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Title: Mechanical reliability and life prediction of coated metallic interconnects within solid oxide fuel cells

Metallic cell interconnects (IC) made of ferritic stainless steels, i.e., iron-based alloys, have been increasingly favored in the recent development of planar solid oxide fuel cells (SOFCs) because of their advantages in excellent imperviousness, low electrical resistance, ease in fabrication, and cost effectiveness. Typical SOFC operating conditions inevitably lead to the formation of oxide scales on the surface of ferritic stainless steel, which could cause delamination, buckling, and spallation resulting from the mismatch of the coefficient of thermal expansion and eventually reduce the lifetime of the interconnect components. Various protective coating techniques have been applied to alleviate these drawbacks. In the present work, a fracture-mechanics-based quantitative modeling framework has been established to predict the mechanical reliability and lifetime of the spinel-coated, surface-modified specimens under an isothermal cooling cycle. Analytical solutions have been formulated to evaluate the scale/substrate interfacial strength and determine the critical oxide thickness in terms of a variety of design factors, such as coating thickness, material properties, and uncertainties. In conclusion, the findings then are correlated with the experimentally measured oxide scale growth kinetics to quantify the predicted lifetime of the metallic interconnects.
Authors:
 [1] ;  [2] ;  [3] ;  [3]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Computational Mathematics Group, Physical and Computational Sciences Directorate
  2. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Computational Engineering Group, Physical and Computational Sciences Directorate
  3. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Energy & Environment Directorate
Publication Date:
Report Number(s):
PNNL-SA-120828
Journal ID: ISSN 0960-1481; PII: S0960148117306079
Grant/Contract Number:
AC05-76RL01830
Type:
Accepted Manuscript
Journal Name:
Renewable Energy
Additional Journal Information:
Journal Volume: 113; Journal Issue: C; Journal ID: ISSN 0960-1481
Publisher:
Elsevier
Research Org:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
30 DIRECT ENERGY CONVERSION; Solid oxide fuel cell (SOFC); Ferritic stainless steel interconnect; Coating; Fracture mechanics
OSTI Identifier:
1368407