What is the process of copper-based powder metallurgy?

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　　 Copper-based powder metallurgy It is a manufacturing technology that uses metal powders—or mixtures of metal and non-metal powders—as raw materials, undergoing forming and sintering to produce metallic structural materials, composite construction materials, and a wide variety of products. Copper-based powder metallurgy is extensively applied in sectors such as transportation, machinery, electronics, aerospace, defense, biotechnology, new energy, information technology, and the nuclear industry, making it one of the most dynamic fields within materials science. This technology offers significant advantages—including energy and resource savings, superior performance, high product precision, and excellent stability—making it well suited for large-scale production. Moreover, materials and complex components that cannot be processed using conventional Chinese casting or machining techniques can also be manufactured through powder metallurgy, thereby attracting considerable attention from the industrial community.

　　The broad copper-based powder metallurgy industry encompasses iron‑ore tools, hard metals, magnetic materials, and various powder‑metallurgy products. The narrow powder‑metallurgy product sector refers specifically to powder‑metallurgy components—primarily powder‑metallurgy parts—oil‑impregnated bearings, and metal injection‑molded products.

　　The basic steps of the copper-based powder metallurgy process are as follows:

　　1. Production of copper-based powder metallurgy raw material powders. Traditional pulverization methods can be broadly classified into two categories: mechanical methods and physicochemical methods. Mechanical methods include mechanical grinding and atomization. Physicochemical methods encompass electrochemical etching, reduction, chemical methods, combined reduction–chemical methods, vapor-phase deposition, liquid-phase deposition, and electrolytic processes. Among these, reduction, atomization, and electrolysis are the most widely employed.

Copper-based powder metallurgy

　　2. For copper-based powder metallurgy, shaped green compacts are formed from powdered materials. The purpose of forming is to impart the green compact with a specific shape and dimensions, as well as a desired density and mechanical strength. Forming processes can generally be categorized into press‑forming and non‑press‑forming methods. Press‑forming commonly employs die pressing, while 3D printing technology can also be used to fabricate green parts.

　　3. Sintering of copper-based powder metallurgy billets. Sintering is the core process in powder metallurgy. The green compact, formed under pressure, undergoes sintering to achieve the desired physical and mechanical properties. Sintering can be classified into single-phase sintering and multi-phase sintering. The sintering temperature is lower than the melting point of the metals and alloys used in both single‑phase and multi‑component solid‑state sintering. In the case of a multi‑component system undergoing liquid‑phase sintering, the sintering temperature is typically maintained below the melting point of the refractory constituent and above that of the easily melted component. In addition to conventional sintering, there are also specialized sintering techniques such as transient liquid‑phase sintering, infiltration, and hot pressing.

　　4. Post‑processing of copper‑based powder metallurgy products. Depending on the product design requirements, a variety of post‑sintering treatments can be employed, including finishing, water immersion, machining, heat treatment, and electroplating. In addition, in recent years, new processes such as rolling and forging have also been applied to the post‑sintering processing of powder metallurgy materials, yielding highly satisfactory results.

　　 Copper-based powder metallurgy : A collective term for all the properties of a powder. These include the powder’s geometric characteristics (particle size, specific surface area, pore size, shape, etc.), its chemical and technological properties (chemical composition, purity, oxygen content, acid‑insoluble matter, etc.), its mechanical properties (bulk density, flowability, formability, compressibility, angle of repose, angle of shearing, etc.), as well as its physical and surface‑related properties (true density, gloss, absorbency, surface activity, zeta potential, magnetic properties, etc.). The properties of a powder often largely determine the performance of powder‑metallurgy products.

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