Reticulated ceramic foam provides a versatile
material form that can be engineered and tailored
for specific applications.
Structure of reticulated foam showing the open cell structure and continuous ligaments.
Picture a structure formed by fibers or ligaments framing
open cells. The structure is lightweight, permeable and shock resistant while
retaining the properties of the parent material. Polymer foam, used for
insulation, cushions and packaging materials, was perhaps the first manmade
material to take advantage of the unique characteristics of cellular solids.
Today, another type of foam-reticulated ceramic foam-is providing industry and
the research community with a versatile material form that can be engineered
with particular properties and tailored for specific applications.
Reticulated foams are low-density, permeable structures
of open cells and continuous ligaments; microscopically, they are rather like
3-D mesh. In fact, it is the continuous nature of the ligaments that make the
foam reticulated (reticulum
being Latin for network
Reticulated foams offer a number of features that benefit
research and design engineers across many industries. The interconnected
lattice of continuous ligaments within the cellular structure provides greater
strength than shorter fibers and also ensures uniform material characteristics
throughout the structure. Other characteristics that offer additional benefits
are discussed below.
Reticulated foam is particularly useful in structural
sandwich panel cores. The isotropic properties of the foam allow for a uniform
response to impact, regardless of impact angle. The foams also add strength and
structure when used as part of a 3-D network of reinforcing fibers in
High Surface Area-to-Volume
Deposition of a high-cost catalyst, such as platinum or
silver, onto the ligament surfaces of a reticulated foam allows contact of a
gas or liquid with the catalyst over a vast surface area. This cost-effective
technique is proving to be particularly valuable in the development of fuel
cells. In addition, reticulated foam offers a large surface area in a compact
and lightweight structure for use as a scaffold for biological growth in
pollution control and other devices.
Depending on the material chosen, a reticulated foam can
provide very low-bulk thermal or electrical conductivity, as well as insulation
against high temperatures. In particular, vitreous carbon and silicon carbide
reticulated foams can endure the same extreme temperatures as solid material,
but at a fraction of the weight. These characteristics lend themselves to use
in aerospace applications; heat exchangers; porous electrodes; and wherever an
exceptionally efficient, lightweight conductor or insulator is required.
Low Flow Resistance
The uniform cell structure and rigid geometry of
reticulated ceramic foam contribute to a low pressure drop for fluid flow.
These characteristics are useful in filters, demisters, gas diffusers and
mixers, as well as liquid and gas separators, among other applications.
Resistance to Fracture and
Because the properties of the parent material extend
throughout the foam in three dimensions, reticulated foam provides enhanced
resistance to fractures and thermal shock. The continuous ligaments of the
material deter crack propagation, since a crack encountering a continuous
ligament (as opposed to a short fiber) is stopped from progressing through the
Although “standard” reticulated ceramic foams are
suitable for many high-tech applications, it is possible to tailor a foam’s
properties during fabrication for a specific application by adjusting its
material composition, pore size, density and ligament structure. In fact,
perhaps the most exciting aspect of working with reticulated foams is the
opportunity to explore and exploit their properties for use in any number of new
and existing applications.
Strong and lightweight, compact with a high surface
area, conductive or insulating-reticulated foams have much to offer researchers
and innovative engineers working in
a range of industries.
For more information
about reticulated foams, contact Goodfellow Corp., 305 High Tech Dr., Oakdale,
PA 15071; (800) 821-2870; e-mail firstname.lastname@example.org; or visit www.goodfellow.com.
SIDEBAR: Standard Types of Reticulated Ceramic Foams
- Silicon Carbide
- Vitreous Carbon