Alumina tubes are widely used for their excellent wear resistance and insulation properties. Edgetech can customize alumina tubes in various sizes. High-temperature sintering is a key step in alumina parts.
The performance of polycrystalline ceramic materials is not only related to the chemical composition, but also closely related to the material’s microstructure. After the formulation, mixing, molding, and other processes are completed, sintering is the key process to make the material obtain the expected microstructure and give the material various properties. The sintering of Al2O3 ceramics is the densification process of its green body at high temperature. With the increase of temperature and the extension of time, the solid particles are bonded to each other, the grains grow, the voids and grain boundaries gradually decrease, and through the transfer of substances, the total volume shrinks, the density increases, and finally becomes a hard polycrystalline sintered body with a certain microstructure. This process is the sintering of Al2O3 ceramics. Sintering is a process to reduce the pores in the molded body, increase the bonding between particles, and improve the mechanical strength. During the sintering process, as the temperature increases and the heat treatment time increases, the pores continue to decrease, and the bonding force between particles continues to increase. When a certain temperature and a certain heat treatment time are reached, the bonding force between particles presents a maximum value. After exceeding the maximum value, there is a tendency for the pores to increase slightly, and at the same time, the grains increase and the mechanical strength decreases. In thermodynamics, sintering refers to the process in which the total energy of the system decreases.