Powder metallurgy (PM) technologies are being leveraged for the production of automotive components, electric motors, rare-earth permanent magnets, and infrastructure for high-speed rail transport . The integration of powder metallurgy with additive manufacturing offers expanded opportunities for manufacturing high-performance metal and ceramic parts with tailored microstructures and enhanced functional properties . Metal injection molding (MIM) feedstock is composed of metal powder and a complex binder system, with powder particle shape playing a critical role in rheological behavior and final component quality .

The production of spherical iron powders is essential for advanced applications such as metal injection molding, additive manufacturing, and soft magnetics due to their sphere morphology, high density, and good flowability . While manufacturing processes like gas atomization and the carbonyl process are the only available routes for synthesis of spherical iron, recent research has demonstrated a novel two-stage (reduction + plasma spheroidization) process using iron oxide by-product from the steel industry . This sustainable approach successfully synthesized irregular iron powders with high purity (Fe(T)-98.2 wt%, Fe(M)-96.8 wt%) and spherical powders with high apparent density (3.84 g/cc) and good flowability (8.8 s/50 g) .

The characteristics of metal powders are important for all aspects of powder metallurgy operations, significantly affecting the performance of the final product, influencing factors like packing density, melt pool stability, and microstructure development . The three main powder production techniques—gas atomization, mechanical milling, and plasma atomization—produce different powder shapes, size distributions, and porosity levels. Gas-atomized powders with spherical shape have better rheology stability than water-atomized powders with dendritic shape, making spherical powders preferable for MIM feedstock .

Powder metallurgy applications span a wide range of industries, including automotive, aerospace, medical, and electronics, with the versatility in material selection and potential for tailored designs making powder metallurgy especially valuable in sectors that prioritize precision, flexibility, and superior performance . The primary powder-based additive manufacturing technologies include Powder Bed Fusion (PBF), Binder Jetting (BJ), Directed Energy Deposition (DED), Material Jetting (MJ), and Cold Spray (CS), each with distinct operating mechanisms, advantages, and industrial use cases .

The future of powder metallurgy applications and metal injection molding powders lies in the continued integration of advanced manufacturing technologies. Emerging developments—including multi-material deposition, hybrid additive-subtractive manufacturing, AI-driven process monitoring, and improved powder recycling—are enhancing sustainability, scalability, and application diversity . Hybrid additive-subtractive manufacturing combines the design freedom of additive manufacturing with the precision of Computer Numerical Control (CNC) milling, improving accuracy, surface finish, and reliability while reducing the need for post-processing operation