Schroers, Jan and Johnson, William L. (2002) Extremely low critical cooling rate measured on dispersed Pd43Ni10Cu27P20. Applied Physics Letters, 80 (12). pp. 2069-2071. ISSN 0003-6951 http://resolver.caltech.edu/CaltechAUTHORS:SCHRapl02
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Crystallization of dispersed Pd43Ni10Cu27P20 melts is studied during constant cooling and heating. Investigations are carried out on samples that are dispersed into several hundred particles which are fluxed in B2O3. The size of the particles is chosen in such a way that crystallization of individual particles can be observed. Constant cooling experiments with rates between 0.3 and 0.0016 K/s are performed. In order to determine the fraction of particles that crystallize upon cooling, the crystallization during subsequent heating at 0.3 K/s is utilized. 10%–15% of the particles do not crystallize during cooling with a rate as low as 0.005 K/s. This is the lowest rate that avoids crystallization ever measured for a metallic system. This extremely low critical cooling rate suggests that a fraction of the particles do not contain the impurities that act as nuclei in bulk samples. Therefore, in these particles, nuclei first have to form and crystallization does not take place, as it was found for bulk Pd43Ni10Cu27P20, by the growth on pre-existing nuclei formed by impurities.
|Additional Information:||©2002 American Institute of Physics. (Received 5 December 2001; accepted 18 January 2002) This work was supported by the National Aeronautics and Space Administration (Grant No. NAG8-1744) and the Department of Energy (Grant No. DEFG-03086ER45242). The authors express their gratitude to Natassia Gaznick for technical assistance.|
|Subject Keywords:||palladium alloys; nickel alloys; copper alloys; phosphorus alloys; crystallisation; cooling; liquid alloys; differential scanning calorimetry|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Archive Administrator|
|Deposited On:||17 Aug 2007|
|Last Modified:||26 Dec 2012 09:39|
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