A schematic representation of the d

A schematic representation of the different phenomena taking place during CS is reported in Figures 3 and 4 for isostatic and uniaxial pressure-assisted sintering.During Stage I, the application of pressure to the liquid medium results in an isostatic compression of the particles (regardless of whether the pressure is applied with a uniaxial or an isotactic press). During Stage I four main phenomena take place: (i) the material is partially dissolved in the liquid, (ii) Ostwald ripening takes place (leading to an increase of the average particle size),(iii) recrystallisation phenomena might occur (leading to the formation of new crystals or new phases from the liquid), and (iv) the sample starts drying. UCS and ICC are characterised by substantially different drying processes. In the former, drying takes place during the whole of Stage I, with evaporation occurring through the gap (clearance) between the punches and the die. Conversely, in the case of ICC drying starts only after the sample has been removed from the isostatic press, so that drying does not occur at all during StageI. After being removed from the press, the sample is dried in ambient conditions or in an environmental chamber (the liquid evaporates at the sample surface).