Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Metal Fibers Baked To Make Filters

09.07.2004


In automotive catalytic converters and industrial exhaust gas filters, porous materials play a crucial role: they filter and break down hot waste gases. It is now possible to process virtually all metal alloys into fibers which can be used to make open-pored sintered materials.

The requirements to be met by a coffee filter are simple: it must retain the powder and not be decomposed by the hot water. The conditions for dealing with exhaust gases in industrial processes are much tougher: temperatures of several hundred degrees and aggressive media are no rarity. In such conditions, manufacturers need different filter materials than cellulose or textiles in order to remove particles and pollutants. A solution is provided by filters made of metal, as produced by researchers at the Fraunhofer Institute for Manufacturing Engineering and Applied Materials Research IFAM. The filters are made of small metallic fibers - a few millimeters long and just a tenth of a millimeter thick. Depending on the application, they can be baked to make semis such as rings, tubes or disks.

In conventional fiber manufacture, however, the metal must be formable. “High-temperature alloys containing lots of aluminum are too brittle for this purpose,” explains Olaf Andersen from the institute’s Powder Metallurgy and Composite Materials unit in Dresden. “We can make fibers from virtually any metal or alloy. This allows us to produce particularly heat-resistant or catalytically active filters tailor-made for specific applications.” The extremely wide range of materials is made possible by a new process applied by Andersen and his colleagues. Formability is not a requirement because the fibers are drawn directly from molten metal. A cooled roll with a fine profile rotates over the melt. The raised areas of the roll’s profile determine the length and width of the resulting fibers. Where they touch the liquid metal’s surface, it cools down, solidifies, contracts and finally disengages from the roll as a thin fiber. In a second step the scientists pack the finished fibers in a mold, cover it with a plate and heat the fibers until they are close to melting point. During sintering the cover plate drops down gradually until it reaches a spacer. The remaining volume and the fiber length determine the size of the cavities in the finished filter.



The porous metal filters are used, for example, to protect electric motors. If the motor catches fire or explodes, the hot gases are expelled through the filter. They cool down rapidly on the large inner metal surface, which reduces risks and further damages. In an EU project, the IFAM researchers are developing a melting furnace filter in cooperation with the French company LECES based near Metz. As the exhaust gases from the furnaces contain dioxins, the filters need to be catalytically active in order to effectively destroy these toxic substances.

Johannes Ehrlenspiel | alfa
Further information:
http://www.fraunhofer.de

More articles from Materials Sciences:

nachricht An innovative high-performance material: biofibers made from green lacewing silk
20.01.2017 | Fraunhofer-Institut für Angewandte Polymerforschung IAP

nachricht Treated carbon pulls radioactive elements from water
20.01.2017 | Rice University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>