vacuum sintering furnace advantages

Vacuum sintering furnace is mainly used for sintering of active metal, refractory metal, hard alloy, magnetic material and stainless steel. Vacuum sintering furnace is actually low pressure sintering. The higher the vacuum degree is, the closer it is to the neutral atmosphere, the more it will not react with the material.

The main advantages of vacuum sintering furnace are:
(1) Vacuum is good for removing the adsorbed gas and promoting the shrinkage in the later stage of sintering.
(2) Vacuum is conducive to the removal of impurities such as silicon, aluminum, magnesium, calcium or their oxides, and plays the role of purifying materials.
(3) Vacuum can improve the wettability of liquid phase sintering, which is beneficial to the shrinkage during the sintering process and the improvement of the structure of the alloy.
(4) Vacuum is an ideal inert atmosphere. When it is not suitable to use other reducing or inert gases, or for materials prone to decarburization and carburization, vacuum sintering furnace can be used.
(5) Reduce the pollution of harmful components (water, oxygen, nitrogen, etc.) in the atmosphere. For example, it is difficult to reduce the water content in electrolytic hydrogen to dew point-40 ℃, while in vacuum sintering, the vacuum degree is equivalent to dew point-40 ℃ as long as it is in hundreds of PA.

The evaporation loss of bonding metal is an important problem in liquid phase sintering under vacuum. This not only changes and influences the final composition and structure of the alloy, but also hinders the sintering process itself. The volatilization loss of bonding metal mainly occurs in the later stage of sintering (i.e. heat preservation stage). The longer the holding time is, the more volatile the bonding metal will lose. Therefore, the impurities and moisture in the chemical react with the carbon in the material and form CO which is discharged with the furnace. At this time, the furnace pressure increases obviously and the total carbon content in the alloy decreases. Obviously, the change of carbon content depends on the oxygen content in the raw material powder and the vacuum degree during sintering. The higher the two, the easier the reaction of carbon monoxide and the more serious the decarbonization.