Preparation And Properties Of TiO₂ Films Fabricated By LPD

TiO₂ is a kind of n-type semiconductor. It has well chemical stability and photo-catalysis activity. Magnesium alloys are new structural light metal materials and used widely in the field of the aviation, spaceflight, automobile, electronic products and biomaterials. Preparing TiO₂ films on the AZ31 Mg alloys substrate by LPD method is a novel surface modification method of the magnesium alloys. The (NH₄)₂TiF₆ and H₃BO₃ were used as the precursor. The nanometer anatase powder was added into the parent solution as the crystallization induction agent. The XRD, DSC-TG, FESEM, SEM, EDS, UV-VIS and UV-VIS-DR were used to characterize the films. The methylene blue was used to value the photocatalysis of the films. And the orthogonal test was carried out to optimize the parameter of the anticorrosion property. The results showed: The transition of the TiO₂ from the deposited state to anatase occurred at 194.2℃. The increase of reaction temperature helped the nucleation and the growth of the anatase. The heat treating temperature had stronger intensity than reaction temperature. The XRD results of the films showed: The increase of reaction temperature helped the formation and growth of the anatase. The average diameter of the crystal grain increased from 100nm to 112nm when the heat treating temperature increased from 300℃ to 420℃. Prolongation of heat treating time had the same effect as with heat treating temperature. The average diameter of the crystal grain increased from 99nm to 109nm when the heat treating time increased from 1h to 2.5h. The heating-up rate had mild influence on the growth of the anatase. The morphology of the films showed: The films comprised particles that had the characteristic crystal appearance of anatase TiO₂. The size of particles is about 150nm. The preferred orientation could be observed clearly.The UV-VIS -DR spectrum of the films prepared at the different temperature in the air atmosphere had the similar shape and the absorption edge shifted to the visible side. However the film heat-treated at 300℃ shift to the VIS side furthest. The heat-up rate had the mild influence on the photo absorption ability. The absorption side edge of the films prepared in the vacuum atmosphere at the different temperature shifted to VIS side with the increase of the treating temperature. And the second absorption edges could be...