Factors Affecting the Sintering Quality of Metal Powder Injection Molding (MIM)

Oct 29, 2022

Metal powder injection molding (MIM) is a technology that uses metal powder (or mixture of metal powder and non-metal powder) as raw materials to produce metal materials, composite materials and various types of products after molding and sintering. The metal powder injection molding method is somewhat similar to the production of ceramics; Therefore, a series of new metal powder injection molding technologies can also be used to prepare MIM ceramic case materials. Due to the advantages of metal powder injection molding technology, it has become the key to solve the problem of new MIM materials and plays a key role in the development of new MIM materials. So, what are the factors that affect the sintering quality of metal powder injection molding (MIM)? The following is a brief explanation by ZHONGWEI of Qinhuangdao.

There are many factors that affect the properties of sinter, namely, the characteristics of powder, molding and sintering conditions. The factors of sintering conditions include heating rate, sintering temperature and time, cooling rate, sintering atmosphere and pressure conditions.

The sintering temperature and time can affect the porosity, density, strength and hardness of the sintered body. High sintering temperature and long heating time will reduce the product performance, even lead to product coking defects. At the same time, low sintering temperature or long heating time may cause performance degradation due to the sintering process.

Sintering atmosphere is usually used for metal powder injection molding. The sintering atmosphere is reducing atmosphere, vacuum, hydrogen atmosphere, etc. The sintering atmosphere directly affects the properties of the sintered body. Sintering in reducing atmosphere can prevent the burning of briquette and allow the reduction of surface oxides. For example, iron and copper based products are usually decomposed by gas or ammonia, while cemented carbide and stainless steel usually use pure hydrogen. Active metals or refractory metals (such as beryllium, titanium, zirconium, tantalum), hard alloys containing Tic alloys and stainless steels can be used for vacuum sintering. Vacuum sintering can avoid harmful components (H2O, O2). If there are two or more components in the powder compacts, sintering may occur above the melting point of the components, resulting in a small amount of liquid phase in the powder compacts.

Pressure sintering exerts pressure on the powder during sintering to promote the densification process. Sometimes pressure sintering and hot pressing are synonymous, but hot pressing refers to the process of directly obtaining products after powder forming and sintering.

At the same time, activated sintering can improve the performance of the sintered body, and it is also a method to reduce the sintering temperature and time by taking some physical or chemical measures. Activated sintering When the powder is introduced into the compaction process, an electric arc is generated between the powder particles through DC and pulse power. Then the sintering process starts. In the sintering process, pressure is gradually added to the workpiece to combine the forming and sintering of the two processes.

The above is a brief explanation of the factors that affect the sintering quality of metal powder injection molding (MIM) made by ZHONGWEI, Qinhuangdao. Is there any good help for you to understand the technology of metal powder injection molding (MIM)? For more information about metal powder injection molding technology, please consult the MIM technical team of zhongwei Precision Metal Powder Injection Molding in Qinhuangdao