Mechanical properties of La1-xSrxCo0.2Fe0.8O3 mixed-conducting perovskites made by the combustion synthesis technique

Yeong Shyung Chou, Jeffrey W. Stevenson, Timothy R. Armstrong, Larry R. Pederson

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Abstract

This paper examined the room-temperature mechanical properties of a mixed-conducting perovskite La1-xSrxCo0.2Fe0.8O3 (x = 0.2-0.8). Powders were made by the combustion synthesis technique and sintered at 1250 °C in air. Sintered density, crystal phase, and grain size were characterized. Young's and shear moduli, microhardness, indentation fracture toughness, and biaxial flexure strength were determined. The Young's and shear moduli slightly increased with increasing strontium content. Young's modulus of 151-188 GPa and shear modulus of 57-75 GPa were measured. Biaxial flexure strength of approximately 160 MPa was measured for lower strontium content batches. Strength greatly decreased to approximately 40 MPa at higher strontium concentrations (x = 0.6-0.8) because of the formation of extensive cracking. Indentation toughness showed a higher value (approximately 1.5 MPa·m1/2) for low strontium (x = 0.2) content and a lower value (approximately 1.1 MPa·m1/2) for the other batches (x = 0.4-0.8). Materials with fine and coarse grain size were also tested at various indent loads and showed no dependence of toughness on crack size. In addition, fractography was used to characterize the critical flaw and fracture mode.

Original languageEnglish
Pages (from-to)1457-1464
Number of pages8
JournalJournal of the American Ceramic Society
Volume83
Issue number6
Publication statusPublished - 2000
Externally publishedYes

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ASJC Scopus subject areas

  • Ceramics and Composites

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