Role of electric and magnetic fields in the densification and grain growth of CaMnO3 perovskite sintered by microwave

This study investigates how electric and/or magnetic fields influence the densification and microstructural evolution of microwave-sintered CaMnO 3 (CMO) thermoelectric ceramics. Experiments used a maximum magnetic field microwave configuration (H-MW) from 900 °C to 1300 °C at various dwell times. Temperature and dwell time strongly influenced both densification and grain growth. Optimal densification (~90% relative density) occurred at 1300 °C for 15 min. Longer dwell times reduced final density due to abnormal grain growth. Furthermore, grain growth mechanisms transitioned with temperature from grain boundary ( n = 4) to lattice diffusion ( n = 3), with activation energy increasing with dwell time, due to marokite consumption into the sintering process. Overall, the H-MW configuration enables efficient densification and microstructural control, demonstrating its effectiveness in tailoring CMO sintering kinetics for thermoelectric applications.