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It is not good to have zeal without knowledge * . . . Book of
Proverbs This volume constitutes the proceedings of the Third
International Workshop on Materials Processing at High Gravity. It
offers the latest results in a new field with immense potential for
commercialization, making this book a vital resource for research
and development professionals in industry, academia and government.
We have titled the proceedings Centrifugal Materials Processing to
emphasize that centrifugation causes more than an increase in
acceleration. It also introduces the Coriolis force and a gradient
of acceleration, both of which have been discovered to play
important roles in materials processing. The workshop was held June
2-8, 1996 on the campus of Clarkson University in Potsdam, New
York, under the sponsorship of Corning Corporation and the
International Center for Gravity Materials Science and
Applications. The meeting was very productive and exciting, with
energetic discussions of the latest discoveries in centrifugal
materials processing, continuing the atmosphere of the first
workshop held in 1991 at Dubna (Russia) and the second workshop
held in 1993 in Potsdam, New York. Results and research plans were
presented for a wide variety of centrifugal materials processing,
including directional solidification of semiconductors,
crystallization of high Tc superconductors, growth of diamond thin
films, welding, alloy casting, solution behavior and growth,
protein crystal growth, polymerization, and flow behavior. Also
described were several centrifuge facilities that have been
constructed for research, with costs beginning at below $1000.
There are two motives for studying materials processing in
centrifuges. First, such research improves our understanding of the
influence of acceleration and convection on materials processing.
Second, there are commercial opportunities for production of unique
and improved materials that cannot be prepared under normal earth
conditions or in space. Through a combination of experiments and
theory, we are gaining an understanding of centrifugation on
phenomena of importance to materials processing. We find that it is
necessary to consider not only acceleration, but also the Corio lis
effect and the variation of acceleration with position. As one
consequence, the vigor of buoyancy-driven convection is sometimes
increased by centrifugation and sometimes decreased. Similarly, the
tendency of the convection to become unstable or oscillatory may
either be increased or decreased by centrifugation. On the other
hand, the observed effects of centrifugation on product quality
have largely gone unexplained. This volume constitutes the
proceedings of The Second International Workshop on Materials
Processing at High Gravity, hosted by Clarkson University in June
of 1993. The concept for a workshop on materials processing in
centrifuges was born at a series of informal meetings held in Paris
in 1990. The First International Workshop on Materials Processing
at High Gravity was held in May of 1991 in Dubna, USSR, on the
banks of the Volga River. The proceedings of this workshop was
published in 1992 as a special issue of the Journal of Crystal
Growth.
This volume constitutes the proceedings of the Fourth International
Workshop on Materials Processing at High Gravity, held at Clarkson
University, May 29 to June 2, 2000. There were 73 attendees from 16
countries. Since the topics extended well beyond materials
processing, it was felt appropriate to name this proceedings
"Centrifugal Processing." Processing by Centrifugation includes the
traditional bench-scale centrifuges, as well as all rotating
systems utilizing the centrifugal and Coriolis forces to provide
unique performance. Centrifugation led to the formation of sticky
porous Teflon membranes, as well as improved polymeric solar cells.
Centrifugation on large equipment improved the chemical vapor
deposition of diamond films, influenced the growth and dissolution
of semiconductor crystals, and elucidated the influence of gravity
on coagulation of colloidal Teflon. A million g centrifuge was
constructed and used to study sedimentation in solids and to
prepare compositionally graded materials and new phases. Rotation
of a pipe about its axis allowed the casting of large-diameter
metal alloy pipes as well as coating the interior of pipes with a
cermet utilizing self-propagating high-temperature synthesis. Such
coatings are highly corrosion and erosion resistant. Flow on a
rotating disk was shown to be useful for process intensification,
such as large-scale manufacturing of nano-particles, polymerization
reactions, and heat & mass transfer. Several theoretical
studies dealt with the influence of rotation on fluid convection on
surfaces and in pipes, tubes, and porous media. These have
applications to integrated-circuit chip manufacturing, alloy
casting, oil production, crystal growth, and the operation of
rotating machinery.
There has been considerable interest recently in microgravity
physics and the effects of gravitation on crystal growth, alloy
solidification, and other processes in space manufacturing. Regel'
[1] has provided an extensive but not exhaustive bibliography on
micro gravity physics and materials science in space, in which the
major aspects are discussed along with the state of the art and
future research prospects. The literature survey in [1] covered a
period of about 10 years, including some publications appearing in
1983 that reflected not only theoretical and experi mental studies
completed by 1983 but also a list of experiments to be carried out
in the next few years. In particular, the closing part of the
survey [1] enumerated ex periments planned under the Intercosmos
program and by the European Space Agency (ESA) for the flight of
Spacelab-l and D-l in 1985 and under the Eureka programs. Some of
the space experiments planned in 1983 have now been com pleted, and
the results have been published. It is therefore desirable to
survey again research on materials science in space for the last
few years and extend the literature survey begun in [1]. The
literature listing on materials science in space begun in [1] is
supplemented (there were 1061 citations in [1]) by recent
publications (beginning with 1982).
This volume constitutes the proceedings of the Fourth International
Workshop on Materials Processing at High Gravity, held at Clarkson
University, May 29 to June 2, 2000. There were 73 attendees from 16
countries. Since the topics extended well beyond materials
processing, it was felt appropriate to name this proceedings
"Centrifugal Processing." Processing by Centrifugation includes the
traditional bench-scale centrifuges, as well as all rotating
systems utilizing the centrifugal and Coriolis forces to provide
unique performance. Centrifugation led to the formation of sticky
porous Teflon membranes, as well as improved polymeric solar cells.
Centrifugation on large equipment improved the chemical vapor
deposition of diamond films, influenced the growth and dissolution
of semiconductor crystals, and elucidated the influence of gravity
on coagulation of colloidal Teflon. A million g centrifuge was
constructed and used to study sedimentation in solids and to
prepare compositionally graded materials and new phases. Rotation
of a pipe about its axis allowed the casting of large-diameter
metal alloy pipes as well as coating the interior of pipes with a
cermet utilizing self-propagating high-temperature synthesis. Such
coatings are highly corrosion and erosion resistant. Flow on a
rotating disk was shown to be useful for process intensification,
such as large-scale manufacturing of nano-particles, polymerization
reactions, and heat & mass transfer. Several theoretical
studies dealt with the influence of rotation on fluid convection on
surfaces and in pipes, tubes, and porous media. These have
applications to integrated-circuit chip manufacturing, alloy
casting, oil production, crystal growth, and the operation of
rotating machinery.
Centrifugal Materials Processing; L.L. Regel, W.R. Wilcox.
Convection in Crystal Growth under High Gravity on a Centrifuge; J.
Friedrich, G. Muller. Segregation in Crystal Growth under High
Gravity on a Centrifuge: A Comparison between Experimental and
Theoretical Results; J. Friedrich, G. Muller. Analysis of Thermal
Convection in Molten Tin Under Centrifugal Conditions; L. Bergelin,
A. Chevy. Thermal Stability During Centrifugation: Flow
Visualization Experiment; Numerical Results; W.A. Arnold, L.L.
Regel. Flow Visualization Study of Convection in a Centrifuge; P.V.
Skudarnov, et al. Determination of Solid/Melt Interface Shape and
Growth Rate During Gradient Freeze Solidification on a Centrifuge
Using Current Interface Demarcation; I. Moskowitz, et al. In Situ
Observation of Directional Solidification in High Gravity; Y.
Inatomi, et al. Impurity Distribution and Superconducting
Properties of PbTe: T1 Crystals Grown in a Centrifuge; R.
Parfeniev, et al. A Low Cost Centrifuge for Materials Processing in
High Gravity; Y.A. Chen, et al. 20 Additional Articles. Index.
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