The influence of process conditions and post-annealing treatments on the ionic transport properties of metakaolin (MK) ceramics prepared by the cold sintering process (CSP) were investigated. Within the temperature range of 120–200 °C, CSP temperature has little influence on densification and microstructure. Impedance spectroscopy revealed that all as-sintered ceramics exhibited significant ionic conduction, with bulk conductivity of approximately 0.001 S/cm at 600 °C. The associated activation energies are confined to a narrow range of 0.63–0.65 eV. In contrast, post-annealing significantly alters the electrical microstructure, giving rise to an additional grain boundary response. Aft... More >