a Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6068, USA
Abstract
To protect silicon nitride ceramics from water vapor corrosion and oxidation, a new multi-layered environmental barrier coating (EBC) system was developed. The EBC system consisted of a highly dense Lu2SiO5/Lu2Si2O7 binary phase layer and slightly porous Lu2SiO5/Lu2Si2O7 layer, which were coated by a sputtering and dipping technique, respectively. A steam jet exposure test was conducted at 1300 degrees C for 500 hours with 35 m/s water vapor velocity. Each grain of the dip-coated layer was peeled off from the surface during the test. Also, the highly dense sputter coated layer converted into a porous layer after the test.

Keywords: EBC; water vapor corrosion; Lu2Si2O7; silicon nitride

This Article

  • 2006; 7(1): 20-23

    Published on Mar 31, 2006