CVD OF TITANIUM CARBIDE AT MODERATE TEMPERATURE FROM TITANIUM SUBCHLORIDESReportar como inadecuado




CVD OF TITANIUM CARBIDE AT MODERATE TEMPERATURE FROM TITANIUM SUBCHLORIDES - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.



Abstract : The in-situ formation of the titanium subchlorides by the reduction of titanium tetrachloride by titanium metal is used together with butane to deposit titanium carbide layers at moderate temperature, in the order of 850°C. The deposition rate, the C-Ti composition of the coatings, the chlorine incorporation and the microhardness are studied as functions of the initial gaseous composition. When compared with the thermodynamical calculations, the variations of the deposition rate and the solid composition allow to discuss the influence of different kinetic limitations of the process which arise as a function of the deposition conditions. In any case a great departure from the equilibrium is observed. It is shown that these conditions of moderate temperature and supersaturation lead to a very fine-grained structure. The microhardness of the deposits varies in a large range. Values as low as 1000 kg.mm2 can be observed when the chlorine content is high. With the best deposition conditions, the deposits are well-crystallized with a low chlorine content and a C-Ti ratio approaching 1. In that case it is shown that the grain size is particularly lower than those observed in layers deposited at classical higher temperatures of 1000-1050°C, the morphology is very dense and the microhardness is in the range 4000-5000 kg.mm-2 under 50g load.





Autor: B. Drouin-Ladouce J. Piton L. Vandenbulcke

Fuente: https://hal.archives-ouvertes.fr/



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