Rietveld refinement and estimation of residual stress in GDC–LSCF oxygen transport membrane ceramic composites. Issue 9 (15th June 2018)

• Record Type: Journal Article
• Authors: Raju, Kati; Kim, Seyoung; Yu, Ji Haeng; Kim, Soo-Hyun; Seong, Young-Hoon; Han, In-Sub
• Is Part Of: Ceramics international. Volume 44:Issue 9(2018)
• Page Start: 10293
• Page End: 10298
• Publication Date: 2018-06-15
• Subjects: Composites -- X-ray diffraction -- Microstructure -- Residual stress; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2018.03.036
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: The phase purity and crystal structure of dual-phase Ce.9 Gd.1 O2–δ –La.6 Sr.4 Co.2 Fe.8 O3–δ (GDC–LSCF) composites were refined using data obtained from X-ray diffraction (XRD) by employing the Rietveld method. Rietveld analysis indicated that the structures of GDC and LSCF phases are well crystallized as cubic Fm 3 ̅ m and rhombohedral R 3 ̅ c space groups, respectively. Scanning electron microscopy images showed smooth and dense structures, depicting a homogeneous crystalline structure of the samples. When the composites were cooled from their sintering temperature (1250 °C), compressive stresses were generated in the GDC and corresponding tensile stresses were generated in the LSCF due to differences in thermal expansion coefficients. The compressive residual stresses of the composites were investigated by high-angle XRD measurements using the well-known sin 2 ψ method. The average compressive residual stresses in GDC phase are estimated to be − 312 and − 290 MPa for 80 GDC–20 LSCF and 50 GDC–50 LSCF, respectively. The aim of this study is to provide a better understanding of the crystal structures and residual stresses in GDC–LSCF composites through XRD and the suitability of these composites for oxygen transport membranes.