What are the common sintering methods for powder metallurgy?

What are the common sintering methods for powder metallurgy?

As we all know, powder metallurgy is made by producing powder, compacting, sintering and post-treatment processes. During the sintering process, the powder particles will flow, diffuse, melt, recrystallize and other physical and chemical processes to further compact the powder and eliminate some or all of the pores. What are the common sintering methods for powder metallurgy? Here is a brief introduction of the Zhongwei Precision Editor:

powder metallurgy

1. Pressurized sintering: during sintering, pressure is applied to the powder to promote its densification process. Pressurized sintering is sometimes synonymous with hot pressing. Hot pressing is the process of combining powder forming and sintering to directly obtain products.

2. Solid phase sintering: the sintering temperature is below the melting point of each component in the powder, generally 0.7 ～ 0.8Tm (Tm is the absolute melting point, calculated by K).

3. Liquid phase sintering: if there are more than two kinds of components in the powder compacts, the sintering may be carried out above the melting point of a certain component, so a small amount of liquid phase appears in the powder compacts during sintering.

4. Electric spark sintering: when the powder is formed and pressed, DC and pulse electricity are applied to make the powder particles produce an arc for sintering; During sintering, pressure is gradually exerted on the workpiece to combine the two processes of forming and sintering.

5. Activated sintering: some physical or chemical measures are adopted in the sintering process to greatly reduce the sintering temperature and shorten the sintering time, while the performance of the sintered body is improved.

6. Infiltration is also called infiltration: in order to improve the strength and other properties of porous blanks, the porous blanks are contacted with liquid metals or alloys that can wet their solid surfaces at high temperatures. Due to the capillary force, the liquid metals will fill the pores in the blanks. This process is suitable for making alloy materials or products such as tungsten silver, tungsten copper, iron copper, etc.

The above are six common methods for powder metallurgy sintering. In addition, powder metallurgy sintering must be carried out in a sintering furnace with a protective atmosphere to avoid oxidation of the sinter or adverse chemical reactions.