Porous aluminium - an option to metal foam.
Metal foam and porous aluminum are both permeable for gaseous and liquid media but have different manufacturing technologies and therefore different properties.
Aluminum is casted together with crystal salt into the desired shape before the salt is washed out. The salt grains and their contact points are thus replaced by pores. This is how porous aluminium is produced.
Thanks to the high strength and low weight, foamed metals are gaining importance as industrial material. Because of the large internal surface area and good thermal conductivity, foamed metals are used in the automative industry and heat engineering.
Metal foams are usually made of aluminum or aluminum alloys, although it is possible to foam copper, zinc or lead.
We know of two manufacturing technologies for metal foams:
- Metal powder or metal chip is mixed with titanium hydride or other explosiv agents and heated above the melting point of the metal, thereby releasing gaseous hydrogen so that the mixture foams.
- Gas is injected into the molten metal, after cooling the porous structure remains.
The main difficulties in the production of metal foams are finding the right combination of metal and explosiv agent and heating them up in the right time to the correct temperature, as this is the only way of obtaining the desired result. In doing so, it is practically unpredictable how porosity, pore size and distribution of pores will be.
For these reasons, porous aluminum, with its simple manufacturing technology, is the valuable alternative. The broad range of precisely defined filter grades from 5µm to 250µm can differentiate the application accurately. The extra strong cast interface between porous and non-porous parts opens up a wide range of different applications.
POROUS ALUMINUM vs. METAL FOAM
- Broad range of precisely defined filter grades from 5µm to 250µm
- Extra strong cast interface between porous and non-porous parts
- Extrem strength thanks to cast structure
- Simple post-processing (e.g. threading)
- Cost-effective manufacturing technology