It have two purpose in powder metallurgy sintering process: the one is that the sintered neck produced by the diffusion of the metal at high temperature bonds the originally mechanically compacted metal particles to form a metallic body.But if want to come true this process, it still need
sintering atmosphere with reducibility.In this way, on the one hand, the oxide layer on the surface of the original metal particles can be reduced to achieve the contact and bonding between the metal atoms of the particles, and on the other hand, the newly formed sintered neck can be prevented
from being destroyed by oxidation.The second purpose is achieve alloying of whole sintering material system, because the alloy elements in this system are mostly as mixed powder form to add base powder. It need well sintering atmosphere for the guarantee when sintering process of
mutual diffusion between various metal elements. Such as usually happen decarburization or carburizing in sintering process, it depend on the control of carbon potential in the sintering atmosphere.When the carbon potential in the atmosphere is lower than the carbon content in the mixture,
it will happen decarburization; on the contrary, it will happen carburizing. Its two phenomenons will have great influence to the quality of sintering steel parts and its performance.
Except prevent oxidation, decarburization and carburizing work, the sintering atmosphere have below works in sintering process:
Remove all of plastic and binders from brown parts.
Removal of impurities adsorbed in the metal powder.
Prevent parts oxidation in colder areas in the sintering furnance.
Ensure the pressure of inside sintering furnance is always higher than the atmospheric pressure outside the furnace.
Ensure stably quality when mass production.
When sintering different material use one sets of sintering furnance, it can remove the impurities in the furnance.
