There are two factors that affect the sintering quality of powder metallurgy products:

1. Sintering temperature and time. Sintering temperature and time have an effect on the porosity, density, strength, hardness, and other properties of the sintered body. If the sintering temperature is too high or the time is too long, it will reduce the performance of the product and even cause over-burning defects. If the sintering temperature is too low or the time is too short, the product will be under-sintered, leading to decreased performance.

2. Sintering atmosphere. The sintering atmosphere used in powder metallurgy includes reducing atmosphere, vacuum, and hydrogen atmosphere, among others. The sintering atmosphere also directly affects the performance of the sintered body. Under reducing atmosphere, sintering can prevent burning and reduce oxidation on the surface. Iron-based and copper-based products usually use furnace gas or decomposed ammonia, while hard alloys and stainless steel typically use pure hydrogen. Reactive metals or refractory metals (such as beryllium, titanium, zirconium, and tantalum), hard alloys containing TiC, and stainless steels can be sintered in a vacuum atmosphere. Vacuum sintering can avoid the harmful effects of harmful components (such as H2O, O2, and H2) in the atmosphere and can reduce the sintering temperature (generally by 100-150℃).

Powder metallurgy is a technology for producing metal materials, composite materials, and various types of products by using metal powder (or a mixture of metal powder and non-metal powder) as raw materials and forming and sintering them.