Cold sintering of colloidal silica particles using different alkali solutions

The present work is focused on the cold sintering of colloidal silica particles with the aid of different alkaline solutions as the transient phase. The studies were carried out with 2 M NaOH, KOH and LiOH water solutions. The densification was optimized, varying the uniaxial applied pressure between 200 and 600 MPa at 200 °C with a dwell time of 15 min. An optimal densification was achieved under 500 MPa pressure. The sintered materials also have relatively low corrosion in water. Delayed densification was observed in the LiOH system compared to KOH and NaOH which exhibited a similar behaviour.