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Titolo:
Low thermal conductivity vapor deposited zirconia microstructures
Autore:
Hass, DD; Slifka, AJ; Wadley, HNG;
Indirizzi:
Univ Virginia, Sch Engn & Appl Sci, Dept Mat Sci, Charlottesville, VA 22903 USA Univ Virginia Charlottesville VA USA 22903 Charlottesville, VA 22903 USA Natl Inst Stand & Technol, Div Mat Reliabil, Boulder, CO 80303 USA Natl Inst Stand & Technol Boulder CO USA 80303 bil, Boulder, CO 80303 USA
Titolo Testata:
ACTA MATERIALIA
fascicolo: 6, volume: 49, anno: 2001,
pagine: 973 - 983
SICI:
1359-6454(20010402)49:6<973:LTCVDZ>2.0.ZU;2-C
Fonte:
ISI
Lingua:
ENG
Soggetto:
BARRIER COATINGS; THIN-FILMS; ADHESION;
Keywords:
physical vapor deposition (PVD); coating; oxides; thermal conductivity;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Engineering, Computing & Technology
Citazioni:
54
Recensione:
Indirizzi per estratti:
Indirizzo: Hass, DD Univ Virginia, Sch Engn & Appl Sci, Dept Mat Sci, Charlottesville, VA 22903 USA Univ Virginia Charlottesville VA USA 22903 esville, VA 22903 USA
Citazione:
D.D. Hass et al., "Low thermal conductivity vapor deposited zirconia microstructures", ACT MATER, 49(6), 2001, pp. 973-983

Abstract

Low thermal conductivity yttria stabilized zirconia (YSZ) coatings have been grown using a low-vacuum (0.20 Torr) electron beam directed vapor deposition process. In this approach, a transsonic helium jet was used to entrainand transport an evaporated YSZ flux to a substrate. The interaction of the helium jet with the coating surface resulted in many of the evaporated species making oblique angles of contact with the substrate. This resulted inthe formation of a highly porous, columnar microstructure without substrate rotation. When the substrate was positioned perpendicular to the axis of the jet, coatings with intercolumnar pores normal to the substrate surface were formed. The ambient temperature thermal conductivity of a coating grown in this arrangement was 1.9 Wm/K, comparable to that of conventinal, high-vacuum electron beam coatings. When the column and pore orientation was inclined (by tilting the substrate) the thermal conductivity was observed to fall. By alternating the inclination angle as growth progressed, coatings containing zig-zag columns and pores could be synthesized. Using this technique, YSZ coatings with thermal conductivities as low as 0.8 W/m K were obtained. The observed thermal conductivity reduction arises from the longer thermal diffusion path of the zig-zag pore micro-structures. (C) 2001 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.

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Documento generato il 01/04/20 alle ore 18:34:59