Conventional or traditional sinteri

Conventional or traditional sintering entails the heating of materials at comparatively high temperatures, T=Tm/2, where Tm is the melting point, and under not too high pressure, P=0.2 GPa (2.0kBar), across a time frame from minutes to hours. These conditions ensure the adhesion and densification of powder through numerous diffusion dependent processes, including surface and grain boundary diffusion [20].Depending on the materials under consideration,the sintering temperature range for conventional sintering technique is at high temperatures typically =1000 °C to facilitate the mass transport processes that allows atoms, cations or molecular groups to diffuse [16]. This mass transport mechanism reduces the surface area of the particulates whilst eliminating porosity [23]. At high temperatures, the fine particles go through numerous changes from particle rearrangement, grain growth and pore elimination. In conventional sintering, energy is transported to the material via conduction and radiation of heat from the surface (i.e. energy transfer is induced by external heating source whereby heat flow is from outside to inside and is not dependent on the materials under consideration)[24].