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1.
对多孔钛表面制备TiO2纳米管的阳极氧化工艺进行研究。在两种电解质溶液中采用阳极氧化法分别对多孔钛和钛箔进行表面处理。一种电解质溶液是含有0.5%HF的冰醋酸,另一种电解质溶液是含有0.5%NH4F(质量分数)的乙二醇溶液(醇水体积比4:1)。结果表明:两种方法在钛箔上都可以生成TiO2纳米管,而多孔钛表面只能在NH4F电解质溶液中生成纳米管,HF溶液中过高的电流密度是纳米管在多孔钛基体上难以生成的主要原因。采用扫描电子显微镜和X射线衍射仪对不同基体上的TiO2纳米管进行表征,相比钛箔基体上的纳米管管壁,多孔钛上的纳米管管壁更薄。对所制备的TiO2热处理研究表明,锐钛矿相在400°C时形成,并在700°C完全转变为金红石相。经450°C热处理样品的光催化性能最好。光催化性能也受到多孔钛孔隙率的影响,在孔隙率为60%时光催化性能最好。 相似文献
2.
采用阳极氧化法在纯钛片表面得到了一种规整有序的TiO2纳米管阵列.利用SEM观察纳米管阵列的形貌,用XRD分析其晶型.并考察了阳极氧化电压、F浓度和溶液的pH值对纳米管阵列形貌和长度的影响.以罗丹明B溶液为目标降解物研究了TiO2纳米管阵列的光催化活性.结果表明,F浓度不仅影响纳米管阵列的形成时间,而且对纳米管阵列的形貌和长度也有一定的影响;溶液的pH值不仅影响纳米管阵列的长度,在很大程度上也影响纳米管阵列的表面形貌.阳极氧化法制备的TiO2纳米管阵列为无定型,在450℃空气中焙烧2h晶相主要为锐钛矿型TiO2,表现出较好的光催化活性. 相似文献
3.
钛上阳极氧化生成TiO2光催化薄膜的结构与性能 总被引:3,自引:0,他引:3
研究了电化学阳极氧化在钛上制备的纳米晶多孔TiO2光催化薄膜的结构与光催化特性。将工业纯钛片或钛箔暴露于电介质溶液并加一定电压,钛表面将氧化生长多孔TiO2薄膜。适当控制氧化电压、溶液温度,得到非晶氧化膜,再进行晶化处理,得到锐钛矿相纳米晶TiO2薄膜。其晶粒尺寸约在10nm~30nm。用SEM,TEM,XRD表征TiO2薄膜的形貌与相结构。用光谱仪测定了薄膜对入射光的吸收特性,表明电化学氧化制备的纳米晶二氧化钛薄膜对近紫外入射光产生强烈的吸收,显示纳米结构的量子效应。测定了薄膜对酸性红溶液的光催化降解效率,结果表明反应30min后薄膜对酸性红的光催化降解率可达95%以上。 相似文献
4.
目的 制备高比容量多孔钛/TiO2纳米管三维自支撑一体化复合电极材料。方法 采用非溶剂致相分离法与高温烧结相结合的方法制备出孔径小、空间利用率高的三维多孔钛平板膜,然后经阳极氧化法在其表面生长TiO2纳米管,从而制备出多孔钛/TiO2纳米管复合薄膜电极。结果 以3 μm粒径钛粉为原料,N-甲基-2-吡咯烷酮、聚乙烯吡咯烷酮、聚丙烯腈为添加剂制备钛膜生坯,经刮膜成型后,在氩气保护下经1000 ℃烧结,得到孔径约为2~6 μm的多孔钛平板膜。采用阳极氧化法在多孔钛平板膜上直接生长TiO2纳米管,制得多孔钛/TiO2纳米管复合薄膜电极。该复合薄膜电极在超级电容器中具有良好的电化学性能,其在2 mA/cm2电流密度下,比电容为385.34 mF/cm2,即使电流密度增加到10 mA/cm2,比电容仍能保持在125.14 mF/cm2。结论 相较于TiO2纳米颗粒,采用此方法制备的多孔钛/TiO2纳米管复合薄膜电极具有良好的电化学性能,可为下一代储能器件提供新的思路。 相似文献
5.
采用阳极氧化在钛基体上原位合成了自组装有序的纳米管TiO2薄膜材料,采用的电解质溶液为0.5mol/L NH4HF2+1mol/LNH4H2PO4水溶液。通过XRD,SEM对TiO2纳米管进行表征。研究表明,外加电压对TiO2薄膜的微观结构有很大的影响。在外加电压为20V时,氧化8h可得到长度为2pm,内径为80nm,外径为100nm的TiO2纳米阵列。经300℃热处理后,可得到锐钛矿型的TiO2。通过对成膜工艺的研究,提出了阳极氧化法制备有序TiO2纳米管的成膜机制。 相似文献
6.
7.
Ti/TiO2-Pt修饰电极的制备及电催化性能研究 总被引:3,自引:0,他引:3
为了提高Ti/TiO2电极的催化性能,采用阳极氧化法在钛基体上制备出具有纳米管状的多孔Ti/TiO2薄膜,在此膜上采用阴极电化学沉积方法沉积Pt来制备Ti/TiO2-Pt修饰电极。用XRD,FESEM分析了沉积前后成分、晶相结构以及表面形貌的变化。结果表明:Pt优先沉积在Ti/TiO2管口以及管边缘处。用循环伏安曲线和极化曲线分析表明,沉积Pt的Ti/TiO2电极其电催化性能得到了明显改善。 相似文献
8.
刘培生 《稀有金属材料与工程》2017,46(3):847-852
本文主要研究了泡沫钛孔隙表面生长二氧化钛纳米管的制备方法及二氧化钛纳米管的生长机理。利用与制备多孔陶瓷类似的方式,通过高温真空烧结法,制备了多孔泡沫钛镍合金。对该泡沫合金进行了表面改性,通过阳极氧化法在多孔泡沫钛镍合金的孔隙表面生成了二氧化钛纳米管结构。借助于扫描电镜的观测和分析,对该二氧化钛纳米管的生长机理进行了表征和研究,同时考察了阳极氧化电压和时间对二氧化钛纳米管结构形貌的影响。 相似文献
9.
《稀有金属材料与工程》2017,(3)
研究了泡沫钛孔隙表面生长二氧化钛纳米管的制备方法及二氧化钛纳米管的生长机理。利用与制备多孔陶瓷类似的方式,采用高温真空烧结法制备了多孔泡沫钛镍合金。对该泡沫合金进行了表面改性,通过阳极氧化法在多孔泡沫钛镍合金的孔隙表面生成了二氧化钛纳米管结构。借助于扫描电镜的观测和分析,对该二氧化钛纳米管的生长机理进行了表征和研究,同时考察了阳极氧化电压和时间对二氧化钛纳米管结构形貌的影响。结果发现,电压不变而延长氧化时间,纳米管层的厚度增大;氧化时间不变而提高电压,纳米管之间的分界越明显。 相似文献
10.
纯钛表面TiO2多孔膜的制备及其晶型研究 总被引:8,自引:0,他引:8
以硫酸为电解液,纯钛(TA1)为阳极,铜片为阴极,以恒压和恒流阳极氧化方式在钛表面直接获得锐钛型和金红石型TiO2多孔膜.采用X射线衍射仪对覆在钛基体上的阳极氧化膜进行了结构分析,研究了电压、硫酸浓度、阳极氧化时间和电流密度对TiO2多孔膜晶型的影响,并讨论了其形成机理.结果表明:在0.5 mol/L硫酸溶液中,恒压(≥80 V)或恒流(≥0.6 A)时出现锐钛相TiO2;恒压(≥100 V)1 min时即可出现锐钛相TiO2;恒压(≥150 V)或恒流(≥0.8 A)时出现金红石相TiO2. 相似文献
11.
《Intermetallics》2002,10(1):95-103
Ni–Ti–Zr materials with Zr 12–25 at.% and Ni 42–50 at.% have been produced by powder metallurgy. Suitable temperatures for sintering in Ar-atmosphere Ni–Ti–Zr compacts are within the range 900–1000 °C. Sintering at temperatures above 1000 °C causes melting of the compacts with high Zr content. The presence of ZrC, ZrO2, Zr3O, TiO2 and TiO of different modifications, complex oxides such as Ni5TiO7, Ti0.5Zr0.5O0.2 and equilibrium phases after sintering at temperatures above 1000 °C in alloys with low Zr-content was derived from X-ray diffractometry. During sintering at temperatures below 1000 °C the phases belonging to the binary Ti–Ni and Ti–Zr systems were formed. Long-term sintering and slow furnace cooling allowed the precipitation of Ni4Ti3 and Ni2Ti. The process of sintering is controlled by the diffusion of Ni in Ti and Zr particles during the early stages of sintering. Slow diffusion of Zr atoms in Ti2Ni, Ti–Ni and diffusion of Ti atoms in Zr2Ni, Ni–Zr controls the later stages of sintering. 相似文献
12.
Han-Jun Oh In-Ki Kim Kyung-Wook Jang Jong-Ho Lee Seunghyun Lee Choong-Soo Chi 《Metals and Materials International》2012,18(4):673-677
The effects of electrolyte and applied potentials on TiO2 nanotube morphologies were investigated. The specific surface area of the TiO2 nanotubes was measured to be 57 m2/g for titania nanotubes formed in HF, and 147 m2/g formed in organic electrolyte, respectively. The results of adsorption-desorption isotherms agree with the morphology of TiO2 nanotubes. The length and average diameter of nanotubes were influenced by electrolyte and anodic potentials. The multilayered TiO2 nanotube arrays can be fabricated by changing the electrolyte composition during anodization. 相似文献
13.
Hui-bin ZHANG Shu-yu SHEN Xin-li LIU Zhong-he WANG Yao JIANG Yue-hui HE 《中国有色金属学会会刊》2018,28(9):1774-1783
High-purity porous Ti3SiC2 with a porosity of 54.3% was prepared by reactive synthesis and its oxidation behavior was evaluated under air in the temperature range from 400 to 1000 °C. Thermogravimetric analysis and differential scanning calorimetry (TG-DSC), scanning electron microscope (SEM), X-ray diffractometometry (XRD), energy dispersive spectrometer (EDS), Raman spectrum, BET surface area analysis, and pore-parameter testing were applied to the studies of the oxidation kinetics, phase composition, micro morphology, and porous structure parameters of porous Ti3SiC2 before and after oxidation. The results showed that the formation of TiO2 oxidized products with different modifications was the primary factor influencing the oxidation resistance and structural stability of porous Ti3SiC2. Cracks were observed in the samples oxidized in the full temperature range of 400-1000 °C because of the growth stress and thermal stress. At 400-600 °C, anomalous oxidation with higher kinetics and the aberrant decrement in pore size and permeability were attributed to the occurrence of severe cracking caused by the formation of anatase TiO2. At raised temperatures over 600 °C, the cracking phenomena were alleviated by the formation of rutile TiO2, but the outward growth of the oxide scales detrimentally decreased the connectivity of porous Ti3SiC2. 相似文献
14.
Ti–46Al–6Nb–0.5W–0.5Cr–0.3Si–0.1C alloy was corroded at 800–1100 °C for 200 h in N2/0.1%H2S gas to characterize its corrosion behavior in an aggressive H2S-containing environment. The alloy displayed superior corrosion resistance because Ti and Al preferentially reacted with impurity oxygen in the gas to form TiO2 and Al2O3. It corroded primarily by outward diffusion of Ti, Al, W, and Cr in addition to inward transport of sulfur, nitrogen, and oxygen. Scales were adherent and consisted of an outer TiO2 layer, an intermediate Al2O3 layer, and an inner (TiO2, Al2O3)-mixed layer. TiN and Ti2AlN formed at the scale/matrix interface where sulfur, Nb, W, and Cr segregated.
相似文献15.
《Intermetallics》1999,7(5):529-541
The isothermal and cyclic oxidation behaviour of Ti–48Al–2Mn–2Nb (at%) were studied at high temperatures in air in comparison with the intermetallic alloys Ti–48Al–2Cr–2Nb and Ti–48Al–2Cr. Tests were performed in air between 800 and 900°C. At 800°C Ti–48Al–2Mn–2Nb showed an excellent oxidation resistance under isothermal and cyclic conditions, comparable with Ti–48Al–2Cr–2Nb, and superior to Ti–48Al–2Cr. At 900°C the isothermal oxidation rate of Ti–48Al–2Mn–2Nb was similar as found for Ti–48Al–2Cr–2Nb, but much lower as that of Ti–48Al–2Cr. Upon cooling the oxide scale formed on Ti–48Al–2Mn–2Nb was prone to spallation. During the cyclic oxidation at 900°C, a steady state condition is reached for both niobium bearing materials, with a net linear mass loss rate, due to spallation and (re-)growth of the oxide scale. The linear mass loss rate for the Ti–48Al–2Mn–2Nb was higher than that of Ti–48Al–2Cr–2Nb, indicative of a higher susceptibility for spallation. During the initial stage of oxidation of all tested materials a complex multi-phased and multi-layered scale was formed consisting of α-Al2O3, TiO2 (rutile), TiN and Ti2AlN. After longer exposure times the outer scale was dominated by TiO2. In case of the niobium containing materials no loss of protectivity of the oxide scale was found during the growth of the outer TiO2 layer (under isothermal conditions). Two-stage oxidation experiments with isotope tracers were performed to study the oxidation mechanism in more detail. 相似文献
16.
《Acta Materialia》2001,49(7):1209-1224
Extruded rods of mechanically alloyed (MA) Al-0.25wt%C-10vol%TiO2 (A1), Al-0.35wt%Li-1wt%Mg-0.25wt%C-10vol%TiO2 (A2), and Al-0.35wt%Li-1wt%Mg-0.25wt%C-7.5vol%TiO2 (A3) have been subjected to thermal treatments at 500°C, 550°C, 600°C, and 655°C for times up to 1500 h. At 550°C and 600°C, the materials displayed hardness increments, but the increase was highest for A1 (∼30 kg/mm2) due to fine Al3Ti precipitation. The starting grain size of ∼0.5 μm in A1 showed virtually no increase even after 1500 h at 600°C. XRD and TEM indicated transformation of TiO2 and TiO to Al3Ti. Numerous “block-shaped” Al2O3 particles (α, δ, η, and γ polymorphs) were formed in A2 at 600°C. The α-Al2O3 particles exhibited some lattice matching with the α-Al matrix. An initially rapid Al3Ti coarsening rate at 600°C in A1 was reduced significantly between 336 h and 1500 h. Dispersion strengthening by Al3Ti and Al2O3 was mainly responsible for the maximum strength of A1 after heat treatment, while the Hall–Petch contribution was less significant, despite the fine grain size. 相似文献
17.
The corrosion behavior of 304 stainless steel (SS) and its corrosion inhibition by brushing nano-sized Ti/silicone coatings on its surface in an environment containing a solid NaCl deposit and water vapor at 400–600°C was studied. Results indicated that water vapor or NaCl, especially water vapor plus NaCl accelerated the corrosion of the steel markedly. The corrosion scales of the uncoated steel had a duplex structure at 400–500°C and internal oxidation occurred for the uncoated steel at 600°C in an environment containing NaCl and water vapor. The corrosion of the 304SS was inhibited efficiently by the coatings at 400–500°C, and the coated steel suffered corrosion to some extent and most of the coatings were destroyed at 600°C. X-ray diffraction (XRD) indicated that the corrosion products of the uncoated steel were mainly Fe2O3, Cr2O3, NiO or Na2CrO4, and the coatings consisted mainly of TiO2 and SiO2 after exposure at 400–500°C. The good corrosion resistance of the nano-sized Ti/silicon coatings was attributed to the formation of SiO2, and TiO2 that resulted from the decomposition of the organic components in the coating and fast oxidation of nano-Ti powder respectively during the experiments, TiO2 mixed together with SiO2 and formed a new coating on the steel surface that played an important role in the protection of the steel. 相似文献
18.
Sanghee Won Seunghee Go Wonhee Lee Kyunghoon Jeong Hyunsuk Jung Chongmu Lee Eungu Lee Jaegab Lee 《Metals and Materials International》2008,14(6):759-765
Thin TiO2 layers grown at 130°C on SiO2-coated Si substrates by atomic layer deposition (ALD) using TTIP and H2O as precursors were annealed, and the effects of the annealing temperature on the resulting electrical properties of TiO2 and the interface properties between a Pt electrode and TiO2 were examined using transmission line model (TLM) structures. The as-deposited TiO2 thin film had an amorphous structure with OH groups and a high resistivity of 6×103Ω-cm. Vacuum annealing at 700 °C transformed the amorphous film into an anatase structure and reduced its resistivity to 0.04Ω-cm.
In addition, the vacuum-annealing of the TiO2/SiO2 structure at 700°C produced free silicon at the TiO2-SiO2 interface as a result of the reaction between the Ti interstitials and SiO2. The SiO2 formed on the TiO2 surface caused a Schottky contact, which was characterized by the TLM method. The use of the TLM method enabled the accurate
measurement of the resistivity of the vacuum-annealed TiO2 films and the characterization of the Schottky contacts of the metal electrode to the TiO2. 相似文献
19.
The aluminum foil for high voltage aluminum electrolytic capacitor was immersed in 0.5 mol/L H3PO4 or 0.125 mol/L NaOH solution at 40 °C for different time and then DC electro-etched in 1 mol/L HCl+2.5 mol/L H2SO4 electrolyte at 80 °C. The pitting potential and self corrosion potential of Al foil were measured with polarization curves (PC). The potentiostatic current—time curve was recorded and the surface and cross section images of etched Al foil were observed with SEM. The electrochemical impedance spectroscopy (EIS) of etched Al foil and potential transient curves (PTC) during initial etching stage were measured. The results show the chemical pretreatments can activate Al foil surface, facilitate the absorption, diffusion and migration of Cl? onto the Al foil during etching, and improve the initiation rate of meta-stable pits and density of stable pits and tunnels, leading to much increase in the real surface area and special capacitance of etched Al foil. 相似文献
20.
The isothermal oxidation behavior in air of high-temperature titanium alloy Ti–5.6Al–4.8Sn–2Zr–1Mo–0.35Si–0.7Nd with bimodal and lamellar microstructures was investigated at 600–800 °C. The results revealed that the alloy with lamellar microstructure has better oxidation resistance than that with bimodal microstructure. The porous oxide scales that form mainly contain TiO2. A noticeable observation concerns the preferential attack around rare-earth particles, associated rapid oxygen diffusion along the incoherent rare-earth precipitate/matrix interface and cracks formed during oxidation. The resulting internal attack caused fragmentation of rare-earth particles and further oxidation of substrate to form TiO2 scale with some fine dispersoids of Al2O3. Tensile tests showed that the ultimate strength and ductility of the specimens with removed surface were higher than that with a surface scale. 相似文献