The solubility of water in raw ceramic powders is considered important in CSP. For water-soluble materials such as NaCl and V2O5, densification was found to occur through a dissolution -precipitation process at the contacts between particles given sufficient external pressure and capillary forces [22]. However, recent studies have shown that the CSP can be promoted not only by acid solutions but also by LiOH, acetic acid solutions, etc. [33, 34]. For instance, ZnO was found to be dramatically densified by using acetic acid solution during CSP below 300℃ [33].