Thermodynamics and kinetic considerations behind the growth of AIN whiskers synthesized by carbothermal reduction
authors Fu, RL; Zhou, HP; Chen, KX; Ferreira, JMF
editors Pan, W; Gong, JH; Ge, CC; Li, JF
nationality International
journal HIGH-PERFORMANCE CERAMICS III, PTS 1 AND 2
author keywords aluminum nitride; crystal growth; thermodynamics; kinetics
keywords ALUMINUM NITRIDE WHISKERS; LOW SUPERSATURATION; NITROGEN; CRYSTALS; MORPHOLOGIES; MECHANISMS; POWDERS; AL2O3
abstract AlN whiskers have been successfully synthesized by carbothermal reduction. The thermodynamics and growth kinetics of AlN whiskers were studied at 1600degreesC using CaCO3 as a catalyst. The research indicated that AlN whiskers are more easily nucleated from the liquid phase than at the surface of solid phase. AlN whiskers are nucleated by VLS mechanism and the liquid, which plays a dominant role in the VLS mechanism, is formed by AlCa interphases, such as CaO.2Al(2)O(3) and CaO.6Al(2)O(3). Kinetic studies suggest that the catalyst reacts with Al2O3 to form a low melting point eutectic (1390degreesC). The liquid phase formed at this low melting point eutectic provides good conditions for nucleation of AlN whiskers. At the synthesis temperature, the liquid phase vaporizes, thus creating suitable conditions for the subsequent growing of whiskers by the VLS mechanism. This growing mechanism conforms to thermodynamics and a lot of proof indicates that screw dislocations play an important role in the process of the whiskers' formation.
publisher TRANS TECH PUBLICATIONS LTD
issn 1013-9826
isbn 0-87849-959-8
year published 2005
volume 280-283
beginning page 1403
ending page 1408
web of science category Materials Science, Ceramics; Materials Science, Composites
subject category Materials Science
unique article identifier WOS:000227051400338
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