Experimental technique for studying high-temperature phases in reactive molten metal based systems

Abstract

Articles you may be interested inHigh-temperature materials testing with full-field strain measurement: Experimental design and practice Rev. Sci. Instrum. 82, 115101 (2011); 10.1063/1.3657835 New sample levitation initiation and imaging techniques for the processing of refractory metals with an electrostatic levitator furnace Rev. Sci. Instrum. 72, 2490 (2001); 10.1063/1.1368861Noncontact technique for measuring surface tension and viscosity of molten materials using high temperature electrostatic levitation Rev.Containerless, microgravity experiments for studying equilibria in molten metal-gas systems have been designed and conducted onboard of a NASA KC-135 aircraft flying parabolic trajectories. An experimental apparatus enabling one to acoustically levitate, laser heat, and splat quench 1 -3 mm metal and ceramic samples has been developed and equipped with computer-based controller and optical diagnostics. Normal-gravity testing determined the levitator operation parameters providing stable and adjustable sample positioning. A methodology for optimizing the levitator performance using direct observation of levitated samples was developed and found to be more useful than traditional pressure mapping of the acoustic field. In microgravity experiments, spherical specimens prepared of pressed, premixed powders of ZrO 2 , ZrN, and Zr, were acoustically levitated inside an argon-filled chamber at one atmosphere and heated by a CO 2 laser up to 2800 K. Using a uniaxial acoustic levitator in microgravity, the location of the laser-heated samples could be maintained for about 1 s, so that local sample melting was achieved. Oscillations of the levitating samples in horizontal direction became pronounced in microgravity. These oscillations increased during the sample heating and eventually resulted in moving the sample out of the stable position and away from the laser beam.

Effect of Temperature Change on Interfacial Behavior of an Acoustically Levitated Droplet

“…Wang et al (1996) observed the deformation behavior of the rotating levitated droplet in the microgravity environment. Ermoline et al (2004) observed the position of samples vertically oscillated under the microgravity condition. They conducted the experiment to heat the metal and ceramic samples of 1-3 mm diameter by the laser heating.…”

Effect of Laser Heating on Nonlinear Surface Deformation of Acoustically Levitated Droplet

“…Wang et al (1996) observed the deformation behavior of the rotating levitated droplet in the microgravity environment. Ermoline et al (2004) heated the ceramic sample of 1-3 mm in diameter by the laser. The sample sphere is heated up to 3,000 K. Position of a heated sample vertically oscillated under the microgravity condition.…”

Novel high-temperature and pressure-compatible ultrasonic levitator apparatus coupled to Raman and Fourier transform infrared spectrometers

“…Here, we report on the development of a new apparatus combining an acoustic levitator with a pressure-compatible process chamber, heating by a carbon dioxide laser, and characterization of the chemical and physical modifications of the levitated particles simultaneously via FTIR (10 000-500 cm −1 ) and Raman spectroscopy (4390-170 cm −1 ). Acoustic levitation has previously been combined separately with Raman spectroscopy, [12][13][14] a FTIR spectrometer, 15 and a carbon dioxide laser; 16,17 but, to our knowledge, all three techniques have not been combined simultaneously into a single, pressure-compatible apparatus. Raman scattering and infrared absorption spectroscopy provide complimentary information on the rovibrational modes of molecules.…”

“…Second, considering astrobiology, we investigate the reaction pathways induced by heating levitated samples of biological relevance such as the amino acid cysteine (HSCH 2 CH 2 CNH 2 COOH). Third, in view of our goal to study combustion processes [22][23][24] and the growth of organics on carbonaceous particles, a graphite grain can be heated by a carbon dioxide laser to elevated temperatures, 16,17 thereby enabling the heated particle to react with the process gases such as oxygen, nitrogen, or hydrocarbon gas. Fourth, the introduction of the FTIR spectrometer enables the study of the scattering of light by small, irregularly shaped particles, such as the organic polymers considered here, where Mie theory does not accurately predict the scattering functions.…”