Figure 1. Global demand for nanomaterials by type ($MM), 2009.
Source: Dedalus Consulting
The world market for nanostructured materials continues to
show strong growth in the face of decreased manufacturing in 2009. In 2010, the
global market for nanostructured materials will surpass $5.0 billion, and
manufacturers continue to look for practical methods that meet quality specifications.
Despite inhibiting factors that slow the ubiquitous incorporation of
nanomaterials into the production of many products, volume growth levels will
exceed 30% annually from 2008 through 2011.
Based on dimensions and nanoscale properties,
the market for nanomaterials can be broken into several general categories,
including nanoparticles, nanofibers and nanolayers (or films). Within each
category, definitions encompass many different types of materials that are
formed both naturally and synthetically.
For example, nanoparticles include metal-oxide nanopowders, compound semiconductors,
metals and alloys. At 65.7%, nanoparticles make up the largest segment of
demand globally (see Figure 1). One
of the most dynamic markets is the use of metal-oxide nanopowders in the
manufacture of structural ceramics.
Quantities of production of
metal-oxide nanopowders are expected to increase dramatically over the next
five years as manufacturing processes continue to be refined and expanded. However,
the major drawback in manufacturing progress continues to be the lack of
unified standards and adequate specifications that define the quality, purity
and production processes, which continually leads to inconsistent research and
application results. Greater research is necessary and will continue to be a
strong driver of the market in an effort to develop standards based on
performance and manufacturing considerations.
Several mechanically or
chemically based methods are currently in use to manufacture nanomaterials, and
other methods are being explored on a research level that would increase
performance and reduce costs. Major mechanical methods include ball milling,
laser ablation, etching, sputtering, sonification and electroexplosion. Major
chemical methods include chemical vapor deposition (CVD), sol-gel processing
and molecular pyrolysis.
With this in mind, several manufacturing
techniques have been researched to determine their cost structures and efficacy
in developing superior products. One production technique that has been
researched in terms of both cost and performance of materials is
electroexplosion of wire (EEW), which has shown promise on the performance side
in the manufacture of metal-oxide nanopowders.
The EEW process involves
the destruction of metal wire through the application of a dense electrical
current within a controlled chamber. The powders produced have a high density
of crystal defects, which further intensifies their internal energy. The
results are affected by characteristics that include electrical density, length
of time during which the current is applied to the wire, temperature of the
wire at the time the current is applied, material of the wire, and the ambient
medium within the chamber.
A variety of metal powders are
currently being produced (in kilogram quantities) in Russia and the U.S. Primary
applications are in the area of microelectronics, namely in thick film paste
formulations; as additives for propellants and pyrotechnics; for coatings; as
sintering aids; and in the self-heating synthesis of high-temperature alloys
Electroexploded metal nanopowders have been manufactured in ranges from 5 to
500 times smaller than commercially available metal powders; typical powder
sizes average 100 nanometers. Nanopowders, particularly ceramic-based alumina
), show increased chemical
purity and more consistent grain size when manufactured using EEW. Also, EEW
results in much higher chemical and metallurgical reactivity.
The challenges in developing
structural ceramics generally have to do with fracture toughness. As is well
documented, ceramics are by nature brittle materials. Thus, there is no yield
stress-when the ceramic fractures, the system or component usually suffers
complete failure. Further, in producing ceramics, another challenge has always
been the development of uniform grains in terms of size, shape and density. EEW
has been extremely effective in addressing these challenges. Thus, on a
performance basis, EEW shows significant promise in the development and
production of ceramic nanopowders.
Table 1. Cost and pricing
structure for EEW-produced Al2O3
Source: Dedalus Consulting
EEW Cost Analysis
The main inhibiting factor in the further development
of these nanopowders is cost. Table 1 evaluates the cost structure involved in
the manufacture of Al2
EEW. When evaluating these costs, primary considerations include:
- The use of machinery that requires a high-voltage
power source, typically in the form of a generator or a direct line into the
main AC power source for the facility
- Expensive equipment, such as vacuum-based systems, chemical reaction
chambers, plasma torches and powder purification units, as well as a limited
choice of materials
- High energy costs
Thus, the main application to date for EEW-produced Al2
exclusively laboratory research.
The use of EEW-produced nanopowders can provide numerous advantages,
including improved combustion for rocket fuels and propellants; enriched
lubricants; improved catalysts; improved filtration systems; enriched lithium
and nickel-metal-hydride batteries; and improved coatings and treatment for
wear and corrosion resistance, as well as conductivity.
Another function of ceramic nanopowders is
the formulation of ceramic nanocomposites to improve thermomechanical
properties and fracture toughness. Ceramic fibers can be used for fortifying
composites where the matrix is a ceramic (CMCs), metal (MMCs) or plastic.
Smaller-diameter fibers are thought to have a greater strengthening benefit
than larger diameter fibers. Using these fibers in CMCs is difficult, however,
because alumina fibers have poor creep resistance. Alumina fibers are also
likely to dissolve into the solid matrix.
The next five years will show some of
the most dramatic changes in nanopowders since the commercialization of
nanomaterials. The most fundamental changes will occur in the standardization
and development of consistent processes for production. Yet, any model for
production will have to find the correct balance between cost and performance.
note: The foregoing information is based on
Materials-World Markets, Products, and End-Users: 2009-2014 Analysis &
an upcoming report to be published by Dedalus Consulting. For more information,
call (718) 622-0830 or visit www.dedalusconsulting.com.