The advanced nature of powder metallurgy technology stems from the scientific classification and precise selection of raw materials.Based on differences in material properties, functional positioning, and preparation processes, powder metallurgy raw materials can be systematically divided into three major categories: metal powders, non-metal powders, and auxiliary materials. Each category independently fulfills a specific purpose while also synergistically contributing to the final performance of the finished product.
Metal powders are the core pillar of the raw material system, and can be further classified according to matrix material into iron-based, copper-based, nickel-based, cobalt-based, and cemented carbide-based series. Iron powder, due to its abundant resources, low cost, and balanced comprehensive mechanical properties, has become the mainstream choice for structural component manufacturing. Its sub-types include reduced iron powder, water-atomized iron powder, and carbonyl iron powder, suitable for conventional pressing, high-density forming, and high-precision filter elements, respectively. Copper powder, with its excellent thermal and electrical conductivity, is widely used in electronic packaging, friction materials, and other fields. The differences in purity and morphology between electrolytic copper powder and atomized copper powder determine their suitability for scenarios prioritizing conductivity or pressing performance. Nickel-based and cobalt-based powders are characterized by their high-temperature resistance and corrosion resistance, and are often used in harsh environments such as hot-end components of aero-engines and chemical reactors. Some highly reactive alloy powders require inert gas protection during preparation to avoid oxidation contamination.
Non-metallic powders mainly serve reinforcing, lubricating, or functionalizing roles. Common categories include ceramic powders (such as silicon carbide and alumina), carbide powders (such as tungsten carbide and titanium carbide), and graphite. Ceramic powders, as reinforcing phases in metal matrix composites, can significantly improve the hardness and wear resistance of the matrix; cemented carbide powders, sintered to form hard alloys, are core materials for cutting tools and drilling equipment; graphite, with its dual functions of lubrication and conductivity, is commonly used in self-lubricating bearings and electrode products.
Auxiliary materials are crucial for optimizing the process window, encompassing lubricants, binders, and forming agents. Lubricants (such as zinc stearate) can reduce internal friction during powder pressing and improve the uniformity of compact density; binders (such as polymer or wax-based systems) impart temporary plasticity to powders during warm pressing and injection molding, overcoming the limitations of complex shape forming; forming agents, by adjusting powder flowability and shape retention, ensure the high efficiency and stability of automated production.
The scientific classification of raw materials not only provides clear guidance for process design but also drives powder metallurgy towards high performance and multifunctionality by precisely matching application scenarios. With the development of new material technologies, the classification system will continue to be refined, injecting richer material genes into precision manufacturing.