Study On Preparation And Properties Of Nb₂O₅ Doped TiO₂

There are many kinds of thin films prepared by Nb₂O₅ doped TiO₂?NTO?with different Doping ratios and oxide powders prepared by proportional synthesis of Nb₂O₅ doped TiO₂,The prepared products whether they are thin films or powders both have a good application prospect,and the research direction is very extensive about them.At present,there is little systematic summary of the research literature and research work on the application of the corresponding products in each doping range in the mutual doping process of Nb₂O₅ and TiO₂with the increase of the molar ratio of Nb₂O₅ doping and the evolution of the whole binary solid solution phase diagram doping and the mixed products.Moreover,when the molar percentage of Nb₂O₅ is more than 88.9%,TiO₂ also has a certain solid solubility in the lattice of Nb₂O₅,that is to say the doping type changed to TiO₂ doped Nb₂O₅,the research on sintering preparation mechanism related to TNO is very rare.Because niobium oxide doped titanium oxide and mixed oxidation products has many applications.In this paper,the preparation process of NTO target and transparent conductive in the phase diagram of rich end TiO₂,the synthesis process of TiNb₂O₇ with Nb₂O₅ and TiO₂molar ratio of 1:1 and Ti₂Nb₁₀O₂₉ mesophase powder with 2:5 in the phase diagram of rich end Nb₂O₅ were selected as the main research direction.The effect of TiO₂ doping molar ratio on the sintering principle of TNO was studied.The main experimental conclusions are as follows:?1?Preparation of NTO targets in chamber furnace with filled air and tube furnace with filled argon respectively.The effects of doping amount,sintering temperature and sintering atmosphere on the density,mechanical properties and electrical properties of the target were investigated.The resistivity of the target prepared by chamber furnace is 280?·cm,the bending strength is 108.5 MPa,the density is 94.3%,and the Vickers hardness is 398.4 HV_2kg;The resistivity of the target prepared by tube furnace is 0.02?·cm,the bending strength is84.8 MPa,the density is 92.2%,and the Vickers hardness is 338 HV_2kg.?2?NTO thin films were prepared by DC sputtering.NTO thin films were prepared by DC sputtering.The film prepared by the target has the best photoelectric properties under the conditions of sputtering power of 80 w,target-substrate distance of 550 mm,sputtering time of 15 min,working pressure of 0.4 Pa and annealing temperature of 550?.The average transmittance of the visible light range is more than 90.2%,the resistivity of the film is6.24×10^-3?·cm.With the increase of sputtering time,the thickness of the film can be increased,the transmittance of the film can be increased and the resistivity of the film can be reduced,but the long sputtering time has an adverse effect on the transmittance of the film.When the working pressure is less than 0.4 Pa,the increase of air pressure can improve the transmittance and decrease the resistivity of the film.When the pressure exceeds 0.4 Pa,the increase of air pressure is not conducive to the formation of polycrystalline structure of the film.The crystallinity of the films can be improved by increasing the annealing temperature,but the polycrystalline structure will be destroyed when the annealing temperature is too high.?3?Niobium oxide and titanium oxide powders by high temperature synthesis with molar ratio of 1:1 and 2:5 were prepared by annealing at 1100?in high temperature chamber furnace.The two kinds of synthetic powders were well matched with PDF cards of TiNb₂O₇and Ti₂Nb₁₀O₂₉ by XRD analysis.Through the quantitative analysis of atomic ratio of XPS elements and the analysis of valence energy spectrum,the atomic ratios of Ti,Nb and O in the two synthetic powders are basically the same as the stoichiometric ratios of TiNb₂O₇ and Ti₂Nb₁₀O₂₉,and the valence states of the main elements Ti and Nb have not changed.The results show that the solid state reaction is sufficient and the main products are TiNb₂O₇ and Ti₂Nb₁₀O₂₉.?4?The TNO ceramics with different TiO₂ doping ratios were prepared in a box furnace with a sintering temperature of 1100°C.The effect of the increase of titanium-doped TiO₂doping ratio on the grain,mechanical properties,electrical performance and density of TNO sintered products was investigated.