Hot-pressing sintering is to apply unidirectional pressure to the sample at high temperature to promote the ceramic to achieve full density. Compared with conventional junctions, sintering at a pressure of 15 MPa reduces the sintering temperature of the ceramic by 200 and increases the density by 2%. And this trend increases with the increase of pressure. For pure alumina ceramics, conventional sintering requires: a temperature of more than 1800%; while the hot-press sintering of 20MP a only requires 1500%C.
The pressure provided by hot press sintering promotes the flow of atoms in the particles. At the same time, pressure and surface energy act as driving forces to strengthen the diffusion effect. Since hot pressing sintering can be sintered at a lower temperature, the growth of crystal grains is inhibited, and the obtained samples are dense and uniform, with small grains and high strength. But it is not suitable to produce products that are too high, too thick, and complex in shape. The production scale is small and the cost is high.