Powder Metallurgy
Powder metallurgy is the technology of using metal powder as raw material after molding and sintering to produce metal materials, composites and various types of products. Powder metallurgy methods are somewhat similar to ceramic production, so a range of new powder metallurgy techniques can also be used to prepare ceramic materials.
Advantages
Due to the advantages of powder metallurgy technology, it has become the key to solve the problems of new materials and plays a key role in the development of new materials. Many factors affect the properties of sintered bodies, namely the properties of powders, forming and sintering conditions. Factors of sintering conditions include heating rate, sintering temperature and time, cooling rate, sintering atmosphere and pressure conditions.
Influencing Factors
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 product performance and even lead to product charred defects. Meanwhile, low sintering temperature or long heating time may lead to performance decline due to sintering process.
Usually used in powder metallurgy sintering atmosphere is reduced atmosphere, vacuum, hydrogen atmosphere, etc.; Sintering atmosphere directly affects the properties of sintered body. Sintering in a reducing atmosphere prevents the burning of the block and allows the reduction of the oxide on the surface. For example, iron and copper-based products typically use gas or ammonia decomposition, while cemented carbide and stainless steel typically use pure hydrogen. Active or refractory metals (e.g. beryllium, titanium, zirconium, tantalum), cemented carbides containing Tic alloys and stainless steels can be used for vacuum sintering.
If two or more components are present in the powder press, sintering may occur above the melting point of the components, resulting in a small amount of liquid phase in the powder press. Pressure is applied to the powder during sintering to promote the densification process. Pressure sintering is sometimes synonymous with hot pressing, but hot pressing refers to the process by which the powder is formed and sintered directly to the product.
At the same time, some physical or chemical measures are adopted to significantly reduce the sintering temperature and sintering time while improving the properties of the sintered body. When the powder is introduced into the compaction process, direct current (DC) and pulse power are passed, and then an electric arc is generated between the powder particles. Then the sintering process begins. During the sintering process, pressure is gradually added to the workpiece, thus combining the molding and sintering of the two processes.
The above by the powder metallurgy gear manufacturer -Jiande Welfine Metal new material Co., Ltd. is a science and technology enterprise specializing in the development, production, sales and service of powder metallurgy products. The company mainly produces powder metallurgy products such as iron base, copper base and stainless steel with high precision, high strength, high density and high hardness. We look forward to win-win cooperation with you.
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