Abstract
Ca3Co4O9+δceramic powders were synthesized by the polymerized complex (PC) method. The same Ca3Co4O9+δceramic bar were treated in turn with three different processes of oxygen treatment: with no treatment, with oxydol (H2O2) treatment, and with N2treatment. Dynamic mechanical analysis (DMA) was performed from 123 to 623 K at rate of 1 K/min while the measuring frequencies are 0.05, 0.1, 0.25, 0.5, 1, 2, and 5 Hz. Two internal friction peaks are observed: one at the temperature range from 360 to 400 K (a broad peak, peak 1) and the other at around 390 K (a sharp peak, peak 2). Peak 2 is in correspondence with sudden metal-semiconductor transition (MST) near 400 K. Peak 1 is a kind of internal friction relaxation peak. For the sample with H2O2treatment and with no treatment, the activation energyHare 1.24 eV and 1.04 eV, respectively, and the preexponential factor τ0are 2.54×10-17sec and 7.82×10-15sec, respectively. We speculate that the mechanical relaxation process occurs in the Ca2CoO3subsystem of Ca3Co4O9+δ. The relaxation process for sample with no treatment is associated with the migration of OVs clusters in Ca2CoO3subsystem, and the relaxation process for the sample with H2O2treatment is associated with the migration of isolated OVs in Ca2CoO3subsystem.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
