Sintered powder metallurgy, metal powder or powder compacts, in the heating to a temperature lower than the melting point of the main component, due to the physical and chemical interactions between the particles occur, to obtain the required strength and characteristics of the material or product process. It is one of the basic processes of the powder metallurgy process.
Sintered powder metallurgy can transform powder-formed compacts from agglomerates of particles into materials or articles of crystallized composites, so the powder sintering theory has its own characteristics. Sintering generally takes place under a protective atmosphere, sometimes with the addition of a certain amount of filler, which is carried out in a high-temperature sintering furnace. For the powder sintering atmosphere, the powder sintering filler and the powder metallurgy sintering furnace should pay attention to and conduct research.
Liquid-phase sintering is commonly used in sintered powder metallurgy:
If there are more than two kinds of components in the powder compact, when sintering, it must be noted that it may be carried out above the melting point of a certain component. In such sintering methods, a small amount of powder compacts will appear. The liquid phase.
Pressurized sintering in sintered powder metallurgy:
During sintering, the powder is pressured to promote its densification process. Pressure sintering is sometimes synonymous with hot-pressing. Hot-pressing is the process of combining the forming and sintering of a powder to obtain the product directly.
Activated sintering in sintered powder metallurgy:
In the sintering process, some physical or chemical measures are adopted, so that the sintering temperature is greatly reduced, the sintering time is significantly shortened, and the performance of the sintered body is improved and improved.
Electrospark sintering in sintered powder metallurgy:
The powder body is subjected to direct current and pulsed electricity during the forming and pressing, so that an arc is generated between the powder particles to be sintered; during the sintering, the workpiece is gradually pressurized, and the forming and sintering are combined together.
On the sintering powder metallurgy, it should be noted that according to the composition of the powder raw materials, sintering itself will be divided into powder solid-phase sintering and powder liquid phase sintering; according to the sintering atmosphere, sintering will be divided into powder atmosphere sintering and powder vacuum sintering; In order to speed up the sintering process, powder activation sintering has also been developed; in order to adapt to the requirements of certain special products, the forming process can sometimes be omitted. The powder is loosely packed in a high temperature resistant die without forming and is directly performed at high temperature. Sintering is called powder loose sintering.