Quest and evaluation of topcoat materials for environmental barrier coatings of SiC/SiC composites

H. Nakayama, Kohei Morishita, S. Ochiai, T. Sekigawa, K. Aoyama, T. Oi, M. Yamamoto, K. Okamura, M. Sato

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

SiC fiber reinforced SiC matrix (SiC/SiC) composites are one of the most promising materials for high temperature structural applications such as power generation and propulsion systems. SiC/SiC composites are, however, susceptible to accelerated attacks in water vapor environments through oxidation and volatilization reaction. For protection from such attacks, Environmental Barrier Coatings (EBCs) are indispensable. We have investigated some oxides and rare-earth silicates as topcoat candidate materials for EBCs. Topcoat materials must be stable in the high-water-vapor pressurized environments at high temperatures. Also, it is important that the thermal expansion coefficient of topcoat materials is similar to that of the SiC/SiC composites. In this study, first, zirconium oxides, lutetium silicates and yttrium silicates were selected as topcoat candidate materials. They were exposed in a water-containing atmosphere at a temperature of 1673 K for 100 h under a total pressure 0.96 MPa. Mass changes, structure of crystals and microstructures were investigated after the exposure experiments in order to evaluate the thermal stability of these materials. After their estimation, lutetium silicates were considered to be promising for topcoat materials. Then, lutetium silicates were coated as the topcoat of an EBC system on SiC/SiC composites, and their fracture toughness and microstructures were investigated after exposure to an oxidizing atmosphere. The evaluation results of the topcoat materials are reported in this paper.

Original languageEnglish
Pages (from-to)549-552
Number of pages4
JournalKey Engineering Materials
Volume317-318
Publication statusPublished - Jul 24 2006
Externally publishedYes

Fingerprint

Lutetium
Silicates
Coatings
Composite materials
Steam
Water vapor
Microstructure
Yttrium
Vaporization
Zirconia
Temperature
Oxides
Rare earths
Propulsion
Power generation
Thermal expansion
Fracture toughness
Thermodynamic stability
Oxidation
Crystals

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Nakayama, H., Morishita, K., Ochiai, S., Sekigawa, T., Aoyama, K., Oi, T., ... Sato, M. (2006). Quest and evaluation of topcoat materials for environmental barrier coatings of SiC/SiC composites. Key Engineering Materials, 317-318, 549-552.

Quest and evaluation of topcoat materials for environmental barrier coatings of SiC/SiC composites. / Nakayama, H.; Morishita, Kohei; Ochiai, S.; Sekigawa, T.; Aoyama, K.; Oi, T.; Yamamoto, M.; Okamura, K.; Sato, M.

In: Key Engineering Materials, Vol. 317-318, 24.07.2006, p. 549-552.

Research output: Contribution to journalArticle

Nakayama, H, Morishita, K, Ochiai, S, Sekigawa, T, Aoyama, K, Oi, T, Yamamoto, M, Okamura, K & Sato, M 2006, 'Quest and evaluation of topcoat materials for environmental barrier coatings of SiC/SiC composites', Key Engineering Materials, vol. 317-318, pp. 549-552.
Nakayama, H. ; Morishita, Kohei ; Ochiai, S. ; Sekigawa, T. ; Aoyama, K. ; Oi, T. ; Yamamoto, M. ; Okamura, K. ; Sato, M. / Quest and evaluation of topcoat materials for environmental barrier coatings of SiC/SiC composites. In: Key Engineering Materials. 2006 ; Vol. 317-318. pp. 549-552.
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