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During the paper manufacturing process, papers are already highly enriched with sinterable metal powders. The powder content is so high that the specialty papers can be thermally converted into porous metal structures by a sintering process. In addition to metallic powders such as stainless steel, copper or molybdenum, metal fibers can also be added to the fiber composite so that the microstructure of the resulting metallic material can be varied over a wide range.
Micro Structure
The cross-section of specialty papers is characterized by the metallic filler. The filler content exceeds 85 wt.%. The cellulose fibres function as fibre reinforcement in the composite and enable paper-technical shaping. Sintering is possible due to the high spatial proximity of the metallic particles.
Shaping Options
The metal-filled specialty papers can be produced in web form and shaped in a paper-typical design. For example, various corrugated geometries and corrugated board structures can be realized, thus enabling lightweight structures.
Thermal Transformation
The metallic sintered papers can be thermally transformed into a metallic material by a debinding process with subsequent sintering. The paper-derived metal structures have an open porous microstructure. Porosities between 20 - 70 vol.% with average pore sizes between 5 and 200 µm can be adjusted.
Sintered metal papers are an innovative semi-finished product for powder metallurgy. In particular, the possibility of representing paper-derived lightweight structures in metal suggests a large application potential, for example in the field of filtration, catalyst technology or heat management.
Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM