In most applications, the key characteristics of porous media are pore
size and permeability. In the case of Dynapore® diffusion-bonded wire
mesh structures and other porous metals, these characteristics are augmented
by the properties of the metal alloy, including mechanical strength, corrosion
resistance, and/or high-temperature oxidation resistance. However, there
is a class of applications for these materials that also depends on thermal
properties of Dynapore® materials. These properties may in turn be
affected by the surface area, mass, density, and void volume of the diffusion-bonded
By its nature, wire mesh has a fairly high surface area to mass ratio.
Depending on the particular weave, a square inch of woven wire cloth
may contain several square inches of wire surface area. A stack of many
layers of wire mesh sintered together therefore creates a three-dimensional
matrix with very high internal surface area.
As an example, consider
a sintered stack of 250 layers of 200x200 mesh, plain square weave, .002"
wire diameter. After diffusion-bonding, this stack may be processed to
a thickness or height of 1". One cubic inch of this material contains
approximately 636 square inches of wire surface area!! Its weight will
be about .094 pounds, reflecting a volumetric density of about 32.3%.
In other words, over 67% of the cubic inch is empty space, with the remaining
volume being solid metal. There will be 250 x (200 + 200) = 100,000 individual
one inch long wire strands in this cubic inch of material. If each aperture
in each layer is counted as a pore, there will be 250 x 200 x 200 = 10,000,000
pores per cubic inch.
In addition, the sintering or diffusion-bonding of the wire mesh matrix
bonds all points of contact within the weave, as well as between adjacent
layers of a laminate. The fused contact points facilitate thermal transfer
throughout the structure, reducing hot-spots and increasing efficiency.
The high surface area
and high void volume of these structures, combined with the thermal capacity
of metals, creates an engineering opportunity. Dynapore® structures
may be remarkably efficient at removing heat from (or imparting heat to)
gases that flow through the porous metal matrix. These properties have
been used to good advantage in many applications, including:
the factory today and find out how DynaporeŽ can help meet your thermal