Advantages of Vacuum Sintering
1. Under the condition of vacuum sintering, it is easy to control the carbon content of the alloy. At sintering temperature, the pressure in the furnace is only tens of pa, or even lower. The molecule of O 2, N 2, H 2 and H 2 are very few. Many reactions can be neglected, and the influence of medium is very small. As long as the dewaxing process is strictly controlled, the carbon content of the alloy changes very little during the vacuum sintering process, and its properties and structure are fairly stable.
2. Under vacuum sintering conditions, the purity of cemented carbide can be improved. Vacuum sintering is conducive to reduction of metal oxides; during the whole sintering cycle, there is no need to open the furnace door, no air entering, and almost no reaction involving N2 and O2 occurs.
3. Under the condition of vacuum sintering, there are less impurities adsorbed on the surface of the hard phase, which can improve the wettability of the drill to the hard phase and the strength of the alloys, especially those containing TiC.
4. Under the condition of vacuum sintering, the process is easy to operate. Because fillers can not be used in vacuum sintering, this not only simplifies the operation, but also avoids the adverse effect of fillers on the surface of sintered body.
5. The integration of dewaxing and sintering can reduce the oxidation of products, reduce the difficulty of carbon control, reduce the unoccupied area and reduce the labor intensity.
6. The integration of multi-atmosphere dewaxing and sintering can control temperature, atmosphere and furnace pressure separately in different temperature sections. It can realize isothermal sintering (insulation) at any temperature and accomplish many functions, such as gradient alloy sintering.