Slurry based multilayer environmental barrier coatings for silicon carbide and silicon nitride ceramics — II. Oxidation resistance

2010 ◽  
Vol 205 (2) ◽  
pp. 266-270 ◽  
Author(s):  
Sivakumar Ramasamy ◽  
Surendra N. Tewari ◽  
Kang N. Lee ◽  
Ramakrishna T. Bhatt ◽  
Dennis S. Fox
Keyword(s):  
Silicon Carbide ◽  
Silicon Nitride ◽  
Oxidation Resistance ◽  
Barrier Coatings ◽  
Environmental Barrier Coatings ◽  
Environmental Barrier ◽  
Nitride Ceramics

Slurry based multilayer environmental barrier coatings for silicon carbide and silicon nitride ceramics — I. Processing

2010 ◽  
Vol 205 (2) ◽  
pp. 258-265 ◽  
Author(s):  
Sivakumar Ramasamy ◽  
Surendra N. Tewari ◽  
Kang N. Lee ◽  
Ramakrishna T. Bhatt ◽  
Dennis S. Fox
Keyword(s):  
Silicon Carbide ◽  
Silicon Nitride ◽  
Barrier Coatings ◽  
Environmental Barrier Coatings ◽  
Environmental Barrier ◽  
Nitride Ceramics

Development and Evaluation of Environmental Barrier Coatings for Si-Based Ceramics

2004 ◽  
Author(s):  
Tania Bhatia ◽  
Venkat Vedula ◽  
Harry Eaton ◽  
Ellen Sun ◽  
John Holowczak ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Silicon Nitride ◽  
Field Tests ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Barrier Coatings ◽  
Environmental Barrier Coatings ◽  
Environmental Barrier ◽  
And Performance ◽  
Combustor Liner

Environmental barrier coatings (EBCs) are being developed for silicon carbide (SiC) based composites and monolithic silicon nitride (Si3N4) to protect against the accelerated oxidation and subsequent silica volatilization in high temperature, high-pressure steam environments encountered in gas turbine engines. While EBCs for silicon carbide (EBCSiC) have been demonstrated in combustor liner applications, efforts are ongoing in the development of EBC systems for silicon nitride (EBCSiN). The challenges of adapting EBCSiC to monolithic Si3N4 are discussed in this paper. Progress in the area of EBCSiN including development and performance during field tests and tests simulating engine conditions are reviewed.

Development and Evaluation of Environmental Barrier Coatings for Silicon Nitride

2002 ◽  
Author(s):  
Ellen Y. Sun ◽  
Harry E. Eaton ◽  
John E. Holowczak ◽  
Gary D. Linsey
Keyword(s):  
Silicon Carbide ◽  
Silicon Nitride ◽  
Ceramic Matrix Composites ◽  
Turbine Engines ◽  
Matrix Composites ◽  
Gas Turbine Engines ◽  
Barrier Coatings ◽  
Environmental Barrier Coatings ◽  
Environmental Barrier ◽  
Temperature Capability

Environmental barrier coatings (EBCs) are required for applications of silicon nitride (Si3N4) and silicon carbide (SiC) based materials in gas turbine engines because of the accelerated oxidation of Si3N4 and SiC and subsequent volatilization of silica in the high temperature high-pressure steam environment. EBC systems for silicon carbide fiber reinforced silicon carbide ceramic matrix composites (SiC/SiC CMC’s) were first developed and have been demonstrated via long-term engine tests. Recently, studies have been carried out at United Technologies Research Center (UTRC) to understand the temperature capability of the current celsian-based EBC systems and its suitability for silicon nitride ceramics concerning thermal expansion mismatch between the EBC coating and silicon nitride substrates. This paper will present recent progress in improving the temperature capability of the celsian –based EBC systems and discuss their effectiveness for silicon nitride.

Environmental Barrier Coatings for Monolithic Silicon Nitride: Bond Coat Development

2007 ◽  
Author(s):  
Tania Bhatia ◽  
G. V. Srinivasan ◽  
Sonia V. Tulyani ◽  
Robert A. Barth ◽  
Venkat R. Vedula ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Bond Coat ◽  
Room Temperature ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Barrier Coatings ◽  
Environmental Barrier Coatings ◽  
Environmental Barrier ◽  
Pressure Steam ◽  
Non Line Of Sight

Environmental barrier coatings (EBCs) are being developed for silicon carbide (SiC) based composites and monolithic silicon nitride (Si3N4) to protect against the accelerated oxidation and subsequent silica volatilization in high temperature high-pressure steam environments encountered in gas turbine engines. It has been found that the application of EBCs developed for SiC-based composites (EBCSiC) to monolithic silicon nitride results in a loss of room temperature mechanical strength of the monolithic substrate. In this paper, we discuss the development of a bond coat system tailored for monolithic silicon nitride that helps retain the strength of the substrate. Some of the unique requirements and challenges associated with the processing of non-line-of-sight EBCs for Si3N4 will also be discussed. Preliminary results from coating of airfoils will be presented.

Advanced Environmental Barrier Coatings for SiC/SiC Composites

2005 ◽  
Author(s):  
Tania Bhatia ◽  
Harry Eaton ◽  
Ellen Sun ◽  
Thomas Lawton ◽  
Venkat Vedula
Keyword(s):  
Silicon Carbide ◽  
Field Tests ◽  
Barrier Coatings ◽  
Environmental Barrier Coatings ◽  
Environmental Barrier ◽  
Carbide Matrix ◽  
Higher Temperature ◽  
Engine Testing ◽  
Sic Composites ◽  
Combustor Liner

Environmental barrier coatings (EBCs) are being developed for silicon carbide fiber reinforced silicon carbide matrix (SiC/SiC) composites to protect against accelerated oxidation and subsequent silica volatilization in high temperature, high-pressure steam environments encountered in gas turbine engines. Engine testing of three-layer barium strontium aluminosilicate (BSAS) has demonstrated a life of over 15,000 hours in a combustor liner application at a nominal temperature of 2200°F (1204°C). The engine field tests have shown that useful engine life is limited by BSAS recession and potential eutectic reactions between BSAS and silica. BSAS based coatings have also been shown to survive severe thermal gradient burner rig tests with 2700°F (1482°C) surface temperature and a 300°F (167°C) gradient through the coating. Promising EBC candidates for longer life and/or higher temperature applications include strontium aluminosilicate (SAS) based coatings.

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