High-temperature deformation and defect chemistry of (La1−xSrx)1−yMnO3+δ

✍ Scribed by R.E. Cook; K.C. Goretta; J. Wolfenstine; P. Nash; J.L. Routbort

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 256 KB
• Volume: 47
• Category: Article
• ISSN: 1359-6454
• DOI: 10.1016/s1359-6454(99)00160-3

✦ Synopsis

AbstractÐThe creep behavior of (La 1Àx Sr x ) 1Ày MnO 3 + d has been studied as a function of oxygen partial pressure (P y2 ) and Sr concentration. Polycrystalline samples (x 0X1, 0.2, 0.3) were deformed at 1523 K in constant-crosshead-speed compression tests in various atmospheres (10 À2 P y2 10 5 ). The material deformed by grain-boundary sliding accommodated by lattice diusion with some possible cavitation and/ or interface reaction control. The defect-chemistry model which is standard in the literature could not explain the dependence of the stress on P y2 and the Sr concentration. A modi®ed defect-chemistry model shows that cation vacancies controlled the creep rate at P y2 10 5 for x 0X3 and at low P y2 for x 0X1 and 0.2, and that oxygen vacancies were rate-controlling at high P y2 for x 0X1 and 0.2.