共查询到20条相似文献,搜索用时 15 毫秒
1.
Pattanayak DK Yamaguchi S Matsushita T Kokubo T 《Journal of materials science. Materials in medicine》2011,22(8):1803-1812
Nanometer-scale roughness was generated on the surface of titanium (Ti) metal by NaOH treatment and remained after subsequent
acid treatment with HCl, HNO3 or H2SO4 solution, as long as the acid concentration was not high. It also remained after heat treatment. Sodium hydrogen titanate
produced by NaOH treatment was transformed into hydrogen titanate after subsequent acid treatment as long as the acid concentration
was not high. The hydrogen titanate was then transformed into titanium oxide (TiO2) of anatase and rutile by heat treatment. Treated Ti metals exhibited high apatite-forming abilities in a simulated body
fluid especially when the acid concentration was greater than 10 mM, irrespective of the type of acid solutions used. This
high apatite-forming ability was maintained in humid environments for long periods. The high apatite-forming ability was attributed
to the positive surface charge that formed on the TiO2 layer and not to the surface roughness or a specific crystalline phase. This positively charged TiO2 induced apatite formation by first selectively adsorbing negatively charged phosphate ions followed by positively charged
calcium ions. Apatite formation is expected on the surfaces of such treated Ti metals after short periods, even in living
systems. The bonding of metal to living bone is also expected to take place through this apatite layer. 相似文献
2.
A. I. Stognij N. N. Novitskii A. A. Evdokimov M. S. Afanas’ev V. A. Ketsko 《Inorganic Materials》2012,48(6):619-621
Polycrystalline, 50- to 70-nm-thick barium strontium titanate films of composition Ba0.8Sr0.2TiO3 have been grown on single-crystal silicon substrates by rf ion-beam sputtering. We have determined their structure and composition
and detected impurities at the film/substrate interface in the form of titanium silicide islands. The deposition of a 4- to
6-nm-thick TiO2 buffer layer onto Si by ion-beam sputtering before ferroelectric film growth is shown to prevent uncontrolled formation of
impurities near the interface. The buffered heterostructures possess high thermal stability. 相似文献
3.
Yuze Dong Yanming Zhao Yanhuan Chen Yaqing Feng Mengyao Zhu Chenggong Ju Bao Zhang Huibiao Liu Jialiang Xu 《Journal of Materials Science》2018,53(12):8921-8932
In this study, graphdiyne (GD)-hybridized nitrogen-doped TiO2 nanosheets with exposed (001) facets (GD-NTNS) have been prepared via a hydrothermal reaction and utilized as photocatalyst for the photodegradation of rhodamine B (RhB) under visible light illumination. The resultant GD-NTNS composites exhibit superior visible light photocatalytic activity than that of the bare TiO2 nanosheets (TNS) and nitrogen-doped TiO2 nanosheets (NTNS). The enhanced photoactivity can be attributed to the synergistic effects of GD and nitrogen doping with efficient electron transfer and strong visible light absorption. It has been revealed that ·O2? and h+ are the major species for the enhanced photoactivity under visible light. Our work will facilitate the potential for future design of hybrid materials for practical applications beyond photocatalysts. 相似文献
4.
5.
Xue Zhang Wenfeng Zhu Weidong Zhang Shuirong Zheng Shuhua Qi 《Journal of Materials Science: Materials in Electronics》2018,29(9):7194-7202
To meet the demand of electromagnetic absorption, cheap and easily available microwave absorbents are urgently required. As an important functional material, carbon fibers (CFs) have been widely reported, however, too high conductivity easily leads to the impedance mismatch, which is not favorable to the microwave absorbing performance (MAP). To address this challenge, in this study, novel TiO2/Fe3O4/CF composites with tunable magnetic were synthesized by hydrothermal method and characterized by SEM, XRD, XPS and VSM. As absorbents, the minimum reflection loss (RL) value is ??41.52 dB at a thickness of 2.1 mm, and the corresponding bandwidth with effective attenuation (RL?<???10 dB) is up to 5.65 GHz (4.54–10.19 GHz). More importantly, the plausible mechanisms for the enhanced MAP are explored. 相似文献
6.
Hemraj M. Yadav Jung-Sik Kim 《Journal of Materials Science: Materials in Electronics》2016,27(10):10082-10088
Transparent antireflective SiO2/TiO2 double layer thin films were prepared using a sol–gel method and deposited on glass substrate by spin coating technique. Thin films were characterized using XRD, FE-SEM, AFM, UV–Vis spectroscopy and water contact angle measurements. XRD analysis reveals that the existence of pure anatase phase TiO2 crystallites in the thin films. FE-SEM analysis confirms the homogeneous dispersion of TiO2 on SiO2 layer. Water contact angle on the thin films was measured by a contact angle analyzer under UV light irradiation. The photocatalytic performance of the TiO2 and SiO2/TiO2 thin films was studied by the degradation of methylene blue under UV irradiation. The effect of an intermediate SiO2 layer on the photocatalytic performance of TiO2 thin films was examined. SiO2/TiO2 double layer thin films showed enhanced photocatalytic activity towards methylene blue dye. 相似文献
7.
Liang Shi Chonglei Xu Xun Sun Hua Zhang Zhaoxin Liu Xiaofei Qu Fanglin Du 《Journal of Materials Science》2018,53(16):11329-11342
BiVO4/TiO2 nanocomposites were fabricated by a facile wet-chemical process, followed by the synthesis of TiO2 hierarchical spheres via hydrothermal method. The BiVO4/TiO2 nanocomposites were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV–Vis diffuse reflectance spectroscopy and X-ray photoelectron spectroscopy. The results showed that prepared TiO2 presented hierarchical spherical morphology self-assembled by nanoparticles and an anatase–brookite mixed crystal phase. The introduction of monoclinic BiVO4 components retained the hierarchical structures and expanded the light response to around 510 nm. Type II BiVO4/TiO2 heterostructured nanocomposites exhibited improved photocatalytic degradation towards methylene blue under visible-light irradiation, especially for the composite photocatalysts with atomic Ti/Bi?=?10, which showed double degradation rate than that of pure BiVO4. The enhanced photocatalytic mechanism of the heterostructured BiVO4/TiO2 nanocomposites was discussed as well. 相似文献
8.
We developed a process for preparing SiO2/TiO2 fibers by means of precursor transformation method. After mixing PCS and titanium alkoxide, continuous SiO2/TiO2 fibers were fabricated by the thermal decomposition of titanium-modified PCS (PTC) precursor. The tensile strength and diameter
of SiO2/TiO2 fibers are 2.0 GPa, 13 μm, respectively. Based on X-ray diffraction (XRD), scanning electron microscopy (SEM), and high resolution
transmission electron microscopy (HRTEM) measurements, the microstructure of the SiO2/TiO2 fibers is described as anatase–TiO2 nanocrystallites with the mean size of ~10 nm embedded in an amorphous silica continuous phase. 相似文献
9.
Yan-Li Shang Yun-Ling Jia Fu-Hui Liao Jun-Ran Li Ming-Xiu Li Juan Wang Shao-Hua Zhang 《Journal of Materials Science》2007,42(8):2586-2590
New nano-sized TiO2 electrorheological (ER) materials doped with different metal (M = Na, Zr, Ce, Al, Ca, Zn) oxides have been prepared. Relationships
between the composition, microstructure, conductivity, dielectric property and ER effect of these materials have been studied.
The results show that doping Na2O, ZrO2, Al2O3 or CeO2 can enhance the ER performance of the TiO2 material, whereas, doping CaO or ZnO would decrease the ER activity of the material. The shear stress (τE) of the suspension (25 wt%) of Na-doped TiO2 in dimethyl silicone oil reaches 1.6 kPa at the electric field strength E = 4.2 kV/mm and shear rate γ = 300 s−1, and its τr value of 54.6 (τr = τE/τ0, where τ0 is the shear stress at no electric field) is seven times higher than that of pure TiO2 suspension. This high τr value is very advantageous to the use. The dielectric loss tangent (tanδ) plays a dominant role in influencing the ER performance
of a particle material, and the effect of the surface area (pore volume, especially) and grain size should be taken into account. 相似文献
10.
A. N. Murashkevich A. S. Lavitskaya O. A. Alisienok I. M. Zharskii 《Inorganic Materials》2009,45(10):1146-1152
Composites in the form of precipitated powders, hybrid xerogels, and SiO2 core/TiO2 shell particles have been produced via hydrolysis of precursors (alkoxides and inorganic derivatives of titanium and silicon)
and have been characterized by differential thermal analysis, X-ray diffraction, adsorption measurements, and macroelectrophoresis.
The results demonstrate that heat treatment of the composites leads to crystallization of the titanium-containing component
and, accordingly, reduces their specific surface area. Hydrothermal treatment enables the fabrication of materials in which
TiO2 nanocrystals are evenly distributed over an amorphous SiO2 matrix. 相似文献
11.
M. N. Solovan P. D. Maryanchuk V. V. Brus O. A. Parfenyuk 《Inorganic Materials》2012,48(10):1026-1032
TiO2 and TiO2:Fe thin films have been grown by electron beam evaporation and the influence of doping and heat treatment on their electrical and optical properties has been studied. 相似文献
12.
Xin Xu Kai Li Zhenzhong Yang Jiangjian Shi Dongmei Li Lin Gu Zhijian Wu Qingbo Meng 《Nano Research》2017,10(2):483-490
Heterojunction interfaces in perovskite solar cells play an important role in enhancing their photoelectric properties and stability.Till date,the precise lattice arrangement at TiO2/CH3NH3PbI3 heterojunction interfaces has not been investigated clearly.Here,we examined a TiO2/CH3NH3PbI3 interface and found that a heavy atomic layer exists in such interfaces,which is attributed to the vacancies of methylammonium (MA) cation groups.Further,first-principles calculation results suggested that an MA cation-deficient surface structure is beneficial for a strong heterogeneous binding between TiO2 and CH3NH3PbI3 to enhance the interface stability.Our research is helpful for further understanding the detailed interface atom arrangements and provides references for interfacial modification in perovskite solar cells. 相似文献
13.
N. I. Steblevskaya V. S. Rudnev M. V. Belobeletskaya M. A. Medkov T. P. Yarovaya P. M. Nedozorov 《Inorganic Materials》2017,53(11):1185-1188
Combining plasma electrolytic oxidation and extract pyrolysis, we have produced composite oxide coatings on titanium, which exhibit bright luminescence in the red spectral region. The present results and data in the literature suggest that combining these approaches is potentially attractive for the ability to produce composite coatings with various properties on the surface of valve metals and alloys. 相似文献
14.
Linghui Peng Shouxiang Jiang Ronghui Guo Jiangtao Xu Xiaoting Li Dagang Miao Yuxiang Wang Songmin Shang 《Journal of Materials Science: Materials in Electronics》2018,29(19):16188-16198
Both humans and objects can emit infrared (IR) wavelengths which generate thermal emissions that can be detected with an IR camera. Therefore, highly IR reflective materials have been the subject of interest recently, for example, in achieving IR stealth. In this work, IR reflective coatings on polyester fabric in the form of a titanium dioxide/copper/titanium dioxide (TiO2/Cu/TiO2; TCT) sandwich-like structure are fabricated by using magnetron sputtering. The coated fabric samples are then examined by using an energy dispersive X-ray detector, a scanning electron microscope and an X-ray diffractometer. The reflection of IR wavelengths which range from 8 to 14 µm of the TCT coated fabric is evaluated. The bending stiffness, and mechanical and adhesion strengths of the coated fabric samples are also investigated. The results show that the TCT sandwich-like structure on the polyester fabric sputtered for 30 min with Cu which results in a Cu film of 200 nm in thickness is observed to have the maximum reflection of IR wavelengths. The color of the TCT coated polyester fabric samples sputtered for 5, 10, 20, and 30 min with Cu is green, yellow, brown and purple, respectively. The TCT coated fabric therefore has potential applications as IR protection textiles for military purposes. 相似文献
15.
K. M. Reddy A. Punnoose 《Journal of Materials Science: Materials in Electronics》2007,18(11):1137-1142
We report the development of ferromagnetism in ∼30 nm sized well-characterized Ti1−x
Co
x
O2 powders with x = 0.00015–0.006 and its absence for x > 0.006. In addition, these studies show the effect of Co doping on the structural stability and anatase to rutile phase
transformation. X-ray diffraction data of samples synthesized by a wet chemical method and annealed at 450 °C indicate a limited
solubility of ∼1.2% for Co in the anatase TiO2 matrix, and with further increase, the CoTiO3 phase is formed along with increased presence of rutile TiO2. The bandgap (∼3.23 eV) of the anatase TiO2 remained almost unchanged for x < 0.006, but decreased rapidly for x ≥ 0.006 approaching 2.8 eV for x = 0.03. The magnetic data from Ti1−x
Co
x
O2 samples with x = 0.006 showed a coercivity H
c ∼ 150 Oe and a weak magnetic moment of 0.2 μB/ion at 300 K. The ferromagnetism of Ti0.994Co0.006O2 with open hysteresis loops continue up to a high superparamagnetic blocking temperature T
B ∼ 675 K, above which a superparamagnetic behavior was observed. Systematic changes in the structural, magnetic and optical
properties suggest that Co doping is an excellent method to tailor the physical properties of TiO2 nanoparticles. 相似文献
16.
R. Lilia Centeno-Sánchez Derek J. Fray George Z. Chen 《Journal of Materials Science》2007,42(17):7494-7501
Reduction of porous titanium oxide precursors by the FFC-Cambridge process is reported in this paper. Porous TiO2 precursors were prepared by mixing the powder with different concentrations of graphite and polyethylene as fugitive agents
and sintered at 1,073 K. The maximum porosity achieved before the mixture saturation was approximately 75%. After the electro-deoxidation
by the FFC-Cambridge process, shrinkage of approximately 40% in volume and increase in porosity were observed, which might
be due to atomic rearrangement, change of density and subsequent grain growth during reduction. The potential applied (below
the decomposition potential of CaCl2) had a direct effect on the minimum level of oxygen achieved, which was approximately 3,000 ppm for 48 h at 3.00 V and the
same level at half the time (24 h) when increasing potential to 3.15 V. On the other hand, thin layers (300 μm thickness)
screen-printed on titanium foils showed shorter reduction time than that observed for thicker porous pellets. This led to
the conclusion that cathode geometry (porosity and thickness of the pellet) might have an effect on the rate of reduction
by increasing the surface area available and improving the mass diffusion of oxygen ions. 相似文献
17.
L. E. Derlyukova T. A. Anufrieva A. V. Grigor’eva A. A. Vinokurov 《Inorganic Materials》2012,48(9):914-917
This paper compares the catalytic performance of platinum catalysts supported on different forms of TiO2. A composite material in the form of Pt supported on titanium dioxide nanotubes is shown to possess the highest catalytic performance for CO oxidation. It exhibits stable catalytic activity at temperatures from 65 to 300°C. 相似文献
18.
The oxygen-ion conductivity of porous materials, the coarse-grained pyrochlore-like Sm2Ti2O7 and fine-grained Sm2TiO5 compounds, produced by mechanical activation of initial oxides is studied at 400–1000 °C. The Sm2TiO5 samples contain ~15 wt % of the nanosized pyrochlore-like Sm2TiO5 phase in addition to the rhombic phase. As determined by impedance spectroscopy, the ionic conductivities of Sm2TiO5 and Sm2Ti2O7 at 1000°C are 1.3 × 10?3 and 1.8 × 10?4 S cm?1, and the activation energies of the bulk and grainboundary conductivities of the materials are 1.04 and 1.24 eV for Sm2TiO5 and 1.69 and 1.80 eV for Sm2Ti2O7. 相似文献
19.
Jian Li Long Yan Yufei Wang Yuhong Kang Chao Wang Shaobo Yang 《Journal of Materials Science: Materials in Electronics》2016,27(8):7834-7838
TiO2/ZnO composite nanofibers have been successfully prepared by electrospinning technique. X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, Raman spectrum, X-ray photoelectron spectroscopy and UV–Vis diffuse reflectance spectroscopy, were used to characterize the as-synthesized nanofibers. The photocatalytic studies revealed that the TiO2/ZnO nanofibers exhibited enhanced photocatalytic efficiency of photodegradation. Additionally, the recycling experiment of TiO2/ZnO nanofibers had been done, demonstrating that TiO2/ZnO nanofibers have high efficiency and stability. 相似文献
20.
Masami Hashimoto Kazumi Hayashi Satoshi Kitaoka 《Materials science & engineering. C, Materials for biological applications》2013,33(7):4155-4159
The oxynitridation of biomedical titanium metal under a precisely regulated oxygen partial pressure (PO2) of 10? 14 Pa in nitrogen atmosphere at 973 K for 1 h strongly enhanced apatite formation compared with that on Ti heated in air. The factors governing the high apatite-forming ability are discussed from the viewpoint of the surface properties of Ti heated under a PO2 of 10? 14 Pa in nitrogen atmosphere determined from X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and zeta potential measurements. Nitrogen (N)-doped TiO2 (interstitial N) was formed on pure Ti heated under a PO2 of 10? 14 Pa in nitrogen atmosphere at 973 K. The XPS O1s main peak shifted toward a lower binding energy upon heating under a PO2 of 10? 14 Pa. This shift may be due to the formation of oxygen vacancies. This Ti surface had a positive zeta potential of approximately 20 mV. According to time-of-flight secondary ion mass spectroscopy results, PO43 ? ions were predominantly adsorbed on Ti soaked in simulated body fluid (SBF) after heat treatment, followed by calcium ions. It was concluded that the apatite formation kinetics can be described using the Avrami–Erofeev equation with an Avrami index of n = 2, which implies the instantaneous nucleation of apatite on the surface of Ti soaked in SBF after heat treatment at 973 K under a PO2 of 10? 14 Pa. 相似文献