GRAIN SIZE OF PLATINUM NANOFILMS FABRICATED BY EB-PVD AND ITS EFFECT ON THERMAL CONDUCTIVITY
CAO Bingyang; ZHANG Qingguang; ZHANG Xing;TAKAHASHI Koji; IKUTA Tatsuya
Key laboratory for Thermal Science and Power Engineering of Ministry of Education; Department of Engineering Mechanics; Tsinghua University;Beijing 100084
Cite this article:
CAO Bingyang; ZHANG Qingguang; ZHANG Xing; TAKAHASHI Koji; IKUTA Tatsuya. GRAIN SIZE OF PLATINUM NANOFILMS FABRICATED BY EB-PVD AND ITS EFFECT ON THERMAL CONDUCTIVITY. Acta Metall Sin, 2006, 42(11): 1207-1211 .
Abstract Six platinum films with thickness 15-62 nm have been fabricated by the method of electron beam- physical vapor deposition (EB-PVD). The grain sizes of the platinum nanofilms and its effect on the thermal conductivity have been studied experimentally. It is found that the grain size increases with the nanofilm thickness increasing and goes to a constant about 20 nm. The grain size is nearly comparable with the nanofilm thickness with the thickness less than 30 nm, while becomes much less than the nanofilm thickness with the thickness larger than 30 nm. Influenced by the size effect caused by the nanofilm interface and the grain boundary effect by the grain structure, the thermal conductivity of the platinum nanofilms is greatly lower than that of the bulk platinum. It is noted that the thermal conductivity of the studied platinum nanofilms increases with the thickness increasing and runs to 35 W/mK, which is much lower than that of the bulk material due to the grain boundary effect.
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