J. Kimmel et al. Journal of the European Ceramic Society 22(2002)2769-2775 Forward Cold side Forward Hot side 246.4cm Fig 3. Environmental barrier coated Hi-Nicalon/SiC CVi outer liner after the 13,937-h field test. 2.1. Visual inspection of liners The CSGT engine was disassembled in December 2000. There was a hole in the inner liner(Fig. 1). The hole was observed in the area where the EBC had spal led off in the early part of the test. The spallation was observed during the first borescope inspection after approximately 900 hours of engine operation. It appeared that the hole had formed due to gradual los of the material in the EBC-spalled area. The test was stopped before the hole could extend through the Nextel 440 fabric insulation layer(see Ref. I for information on combustor design). The Sic seal coat was unin Fig.4.Pinholes in the environmental barrier coated Hi-Nicalon/Sic tentionally applied very thick on both liners, on the CVI outer liner after the 13, 937-h field test. The location of several order of 500 um, and was partly responsible for the pinholes correlated with the processing asperities. inner liner to survive almost 14,000 h in the EBC-spalled +Bsas and BSAs for the outer liner. The post-test Digital images of the gas-path(hot side)and non gas evaluation of the liners by Solar, UTRC, Argonne path(cold side) surfaces of the two liners are presented National Laboratory(ANL) and ORnl is discussed inin Figs. 2 and 3. On the cold side, oxidation of silicon this paper. The focus of the evaluation was on how the carbide occurred to varying degrees. On the hot side, it EBCs performed in the engine environment in relation is evident from Figs. 2 and 3 that the EBC was still to their performance in the Keiser rig at ORNL present on large sections of the liners. However, EBC Fig. 5.(a) Thermal diffusivity images of Hi-Nicalon/SiC CVI outer liner after the 13, 937-h field test; (b)digital image of the liner after the 13.937-h+BSAS and BSAS for the outer liner. The post-test evaluation of the liners by Solar, UTRC, Argonne National Laboratory (ANL) and ORNL is discussed in this paper. The focus of the evaluation was on how the EBCs performed in the engine environment in relation to their performance in the Keiser rig at ORNL. 2. Results 2.1. Visual inspection of liners The CSGT engine was disassembled in December 2000. There was a hole in the inner liner (Fig. 1). The hole was observed in the area where the EBC had spal￾led off in the early part of the test. The spallation was observed during the first borescope inspection after approximately 900 hours of engine operation. It appeared that the hole had formed due to gradual loss of the material in the EBC-spalled area. The test was stopped before the hole could extend through the Nextel 440 fabric insulation layer (see Ref. 1 for information on combustor design). The SiC seal coat was unin￾tentionally applied very thick on both liners, on the order of 500 mm, and was partly responsible for the inner liner to survive almost 14,000 h in the EBC-spalled area. Digital images of the gas-path (hot side) and non gas￾path (cold side) surfaces of the two liners are presented in Figs. 2 and 3. On the cold side, oxidation of silicon carbide occurred to varying degrees. On the hot side, it is evident from Figs. 2 and 3 that the EBC was still present on large sections of the liners. However, EBC Fig. 3. Environmental barrier coated Hi-Nicalon/SiC CVI outer liner after the 13,937-h field test. Fig. 4. Pinholes in the environmental barrier coated Hi-Nicalon/SiC CVI outer liner after the 13,937-h field test. The location of several pinholes correlated with the processing asperities. Fig. 5. (a) Thermal diffusivity images of Hi-Nicalon/SiC CVI outer liner after the 13,937-h field test; (b) digital image of the liner after the 13,937-h field test. J. Kimmel et al. / Journal of the European Ceramic Society 22 (2002) 2769–2775 2771