One of the main problems of stainless steel is its poor pitting corrosion resistance in the aggressive environment containing Cl-, such as seawater. In this paper we investigated the corrosion behavior of the 316 stai...One of the main problems of stainless steel is its poor pitting corrosion resistance in the aggressive environment containing Cl-, such as seawater. In this paper we investigated the corrosion behavior of the 316 stainless steel coated by cerium oxide nanocoating prepared by sol-gel process. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were used to study the corrosion behavior of cerium oxide nanocoatings in 3.5% NaCl solution. The microstructure of the cerium oxide was examined by scanning electron microscopy (SEM) and the formed phases was identified by X-ray diffraction (XRD). The pitting corrosion resistance of the cerium oxide nanocoating was found to be improved after heat treatment of the cerium oxide nanocoating at 300℃ for 30 min.展开更多
A NiP/TiO2 composite film on carbon steel was prepared by electroless plating and sol-gel composite process. An artificial neural network was applied to optimize the prepared condition of the composite film. Corrosion...A NiP/TiO2 composite film on carbon steel was prepared by electroless plating and sol-gel composite process. An artificial neural network was applied to optimize the prepared condition of the composite film. Corrosion behavior of the NiP/TiO2 composite film was investigated by polarization resistance measurement, anode polarization, ESEM (environmental scanning electron microscopy) and EIS (electrochemical impedance spectroscopy) measurements. Results showed that the NiP/ TiO2 composite film has a good corrosion resistance in 0.5mol/L H2SO4 solution. The element valence of the composite film was characterized by XPS (X-ray photoelectron spectroscopy) spectrum, and an anticorrosion mechanism of the composite film was discussed.展开更多
A new TiO2 modified film on carbon steel was prepared by electroless plating and sol gel composite process. An artificial neural net was used to optimize the preparing condition of the film. The optimized condition of...A new TiO2 modified film on carbon steel was prepared by electroless plating and sol gel composite process. An artificial neural net was used to optimize the preparing condition of the film. The optimized condition of the TiO2-modified film on carbon steel is as follows: plating time of NiP is 50 min, number of dip coating is 4, heat treatment time is 2 h, and the molar ratio of complexing reagent to Ti(OC4 H9)4 is 1.5 : 1. Corrosion behavior of carbon steel with coating was investigated by polarization resistance measurement, anode polarization, EIS and ESEM measurement. XPS was used to characterize the element valence of the modified film. Results show that carbon steel with TiO2 modified film has good corrosion resistance in 0.5 mol/L of H2SO4 solution and 0.5 mol/L of NaCl solution. It is also found that the preparing condition of forming TiO2-modified film can be obtained easily by the artificial neural net.展开更多
Al specimens were covered with TiO2 film by sol-gel dip-coating and then anodized in ammonium adipate solution.The structure,composition and capacitance properties of the anodic oxide film were investigated by transmi...Al specimens were covered with TiO2 film by sol-gel dip-coating and then anodized in ammonium adipate solution.The structure,composition and capacitance properties of the anodic oxide film were investigated by transmission electron microscopy (TEM),Auger electron spectroscopy (AES),X-ray diffractometry (XRD) and electrochemical impedance spectroscopy (EIS).It was found that an anodic oxide film with a dual-layer structure formed between TiO2 coating and Al substrate.The film consisted of an inner Al2O3 layer and an outer Ti-Al composite oxide layer.The thickness of layers varied with the number of times of sol-gel dip-coating.The capacitance of anodic oxide films formed on coated specimens was at most 80% higher than that without TiO2.In film formation mechanism,it was claimed that the formation of composite oxide film was mainly affected by the structure of micro-pores network in TiO2 coating which had an influence on Al3+ and O2? ions transport during the anodizing.展开更多
To improve the oxidation resistance property of iron fibers, a SiO2 coated iron fiber was prepared by sol-gel method, and its microstructure, element and phase composition, antioxidation property, and crystallization ...To improve the oxidation resistance property of iron fibers, a SiO2 coated iron fiber was prepared by sol-gel method, and its microstructure, element and phase composition, antioxidation property, and crystallization were characterized by scanning electron microscopy, thermal gravimetric analysis, X-ray diffraction and 3% CuSO4 solution dripping. It was found that the surface of the iron fiber can be fully covered with SiO2 by using Sol-Gel method. Our results also indicated that the time of iron begin to be corrupted in 3% CuSO4 solution drip increased from 30 s to 240 s, and the temperature increased from 200?C to 310?C. In addition, the oxidation and antioxidation mechanisms of the SiO2 coated iron fiber have also been discussed in this work.展开更多
In the present work, undoped (SnO2) and fluorine-doped tin oxide (FTO) thin films were prepared by sol-gel process using a solution composed of (SnCl2, H2O), (NH4F), and ethanol mixture. The fluorine concentration eff...In the present work, undoped (SnO2) and fluorine-doped tin oxide (FTO) thin films were prepared by sol-gel process using a solution composed of (SnCl2, H2O), (NH4F), and ethanol mixture. The fluorine concentration effect on structural, optical and electrical properties of SnO2 films is investigated. The electrical properties of FTO films prepared by sol gel remain relatively lower than the ones deposited by other techniques. In present paper, we try to elucidate this difference. Films composition and the FTIR analysis, of films and formed precipitate during film growth, indicate that few amounts of fluorine are incorporated in SnO2 network, most of fluorine atoms remain in the solution. The films resistivity is reduced from 1.1 Ω·cm for undoped films to 3 × 10-2 Ω·cm for 50 wt.% doped FTO, but remains higher than the reported ones in the literature. This high resistivity is explained in terms of fluorine bonding affinity in the solution.展开更多
The Indium tin oxide(ITO) thin film possesses excellent photoelectric properties that enable it to act as an ideal transparent conductor.To obtain high-quality ITO films through sol-gel method, the ionic surfactant ...The Indium tin oxide(ITO) thin film possesses excellent photoelectric properties that enable it to act as an ideal transparent conductor.To obtain high-quality ITO films through sol-gel method, the ionic surfactant monoethanolamine and the non-ionic surfactant polyethylene glycol(PEG) were added to the ITO precursor slurry.The influences of surfactants on the structural and photoelectric properties of ITO film samples were investigated.XRD patterns indicated that surfactant monoethanolamine contributed to film predominant grain orientation along the(400) plane.The high transmittance(over 95%) was attributed to the preferred orientation and the grain size expansion of ITO films.SEM showed that the surface particle size and the morphology of ITO films were strongly dependent on the kind of surfactants used.Moving to the shortwave region, the absorption edge of the films exhibited the Burstein-Moss shift.展开更多
Microstructure and electrical properties of La2 O3-doped ZnO-Bi2 O3 thin films prepared by sol–gel process have been investigated.X-ray diffraction shows that most diffraction peaks of ZnO are equal,and the crystals ...Microstructure and electrical properties of La2 O3-doped ZnO-Bi2 O3 thin films prepared by sol–gel process have been investigated.X-ray diffraction shows that most diffraction peaks of ZnO are equal,and the crystals of ZnO grow well.Scanning electron microscopy and atomic force microscopy results indicate that the samples have a good structure and lower surface roughness.The nonlinear V–I characteristics of the films show that La2 O3 develops the electrical properties largely and the best doped content is 0.3% lanthanum ion,with the leakage current of 0.25 mA,the threshold field of 150 V/mm and the nonlinear coefficient of 4.0 in detail.展开更多
Hafnium oxide thin films (HOTFs) were successfully deposited onto amorphous glasses using chemical bath deposition, successive ionic layer absorption and reaction (SILAR), and sol-gel methods. The same reactive pr...Hafnium oxide thin films (HOTFs) were successfully deposited onto amorphous glasses using chemical bath deposition, successive ionic layer absorption and reaction (SILAR), and sol-gel methods. The same reactive precursors were used for all of the methods, and all of the films were annealed at 300℃ in an oven (ambient conditions). After this step, the optical and structural properties of the films produced by using the three different methods were compared. The structures of the films were analyzed by X-ray diffTaction (XRD). The optical properties are investigated using the ultraviolet-visible (UV-VIS) spectroscopic technique. The film thickness was measured via atomic force microscopy (AFM) in the tapping mode. The surface properties and elemental ratios of the films were investigated and measured by scanning electron microscopy and energy-dispersive X-ray spectroscopy (EDX). The lowest transmittance and the highest reflectance values were observed for the films produced using the SILAR method. In addition, the most intense characteristic XRD peak was observed in the diffraction pattern of the film produced using the SILAR method, and the greatest thickness and average grain size were calculated for the film produced using the SILAR method. The films produced using SILAR method contained fewer cracks than those produced using the other methods. In conclusion, the SILAR method was observed to be the best method for the production of HOTFs.展开更多
Pure and rare earth doped gadolinium oxide (Gd 2O 3) waveguide films were prepared by a simple sol-gel process and dip-coating method. Structure of Gd 2O 3 films annealed at different temperature was investigated ...Pure and rare earth doped gadolinium oxide (Gd 2O 3) waveguide films were prepared by a simple sol-gel process and dip-coating method. Structure of Gd 2O 3 films annealed at different temperature was investigated by X-ray diffraction and transmission electron microscopy. Oriented growth of (400) face of Gd 2O 3 has been observed when the films were deposited on amorphous substrate. The refractive index and thickness of films were determined by m-lines spectroscopy. The laser beam (λ=632.8 nm) was coupled into the film by a prism coupler and the propagation length is about 3.5 cm. Luminescence properties of europium ions doped films were measured by waveguide fluorescence spectroscopy, which shows disordered environment for Eu 3+ at 400 ℃.展开更多
We prepare CuGaO2 thin films on SiO2 substrates by using the sol-gel spin-coating method with two combinations of Cu and a Ga source, Cu and Ga nitrate, or acetylacetonate. X-ray diffraction analysis reveals that the ...We prepare CuGaO2 thin films on SiO2 substrates by using the sol-gel spin-coating method with two combinations of Cu and a Ga source, Cu and Ga nitrate, or acetylacetonate. X-ray diffraction analysis reveals that the thin films prepared using nitrate sol that are annealed at a temperature of 850°C - 950°C show both c-axis-orientated peaks, (006) and a non-c-axis-oriented peak (012) with similar intensity;little dependence of signal intensity on annealing temperature is also shown. The films are opaque in appearance at these annealing temperatures. Scanning electron microscope observation reveals that the opaque appearance is due to the texture or cracks on the surface of the films. In contrast, the films prepared using acetylacetonate show a (006) peak with higher signal intensity than the (012) peaks. The films show more transparent appearance than that of the films by nitrate. The highest conductivity of the film is 5.7 × 10-4Ω-1·cm-1, obtained in the films by nitrate annealed at 850°C.展开更多
Hydrogen has been recently attracted much attention with respect to high energy-conversion efficiency and low environmental burden. However, hydrogen gas is dangerous due to an explosive gas and a fast combustion rate...Hydrogen has been recently attracted much attention with respect to high energy-conversion efficiency and low environmental burden. However, hydrogen gas is dangerous due to an explosive gas and a fast combustion rate. Therefore, the development of hydrogen sensor with high accuracy and reliability that can detect hydrogen easily is required. Especially, a flexible hydrogen sensor is useful because it has a high degree of freedom with respect to the shape of location in which the sensor is to be located. A flexible hydrogen sensor—namely, a WO3 thin film formed on a PET film by the sol-gel method using photo irradiation—based on gasochromism of WO3 was developed. By irradiating a thin film, which was prepared by using WO3 precursor solution synthesized by the sol-gel method, with ultraviolet rays, a high-purity WO3 film could be prepared on PET at low temperature. The sensor was structured as a polystyrene (PS) film containing palladium (Pd) laminated on a WO3 film. The WO3 layer was porous, so the PS containing Pd atoms solution penetrated the WO3 layer. WO3 reacted with hydrogen gas and instantly turned blue as the transmittance of the WO3 layer changed. The sensor showed high reactivity even for hydrogen concentration below 4% (1%, 0.5%, 0.25%, and 0.1%), which was the lower limit of hydrogen ignition, and a linear relationship between hydrogen concentration and change in transmittance was found. Moreover, the resistance of the WO3 film significantly and instantaneously changed due to hydrogen-gas exposure, and the hydrogen concentration and resistance change showed a linear relationship. It is therefore possible to quantitatively detect low concentrations of hydrogen by using changes in transmittance and resistance as indices. Since these changes occur selectively under hydrogen at room temperature and normal pressure, they form the basis of a highly sensitive hydrogen sensor. Since the developed sensor is flexible, it has a high degree of freedom with respect to the shape of location in which the sensor is to be展开更多
A new technique for preparing TiO2 modified film on carbon steel was accomplished by electroless plating and sol-gel composite process. The artificial neural network was applied to optimize the preparing condition of ...A new technique for preparing TiO2 modified film on carbon steel was accomplished by electroless plating and sol-gel composite process. The artificial neural network was applied to optimize the preparing condition of TiO2 modified film. The optimized condition for forming TiO2 modified film on carbon steel was that NiP plating for 50 min, dip-coating times as 4, heat treatment time for 2 h, and the molar ratio of complexing agent and Ti(OC4HZ9)4 kept 1.5:1. The results showed that TiO2 modified film have good corrosion resistance. The result conformed that it is feasible to design the preparing conditions of TiO2 modified film by artificial neural network.展开更多
A PANI/TiO2 composite film deposited on the glass surface was successfully prepared using sol-gel dip-coating technique and chemical oxidation method. The film was characterized using XRD, AFM, and UV. The result show...A PANI/TiO2 composite film deposited on the glass surface was successfully prepared using sol-gel dip-coating technique and chemical oxidation method. The film was characterized using XRD, AFM, and UV. The result showed that the TiO2 film consists of both cuboid-shaped and anatase-phased TiO2 nanoparticles. The average grain size of TiO2 in the film was approximately 20 nm. After coating with PANI, the particle was changed into irregular spherical-shaped and the size was increased up to approximately 35 nm in diameter. UV-Vis spectroscopy analysis indicated that the coating of TiO2 with PANI would result in an enhancement of photocatalytic efficiency and an extension of the photoresponse of TiO2. The band gap of the PANI/TiO2 film was 3.18 eV. The photocatalytic property of the film was evaluated by the degradation of rhodamine-B. It was found that 67.1% and 83.2% of rhodamine-B could be degraded under sunlight and UV irradiation within 120 min using the PANI/TiO2 composite t-tim as photocatalyst.展开更多
Polydimethylsiloxane(PDMS),tetraethoxysilane(TEOS),ethyl alcohol(EtOH) and deionized water were main raw materials to prepare silicone-modified hybrid thin films using sol-gel method.The effect of the contents of H2O ...Polydimethylsiloxane(PDMS),tetraethoxysilane(TEOS),ethyl alcohol(EtOH) and deionized water were main raw materials to prepare silicone-modified hybrid thin films using sol-gel method.The effect of the contents of H2O and PDMS on thin films was studied.When the volume ratio of H2O to TEOS is 0.5,the optimum quality of thin films is obtained.And the gelation time is affected slightly by H2O content.Uniform thin films are obtained when the volume ratio of PDMS to TEOS is 0.2.Yet,the sol would be inactive in 6 d.Various properties of thin films were studied,including hardness,adhesive quality,hydrophobic property,corrosion protection property,and abrasion resistance.Test results show that the pencil hardness is generally 3-6 H,and adhesive quality achieves the highest standard of 0.When the sintering temperature is below 400 oC,the contact angle is about 95° and hydrophobic films are obtained.The abrasion resistance of thin films is better than that of aluminum alloy when the sintering temperature is higher than 300 oC.And the excellent corrosion protective effect is obtained by single-layer coating when the sintering temperature is higher than 400 oC.展开更多
基金supported by the Iranian Nanotechnology and Nanoscience Organization.
文摘One of the main problems of stainless steel is its poor pitting corrosion resistance in the aggressive environment containing Cl-, such as seawater. In this paper we investigated the corrosion behavior of the 316 stainless steel coated by cerium oxide nanocoating prepared by sol-gel process. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were used to study the corrosion behavior of cerium oxide nanocoatings in 3.5% NaCl solution. The microstructure of the cerium oxide was examined by scanning electron microscopy (SEM) and the formed phases was identified by X-ray diffraction (XRD). The pitting corrosion resistance of the cerium oxide nanocoating was found to be improved after heat treatment of the cerium oxide nanocoating at 300℃ for 30 min.
文摘A NiP/TiO2 composite film on carbon steel was prepared by electroless plating and sol-gel composite process. An artificial neural network was applied to optimize the prepared condition of the composite film. Corrosion behavior of the NiP/TiO2 composite film was investigated by polarization resistance measurement, anode polarization, ESEM (environmental scanning electron microscopy) and EIS (electrochemical impedance spectroscopy) measurements. Results showed that the NiP/ TiO2 composite film has a good corrosion resistance in 0.5mol/L H2SO4 solution. The element valence of the composite film was characterized by XPS (X-ray photoelectron spectroscopy) spectrum, and an anticorrosion mechanism of the composite film was discussed.
文摘A new TiO2 modified film on carbon steel was prepared by electroless plating and sol gel composite process. An artificial neural net was used to optimize the preparing condition of the film. The optimized condition of the TiO2-modified film on carbon steel is as follows: plating time of NiP is 50 min, number of dip coating is 4, heat treatment time is 2 h, and the molar ratio of complexing reagent to Ti(OC4 H9)4 is 1.5 : 1. Corrosion behavior of carbon steel with coating was investigated by polarization resistance measurement, anode polarization, EIS and ESEM measurement. XPS was used to characterize the element valence of the modified film. Results show that carbon steel with TiO2 modified film has good corrosion resistance in 0.5 mol/L of H2SO4 solution and 0.5 mol/L of NaCl solution. It is also found that the preparing condition of forming TiO2-modified film can be obtained easily by the artificial neural net.
文摘Al specimens were covered with TiO2 film by sol-gel dip-coating and then anodized in ammonium adipate solution.The structure,composition and capacitance properties of the anodic oxide film were investigated by transmission electron microscopy (TEM),Auger electron spectroscopy (AES),X-ray diffractometry (XRD) and electrochemical impedance spectroscopy (EIS).It was found that an anodic oxide film with a dual-layer structure formed between TiO2 coating and Al substrate.The film consisted of an inner Al2O3 layer and an outer Ti-Al composite oxide layer.The thickness of layers varied with the number of times of sol-gel dip-coating.The capacitance of anodic oxide films formed on coated specimens was at most 80% higher than that without TiO2.In film formation mechanism,it was claimed that the formation of composite oxide film was mainly affected by the structure of micro-pores network in TiO2 coating which had an influence on Al3+ and O2? ions transport during the anodizing.
文摘To improve the oxidation resistance property of iron fibers, a SiO2 coated iron fiber was prepared by sol-gel method, and its microstructure, element and phase composition, antioxidation property, and crystallization were characterized by scanning electron microscopy, thermal gravimetric analysis, X-ray diffraction and 3% CuSO4 solution dripping. It was found that the surface of the iron fiber can be fully covered with SiO2 by using Sol-Gel method. Our results also indicated that the time of iron begin to be corrupted in 3% CuSO4 solution drip increased from 30 s to 240 s, and the temperature increased from 200?C to 310?C. In addition, the oxidation and antioxidation mechanisms of the SiO2 coated iron fiber have also been discussed in this work.
文摘In the present work, undoped (SnO2) and fluorine-doped tin oxide (FTO) thin films were prepared by sol-gel process using a solution composed of (SnCl2, H2O), (NH4F), and ethanol mixture. The fluorine concentration effect on structural, optical and electrical properties of SnO2 films is investigated. The electrical properties of FTO films prepared by sol gel remain relatively lower than the ones deposited by other techniques. In present paper, we try to elucidate this difference. Films composition and the FTIR analysis, of films and formed precipitate during film growth, indicate that few amounts of fluorine are incorporated in SnO2 network, most of fluorine atoms remain in the solution. The films resistivity is reduced from 1.1 Ω·cm for undoped films to 3 × 10-2 Ω·cm for 50 wt.% doped FTO, but remains higher than the reported ones in the literature. This high resistivity is explained in terms of fluorine bonding affinity in the solution.
基金supported by the National High-Tech Research and Development Program of China (No. 2004AA303542)
文摘The Indium tin oxide(ITO) thin film possesses excellent photoelectric properties that enable it to act as an ideal transparent conductor.To obtain high-quality ITO films through sol-gel method, the ionic surfactant monoethanolamine and the non-ionic surfactant polyethylene glycol(PEG) were added to the ITO precursor slurry.The influences of surfactants on the structural and photoelectric properties of ITO film samples were investigated.XRD patterns indicated that surfactant monoethanolamine contributed to film predominant grain orientation along the(400) plane.The high transmittance(over 95%) was attributed to the preferred orientation and the grain size expansion of ITO films.SEM showed that the surface particle size and the morphology of ITO films were strongly dependent on the kind of surfactants used.Moving to the shortwave region, the absorption edge of the films exhibited the Burstein-Moss shift.
基金Project(20123227120021)supported by the Specialized Research Fund for the Doctoral Program of Higher Education of ChinaProject(BK2012156)supported by the Natural Science Foundation of Jiangsu Province,China+3 种基金Project(KFJJ201105)supported by the Opening Project of State Key Laboratory of Electronic Thin Films and Integrated Devices,ChinaProject(CJ20125001)supported by the Application Program for Basic Research of Changzhou,ChinaProject(13KJB430006)supported by the Universities Natural Science Research project of Jiangsu Province,ChinaProject supported by the Industrial Center of Jiangsu University Undergraduate Practice-Innovation Training Program,China
文摘Microstructure and electrical properties of La2 O3-doped ZnO-Bi2 O3 thin films prepared by sol–gel process have been investigated.X-ray diffraction shows that most diffraction peaks of ZnO are equal,and the crystals of ZnO grow well.Scanning electron microscopy and atomic force microscopy results indicate that the samples have a good structure and lower surface roughness.The nonlinear V–I characteristics of the films show that La2 O3 develops the electrical properties largely and the best doped content is 0.3% lanthanum ion,with the leakage current of 0.25 mA,the threshold field of 150 V/mm and the nonlinear coefficient of 4.0 in detail.
文摘Hafnium oxide thin films (HOTFs) were successfully deposited onto amorphous glasses using chemical bath deposition, successive ionic layer absorption and reaction (SILAR), and sol-gel methods. The same reactive precursors were used for all of the methods, and all of the films were annealed at 300℃ in an oven (ambient conditions). After this step, the optical and structural properties of the films produced by using the three different methods were compared. The structures of the films were analyzed by X-ray diffTaction (XRD). The optical properties are investigated using the ultraviolet-visible (UV-VIS) spectroscopic technique. The film thickness was measured via atomic force microscopy (AFM) in the tapping mode. The surface properties and elemental ratios of the films were investigated and measured by scanning electron microscopy and energy-dispersive X-ray spectroscopy (EDX). The lowest transmittance and the highest reflectance values were observed for the films produced using the SILAR method. In addition, the most intense characteristic XRD peak was observed in the diffraction pattern of the film produced using the SILAR method, and the greatest thickness and average grain size were calculated for the film produced using the SILAR method. The films produced using SILAR method contained fewer cracks than those produced using the other methods. In conclusion, the SILAR method was observed to be the best method for the production of HOTFs.
文摘Pure and rare earth doped gadolinium oxide (Gd 2O 3) waveguide films were prepared by a simple sol-gel process and dip-coating method. Structure of Gd 2O 3 films annealed at different temperature was investigated by X-ray diffraction and transmission electron microscopy. Oriented growth of (400) face of Gd 2O 3 has been observed when the films were deposited on amorphous substrate. The refractive index and thickness of films were determined by m-lines spectroscopy. The laser beam (λ=632.8 nm) was coupled into the film by a prism coupler and the propagation length is about 3.5 cm. Luminescence properties of europium ions doped films were measured by waveguide fluorescence spectroscopy, which shows disordered environment for Eu 3+ at 400 ℃.
文摘We prepare CuGaO2 thin films on SiO2 substrates by using the sol-gel spin-coating method with two combinations of Cu and a Ga source, Cu and Ga nitrate, or acetylacetonate. X-ray diffraction analysis reveals that the thin films prepared using nitrate sol that are annealed at a temperature of 850°C - 950°C show both c-axis-orientated peaks, (006) and a non-c-axis-oriented peak (012) with similar intensity;little dependence of signal intensity on annealing temperature is also shown. The films are opaque in appearance at these annealing temperatures. Scanning electron microscope observation reveals that the opaque appearance is due to the texture or cracks on the surface of the films. In contrast, the films prepared using acetylacetonate show a (006) peak with higher signal intensity than the (012) peaks. The films show more transparent appearance than that of the films by nitrate. The highest conductivity of the film is 5.7 × 10-4Ω-1·cm-1, obtained in the films by nitrate annealed at 850°C.
文摘Hydrogen has been recently attracted much attention with respect to high energy-conversion efficiency and low environmental burden. However, hydrogen gas is dangerous due to an explosive gas and a fast combustion rate. Therefore, the development of hydrogen sensor with high accuracy and reliability that can detect hydrogen easily is required. Especially, a flexible hydrogen sensor is useful because it has a high degree of freedom with respect to the shape of location in which the sensor is to be located. A flexible hydrogen sensor—namely, a WO3 thin film formed on a PET film by the sol-gel method using photo irradiation—based on gasochromism of WO3 was developed. By irradiating a thin film, which was prepared by using WO3 precursor solution synthesized by the sol-gel method, with ultraviolet rays, a high-purity WO3 film could be prepared on PET at low temperature. The sensor was structured as a polystyrene (PS) film containing palladium (Pd) laminated on a WO3 film. The WO3 layer was porous, so the PS containing Pd atoms solution penetrated the WO3 layer. WO3 reacted with hydrogen gas and instantly turned blue as the transmittance of the WO3 layer changed. The sensor showed high reactivity even for hydrogen concentration below 4% (1%, 0.5%, 0.25%, and 0.1%), which was the lower limit of hydrogen ignition, and a linear relationship between hydrogen concentration and change in transmittance was found. Moreover, the resistance of the WO3 film significantly and instantaneously changed due to hydrogen-gas exposure, and the hydrogen concentration and resistance change showed a linear relationship. It is therefore possible to quantitatively detect low concentrations of hydrogen by using changes in transmittance and resistance as indices. Since these changes occur selectively under hydrogen at room temperature and normal pressure, they form the basis of a highly sensitive hydrogen sensor. Since the developed sensor is flexible, it has a high degree of freedom with respect to the shape of location in which the sensor is to be
文摘A new technique for preparing TiO2 modified film on carbon steel was accomplished by electroless plating and sol-gel composite process. The artificial neural network was applied to optimize the preparing condition of TiO2 modified film. The optimized condition for forming TiO2 modified film on carbon steel was that NiP plating for 50 min, dip-coating times as 4, heat treatment time for 2 h, and the molar ratio of complexing agent and Ti(OC4HZ9)4 kept 1.5:1. The results showed that TiO2 modified film have good corrosion resistance. The result conformed that it is feasible to design the preparing conditions of TiO2 modified film by artificial neural network.
基金This work was financially supported by the Combined Project between the Educational Commission and the Economic Commission of Gansu Province (Nos. 99CX-04, 0310B-08)the Natural Science Foundation of Gansu Province (No. 3ZS041-A25-028)the Invention Project of Science & Technology (No. KJCXGC-01, NWNU), China.
文摘A PANI/TiO2 composite film deposited on the glass surface was successfully prepared using sol-gel dip-coating technique and chemical oxidation method. The film was characterized using XRD, AFM, and UV. The result showed that the TiO2 film consists of both cuboid-shaped and anatase-phased TiO2 nanoparticles. The average grain size of TiO2 in the film was approximately 20 nm. After coating with PANI, the particle was changed into irregular spherical-shaped and the size was increased up to approximately 35 nm in diameter. UV-Vis spectroscopy analysis indicated that the coating of TiO2 with PANI would result in an enhancement of photocatalytic efficiency and an extension of the photoresponse of TiO2. The band gap of the PANI/TiO2 film was 3.18 eV. The photocatalytic property of the film was evaluated by the degradation of rhodamine-B. It was found that 67.1% and 83.2% of rhodamine-B could be degraded under sunlight and UV irradiation within 120 min using the PANI/TiO2 composite t-tim as photocatalyst.
基金supported partly by the School of Mechanical,Electronic and Control Engineering,Beijing Jiaotong university,China
文摘Polydimethylsiloxane(PDMS),tetraethoxysilane(TEOS),ethyl alcohol(EtOH) and deionized water were main raw materials to prepare silicone-modified hybrid thin films using sol-gel method.The effect of the contents of H2O and PDMS on thin films was studied.When the volume ratio of H2O to TEOS is 0.5,the optimum quality of thin films is obtained.And the gelation time is affected slightly by H2O content.Uniform thin films are obtained when the volume ratio of PDMS to TEOS is 0.2.Yet,the sol would be inactive in 6 d.Various properties of thin films were studied,including hardness,adhesive quality,hydrophobic property,corrosion protection property,and abrasion resistance.Test results show that the pencil hardness is generally 3-6 H,and adhesive quality achieves the highest standard of 0.When the sintering temperature is below 400 oC,the contact angle is about 95° and hydrophobic films are obtained.The abrasion resistance of thin films is better than that of aluminum alloy when the sintering temperature is higher than 300 oC.And the excellent corrosion protective effect is obtained by single-layer coating when the sintering temperature is higher than 400 oC.