Study on Nano-TiO_2 Films Deposited by Vacuum Arc Source

Nano-TiQ Thin Films Prepared by Vacuum Arc Welding with Vacuum Source ZHOU You-su, ZHANG Li-shan (School of Electromechanical Engineering, Beijing Union University, Beijing 100020, China) The oxygen working pressure and bias voltage were studied. X-ray diffraction structure analysis showed that Ti2 films were mainly anatase. The main phase and a small amount of rutile phase. The physical properties and chemical properties of Ti2 thin films have been primarily tested. In recent years, titanium dioxide (Ti2) has been increasingly used as a photocatalytic material to eliminate environmental pollution. Ti2 has excellent optical properties and dielectric properties, and has photocatalysis and photolysis. Water, photo-electricity, transformation, sterilization, etc. Function Ti2 as a transparent dielectric material, has a high refractive index and dielectric constant, good mechanical properties and chemical stability. Recently, it was found that the surface of Ti2 film was irradiated with ultraviolet light of less than 380 nm due to light. Catalytic action produces vine-proof, anti-fog and self-cleaning effects. The vacuum arc discharge is performed in the vacuum chamber 1 so that the vacuum chamber reaches the background vacuum and the working gas oxygen is introduced. The oxygen pressure is controlled to be 5 The metal atoms entering the vacuum chamber collide with electrons and ions and undergo ionization. Titanium metal ions and oxygen ions are subjected to the substrate bias electric field to reach the substrate sample at a certain speed. At the same time, electrons are obtained and combined into a Ti2 vacuum arc discharge process with certain randomness. In order to stabilize the arc work, ionization and reduction are added. In the droplets in the plasma region, the system has a permanent magnet field at the cathode arc source, and a direct water-cooled bias power supply to the cathode target to provide a negative bias voltage Vs to the substrate has an important influence on the coating process and the quality of the formed film. On the one hand, the space electric field formed by negative bias can increase the ionization degree and reduce the deposition rate of metal atoms on the substrate. On the other hand, the negative bias electric field can increase the energy of positive ions and improve the quality of Ti2 film.

2 Experimental results and analysis X-ray diffraction experiment X-ray diffraction analysis of stainless steel-based samples Table 1 is the original sample of the Ti2 thin film deposited, Table 2 is the 600*C annealing of the sample as follows .

Table 1 X-ray diffraction analysis results Peak number Crystal face Note Anatase rutile content of anatase can be calculated using the following formula Sample anatase percentage before annealing was 81.6%, annealed after anatase The percentage decrease to 44.4% is due to the transition from anatase to rutile at 60C. It is reported that when the temperature reaches 850C, the anatase will be completely converted to the temperature at which the rutile changes from anatase to rutile and the original film. The state is concerned, the finer the crystal grain, the lower the transformation temperature is. The vacuum degree is 5 Table 2 X-ray diffraction analysis results It was found in the experiment that the deposition temperature has an influence on the structure of Ti2. Before the oxygen is introduced, the ion bombardment method is used to test. This kind of heating is beneficial to the deposition of Ti2 below 25C, and the Ti2 film is completely amorphous. When the deposition temperature is above 35C, an anatase-based Tift film can be formed. Therefore, an appropriate bias voltage is applied to the sample during the deposition process, which is favorable for maintaining the deposition temperature and enables the particles to reach the surface of the sample when compared. High energy, favorable for particle migration and nucleation and crystallization. Photocatalytic experiments of 2.2 TiO thin films were pre-configured with methyl orange solution at a concentration of 15 mg/L. The absorbance was measured to be 1.030. Samples coated with Ti2 films were placed in methyl groups. The comparison of the absorbance changes in the orange solution and the sample-free methyl orange solution showed the comparison results of the photocatalytic experiments of the TiO2 films shown in Table 3 and Table 3. The absorbance of the methyl orange solution added with the Ti2 film-coated sample was lower than that of the sample. The methyl orange solution shows a significant decrease. This proves that photocatalytic reaction occurs between Ti2 and some methyl oranges, which reduces the concentration of methyl orange. 2.3 Hardness of TiO2 films Hardness measurement of Ti2 films using HV-200 microhardness tester The hardness of the layer is in the range of 1900 to 2500 HV because pure titanium deposits on the sample during the coating process. The hardness value of the film is reduced several times. The hardness test and X-ray diffraction analysis show that only when Ti2 When the thickness of the film reaches 5 μm or more, X-ray diffraction experiment and hardness test will have effective results. Conclusion The application of vacuum cathodic arc source plating Ti2 can obtain an anatase-based film, quenched by 600*C. The structure of the thin film undergoes phase transition from anatase to rutile. The Ti2 thin film has a photocatalytic effect, decomposes organics, and decreases the absorbance of methyl orange. The Ti2 film deposited by a vacuum cathodic arc source has higher hardness.

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