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Performance
of 50 Completed ATP Projects
Status
Report - Number 2
NIST SP 950-2
Chapter
2 - Advanced Materials and Chemicals
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AlliedSignal,
Inc.
A Process for Making Ceramic Parts
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| Many
types of industrial and commercial equipment contain parts that revolve
at very high speeds, under great stress, and in extreme heat. Jet
engines, power generation turbines, and automobile engines are a few
examples. In the past, metal has been accepted as the only material
for making such parts. |
COMPOSITE
PERFORMANCE SCORE
(Based on a four star rating.)
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Safe, Low-Cost Fabrication
of High-Performance Ceramic Parts
With the recent development of high-performance structural ceramic materials,
this ATP project with AlliedSignal asked whether it was possible to develop
a process for fabricating ceramic parts inexpensively enough to allow them
to be substituted for metal parts, thereby significantly improving equipment
performance and reliability.
Ceramic substitutes
for metal have performed well in certain critical situations. Space flight
is one. Ceramic tile coverings on spacecraft form heat shields that protect
astronauts re-entering earth atmosphere. Atmospheric friction heats the
tiles to a fiery glow. But the tiles stay in place and dissipate enough
heat for safe re-entry. Metal surfaces would melt under these circumstances,
with disastrous results.
Cost and Safety Issues
Hinder Use
Despite such performance advantages, the application of advanced ceramics
has been held back by the high cost of fabrication. Whereas metal can
be melt-processed or plastically deformed using molding, extruding, stamping,
or other standard metalworking techniques, many ceramics cannot be processed
by these methods. Ceramic parts must be made by forming ceramic powder
into a desired shape at room temperature and then “reacting”
the powder compact at various temperatures to densify it. This process
is much more limited in the shapes it can achieve than melt-processing
or plastic deformation approaches.
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A
16-blade silicon nitride turbine wheel for use in small turbogenerators. |
This ATP project offered
a novel approach to ceramics production via a relatively new process called
gelcasting, a technology developed at Oak Ridge National Laboratory. In
gelcasting, powdered ceramic precursors are mixed with a polymer precursor
(monomer) and solvent (usually water) to make a slurry that is poured
into a mold. The gel is then polymerized, locking the ceramic powder in
a polymer matrix. The solvent is removed, and the part is heated to burn
out the polymer. At this point, if necessary, the “green” part
can be machined to some degree. Finally, the part is fired to produce
the ceramic. The process is capable of making very complex parts such
as turbine wheels. Some shapes made with this technique cannot be made
any other way.
A major drawback to
the original gelcasting technology was its reliance on acrylamide as the
gelling additive. Acrylamide is highly sensitive to oxygen, which inhibits
polymerization. So the process must be done in an inert environment, which
raises the cost. Acrylamide gel is also very difficult to remove if an
inert environment is used, raising costs even more. Most important, however,
acrylamide is a cumulative neurotoxin, and safety concerns had prevented
the technology’s widespread use.
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An
automated gelcasting machine capable of forming 10,000 ceramic turbine
wheels per year. |
AlliedSignal’s
innovation in this ATP project was to develop a low-cost, nontoxic alternative
that retains acrylamide’s excellent process characteristics. During
the project, AlliedSignal researchers developed and demonstrated a novel
near net-shape (requiring almost no machining) process for making high-performance
ceramic parts for automobile and aircraft engines. In addition, the new
gelcasting process has potential applications in energy, chemicals, aerospace,
electronics, advanced materials, and telecommunications.
Early Commercialization
Expected
Development
of the technology is continuing. In 1995, under the “Partnership
to Productionize and Commercial-ize a Manufacturing Process for Silicon
Nitride Turbo-machinery Components,” AlliedSignal began receiving
funds from the Defense Advanced Research Projects Agency for work that
grew directly out of the ATP-funded gelcasting project. The company received
additional funding for this effort from the Department of Energy in 1997,
and it has made substantial progress toward a commercially viable manufacturing
process. Marketable products have yet to be sold. But commercial production
is expected to begin in the very near future, with annual sales projected
to be several million dollars.
AlliedSignal has constructed
a new plant for manufacturing ceramic parts, including those made with
the gelcasting technology. Since the close of the ATP project in June
1995, the company has invested $3 million to further develop the technology
for particular commercial applications. In addition, based explicitly
on the successful completion of the ATP project, it received funding from
the Department of Energy and the Defense Advanced Research Projects Agency
to advance gelcasting technology into commercialization.
Cost Reductions and
Improved Performance
Users of vehicles and other equipment using gelcast ceramic parts instead
of metal ones will benefit from cost reduction and improved performance
— in the case of some applications, to a considerable degree. Since
Oak Ridge National Laboratory holds the underlying intellectual property
for gelcasting, additional spillover benefits are likely to accrue. As
a national laboratory, Oak Ridge offers its technologies to the public,
and other companies are likely to realize considerable spillover benefits
from the AlliedSignal/ATP-funded gelcasting technology. Oak Ridge has
already licensed gelcasting technology to two other U.S. companies —
a magnetic ferrite manufacturer and a small manufacturer of ceramics for
automotive and fuel cell applications — and is working with a number
of other companies evaluating the technology.
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Near
net-shape turbine wheels for use in commercial or military jet engine
starters. |
Future benefits are
also expected to come from applications of the new gelcasting process
in a number of sectors, including large aircraft engine parts. In addition,
there may be applications in small parts for jet engines, small turbine
generators for hybrid electric/fossil fuel cars and auxiliary power systems
for aircraft.
Progress Accelerated
by Five Years
Because of its success in developing the new gelcasting technology, AlliedSignal
has also succeeded in developing the manufacturing technology and component
fabrication projects that allow commercialization to progress. The company
says that without the ATP funds, it would have needed another five years
to reach this stage of development. And it would have been that much further
behind its major competitor, Kyocera of Japan. Instead, AlliedSignal believes
that with the help of the ATP funds, it has now pulled even with Kyocera
in most applications and is able to make superior-quality products in
several areas.
Another clear benefit
made possible by the ATP grant was the establishment of a technology-development
relationship between AlliedSignal and Oak Ridge National Laboratory. Relations
have continued through a scientific exchange agreement for an Oak Ridge
scientist who co-invented the original gelcasting technology to work at
AlliedSignal for two years.
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Project
Highlights
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PROJECT:
To develop a low-cost, near-net-shape gelcasting process for making
structural ceramics in a safer, less-costly way than conventional
gelcasting based on acrylamide, a cumulative neurotoxin. Successful
development of this process would open the door to commercial gelcasting
production of these high-performance ceramics.
Duration: 7/1/1992 — 6/30/1995
ATP Number: 91-01-0187
FUNDING (in
thousands):
| ATP |
$1,136
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56%
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| Company |
884
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44%
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| Total |
$2,020
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ACCOMPLISHMENTS:
AlliedSignal achieved its R&D goal. The company also:
- presented
the new technology at several professional conferences;
- invested
after the ATP project another $3 million of its own money on additional
gelcasting R&D aimed at the development and installation in
1998 of an automated gelcasting system that can fabricate ceramic
automotive turbogenerator wheels at a rate of 10,000 per year;
and
- received
funding from the Department of Energy and the Defense Advanced
Research Projects Agency to further advance gelcasting technology,
with the specific goal of establishing viable manufacturing processes.
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COMMERCIALIZATION
STATUS:
Commercialization is in progress, and the first gelcast parts made
with the new technology are expected to reach the market very soon.
Opportunities exist for commercialization in a variety of fields.
OUTLOOK:
The company is making excellent progress toward its commercialization
goals and is expected to start producing gelcast parts in large
volume in the near future. Users of vehicles or equipment made with
gelcast ceramic parts will benefit from lower cost and better performance,
with potentially huge benefits accruing in areas like auto engines,
commercial aircraft and industrial applications such as stationary
power generation.
Composite
Performance Score:
COMPANY:
AlliedSignal, Inc., Ceramic Components
(formerly Garrett Ceramic Components
Division, AlliedSignal Aerospace)
2525 W. 190th St.
Torrance, CA 90504
Contact:
John Pollinger
Phone: (310) 512-5654
Informal Collaborator: Oak Ridge National Laboratory
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of Contents or go to next section.
Date created: April
2002
Last updated:
April 12, 2005
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