Materials
·
2019
·Vol. 12
·期 22
·3751
·
IF 2.972
Gongjun Cui,Yanping Liu,Guijun Gao,Huiqiang Liu,Sai Li,Ziming Kou
Ti–Al matrix alloy reinforced with a high content of boron was fabricated by using a high-temperature alloying method and powder metallurgy technique (P/M). The preparation method of Ti–Al–B alloying powder was put forward. Phases, microstructure, and mechanical properties of the alloys were investigated. Wear and friction performance were studied by using a ball-on-disc tribotester sliding against a Si3N4ceramic ball from 23 °C (room temperature) to 900 °C. The Ti–Al–B alloy had a higher specific strength than that of the Ti–Al alloy. The boron element obviously enhanced the wear resistance and mechanical properties of the alloys because of the formation of borides (TiB2and AlB2) in matrices and the stable oxide film on the wear tracks. Friction coefficients of alloys were independent of the boron element. The wear mechanisms of the alloys transferred from fatigue wear to oxidative wear with the increase in temperature.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2022
·
IF 6.371
Mingyuan Zhang,Taotao Cai,Weiliang Lu,Shili Zheng,Ying Zhang,Yi Zhang
Given the high cost of fabricating the Ti-6Al-4V alloy powder by the traditional hydriding-dehydriding and atomization methods, a novel sintering-deoxygenation process was proposed and studied in this research. With the help of the developed deoxygenation treatment, value-added raw materials such as Ti sponge can be substituted by low-cost and low-grade materials with high oxygen content. In addition, sintering in a solid state saves a significant amount of processing energy compared to alloying above the melting point of Ti in the conventional alloy production process. This paper prepared six sintering precursors with different initial compositions and oxygen contents using the low-valued raw materials of crude titanium, crude vanadium, V 2 O 3 , Al powder, and Al 2 O 3 powder. These precursors' sintering performances on shrinkage, phase composition, microstructure, and porosity were investigated. The results show that the sintering shrinkage is positively correlated with the sintering temperature and holding time and is also affected by the raw materials. The pellet made by mixed crude titanium and AlV master alloy showed the largest shrinkage and the densest bulk. The various combinations of the raw materials led to the changes in the oxygen contents in the precursors, the alpha-beta phase ratio, and the shift of the diffraction peaks of the α-phase. The dissolving of the AlV master alloy and the formation of the Ti 3 Al intermediate phase took place during sintering due to diffusion. Sintering at 900–1000 °C is critical for elemental diffusion and densification, and sintering at higher temperatures is decisive for microstructure homogenization and further densification. Using the hydrogen-assisted Mg deoxygenation method, all the sintered samples could be treated to an oxygen level of around 0.4 wt% regardless of oxygen content in precursors. The contents of Ti, Al, V, and Fe in the obtained Ti-6Al-4V powders met the requirements of GB/T 34486-2017. This research has demonstrated the feasibility of fabricating Ti-6Al-4V alloy powder by the novel sintering-deoxygenation process.
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MATERIALS CHEMISTRY AND PHYSICS
·
2021
·
IF 4.094
Shenghang Xu,Tingting Lu,Kaijie Shen,Junjie Lan,Bin Hu,Huibin Zhang,Yiping Tang,Huazhen Cao,Guoqu Zheng
Ti–5Al–5V–5Mo–3Cr (Ti-5553) metastable β titanium alloy possesses excellent high temperature mechanical properties , however, the oxidation resistance is fairly poor. In this work, a SiO 2 coating was prepared on Ti-5553 alloy by cathodic electro-deposition. The high temperature oxidation resistance of the deposited SiO 2 coating was evaluated at 800 °C. The results show that the optimal current density of deposition is −2.0 mA/cm 2 for 300 s, and the thickness of the compact SiO 2 film reaches 5.5 μm. The SiO 2 film can react with Ti-5553 substrate and form protective Ti 5 Si 3 layer, which inhibits the inward diffusion of oxygen from air, leading to the remarkable improvement of oxidation resistance. The mass gain is only 1.13 mg/cm 2 after oxidation at 800 °C for 80 h. The oxide scale consists of TiO 2 , Al 2 O 3 , V 2 O 5 , Cr 2 O 3 and SiO 2 , but Mo 2 O 5 is absent. The occurrence of Kirkendall voids as well as the cracks induced by internal stress should be responsible for the deterioration of oxidation resistance, which may provide extra channels for oxygen diffusion inwards the substrate.
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JOURNAL OF THE ELECTROCHEMICAL SOCIETY
·
2021
·Vol. 168
·期 10
·103508
·
IF 4.316
Donghua Tian,Mingyong Wang,Jingxiu Wang,Jiguo Tu,Shuqiang Jiao
USTB technology is widely considered as a low-cost and environmentally-friendly method for titanium extraction from a consumable TiCxOy anode. It is expected to directly prepare TiCxOy by selective carbothermal reduction of titanium ores, not pure TiO2. However, impurities in titanium ores, particularly Al2O3, may affect the electrochemical dissolution of TiCxOy and Ti extraction. In this work, the effects of Al2O3 impurity on the preparation and dissolution behaviors of Ti2CO are studied. It is found that the existence form of Al2O3 is not changed during carbothermal reduction. With the increase of Al2O3 content, the conductivity of Ti2CO anode slightly decreases from 143.1 to 131.6 S cm−1 and the anodic polarization curves of Ti2CO@Al2O3 shifts to the positive direction due to the increase of dissolution resistances. Al2O3 in Ti2CO@Al2O3 anode will drop into molten salts to form anode slime during USTB process. On both liquid Zn and solid nickel cathodes, Ti is electrodeposited, which is not affected by Al2O3 impurity. Therefore, it is confirmed that typical Al2O3 impurity has no obvious effect on the electrochemical dissolution of Ti2CO anode and Ti extraction. The advanced USTB process is expectedly developed by the selective carbothermal reduction of titanium ores to prepare Ti2CO anode.
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SURFACE ENGINEERING
·
2021
·
IF 3.169
Songnan Wang,Shiai Xu
Trivalent chromium (Cr(III)) was added into a titanium (Ti)-based solution in this study to prepare Ti/Cr(III) conversion coatings on the aluminium (Al) foil for lithium-ion battery package. Their surface morphology and chemical composition were characterized by field-emission scanning electron microscope (FE-SEM), energy-dispersive spectroscopy and X-ray photoelectron spectroscopy (XPS). The corrosion resistance and the adhesive strength between Al foil and hot melt adhesive (modified polypropylene film) were determined. The results reveal that the Ti/Cr(III) conversion coating is mainly composed of Al2O3, TiO2, Cr(OH)3 and Cr2O3, and possesses the best anticorrosive performance with a corrosion current density of 1.05 µA cm−2, which is one order of magnitude lower than pure Al foil. The adhesive strength between Ti/Cr(III)-treated Al foil and the adhesive is 14.3 N/15 mm with an increase of 250% compared with the pure Al foil, which meets the industry standard (12 N/15 mm).
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ACS Omega
·
2020
·
IF 2.87
Xiaoping Chen,Yuansong Wei,Bohong Chen,Jiaqi Fu
In this study, a Ti foam-based photocatalytic membrane reactor (PMR) was constructed for rhodamine B (RhB) wastewater decolorization. Ti foam was chosen as a membrane and visible-light-driven C3N4 was chosen as a photocatalyst. The results showed that the decolorization efficiency could be up to 100% with a flow rate of 6.93 mL/min when the PMR was applied in the treatment of a 30 mg/L RhB solution and the concentration of C3N4 was 1 g/L. pH played an important role in the decolorization performance of the PMR. Alkalinity was not conducive to the decolorization of RhB in the PMR, which was mainly due to the property that RhB was difficult to dissolve in an alkaline solution. Membrane fouling was mainly caused by a C3N4 photocatalyst, while the effect of RhB on membrane fouling was negligible. Membrane fouling could be retarded when the PMR was applied for RhB treatment under visible-light irradiation, which was because of photoinduced hydrophilicity of C3N4. The membrane flux could be restored to its initial values after simple ultrasonic cleaning and backwashing. This was due to the large difference between the pore size of Ti foam and the particle size of C3N4 and the super hydrophilicity of Ti foam and C3N4.
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COLLOIDS AND SURFACES B-BIOINTERFACES
·
2020
·
IF 4.389
Lin Qiaoxia,Zhou Yujie,Yin Meng,Cheng Yizhu,Wei Yan,Hu Yinchun,Lian Xiaojie,Chen Weiyi,Huang Di
Oxidative stress induced by reactive oxygen species (ROS) overproduction and accumulation would hinder the osseointegration process at the bone-implant interface, leading to a higher rate of implant failure. To endow titanium (Ti) implants with antioxidant activity, we developed a coating approach mediated by tannic acid (TA)-Ca 2+ coordination complexation. A hydroxyapatite (HA)/TA composite coating was prepared, based on Ti substrates modified by anodized and annealed titanium dioxide (TiO 2 ) nanotube arrays. The results reveal that highly ordered TiO 2 nanotubes with a diameter of 142.23 ± 14.52 nm and a length of 374.17 ± 42.47 nm were fabricated on the Ti substrate and the XRD pattern shows the TiO 2 anatase phase after annealing at 450 ℃. TA-Ca complexes were formed on the surface of TiO 2 nanotubes by immersing the constructs into the mixed solution of TA and CaCl 2 , where they are served as calcium sites for the HA growth by later phosphorylation. The HA nanoparticles present needle-shape with the diameter of 18 ∼ 20 nm. The total antioxidant capacity assay was employed to confirm the antioxidant effect of the HA/TA composite coating. The results indicate that it has a persistent and strong antioxidative activity. In vitro cytological test results show that HA/TA coating exhibits good cytocompatibility for osteoblasts proliferation and adhesion.
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高影响因子
RARE METALS
·
2020
·Vol. 40
·期 7
·1940-1948
·
IF 2.161
Li Jia-Xin,Chen Yu-Hong,Bai Zhang-Jun,Zhao Bao-Jun,Jiang Liang,Wu Lan-Er
Ta–W alloys have unique properties but their applications at high temperatures are restricted due to their poor oxidation resistances. The addition of Al and Ti decreases the oxidation rate of the alloy, as Al-contained protective oxide layer could be formed. In this study, ternary and quaternary Ta–W alloys containing Al and Ti were prepared by hot press sintering. The microstructures and oxidation behaviors of the alloys were studied at 1173 K. The results show that the oxidation kinetics of all alloys follows a parabolic law at short oxidation periods. After cyclic oxidation, the kinetics of quaternary alloys still obeys the parabolic law but that of ternary alloy has been changed into linear law kinetics after 8-h oxidation. For ternary alloy, an outer layer with dense and continuous alumina was formed during the initial stage, and phase transformation caused the oxides to peel off. By comparison, the quaternary alloys depicted continuously solid solution of the oxides layer. Overall, Al and Ti played key roles in oxidation degree and affected the oxidation kinetics of ternary and quaternary alloys.
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CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Wanjun Zhao,Hui Ren,Tao Yan,Yapeng Ou,Qingjie Jiao,Haiyang Wang,Dylan J. Kline,Michael R. Zachariah
This work explores the ignition mechanism of silicon (Si) based thermites, and it is supposed that the phase change of silica (SiO 2 ) coating on the Si core producing fractures may play a crucial role in the ignition of Si-based thermites. Several Si-based thermites were evaluated by the combustion test and calorimeter, and potassium perchlorate (KClO 4 ) is turned out to be a promising oxidizer given the high reactivity and considerable heat release. Titanium (Ti) nanoparticles with a lower onset oxidization temperature than Si were incorporated into Si/KClO 4 system via a facile sonicating method. The ignition temperature of Si/KClO 4 has reduced markedly by ~80–130 °C with significant increases of ~5-8x in pressurization rate and decreases by a factor of ~2–3 in burn time when adding 30–70% Ti by mole into the fuel. The combustion efficiency is improved dramatically from ~59% to ~73%. The enhanced combustion performance could be attributed to the lower ignition temperature of Ti/KClO 4 leading to the initiation reaction of the ternary composites, thus promoting energy release and the reactivity of the ternary system. This work not only investigates the ignition mechanism of Si-based thermites but also sets a stage for tuning the ignition and combustion of Si-based thermites via facile incorporation of Ti nanoparticles.
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Journal of Energy Chemistry
·
2020
·
IF 7.216
Xiao Liu,Peijie Fan,Liangping Xiao,Jian Weng,Qingchi Xu,Jun Xu
The generation of green hydrogen (H 2 ) energy is of great significance to solve worldwide energy and environmental issues. Reduced Ti based photocatalyst has recently attracted intensive attention due to its excellent photocatalytic activity, while the synthesis of reduced Ti based photocatalysts with high stability is still a great challenge. Here, we report a facile method for synthesis of reduced Ti metal organic frameworks (small amounts of Pt incorporated) encapsulated BP (BP/R-Ti-MOFs/Pt) hybrid nanomaterial with enhanced photocatalytic activity. The strong interaction between Ti and P reduces the valence state of the binding Ti 4+ on the BP surface, forming abundant reduced Ti 4+ within R-Ti-MOFs/BP. Such reduced Ti 4+ render R-Ti-MOFs/BP efficient charge transfer and excellent light absorption capability, thus promote the photocatalytic H 2 production efficiency. Furthermore, the Ti-P interaction stabilizes both reduced Ti 4+ and BP during the photocatalytic reaction, which greatly enhanced the stability of the obtained BP/R-Ti-MOFs/Pt photocatalyst.
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CHEMICAL PHYSICS LETTERS
·
2020
·
IF 2.029
Zijun Sun,Guisong Fang,Jinglin Li,Jiahuan Mo,Xiong He,Xu Wang,Zhiqiang Yu
Hematite (α-Fe 2 O 3 ) is one of the promising photoanode materials for photoelectrochemical (PEC) water splitting, but its poor bulk charge transfer has been challenging towards its practical application. Herein, we have synthesized the (Ti, Zr) co-doped hematite by a facile hydrothermal method. The cooperation of (Ti, Zr) co-doped hematite yields photocurrent density of 1.51 mA cm −2 at 1.23 V vs. RHE and IPCE of 17.3% at 400 nm. The structural and PEC analysis indicate that the considerably PEC performance improvement is contributed to the higher carrier density and enhanced charge transfer of the synergistic effect of Ti and Zr co-doping.
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Journal of the American Chemical Society
·
2020
·
IF 14.612
Mei-Yan Gao,Kai Wang,Yayong Sun,Dejing Li,Bai-Qiao Song,Yassin H. Andaloussi,Michael J. Zaworotko,Jian Zhang,Lei Zhang
A series of increasingly large silver nanoclusters with a varied combination of Archimedean and/or Platonic solid arrangements was constructed using a flexible trifurcate TiL3 (L = Salicylic acid or 5-fluorosalicylic acid) metalloligand: Ag4@Ag4@Ti4 (PTC-85), Ag12@Ti4 (PTC-86), Ag4@Ag6@Ag12@Ti4 (PTC-87), Ag6@Ag24@Ag12@Ti4 (PTC-88), and Ag12@Ag24@Ti4 (PTC-89). The silver nanoclusters are each capped by four TiL3 moieties, thereby forming {Ti4} supertetrahedra with average edge lengths ranging from ∼8.12 Å to ∼17.37 Å. Such {Ti4} moieties further induce the tetrahedral geometry of the encapsulated silver nanoclusters. These atomically precise metallic clusters were found to be ultrastable with respect to air for several months, and to water for more than 3 days, due to the stabilizing effects of the TiL3 metalloligand. Moreover, the obtained clusters exhibit nonlinear optical (NLO) effects in optical limiting tests and also temperature-dependent photoluminescent properties. This work provides an interesting metalloligand method not only to induce the spatial growth of metallic clusters to achieve highly symmetric structures, but also to enhance their stability which is crucial for future application.
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