Following are brief descriptions of recent research projects carried out at the International Center for Gravity Materials Science and Applications, Clarkson University, Potsdam, NY 13699-5814, USA. For additional information, contact the Center Director.
Objective: To study,
develop and commercialize a new technique for growing polycrystalline diamond
films and single-crystal diamond at low pressure and temperature.
Methods: Experiments are performed in a closed chamber containing graphite and hydrogen at low pressure and temperatures down to 150oC, both at earth's gravity and with centrifugation, on a wide variety of substrates including graphite, glass, metals, carbon felt, polymers and device structures. Theoretical modeling of heat transfer, convection and chemical reactions using FLUENT. Diamond verified by micro-Raman spectroscopy. (This is not diamond-like carbon.)
Sponsors: Corning Corporation, Eastman Kodak Corporation, The New York State Center for Advanced Materials Processing (CAMP) at Clarkson University, and the U.S. National Science Foundation (NSF).
deposition on copper pattern on oxidized silicon, with submicron resolution
Presentation at 1999 International Astronautical Congress
Selective patterned deposition plus cover photo
Deposition on graphite and carbon felt plus cover photo
Objective: To determine
the influence of centrifugation on materials processing and on buoyancy-driven
Methods: Use the large Clarkson centrifuge HIRB for studies of solidification of eutectic and off-eutectic aluminum alloys (see below), CdTe solidification, Teflon agglomeration, interferometric observation of dissolution and growth of InP, deposition of diamond films (see above), and flow visualization. Numerical modeling using FLUENT.
Sponsors: NSF, CRDF
Flow cell on centrifuge
Bottom view of experimentally observed flow field on centrifuge
Theoretical flow field with centrifugation at 40 rpm
Experimental values of maximum and average velocity
Objective: To understand the influence of freezing rate oscillations, convection, centrifugation and levitation on the microstructure of eutectics.
solidification of the MnBi-Bi eutectic with
application or periodic current pulses. Directional solidification of the
Al-Si eutectic with application of the accelerated crucible rotation technique
(ACRT). Solidification of Al-Si, Al-Ge, and Al-Ge,Si
eutectics during levitation and centrifugation.
Numerical modeling using the phase-field method.
Sponsors: The U.S. National Aeronautics and Space Administration (NASA) and the U.S. Civilian Research and Development Foundation (CRDF).
Video of phase-field simulation with varying freezing rate (a large zip file)
Influence of electric current pulses on MnBi-Bi microstructure
Phase-field simulation of steady eutectic growth
Evolution of microstructure when the freezing rate is increased 6X
Presentation at International Astronautical Congress
To increase our understanding of detached solidification, which has produced
vastly superior crystals in space. To achieve detached solidification on
Methods: Directional solidification of transparent materials such as water and naphthalene, which contain dissolved gas. Directional solidification of InSb in BN-coated ampoules. Numerical and approximate analytical solutions for our Moving Meniscus Model. Measurement of the oxygen-dependence of the surface tension and contact angle of molten InSb.
Review of literature on detached solidification in microgravity
Schematic diagram of Moving Meniscus Model
Modeling results for InSb and water
Can propagation of gas bubbles lead to detachment?
Approximate material balance solution to the Moving Meniscus Model
Student researchers since 1999
Ms. Fengcui Li, former Ph.D.
student in Chemical Engineering
Dr. Dimitri Popov, former Ph.D. student in interdisciplinary Engineering Science
Mr. Ram Ramanathan, former M.S. student in Chemical Engineering
Dr. Peter Skudarnov, former Ph.D. student in interdisciplinary Engineering Science
Ms. Yazhen Wang, former Ph.D. student in Chemical Engineering
Mr. Jeffrey Chung, former M.Eng. in Chemical Engineering & MBA student
Mr. Francis Olajide, former B.S. student in Chemical Engineering
Ms. Katie Flow, former B.S. honors student in Chemical Engineering
Mr. Suresh Ramakrishnan, former M.S. student in Chemical Engineering
Mr. Jianbin Wang, former M.S. student in Chemical Engineering
Ms. Siliu Tan, former M.S. student in interdisciplinary Engineering Science
Mr. Thomas Adsit, former M.S. student in Chemical Engineering
Mr. Arun Kumar Kota, former M.S. student in Chemical Engineering
Mr. Karthik Jayaraman, former M.S. student in Chemical Engineering
Mr. Craig Burkhard, former M.S. student in Chemical Engineering
Mr. Gaurav Anan, former M.S. student in Chemical Engineering
Mr. Hasan Shodiev, former Ph.D. student in interdisciplinary Engineering Science
Visiting scientists since 1999
· Spring 2000: Professor Gamaleldin Ata Gadelkarim, South Valley University, Qena, Egypt
· Summers 2002, 2003: Drs. Stanislav Nikanorov, Mikhail P. Volkov and Vladimir N. Gurin, Ioffe Physical-Technical Institute, St. Petersburg, Russia
Last updated November 22, 2006