Preparation And Performance Of The Duplex TiO₂Film On The Surface Of Stainless Steel

In recent years, organic matter pollution is more and more serious, and it is in the form of high concentration of organic matter, poor biodegradability and biological toxicity. The photocatalytic reaction can be happened under normal temperature and pressure though nanometer TiO2particle by using part of sunlight. TiO2has the performance of the degradation of water pollutants, air purification, sterilization and super hydrophilic. Furthermore, TiO2photocatalyst with the characters of high photocatalytic reaction speed, pollutant degraded thoroughly and no secondary pollution, it is perfectly to fit in environmental governance with the requirement of high efficiency and low consumption. However, the nano TiO2photocatalyst with the shortcoming of deactivated and agglomerated easily, separated and recycled difficultly, so it is difficult for the practical application and industrialization. The effective way to overcome these obstacles is the preparation of load-type TiO2photocatalyst, namely titanium dioxide thin film. In this paper, the pure titanium film was deposited on the surface of304stainless steel by using multi-arc ion plating technology. And on the basis of pure titanium film, the TiO2-SnO2composite film was synthetized by using micro-arc oxidation technology though changing the micro-arc oxidation electrolyte composition. And the micro-arc oxidation composite film organization structure, surface morphology, chemical element content and distribution, light catalytic properties and corrosion resistance were studied by Scanning electron microscopy (SEM), energy spectrum analyzer (EDS), X-ray diffraction (XRD), X-ray photoelectron spectrometer (XPS) and ultraviolet-visible spectrophotometer, and electrochemical workstation. The main results were as follows:(1)The pure titanium film was deposited on the surface of304stainless steel by using multi-arc ion plating. And the film was divided into two layers: oozed layer and coated layer. Due to the gradient transition of the component of the oozed layer in the interface of the film, the combination of the film and substrate was good.(2) The surface of the film was smooth and poriferous, and the large particles in multi-arc ion plating have no effect on the film. The pore ratio of the micro-arc oxidation composite film synthetized in the electrolyte with the addition of the stannate was higher than the without, pore distribution was more uniform and specific surface area is larger.(3) The Ti film synthetized by multi-arc ion plating and the micro-arc oxidation composite film was composed of pure titanium, anatase, rutile and little tin oxide phase. And in the micro-arc oxidation composite film synthetized for longer time and higher electrolyte concentration, the relative amount of the anatase was reduced. In addition, the grain size of titanium dioxide calculated achieved nano-scale.(4) The SnO2-TiO2composite semiconductor was formed in micro-arc oxidation on the stainless steel. In addition, the composite film was composed of oozed layer, pure Ti layer and micro-arc oxidation layer.(5) Adding the right amount of stannate in MAO electrolyte was beneficial to the improvement photocatalytic efficiency, while excessive SnO2doping resulted in the decrease of photocatalytic activity. In addition, the longer time of micro-arc oxidation, the relative content of anatase was reduced, which resulted in the decrease of the photocatalytic efficiency of composite film.(6) The corrosion resistance of the micro-arc oxidation composite film synthetized in different electrolyte was obviously higher than that the stainless steel substrate. However, the corrosion resistance of different micro-arc oxidation composite film was similar.