Scholarlink

<p>Environmental barrier coatings (EBCs) have enabled the implementation of SiC/SiC ceramic matrix composites (CMCs) in gas turbines by protecting CMCs from H<sub>2</sub>O-induced volatilization and oxidation. Improving the reliability of CMC components requires long-life EBCs and accurate EBC lifing. Steam oxidation-induced failure is the most frequently observed EBC failure mode. Si/RE<sub>2</sub>Si<sub>2</sub>O<sub>7</sub> EBCs, where RE = rare earth element such as Y, Yb, Lu, Sc, etc. are the current state-of-the-art EBCs (Gen 2 EBC). Modifying the NASA Gen 2 EBC (Si/Yb<sub>2</sub>S<sub>2</sub>iO<sub>7</sub>) by adding Al<sub>2</sub>O<sub>3</sub> or Al<sub>2</sub>O<sub>3</sub>-containing compound, such as mullite (3Al<sub>2</sub>O<sub>3</sub>·2SiO<sub>2</sub>) and YAG (Y<sub>3</sub>Al<sub>5</sub>O<sub>12</sub>), in the Yb<sub>2</sub>Si<sub>2</sub>O<sub>7</sub> topcoat (Mod Gen 2 EBCs) reduced the Si/Yb<sub>2</sub>S<sub>2</sub>iO<sub>7</sub> Gen 2 EBC parabolic oxidation rates by &gt; 10x at 1316&#xa0;°C in steam. This paper expanded the steam oxidation studies of the Si/Yb<sub>2</sub>S<sub>2</sub>iO<sub>7</sub> Gen 2 and Mod Gen 2 EBCs by adding additional variables, i.e., CMC chemistry (chemical vapor infiltration (CVI), melt infiltration (MI)) and temperature (1250, 1316, 1350&#xa0;°C), to understand the synergistic effects of the three variables (EBC chemistry, CMC chemistry, temperature) on oxidation. Interactions among these variables, specifically the dissolution of aluminum and boron in the SiO<sub>2</sub> oxide scale, determined the chemistry of the SiO<sub>2</sub> oxide scale, which had overarching influences on the oxidation kinetics.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Steam Oxidation of Modified Silicon/Ytterbium Disilicate Environmental Barrier Coatings on SiC/SiC Ceramic Matrix Composites at 1250-1350 °C

  • 期刊论文

  • 发表日期：

    2025年10月30日

查看全文
  • Kang N. Lee,
  • Josh Stuckner,
  • Anita Garg,
  • Bernadette Puleo,
  • Laura G. Wilson

摘要

Environmental barrier coatings (EBCs) have enabled the implementation of SiC/SiC ceramic matrix composites (CMCs) in gas turbines by protecting CMCs from H2O-induced volatilization and oxidation. Improving the reliability of CMC components requires long-life EBCs and accurate EBC lifing. Steam oxidation-induced failure is the most frequently observed EBC failure mode. Si/RE2Si2O7 EBCs, where RE = rare earth element such as Y, Yb, Lu, Sc, etc. are the current state-of-the-art EBCs (Gen 2 EBC). Modifying the NASA Gen 2 EBC (Si/Yb2S2iO7) by adding Al2O3 or Al2O3-containing compound, such as mullite (3Al2O3·2SiO2) and YAG (Y3Al5O12), in the Yb2Si2O7 topcoat (Mod Gen 2 EBCs) reduced the Si/Yb2S2iO7 Gen 2 EBC parabolic oxidation rates by > 10x at 1316 °C in steam. This paper expanded the steam oxidation studies of the Si/Yb2S2iO7 Gen 2 and Mod Gen 2 EBCs by adding additional variables, i.e., CMC chemistry (chemical vapor infiltration (CVI), melt infiltration (MI)) and temperature (1250, 1316, 1350 °C), to understand the synergistic effects of the three variables (EBC chemistry, CMC chemistry, temperature) on oxidation. Interactions among these variables, specifically the dissolution of aluminum and boron in the SiO2 oxide scale, determined the chemistry of the SiO2 oxide scale, which had overarching influences on the oxidation kinetics.