Sintered

Sintered refers to a material or part that has been produced by sintering, a diffusion-assisted bonding process carried out at a temperature below the melting point of the material. In sintering, powdered particles are compacted into a desired shape and then heated in a controlled atmosphere to promote neck growth and mass transport between particles, which densifies the compact and creates a solid piece with controlled porosity.

The typical process starts with powder preparation, followed by shaping through pressing (uniaxial or cold isostatic pressing). The shaped compact is then fired at a temperature below the material’s melting point, allowing diffusion to bond particles without liquefaction. Post-sintering treatments such as hot isostatic pressing (HIP) or surface densification can further reduce porosity and improve uniformity. The resulting microstructure features grain boundaries and interparticle contacts formed during the firing.

Materials commonly sintered include ceramics (such as alumina and silicon carbide), metals and alloys used in powder metallurgy (including iron-based steels, copper, and nickel-based alloys), carbides and cermets, as well as certain polymer and composite powders. Sintered products often exhibit high hardness and wear resistance, good dimensional stability, and porosity that can be controlled for filtration or lubrication applications. However, residual porosity can limit strength and leakage resistance, and properties depend on density, particle size, and processing conditions.

Applications are widespread in industry and include powder metallurgy components (gears, bearings, bushings), dental ceramics and dental implants, filters and catalyst supports, porous metal foams, and certain electrical or thermal applications where net-shaped parts are advantageous. Variants such as hot pressing and hot isostatic pressing are used to achieve higher density and improved properties.