Powder metallurgy is a technology that uses metal powders as raw materials to produce metallic materials, composite materials, and various types of products after forming and sintering. The powder metallurgy process shares some similarities with ceramic production; therefore, a range of new powder metallurgy techniques can also be applied to the preparation of ceramic materials.

　　Thanks to the advantages of powder metallurgy technology, it has become a key solution for addressing challenges in new materials and plays a crucial role in the development of novel materials. Many factors influence the performance of sintered bodies, including the characteristics of the powders as well as the conditions under which they are formed and sintered. The factors related to sintering conditions include the heating rate, sintering temperature and duration, cooling rate, sintering atmosphere, and pressure conditions.

　　The sintering temperature and holding time can affect the porosity, density, strength, and hardness of the sintered body. A high sintering temperature and a long heating time may degrade product performance and even lead to burning defects. Conversely, a low sintering temperature or an excessively long heating time may also result in performance degradation due to the sintering process itself.

　　The sintering atmospheres commonly used in powder metallurgy include reducing atmospheres, vacuum, and hydrogen atmospheres. The sintering atmosphere directly affects the performance of the sintered body. Sintering in a reducing atmosphere can prevent the green compact from burning and allow the reduction of surface oxides. For example, iron- and copper-based products typically use gas or ammonia decomposition, while cemented carbides and stainless steels usually employ pure hydrogen. Active metals or refractory metals (such as beryllium, titanium, zirconium, and tantalum), as well as cemented carbides containing TiC alloys and stainless steels, can be sintered under vacuum conditions.

　　If two or more components are present in a powder compact, sintering may occur at temperatures above the melting points of these components, leading to the formation of a small amount of liquid phase within the compact. During sintering, pressure is applied to the powder to promote densification. Sometimes, pressure sintering and hot pressing are used interchangeably; however, hot pressing refers to the process in which the product is obtained directly after powder forming and sintering.

　　At the same time as improving the performance of the sintered body, this approach also employs certain physical or chemical measures to significantly reduce the sintering temperature and shorten the sintering time. When the powder is introduced into the compaction process, direct current (DC) and pulsed power are applied, thereby generating an electric arc between the powder particles. The sintering process then begins. During sintering, pressure is gradually applied to the workpiece, thus integrating the forming and sintering processes into a single step.

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