%0 Journal Article
%T Hybrid Processing Combining Electrostatic Levitation and Laser Heating: Application to Terrestrial Analogues of Asteroid Materials
%A Paul-Fran£żois Paradis
%A Takehiko Ishikawa
%A Yuki Watanabe
%A Junpei Okada
%J Advances in Optical Technologies
%D 2011
%I Hindawi Publishing Corporation
%R 10.1155/2011/454829
%X Electrostatic levitation combined with laser heating is becoming a mature technique that has been used for several fundamental and applied studies in fluid and materials sciences (synthesis, property determination, solidification studies, atomic dynamic studies, etc.). This is attributable to the numerous processing conditions (containerless, wide heating temperature range, cooling rates, atmospheric compositions, etc.) that levitation and radiative heating offer, as well as to the variety of diagnostics tools that can be used. In this paper, we describe the facility, highlighting the combined advantages of electrostatic levitation and laser processing. The various capabilities of the facility are discussed and are exemplified with the measurements of the density of selected iron-nickel alloys taken over the liquid phase. 1. Introduction Noncontact processing of materials is required when dealing with corrosive materials or when there is a need to reach and maintain samples at high temperatures for times long enough to complete the processing. This is a stringent requirement for materials (e.g., refractory metals and ceramics) with melting temperatures higher than those of crucibles. In particular, containerless conditions are desirable to allow a host of investigations (thermophysical property measurements, high energy beam interaction (neutron, synchrotron, etc.)), solidification studies, synthesizing new phases, to name but a few. Moreover, processing without containers avoids any physical contact which can contaminate or change the shape of a sample. By doing so, data analysis is also simplified and it is possible to obtain properties of a material in its purest form. In addition, this allows to reach and maintain a material under undercooled conditions (below melting temperature). This limits heteregeneous nucleation and eases vitrification. Similarly, the reduced gravity conditions prevailing on orbiting platform (space shuttle, International Space Station, etc.), in sounding rockets, in airborne laboratory or in drop shaft, all require some sort of positioning system to maintain a processed material subject to residual forces in a specific location [1¨C6]. Electrostatic levitation is very well suited to meet the above requirements for the noncontact processing of materials. In particular, the method does not intrinsically heat the samples and does not deform them. Furthermore, it allows the processing of conducting and nonconducting materials, solid or liquid, while offering a wide field of view of the processed materials. It can operate under
%U http://www.hindawi.com/journals/aot/2011/454829/