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In situ stress analysis of multilayer environmental barrier coatings

Published online by Cambridge University Press:  29 February 2012

B. J. Harder
Affiliation:
Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois, USA
J. Almer
Affiliation:
Argonne National Laboratory, Advanced Photon Source, Argonne, Illinois, USA
K. N. Lee
Affiliation:
Rolls-Royce Corporation, Materials, Processes, and Repair Technology, Indianapolis, Indiana, USA
K. T. Faber
Affiliation:
Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois, USA

Abstract

The biaxial stress and thermal expansion of multilayer doped-aluminosilicate environmental barrier coatings were measured in situ during cooling using microfocused high-energy X-rays in transmission. Coating stresses during cooling from 1000 °C were measured for as-sprayed and thermally cycled samples. In the as-sprayed state, tensile stresses as high as 75 MPa were measured in the doped-aluminosilicate topcoat at 375 °C, after which a drop in the stress occurred accompanied by through-thickness cracking of the two outermost layers. After thermally cycling the samples, the stress in the topcoat was reduced to approximately 50 MPa, and there was no drop in stress upon cooling. This stress reduction was attributed to a crystallographic phase transformation of the topcoat and the accompanying change in thermal expansion coefficient. The addition of a doped aluminosilicate to the mullite layer did not lower the stress in the topcoat, but may offer increased durability due to an increased compressive stress.

Type
X-Ray Diffraction
Copyright
Copyright © Cambridge University Press 2009

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References

Almer, J., Lienert, U., Peng, R. L., Schlauer, C., and Oden, M. (2003). “Strain and texture analysis of coatings using high-energy x-rays,” J. Appl. Phys.JAPIAU 94, 697702.10.1063/1.1582351Google Scholar
Bhatia, T., Eaton, H., Sun, E., Lawton, T., and Vedula, V. (2005). “ASME Turbo Expo: Power for Land, Sea, and Air,” Reno, NV, pp. 253258.Google Scholar
Evans, A. G. and Hutchinson, J. W. (1984). “On the mechanics of delamination and spalling in compressed films,” Int. J. Solids Struct.IJSOAD 20, 455466.10.1016/0020-7683(84)90012-XCrossRefGoogle Scholar
Faber, K. T., Weyant, C. M., Harder, B. H., Almer, J., and Lee, K. N. (2007). “Internal stresses and phase stability in multiphase environmental barrier coatings,” Int. J. Mater. Res.IJMRFV 98, 1188–95.CrossRefGoogle Scholar
He, B. B. and Smith, K. L. (1998). “Fundamental equation of strain and stress measurement using 2D detectors,” Proceedings of the 1998 SEM Spring Conference on Experimental and Applied Mechanics, Houston, TX, pp. 217220.Google Scholar
Hellwege, K. H. (1979). Elastic, Piezoelectric, and Related Constants of Crystals (Springer-Verlag, Berlin), Vol. 11.Google Scholar
Hyatt, M. J. and Bansal, N. P. J. (1996). “Crystal growth kinetics in BaOAl2O32SiO2 and SrOAl2O32SiO2 glasses,” Mater. Sci.MSCJDS 31, 172184.10.1007/BF00355142Google Scholar
Jacobson, N. S. (1993). “Corrosion of silicon-based ceramics in combustion environments,” J. Am. Ceram. Soc.JACTAW 76, 328.10.1111/j.1151-2916.1993.tb03684.xGoogle Scholar
Kimmel, J. B., Miriyala, N., Price, J. R., More, K. L., Tortorelli, P. F., Eaton, H. E., Linsey, G. D., and Sun, E. Y. (2002). “Evaluation of CFCC liners with EBC after field testing in a gas turbine,” J. Eur. Ceram. Soc.JECSER 22, 27692775.10.1016/S0955-2219(02)00142-5CrossRefGoogle Scholar
Lee, K. N., Fox, D. S., Eldridge, J. I., Zhu, D. M., Robinson, R. C., Bansal, N. P., and Miller, R. A. (2003). “Upper temperature limit of environmental barrier coatings based on mullite and BSAS,” J. Am. Ceram. Soc.JACTAW 86, 12991306.Google Scholar
Lee, K. N. (2000a). “Current status of environmental barrier coatings for Si-based ceramics,” Surf. Coat. Technol.SCTEEJ 133–134, 1–7.10.1016/S0257-8972(00)00889-6Google Scholar
Lee, K. N. (2000b). “Key durability issues with mullite-based environmental barrier coatings for Si-based ceramics,” J. Eng. Gas Turbines PowerJETPEZ 122, 632636.10.1115/1.1287584Google Scholar
Lee, K. N., Miller, R. A., and Jacobson, N. S. (1995). “New generation of plasma-sprayed mullite coatings on silicon carbide,” J. Am. Ceram. Soc.JACTAW 78, 705710.10.1111/j.1151-2916.1995.tb08236.xGoogle Scholar
Noyan, I. C. and Cohen, J. B. (1987). Residual Stress: Measurement by Diffraction and Interpretation (Springer-Verlag, New York).Google Scholar
Opila, E. J. (1999). “Variation of the oxidation rate of silicon carbide with water-vapor pressure,” J. Am. Ceram. Soc.JACTAW 82, 18261834.10.1111/j.1151-2916.1999.tb02005.xGoogle Scholar
Opila, E. J., Smialek, J. L., Robinson, R. C., Fox, D. S., and Jacobson, N. S. (1999). “SiC recession caused by SiO2 scale volatility under combustion conditions: II, thermodynamics and gaseous-diffusion model,” J. Am. Ceram. Soc.JACTAW 82, 18261834.10.1111/j.1151-2916.1999.tb02005.xCrossRefGoogle Scholar
Smialek, J. L., Robinson, R. C., Opila, E. J., Fox, D. S., and Jacobson, N. S. (1999). “SiC and Si3N4 recession due to SiO2 scale volatility under combustor conditions,” Adv. Compos. Lett.ZZZZZZ 8, 3345.10.1163/156855199X00056CrossRefGoogle Scholar
Thouless, M. D. (1991). “Cracking and delamination of coatings,” J. Vac. Sci. Technol. AJVTAD6 9, 25102515.10.1116/1.577265CrossRefGoogle Scholar
Touloukian, Y. S., Kirby, R. K., Taylor, R. E., and Lee, T. Y. (1977). Thermal Expansion of Nonmetallic Solids (Plenum, New York), Vol. 13.CrossRefGoogle Scholar
Weyant, C. M., Faber, K. T., Almer, J. D., and Guiheen, J. V. (2005). “Residual stress and microstructural evolution in tantalum oxide coatings on silicon nitride,” J. Am. Ceram. Soc.JACTAW 88, 21692176.CrossRefGoogle Scholar
Weyant, C. M., Faber, K. T., Almer, J. D., and Guiheen, J. V. (2006). “Residual stress and microstructural evolution in environmental barrier coatings of tantalum oxide alloyed with aluminum oxide and lanthanum oxide,” J. Am. Ceram. Soc.JACTAW 89, 971978.10.1111/j.1551-2916.2005.00830.xCrossRefGoogle Scholar