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Titolo:
High performance Al-N cermet solar coatings deposited by a cylindrical direct current magnetron sputter coater
Autore:
Zhang, QC; Zhao, K; Zhang, BC; Wang, LF; Shen, ZL; Lu, DQ; Xie, DL; Li, BF;
Indirizzi:
Univ Sydney, Dept Appl Phys, Sydney, NSW 2006, Australia Univ Sydney Sydney NSW Australia 2006 l Phys, Sydney, NSW 2006, Australia Peking Univ, Dept Tech Phys, Beijing 100871, Peoples R China Peking Univ Beijing Peoples R China 100871 ijing 100871, Peoples R China Beijing Turbosun Co, Beijing 100083, Peoples R China Beijing Turbosun Co Beijing Peoples R China 100083 0083, Peoples R China
Titolo Testata:
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS
fascicolo: 5, volume: 17, anno: 1999,
pagine: 2885 - 2890
SICI:
0734-2101(199909/10)17:5<2885:HPACSC>2.0.ZU;2-E
Fonte:
ISI
Lingua:
ENG
Soggetto:
FILM STRUCTURES; SELECTIVE ABSORPTION; OPTICAL-PROPERTIES; THIN-FILMS; SURFACES; ENERGY; OXIDE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Engineering, Computing & Technology
--discip_EC--
Citazioni:
30
Recensione:
Indirizzi per estratti:
Indirizzo: Zhang, QC Univ Sydney, Dept Appl Phys, Sydney, NSW 2006, Australia Univ Sydney Sydney NSW Australia 2006 dney, NSW 2006, Australia
Citazione:
Q.C. Zhang et al., "High performance Al-N cermet solar coatings deposited by a cylindrical direct current magnetron sputter coater", J VAC SCI A, 17(5), 1999, pp. 2885-2890

Abstract

High efficiency Al-N cermet solar selective coatings have been designed using a numerical computer model and deposited experimentally. In numerical modeling calculations, Bruggeman approximations of dielectric function for composite materials were employed. Aluminum is used as a metallic component and AlON as a ceramic component in cermet. Numerical calculation results show that the double cermet layer film structure has the highest photothermalconversion efficiency for the Al-AlON cermet solar selective coatings. Theoptimized film has a solar absorptance of 0.958 and a hemispherical emittance of 0.035 at 80 degrees C. The optimized film yields two cermet layers with metal volume fractions of 0.143 and 0.275, and with layer thicknesses of 43 and 80 nm, going from the antireflection coating to the infrared reflector layer. In the optimized double cermet layer film the solar radiation is efficiently absorbed internally and by phase interference. Thermal loss is also efficiently reduced by using thin cermet layers with such low metal volume fractions, which are substantially transparent in the main wavelength region of blackbody radiation within the temperature range of interest, 50-200 degrees C. The predicted film structure has been used as a guide for the experimental deposition. The Al-N cermet solar selective coatings with double cermet layer film structure have been deposited onto batches of solar collector tubes using a commercial-scale cylindrical dc magnetron sputtercoater. Two Al-N cermet solar absorber layers are deposited by de reactivesputtering in a gas mixture of argon and nitrogen. The different metal volume fractions in the cermet layers are achieved by changing the reactive nitrogen gas flow rate, while the sputtering current is fixed. A solar absorption of 0.96 and a normal emittance of 0.08 at 80 degrees C have been achieved for deposited Al-N cermet solar coatings. The baking process, for Ih at400 degrees C in vacuum, hardly affects solar absorptance, however the emittance reduces about 0.01 at 80 degrees C. These high-performance low-cost Al-N cermet solar collector tubes may be a less-polluting replacement for black chromium solar collectors produced by electrochemical methods. (C) 1999 American Vacuum Society. [S0734-2101(99)05205-7].

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 25/09/20 alle ore 00:08:56