Resumo

MAIMONE, Alberto; CAMERO, Sonia  e  BLANCO, Sergio. Characterization of titanium oxide obtained by heat treatment and electrochemical anodized. Rev. Fac. Ing. UCV [online]. 2015, vol.30, n.1, pp.189-200. ISSN 0798-4065.

The titanium oxide (TiO₂) is an n-type semiconductor of great interest for their photocatalytic properties and photoconductive, and others associated with the morphological and structural characteristics of the constituent phases. This is characterized by having two main polymorphs: anatase, metastable phase, which may suffer irreversible transition phase and rutile phase thermodynamically stable. Therefore, it is interesting to determine the morphology and growth of this oxide, considering the presence of these phases when subjected to physical and chemical treatments. In this paper, flat TiO₂ films on a titanium substrate - induced with the application of thermal treatments (TT) at different temperatures and times were synthesized by an electrochemical and rear anodized heat treatment (ATT). The samples were characterized by optical microscopy (OM) and scanning electron microscopy (SEM) with X-ray spectroscopy by energy-dispersive (EDS), in order to determine the microstructural and morphological changes of the layer formed, considering mainly oxygen diffusion through it. Furthermore, the photoelectrochemical behavior of the TiO₂ film was obtained by electrochemical methods. The TiO₂ layer in specimens presented a granular morphology TT, uniform, dense, growing by a directly proportional to the heat treatment conditions. At 800 ° C the layer showed fragility and a partial release, the product of the thermal expansion and the volume ratio for rutile. The oxide layer formed by anodizing electrochemical showed high density and uniformity, replicating the microstructure of the sample and its thickness varying with the heat treatment applied. The proportion of anatase / rutile samples TT reached 600 ° C for 8 h, showed the highest photocurrent flow, favored by the less rate of recombination of electron-hole pair. In the TT temperature samples had the highest impact on the growth rate of the TiO₂ layer by diffusion, while the anodized samples corresponded to the applied potential in synthesis is in the primary layer.

Palavras-chave : TiO₂; Anatase; Rutile; Heat treated; Electrochemical anodized.

        · resumo em Espanhol     · texto em Espanhol     · Espanhol ( pdf )