Metal Foam

Metal foam is a cellular structure consisting of a solid metal with pore size ranging from 450 to 6000 µm, homogeneous and reproducible morphology with thin struts and surface extremely rough. The pores can be sealed (closed-cell foam), or they can form an interconnected network (open-cell foam).

Basic Properties

Metal foam is characterized structurally by its cell topology, relative density, cell size, cell shape and anisotropy. Generally, the properties of metal foam depend upon the metal properties, relative density and cell topology. The key properties of metal foam are as follows:

• High porosity

The porosity of metal foams is very high, typically 75–95% of the volume consists of void spaces. As the high porosity, they offer light weight and a large surface area. And their open-cell structure makes them even less resistant to the fluids flowing through them, and hence, the pressure drop across them is much less than it is in the case of fluid flow via packed beds or granular porous materials.

• High specific stiffness

The specific stiffness (stiffness to weight ratio) of metal foam is high. For example, the specific stiffness of a metal foam with 1/5 density is five times the specific stiffness of a normally dense metal of same weight.

• Functional properties

As the cellular character, there is a wide range of functional properties of metal foams. Very often, the combination of functional properties, such as acoustic, thermal, electrical or chemical resistance, with mechanical properties, like strength or stiffness, allows interesting new applications: i) metal foams' thermal conductance is less than that of the corresponding bulk metal, ii) the combination with a large sponge surface allows their utilization as electrodes in batteries or for other electro-chemical purposes, iii) metal foams are good for acoustic and vibration damping over a large frequency range and can provide additionally electromagnetic shielding.

Common Metal Foams

Most metal foams, in both industry and research, are based on aluminum, nickel or titanium; however, a growing number of metallic systems have now been produced and characterized (see table 1) ^[1].

Tab. 1 Examples of already developed metal foams and their processing routes

Alfa Chemistry is a leading manufacturer of foam materials. We offer metal foams in various of specification which can be used in civil and industrial applications. To place an order or request a quote, please don't hesitate to contact us.

Reference

1. Russell Goodall, Andreas Mortensen, in Physical Metallurgy (Fifth Edition), 2014.