報告書番号

W03009

タイトル（和文）

ガスタービン用セラミックスの耐減肉コーティングの開発 -燃焼ガス流中におけるジルコニアの耐減肉特性と不純物の影響-

タイトル（英文）

Development of Environmental Barrier Coating on Ceramics for Gas Turbine -Recession Characteristic for Yttria Stabilized Zirconia and Influence of Impurity on Recession in Combustion Gas Flow-

概要 （図表や脚注は「報告書全文」に掲載しております）

不純物含有量を抑制し高純度化したYSZ（高純度YSZ）、ならびに、不純物としてAl2O3(1, 3, 5mass.%)またはSiO2(1, 3, 5mass.%)を含むYSZ（不純物含有YSZ）の燃焼ガス流中曝露試験3)を行い、以下の結果を得た。(1)高純度YSZは耐減肉コーティング材料の候補材として有望であることを明らかにした。(2)耐減肉性を高めるためには不純物量の低減が必要であることを明らかにした。(3)不純物含有YSZでは不純物(Al2O3、SiO2)が表面から選択的に消失し、試験片表面近傍には不純物消失層が形成された。また、不純物消失層は時間の経過に伴い厚くなる傾向を示した。これより、水蒸気もしくは不純物の拡散など、材料内部での物質移動が生じていることを明らかにした。

概要 （英文）

The research and development of ceramic gas turbine have been carried out as national projects in Japan and the United States. However, ceramic parts degrade in the combustion gas flow since recession proceeds due to steam. In order to maintain their durability, development of coating that preventing the recession (Environmental Barrier Coatings: EBC) is indispensable. For the development of EBC, it is important to select coating materials excellent in the characteristic preventing the recession and it is necessary to establish the method to evaluate the durability of the coating. For the selection of EBC material, the exposure test was performed in a combustion gas flow (T=1500℃, P=0.4MPa, V=150m/s, PO2≒22kPa, PH2O≒44kPa) by means of Yttria Stabilized Zirconia (YSZ) as a candidate material. Moreover, the influence of the impurities (Al2 O3, SiO2) contained in YSZ was examined. It is clarified that highly purified YSZ is promising candidate material. Moreover, in order to improve the characteristic preventing the recession, the increase of purity is required. Furthermore, impurities contained in YSZ disappeared selectively from the surface during the exposure test. The layer with decreased impurities was formed under the surface and its thickness increased according to the exposure. It implies that mass transfer such as diffusion of steam or impurities occurs in the inside of the specimen.

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