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Title: CRACK GROWTH ANALYSIS OF SOLID OXIDE FUEL CELL ELECTROLYTES

Abstract

Defects and Flaws control the structural and functional property of ceramics. In determining the reliability and lifetime of ceramics structures it is very important to quantify the crack growth behavior of the ceramics. In addition, because of the high variability of the strength and the relatively low toughness of ceramics, a statistical design approach is necessary. The statistical nature of the strength of ceramics is currently well recognized, and is usually accounted for by utilizing Weibull or similar statistical distributions. Design tools such as CARES using a combination of strength measurements, stress analysis, and statistics are available and reasonably well developed. These design codes also incorporate material data such as elastic constants as well as flaw distributions and time-dependent properties. The fast fracture reliability for ceramics is often different from their time-dependent reliability. Further confounding the design complexity, the time-dependent reliability varies with the environment/temperature/stress combination. Therefore, it becomes important to be able to accurately determine the behavior of ceramics under simulated application conditions to provide a better prediction of the lifetime and reliability for a given component. In the present study, Yttria stabilized Zirconia (YSZ) of 9.6 mol% Yttria composition was procured in the form of tubes of lengthmore » 100 mm. The composition is of interest as tubular electrolytes for Solid Oxide Fuel Cells. Rings cut from the tubes were characterized for microstructure, phase stability, mechanical strength (Weibull modulus) and fracture mechanisms. The strength at operating condition of SOFCs (1000 C) decreased to 95 MPa as compared to room temperature strength of 230 MPa. However, the Weibull modulus remains relatively unchanged. Slow crack growth (SCG) parameter, n = 17 evaluated at room temperature in air was representative of well studied brittle materials. Based on the results, further work was planned to evaluate the strength degradation, modulus and failure in more representative environment of the SOFCs.« less

Authors:
;
Publication Date:
Research Org.:
University of Alaska (US)
Sponsoring Org.:
(US)
OSTI Identifier:
822680
DOE Contract Number:  
FC26-01NT41248
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 1 Oct 2003
Country of Publication:
United States
Language:
English
Subject:
30 DIRECT ENERGY CONVERSION; CERAMICS; CRACK PROPAGATION; DEFECTS; DESIGN; ELECTROLYTES; FORECASTING; FRACTURES; FUNCTIONALS; LIFETIME; MICROSTRUCTURE; PHASE STABILITY; RELIABILITY; SOLID OXIDE FUEL CELLS; STATISTICS; STRESS ANALYSIS

Citation Formats

Bandopadhyay, S, and Nagabhushana, N. CRACK GROWTH ANALYSIS OF SOLID OXIDE FUEL CELL ELECTROLYTES. United States: N. p., 2003. Web. doi:10.2172/822680.
Bandopadhyay, S, & Nagabhushana, N. CRACK GROWTH ANALYSIS OF SOLID OXIDE FUEL CELL ELECTROLYTES. United States. https://doi.org/10.2172/822680
Bandopadhyay, S, and Nagabhushana, N. Wed . "CRACK GROWTH ANALYSIS OF SOLID OXIDE FUEL CELL ELECTROLYTES". United States. https://doi.org/10.2172/822680. https://www.osti.gov/servlets/purl/822680.
@article{osti_822680,
title = {CRACK GROWTH ANALYSIS OF SOLID OXIDE FUEL CELL ELECTROLYTES},
author = {Bandopadhyay, S and Nagabhushana, N},
abstractNote = {Defects and Flaws control the structural and functional property of ceramics. In determining the reliability and lifetime of ceramics structures it is very important to quantify the crack growth behavior of the ceramics. In addition, because of the high variability of the strength and the relatively low toughness of ceramics, a statistical design approach is necessary. The statistical nature of the strength of ceramics is currently well recognized, and is usually accounted for by utilizing Weibull or similar statistical distributions. Design tools such as CARES using a combination of strength measurements, stress analysis, and statistics are available and reasonably well developed. These design codes also incorporate material data such as elastic constants as well as flaw distributions and time-dependent properties. The fast fracture reliability for ceramics is often different from their time-dependent reliability. Further confounding the design complexity, the time-dependent reliability varies with the environment/temperature/stress combination. Therefore, it becomes important to be able to accurately determine the behavior of ceramics under simulated application conditions to provide a better prediction of the lifetime and reliability for a given component. In the present study, Yttria stabilized Zirconia (YSZ) of 9.6 mol% Yttria composition was procured in the form of tubes of length 100 mm. The composition is of interest as tubular electrolytes for Solid Oxide Fuel Cells. Rings cut from the tubes were characterized for microstructure, phase stability, mechanical strength (Weibull modulus) and fracture mechanisms. The strength at operating condition of SOFCs (1000 C) decreased to 95 MPa as compared to room temperature strength of 230 MPa. However, the Weibull modulus remains relatively unchanged. Slow crack growth (SCG) parameter, n = 17 evaluated at room temperature in air was representative of well studied brittle materials. Based on the results, further work was planned to evaluate the strength degradation, modulus and failure in more representative environment of the SOFCs.},
doi = {10.2172/822680},
url = {https://www.osti.gov/biblio/822680}, journal = {},
number = ,
volume = ,
place = {United States},
year = {2003},
month = {10}
}