What Are the Differences Between Sintered Metal Powders and ...

08, Sep. 2025

 

What Are the Differences Between Sintered Metal Powders and ...

Porous metal materials, characterized by their porous structures, are innovative engineering materials that offer impressive strength while being light. These materials are used across different industries, including aerospace, metallurgy, mechanics, petrochemicals, energy, pharmaceuticals, architecture, and transportation. Their unique properties make them suitable for specialized applications, such as in life support systems, energy storage, hydrogen generation, and filtration systems.

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Porous metal materials can be categorized into three types:

  • Metal Foams. Metal foams are lightweight cellular structures composed of a solid base metal with gas-filled pores, inspired by natural materials like wood, bones, and sea sponges. This design gives metal foams high strength-to-weight ratios and excellent energy absorption properties, making them ideal for use in diverse industries such as aerospace and automotive applications.
  • Sintered Metal Powder. Sintered metal powder is a porous material produced by sintering, a process wherein the metallic powder is compressed and then heated at temperatures below its melting point. Sintering causes the particles to bond into a solid piece with small pores. Typically, sintered metal powders have a high solid volume fraction, ranging from 0.35 to 0.65; thus, this type of porous material is commonly used in applications where good mechanical strength is required.
  • Sintered Fiber Felts. Advancements in fiber-pullout techniques have led to the development of sintered metal fiber felt, a non-woven, porous material made of long metallic fibers typically over 1.5 µm in diameter. These fiber felts are used in structural applications, such as the core of sandwich panels, as well as in functional applications like anodic gas diffusion layers, catalyst supports, and filtration nets.

Manufacturing Sintered Metal Powders vs. Sintered Metal Fiber Felts

Unlike metal foams, which are typically created through a foaming process that introduces gas into metallic melts, sintered metal powders and fiber felts are formed by sintering compacted powders or laminated fibers, respectively. 

These changes are vital for different applications, as they determine the material’s porosity, strength, and overall performance. Therefore, sintering plays a major role in achieving the properties needed for specific uses.

Sintering Mechanism in Metal Powders

The different sintering stages show how loose metal powders transform into a solid object:

In the final stage of sintering, interconnected open pores close and turn into isolated closed pores. As this happens, grain growth occurs, which slows down the surface and bulk diffusion processes. Consequently, this stage becomes the slowest, as densification increases from 95% to 99%.

(SD: Surface Diffusion, VD: Vacancy Diffusion, GB: Grain Boundary Diffusion)

Sintering Mechanism in Metal Fiber Felts

Conversely, the other three modes lead to densification: boundary diffusion, lattice diffusion from the grain boundary, and lattice diffusion from dislocation. To predict the sintering conditions necessary to achieve desired properties, sintering diagrams have been developed for different powders and wires.  Originally, these diagrams were based on simple models, like the two-sphere model, which worked well for powders and wires. However, fiber felts, with their complex geometry, require a different approach. 

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Unlike in powders, where sintering occurs between particles bonded by van der Waals forces, sintering in fiber felts takes place in the joints between adjacent fibers at random angles. During the pressing or shaping of fibers, sintering joints primarily develop at points where fibers make contact. Under pressure, fibers interlock, forming many contact areas. These contact regions can be categorized as either fiber-to-fiber contact joints or fiber-to-fiber mechanical meshing. 

During sintering, material migrates in fiber-to-fiber contact joints or mechanical meshing to reduce surface energy. Initially, sintering begins on microstructures’ surfaces, forming contact points between fibers, which then strengthen. This process continues across the fiber network, forming a mesh-like structure. In comparison to sintering powders, sintering metal fiber felts undergo less densification. This is because surface processes, grain growth, and neck growth mechanisms dominate over densification processes like grain boundary diffusion.

Difference between Sintered Metal Powder and Sintered Metal Fiber Felt

For instance, sintered metal fiber felts can have porosities as high as 98%, with pore sizes smaller than 10 µm. In the case of LINQCELL sintered titanium fiber felts, our products boast a tailored porosity level ranging from 50% to 80%. Additionally, sintered metal fiber felts exhibit a three-dimensional reticulated structure. This structure not only provides well-defined conductive paths but also offers controlled electrical conductivity-temperature characteristics. The high porosity and decreased electrical resistivity due to the rupture of joint fiber contacts after sintering make sintered metal fiber felt an excellent material for applications such as water electrolyzers and fuel cells.

Conclusion

Having said that… should we prefer sintered metal fiber felts over sintered metal powders? The answer lies within your target application. For example, water electrolyzer manufacturing typically can work with porous transport layers with porosities as low as 40% (something achievable using sintered metal powders). In contrast, fuel cells require gas diffusion layers with high porosities, and so sintered metal fibers will be more appropriate in that case.

SS Sintered Fiber Felt - Zhuan Lv

SS Sintered Fiber Felt

SS sintered fiber felt is made by using extremely fine stainless steel fibers (with a diameter accurate to micrometers), non woven laying, stacking, and high-temperature sintering. The finished felt is formed by different pore size layers to form a pore gradient, which can control extremely high filtration accuracy and larger pollutant absorption. It has a three-dimensional network, porous structure, high porosity, large surface area, and uniform pore size distribution, which can continuously maintain the filtration
stainless steel fiber sintered felt is an ideal filtering material that is resistant to high temperature, corrosion, and high precision.

Product specifications and dimensions:

Standard size
mmx500mm; mmx600mm;
mmxmm; mmxmm;
Maximum size: mmxmm
Standard material: SUS316; US304; SUS316L
(The dimensions within the above range can be customized according to user requirements.)

Main features

1. Large pollution capacity, high filtration accuracy,slow pressure rise, and long replacement cycle;
2.High porosity and excellent permeability, low pressure loss, and high flow rate;
3. It is resistant to corrosion, high temperature, acid, alkali, organic solvents, drugs, etc., and can be used for a long time in an environment of 480 ℃;
4. Easy to process, shape, and weld;
5.We can produce reinforced, thickened, reinforcedmesh, and various other specifications according to user requirements.

Application Areas