Melt Infiltrated (MI) SiC/SiC Composites for Gas Turbine Applications

Silicon carbide fiber reinforced silicon carbide composites (SiC/SiC) are attractive for use in gas turbine engines as combustor liner materials, in part, because the temperature capability allows for reduced cooling. This enables the engine to operate more efficiently and to meet very stringent emission goals for NOx and CO. It has been shown, however, that SiC/SiC and other silica formers can degrade with time in the high steam environment of the gas turbine combustor due to accelerated oxidation and subsequent volatilization of the silica due to reaction with high pressure water (ref.s 1 & 2). As a result, an environmental barrier coating (EBC) is required in conjunction with the SiC composite in order to meet long life goals. Under the U.S. Department of Energy (DOE) sponsored Solar Turbines Incorporated Ceramic Stationary Gas Turbine (CSGT) engine program (ref. 3), EBC systems developed under the HSCT EPM program (NASA contract NAS3-23685) were applied to both SiC/SiC composite coupons and SiC/SiC combustion liners which were then evaluated in long term laboratory testing and in ground based turbine power generation, respectively. This paper discusses the application of the EBC’s to SiC/SiC composites and the results from laboratory and engine test evaluations.

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EBC Protection of SiC/SiC Composites in the Gas Turbine Combustion Environment: Continuing Evaluation and Refurbishment Considerations

Volume 4: Manufacturing Materials and Metallurgy; Ceramics; Structures and Dynamics; Controls, Diagnostics and Instrumentation; Education; IGTI Scholar Award ◽

10.1115/2001-gt-0513 ◽

2001 ◽

Cited By ~ 13

Author(s):

Harry E. Eaton ◽

Gary D. Linsey ◽

Ellen Y. Sun ◽

Karren L. More ◽

Joshua B. Kimmel ◽

...

Keyword(s):

Silicon Carbide ◽

Gas Turbine ◽

Department Of Energy ◽

Turbine Engines ◽

Gas Turbine Engines ◽

Barrier Coating ◽

Temperature Capability ◽

Pressure Water ◽

Sic Composites ◽

Combustor Liner

Silicon carbide fiber reinforced silicon carbide composites (SiC/SiC CMC’s) are attractive for use in gas turbine engines as combustor liner materials because the temperature capability allows for reduced cooling. This enables the engine to operate more efficiently and enables the design of very stringent emission goals for NOx and CO. It has been shown, however, that SiC/SiC CMC’s and other silica formers can degrade with time in the high steam environment of the gas turbine combustor due to accelerated oxidation and subsequent volatilization of the silica due to reaction with high pressure water (ref.s 1, 2, 3, & 4). As a result, an environmental barrier coating (EBC) is required in conjunction with the SiC/SiC CMC in order to meet long life goals. Under the U.S. Department of Energy (DOE) sponsored Solar Turbines Incorporated Ceramic Stationary Gas Turbine (CSGT) engine program (ref. 5), EBC systems developed under the HSCT EPM program and improved under the CSGT program have been applied to both SiC/SiC CMC coupons and SiC/SiC CMC combustion liners which have been evaluated in long term laboratory testing and in ground based turbine power generation. This paper discusses the continuing evaluation (see ref. 6) of EBC application to SiC/SiC CMC’s and the results from laboratory and engine test evaluations along with refurbishment considerations.

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Experimental Assessment of Fiber Reinforced Ceramics for Combustor Walls

Volume 4: Manufacturing Materials and Metallurgy; Ceramics; Structures and Dynamics; Controls, Diagnostics and Instrumentation; Education; IGTI Scholar Award ◽

10.1115/97-gt-154 ◽

1997 ◽

Author(s):

D. Filsinger ◽

S. Münz ◽

A. Schulz ◽

S. Wittig ◽

G. Andrees

Keyword(s):

High Temperature ◽

Gas Turbine ◽

Gas Turbines ◽

Gas Flow ◽

Ceramic Materials ◽

Inlet Temperature ◽

Test Duration ◽

Fiber Reinforced ◽

Hot Gas ◽

Sic Composites

Experimental and theoretical work concerning the application of ceramic components in small high temperature gas turbines has been performed for several years. The significance of some non-oxide ceramic materials for gas turbines in particular is based on their excellent high temperature properties. The application of ceramic materials allows an increase of the turbine inlet temperature resulting in higher efficiencies and a reduction of pollution emissions. The inherent brittleness of monolithic ceramic materials can be virtually reduced by reinforcement with ceramic fibers leading to a quasi-ductile behavior. Unfortunately, some problems arise due to oxidation of these composite materials in the presence of hot gas flow containing oxygen. At the Motoren- und Turbinen Union, München GmbH, comprehensive investigations including strength, oxidation, and thermal shock tests of several materials that seemed to be appropriate for combustor liner applications were undertaken. As a result, C/C, SiC/SiC, and two C/SiC-composites coated with SiC, as oxidation protection, were chosen for examination in a gas turbine combustion chamber. To prove the suitability of these materials under real engine conditions, the fiber reinforced flame tubes were installed in a small gas turbine operating under varying conditions. The loading of the flame tubes was characterized by wall temperature measurements. The materials showed different oxidation behavior when exposed to the hot gas flow. Inspection of the C/SiC-composites revealed debonding of the coatings. The C/C- and the SiC/SiC-materials withstood the tests with a maximum cumulated test duration of 90 hours without damage.

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Experimental Assessment of Fiber-Reinforced Ceramics for Combustor Walls

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.1364523 ◽

1997 ◽

Vol 123 (2) ◽

pp. 271-276 ◽

Cited By ~ 16

Author(s):

D. Filsinger ◽

S. Mu¨nz ◽

A. Schulz ◽

S. Wittig ◽

G. Andrees

Keyword(s):

High Temperature ◽

Gas Turbine ◽

Gas Turbines ◽

Gas Flow ◽

Ceramic Materials ◽

Inlet Temperature ◽

Test Duration ◽

Fiber Reinforced ◽

Hot Gas ◽

Sic Composites

Experimental and theoretical work concerning the application of ceramic components in small high-temperature gas turbines has been performed for several years. The significance of some nonoxide ceramic materials for gas turbines in particular is based on their excellent high-temperature properties. The application of ceramic materials allows an increase of the turbine inlet temperature resulting in higher efficiencies and a reduction of pollution emissions. The inherent brittleness of monolithic ceramic materials can be virtually reduced by reinforcement with ceramic fibers leading to a quasiductile behavior. Unfortunately, some problems arise due to oxidation of these composite materials in the presence of hot gas flow containing oxygen. At the Motoren und Turbinen Union, Mu¨nchen GmbH, comprehensive investigations including strength, oxidation, and thermal shock tests of several materials that seemed to be appropriate for combustor liner applications were undertaken. As a result, C/C, SiC/SiC, and two C/SiC composites coated with SiC, as oxidation protection, were chosen for examination in a gas turbine combustion chamber. To prove the suitability of these materials under real engine conditions, the fiber-reinforced flame tubes were installed in a small gas turbine operating under varying conditions. The loading of the flame tubes was characterized by wall temperature measurements. The materials showed different oxidation behavior when exposed to the hot gas flow. Inspection of the C/SiC composites revealed debonding of the coatings. The C/C and SiC/SiC materials withstood the tests with a maximum cumulated test duration of 90 h without damage.

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