Effect of Heating Modes on Reactive Sintering of Ca3Co4O9 Ceramics |
| |
Authors: | P Ravi Teja A Raja Annamalai Gecil Evangeline T Muthe Srikanth Dinesh K Agrawal Chun-Ping Jen |
| |
Institution: | 1.Department of Manufacturing Engineering, School of Mechanical Engineering, VIT Vellore, Vellore 632014, India; (P.R.T.); (G.E.T.); (M.S.);2.Centre for Innovative Manufacturing Research, VIT Vellore 632014, India;3.Material Research Institute, Pennsylvania State University, Pennsylvania, PA 16802, USA;4.Department of Mechanical Engineering and Advanced Institute of Manufacturing for High-Tech Innovations, National Chung Cheng University, Chia-Yi 62102, Taiwan |
| |
Abstract: | The traditional solid-state reaction method was employed to synthesize bulk calcium cobaltite (Ca349/Ca3Co4O9) ceramics via ball milling the precursor mixture. The samples were compacted using conventional sintering (CS) and spark plasma sintering (SPS) at 850, 900, and 950 °C. The X-ray diffraction (XRD) pattern indicates the presence of the Ca349 phase for samples sintered at 850 and 900 °C. In addition, SPS fosters higher densification (81.18%) than conventional sintering (50.76%) at elevated sintering temperatures. The thermo-gravimetric analysis (TGA) and differential thermal analysis (DTA) performed on the precursor mixture reported a weight loss of ~25.23% at a temperature range of 600–820 °C. This current work aims to analyze the electrical properties (Seebeck coefficient (s), electrical resistivity (ρ), and power factor) of sintered samples as a function of temperature (35–500 °C). It demonstrates that the change in sintering temperature (conventional sintering) did not evince any significant change in the Seebeck coefficient (113–142 μV/K). However, it reported a low resistivity of 153–132 μΩ-m and a better power factor (82–146.4 μW/mK2) at 900 °C. On the contrary, the SPS sintered samples recorded a higher Seebeck coefficient of 121–181 μV/K at 900 °C. Correspondingly, the samples sintered at 950 °C delineated a low resistivity of 145–158 μΩ-m and a better power factor (97–152 μW/mK2). |
| |
Keywords: | calcium cobaltite reactive sintering solid-state synthesis spark plasma sintering (SPS) electrical properties |
|
|