Selective absorbers utilize in many cases the enhanced solar absorptance of small metal particles embedded in a layered ceramic medium. A crucial factor in determining the performance of such an absorber is the degradation rate of this layer. The oxidation of ultrafine gas evaporated metal particles is examined here. Several metal develop a stable oxide film around the surface of small particles. It is shown that there is a linear dependence between the size of the metal core and the particle radius for Al, Mg, Be and Sn in room temperature and for Si at high temperatures. Charge quantization is proposed as a possible mechanism responsible for this phenomenon. Thermogravimetric measurements on Ni particles show a rapid oxidation for intermediate temperatures.

Date Published: 22 October 1993
PDF: 7 pages
Proc. SPIE 2017, Optical Materials Technology for Energy Efficiency and Solar Energy Conversion XII, (22 October 1993); doi: 10.1117/12.161974

Published in SPIE Proceedings Vol. 2017:
Optical Materials Technology for Energy Efficiency and Solar Energy Conversion XII
Carl M. Lampert, Editor(s)