Different electrolyte specimens were prepared with 5 wt% of water and under 375 MPa at different temperatures (called "cold-sintering temperature") comprised in the 120℃–180℃ range. Fig. 6 illustrates the relative density evolution of pellets as a function of the cold-sintering temperature, just after cold sintering and after annealing at 1200℃. For the as cold sintered pellet, the obtained densities are relatively low (75 %) when the sintering temperature is lower than 180 °C, whereas an increase of the relative density is observed at 180 °C reaching a value of 83 %.