I. Definition of Powder Metallurgy

A sophisticated manufacturing technology that uses metal powders (or mixtures of metal and non-metal powders) as raw materials. It produces metal materials, composite materials, and various types of components through forming (primarily pressing) and sintering processes.

II. Core Process Steps

1. Powder Preparation

• Methods: Atomization (water/gas atomization), reduction, electrolysis, mechanical alloying, etc.
• Objective: To obtain powders with desired composition, particle size distribution, shape, and flowability.

2. Pressing (Compaction)

• Process: Powders are loaded into precision molds and compacted under high pressure (typically tens to hundreds of MPa).
• Result: Formation of a “green compact” with specific shape, dimensions, and preliminary strength.
• Key Factors: Powder flowability, mold design, and pressing parameter control.

3. Sintering

• Process: Green compacts are heated to 70%-90% of the main constituent’s melting point (below melting) under a protective atmosphere (or vacuum) and held for a defined time.
• Mechanism: Atomic diffusion, neck formation and growth between particles, leading to metallurgical bonding.
• Result: Final product achieves enhanced physical/mechanical properties (strength, hardness, density), shrinkage, and densification. Powder metallurgy sintering mesh belt is needed in the transportation process of powder metallurgy sintering furnace.

III. Main Advantages (vs. Traditional Casting, Forging, Machining)

• High Material Utilization (Near-Net Shape): Significantly reduces/eliminates machining; material utilization can exceed 95%, greatly lowering costs.
• Complex Shape Capability: Produces intricate geometries difficult/impossible with traditional methods (e.g., gears, pulleys, porous structures, internal cavities).
• Enhanced Material Design Flexibility: Enables special alloys (refractory metals, pseudo-alloys), composites (metal-ceramic, metal-polymer), porous materials, functionally graded materials. Allows precise control of composition, porosity, and properties (strength, wear resistance, friction reduction, magnetism, filtration).
• High Dimensional Accuracy & Surface Finish: High-precision molds and minimal sintering distortion yield good dimensional consistency and surface quality.
• Lower Relative Energy Consumption: Avoids melting; primary energy use is during sintering, typically lower than melting/casting processes.
• High Production Efficiency: Ideal for high-volume production of fixed-shape parts with high automation.

IV. Typical Application Areas (Demonstrating Advantages)

• Automotive Industry: Engine parts (connecting rods, bearing caps, sprockets, valve seats), transmission parts (synchronizer hubs, planetary carriers), shock absorber parts, oil pump gears. (High complexity, precision, volume)
• Aerospace: Superalloy turbine disks/blades, brake pads, structural components, filters. (High performance, specialty materials)
• Tooling Industry: Cemented carbide tools, drill bits, dies, diamond tools. (High hardness, wear resistance)
• Electronics & Electrical Engineering: Electrical contacts, magnetic materials (soft magnetic, permanent magnet), thermal management parts (heat sinks). (Special electrical, magnetic, thermal properties)
• Medical Devices: Surgical instruments, porous implants (e.g., artificial joints). (Biocompatibility, complex structures)
• Home Appliances & Hardware: Lock parts, power tool gears, sewing machine parts. (Cost-effectiveness, high volume)

V. Summary and Prospects

Powder metallurgy is an advanced manufacturing technology with significant vitality and promising prospects. Its unique capabilities – near-net shaping, material design freedom, high efficiency, and resource efficiency – make it increasingly vital in modern manufacturing, especially in fields demanding high-performance, precision, complex-shaped parts (e.g., new energy, electric vehicles, additive manufacturing/3D printing metal powder feedstocks). Continuous technological advancements (e.g., warm compaction, high-velocity compaction, metal injection molding, sinter hardening, integration with AM) are constantly expanding its application boundaries and performance limits.