The formation of titanite coronae after rutile is common in retrograde high-to ultrahigh-pressure meta-mafic rocks,which provides a good opportunity to address the geochemical behavior of HFSE in crustal environments....The formation of titanite coronae after rutile is common in retrograde high-to ultrahigh-pressure meta-mafic rocks,which provides a good opportunity to address the geochemical behavior of HFSE in crustal environments.In the Sumdo eclogite,titanite occurs either as a corona around rutile grains or as semi-continuous veins cross-cutting the major foliation,whereas rutile grains occur either as inclusions in garnet or omphacite or as a relict core surrounded by titanite.Textural relationships and trace elements characteristics of rutile and titanite with different occurrences indicate that both minerals preferentially incorporate Nb and Hf over Ta and Zr in aqueous fluid.Moreover,the breakdown of omphacite and epidote could release substantial amounts of aqueous fluids enriched in Ca,Si,Fe and REE,which would react with rutile to form titanite coronae and veins.During this process,water-insoluble elements,like HFSE and HREE,behave like mobile elements,but they do not migrate substantially out of the system,instead,tending to react in situ.This suggests that the aqueous fluids released during the retrograde metamorphic reactions in mafic rocks could not substantially transfer fluidimmobile elements into the overlying mantle wedge in subduction environments.展开更多
We report the discovery of TiO_(2)-Ⅱ in the unmelted rock of the shocked Suizhou L6 chondrite.Natural TiO_(2)-Ⅱ was previously found in ultrahigh-pressure metamorphic and mantle-derived rocks,terrestrial impact stru...We report the discovery of TiO_(2)-Ⅱ in the unmelted rock of the shocked Suizhou L6 chondrite.Natural TiO_(2)-Ⅱ was previously found in ultrahigh-pressure metamorphic and mantle-derived rocks,terrestrial impact structures,and tektite.Our microscopic,Raman spectroscopic,electron microprobe and transmission electron microscopic investigations have revealed:(1) All observed TiO_(2)-Ⅱ grains are related with ilmenite and pyrophanite;(2) TiO_(2)-Ⅱ occurs as needle-and leaf-shaped inclusions in llmenite and patch-,tape-shaped body in pyrophanite;(3)The composition of TiO_(2)-Ⅱ is identical with that of its precursor rutile;(4) The Raman spectrum of TiO_(2)-Ⅱ is in good agreement with that of natural and synthesized α-PbO_(2)-type TiO_(2);(5) TiO_(2)-Ⅱ occurs mainly in the form of well-ordered nano-domains and small mis-orientation among the domains can be observed.(6) All electron diffraction reflections from TiO_(2)-Ⅱ can be indexed to α-PbO_(2)structure in space group Pbcn with lattice parameters of a=4.481 ?,b=5.578 A and c=4.921 A;(7) The exsolution inclusions of rutile from host ilmenite are mostly connected with an alternation process along the lamellar twinning plane of ilmenite induced by shockinduced high pressure and high temperature;(8) The P-T regime of 20-25 GPa and 1000 ℃ estimated for the Suizhou unmelted rock is suitable for phase transition of rutile into TiO_(2)-Ⅱ phase.展开更多
Two non-destructive analytical techniques (gamma spectrometer and X-ray diffractometer) were employed in the analysis of bauxite and rutile ore and their vicinity soil and control sourced within the Kanam and Wase min...Two non-destructive analytical techniques (gamma spectrometer and X-ray diffractometer) were employed in the analysis of bauxite and rutile ore and their vicinity soil and control sourced within the Kanam and Wase mineral exploration sites. The activity concentrations of natural radionuclides <sup>238</sup>U, <sup>232</sup>Th, and <sup>40</sup>K in the soil samples received from bauxite and rutile mineral mining vicinities revealed high concentrations of <sup>238</sup>U, <sup>232</sup>Th, and <sup>40</sup>K compared to the control soil samples sourced 500 m away from the mineral exploration vicinities. Radiological detriments RLI, AUI, Hin and Hex unveiled values exceeding the radiation standard concentration (>1) for soil. X-ray diffraction characterization of bauxite ore revealed the interlocking minerals of Bauxite (18)%, Albite (11)%, Garnet (15)%, Illite (6)% and Muscovite (43)% in various proportions obtained within the 2θ range (9.18 to 64.4) and a peak value (intensity, cps) of 3400. Pure bauxite percentage in the ore meets metallurgical grade (15 - 25)%. X-ray diffraction of rutile ore revealed the minerals of rutile (40)%, quartz (21.4)%, ilmenite (27)% and garnet (11.8)% found within the 2θ range (27.5 to 35.6) and a peak value intensity of 31.1 - 100.0 cps also meeting the metallurgical grade of 15% - 25%. The major environmental concern associated with the mineral-sands industry is the radiation hazards, pollution of ground-water sources from heavy metals, mineral transport with heavy equipment’s, dredging operations in fragile coastal area and clearing of vegetation.展开更多
Rutile titania(TiO2)was successfully prepared via hydrolysis of TiCl4 in the presence of AlCl3.The powders were characterized by X-ray powder diffraction(XRD),scanning electron microscopy(SEM),and Brunauer-Emmett-Tell...Rutile titania(TiO2)was successfully prepared via hydrolysis of TiCl4 in the presence of AlCl3.The powders were characterized by X-ray powder diffraction(XRD),scanning electron microscopy(SEM),and Brunauer-Emmett-Teller(BET)surface area analysis.In the present system,AlCl3 functions as a nucleating agent and induces the formation of rutile TiO2.The influences of HCl and isopropanol concentrations on the purity and morphology of the rutile TiO2 were investigated.The purity of the rutile TiO2 increased with increasing concentration of HCl.Evenly dispersed rutile TiO2 particles with a spherical morphology were obtained when the HCl and isopropanol concentrations were 0.5 and 1 mol·L-1,respectively.Furthermore,the prepared TiO2 powders were used in adsorption tests of the heavy metal pollutant Cr(Ⅵ).Rutile TiO2 sample S-9 demonstrated greater adsorption performance and a removal efficiency that was greater than 99.95%after60 min of adsorption when the Cr(Ⅵ)concentration was 200 mg·L-1.The maximum adsorption capacity on rutile TiO2 was 28.9 mg·g-1.This work provides an easy path to prepare a high-performance rutile TiO2 adsorbent with potential applications in water pollution treatment.展开更多
Rutile separation from calcite, apatite and quartz by flotation was investigated. The results show that the rutile separation from calcium and silicon gangue minerals can be realized with alkyl-imino-bismethylene phos...Rutile separation from calcite, apatite and quartz by flotation was investigated. The results show that the rutile separation from calcium and silicon gangue minerals can be realized with alkyl-imino-bismethylene phosphoric acid (TF112) as a collector and sodium hexametaphosphate (SH) as a regulator.展开更多
This study aims to prepare a composite polyurethane coating through a facile synthesis process. Titanium dioxide, which is a component of the prepared hydroxyl acrylic resin polyurethane varnish, was partially substit...This study aims to prepare a composite polyurethane coating through a facile synthesis process. Titanium dioxide, which is a component of the prepared hydroxyl acrylic resin polyurethane varnish, was partially substituted by wollastonite, and an optimal substitution ratio was obtained. Analyses based on scanning electron microscope, powder X-ray diffraction, and Raman scattering measurements demonstrated that the addition of wollastonite caused nearly no change in the basic structure of the coating. Coating with a substitution ratio of 25% showed high thermal stability, good cover effect, considerable moisture-proof and water resistance ability, great acidic and basic resistance, and improved performance and hardness in performance tests. Furthermore, the production cost was reduced significantly at this substitution ratio.展开更多
Nanocrystalline titania was prepared by the homogeneous-precipitation method at temperature lower than 120℃. The properties of powders were identified by XRD,TEM and diffuse reflection spectra.The results showed that...Nanocrystalline titania was prepared by the homogeneous-precipitation method at temperature lower than 120℃. The properties of powders were identified by XRD,TEM and diffuse reflection spectra.The results showed that rutile titania formed at 70℃without calcination in air.Nanometer rutile TiO_2 had good crystalline and small particle size.The formation mechanism of rutile was also discussed.The photocatalytic activity of the prepared particles was tested for the degradation of methyl orange.The photocatalytic activity of rutile TiO_2 was higher than those obtained from Degussa P-25 TiO_2.The reasons for high photocatalytic activity of futile were discussed.展开更多
A new zinc 1,3,5-benzenetricarboxylate Zn3(BTC)2(DMSO)4(BTC=1,3,5-benzenetricarboxylate) has been solvothermally synthesized in DMSO and structurally determined by X-ray single-crystal diffraction.It crystallize...A new zinc 1,3,5-benzenetricarboxylate Zn3(BTC)2(DMSO)4(BTC=1,3,5-benzenetricarboxylate) has been solvothermally synthesized in DMSO and structurally determined by X-ray single-crystal diffraction.It crystallizes in the monoclinic system,space group P21/c with a=10.0861(11),b=10.2527(11),c=16.4013(18),β=95.478(2)°,V=1688.3(3)3,Z=2,Zn3S4C26H30O16,Mr=922.85,Dc=1.815 g/cm3,F(000)=936,μ=2.434 mm-1,R=0.0319 and wR=0.0755.This compound consists of trimeric zinc clusters and BTC linkers.Alternate connection of these trimeric zinc clusters and BTC linkers results in a three-dimensional(3,6)-connected frame-work with rutile topology.展开更多
The systematic trends of electrionic structure and optical properties of rutile (P42/mnm) RuO2 have been cal- culated by using the plane-wave norm-conserving pseudopotential density functional theory (DFT) method ...The systematic trends of electrionic structure and optical properties of rutile (P42/mnm) RuO2 have been cal- culated by using the plane-wave norm-conserving pseudopotential density functional theory (DFT) method within the generalised gradient approximation (GGA) for the exchange-correlation potential. The obtained equilibrium structure parameters are in excellent agreement with the experimental data. The calculated bulk modulus and elastic constants are also in good agreement with the experimental data and available theoretical calculations. Analysis based on elec- tronic structure and pseudogap reveals that the bonding nature in RuO2 is a combination of covalent, ionic and metallic bonds. Based on a Kramers Kronig analysis of the reflectivity, we have obtained the spectral dependence of the real and imaginary parts of the complex dielectric constant (~1 and z2, respectively) and the refractive index (n); and comparisons have shown that the theoretical results agree well with the experimental data as well. Meanwhile, we have also calculated the absorption coefficient, reflectivity index, electron energy loss function of RuO2 for radiation up to 30 eV. As a result, the predicted reflectivity index is in good agreement with the experimental data at low energies.展开更多
TiO2 coatings are of technical importance owing to their promising applications to photocatalytical, electrical, optical and tribological coatings. Thermal spraying process has been widely used to deposit both metalli...TiO2 coatings are of technical importance owing to their promising applications to photocatalytical, electrical, optical and tribological coatings. Thermal spraying process has been widely used to deposit both metallic and nonmetallic coatings. During thermal spraying, spray particle at fully or partially melted condition is projected to a substrate and subsequently flattens, rapidly cools and solidifies. Therefore, a coating in lamellar structure is usually formed as a quenched microstructure. TiO2 coatings were deposited on different substrates through plasma spraying with fused-crushed powder in rutile phase as feedstock to reveal the crystalline orientation in the coatings. XRD results show that the coatings consist of rutile phase with a fraction of anatase phase, and the rutile phase presents a preferable crystalline orientation along [101] direction. It is found that the orientation factors of rutile phase in the thin coatings are significantly influenced by substrate materials. The thick coatings yield the same orientation factors of 0.22 to 0.23 on all substrates in spite of substrate materials. It is considered that the thermal properties of substrate materials are the dominant factors for the preferable crystalline orientation in rutile phase within plasmasprayed TiO2 coating.展开更多
The laser ablation technique was employed to prepare TiO2 nanoparticles by pulsed laser ablation of a titanium target immersed in the poly-(vinylpyrrolidone) solution using wavelength of 1 064 nm. The as-prepared prod...The laser ablation technique was employed to prepare TiO2 nanoparticles by pulsed laser ablation of a titanium target immersed in the poly-(vinylpyrrolidone) solution using wavelength of 1 064 nm. The as-prepared products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The results indicate that the rutile TiO2 nanoparticles are synthesized at room temperature and the average size is about 35 nm with narrow size distribution. A possible formation mechanism was discussed and the UV-vis absorption and photoluminescence were measured. The optical study shows that rutile nanoparticle possesses direct optical transition with band gap of 3.15 eV.展开更多
The emulsifiable conditions of composite collector(FP-2)inindustry are systematically re- searched in the paper. It is foundthat types of the emulsifiers, emulsification temperature, the mixedproportion of FP-2 to emu...The emulsifiable conditions of composite collector(FP-2)inindustry are systematically re- searched in the paper. It is foundthat types of the emulsifiers, emulsification temperature, the mixedproportion of FP-2 to emulsifier are the important parametersaffecting emulsification effect rutile flotation targets. When Theproportion of FP-2 to emulsifier(E-4)is 100, by means ofemulsification of mechanical stirring, the rutile Flotation recoveryis 85.6/100 and the grade is 75.3/100, which approach the flotationtargets of FP-2 used as col- Lector by ultrasonic emulsificationunit.展开更多
A Fe doped rutile TiO2 single crystal is grown in an O2 atmosphere by the floating zone technique. Electron spin resonance (ESR) spectra clearly demonstrate that Fe^3+ ions are substituted for the Ti^4+ ions in th...A Fe doped rutile TiO2 single crystal is grown in an O2 atmosphere by the floating zone technique. Electron spin resonance (ESR) spectra clearly demonstrate that Fe^3+ ions are substituted for the Ti^4+ ions in the rutile TiO2 matrix. Magnetization measurements reveal that the Fe:TiO2 crystal shows paramagnetic behaviour in a temperature range from 5 K to 350 K. The Fe^3+ ions possess weak magnetic anisotropy with an easy axis along the c axis. The annealed Fe:TiO2 crystal shows spin-glass-like behaviours due to the aggregation of the ferromagnetic clusters.展开更多
Rutile phase exhibits higher refractive index and h id ing power, good chemical stability, and is becoming a candidate material for the high-temperature separation and catalysis applications. The thermodynamically sta...Rutile phase exhibits higher refractive index and h id ing power, good chemical stability, and is becoming a candidate material for the high-temperature separation and catalysis applications. The thermodynamically stable feature of rutile among the three polymorphs of TiO 2 usually hinders ob taining nano-sized rutile phase by a conventional calcining way. However, acid peptization of amorphous TiO 2 is favorable to the formation of rutile phase. I n this work, well-crystallized and well-dispersed rod-like rutile particles w ith specific surface areas of 49.1 and 35.0 m 2/g were prepared by hydrothermal ly treating the acid peptized TiO 2 amorphous sols at relatively low temperatur es of 200 ℃ or 240 ℃, respectively. The formation of non-touching rutile part icles is attributed to high long-range electrostatic forces between particles i n the presence of the high concentration of the peptizer. The acid peptization w ould easily break the ≡Ti-O-Ti≡ bonds to form ≡Ti-OH or HO-Ti-OH species depending on the amount of acid, and create conditions for the formation of rut ile nuclei after structural rearrangements.展开更多
Titanium oxide (rutile, TiO2) and zircon (ZrSiO4), known insoluble ceramic materials, are commonly used for coatings of implant materials. We investigate the release of zirconium, titanium, aluminum, iron, and silicon...Titanium oxide (rutile, TiO2) and zircon (ZrSiO4), known insoluble ceramic materials, are commonly used for coatings of implant materials. We investigate the release of zirconium, titanium, aluminum, iron, and silicon from different micron-sized powders of 6 powders of natural rutile (TiO2) and zircon (ZrSiO4) from a surface perspective. The investigation includes five different synthetic body fluids and two time periods of exposure, 2 and 24 hours. The solution chemicals rather than pH are important for the release of zirconium. When exceeding a critical amount of aluminum and silicon in the surface oxide, the particles seem to be protected from selective pH-specific release at neutral or weakly alkaline pH. The importance of bulk and surface composition and individual changes between different kinds of the same material is elucidated. Changes in material properties and metal release characteristics with particle size are presented for zircon.展开更多
A green, rapid and facile method for synthesis of pure rutile TiO2 has been developed. Rutile TiO2 of high purity was synthesized by controlled hydrolysis of TiCl3 in aqueous medium at room temperature. Addition of ni...A green, rapid and facile method for synthesis of pure rutile TiO2 has been developed. Rutile TiO2 of high purity was synthesized by controlled hydrolysis of TiCl3 in aqueous medium at room temperature. Addition of nitric acid to TiCl3 greatly increased the rate of TiCl3 hydrolysis, crystallization and surface area of the prepared TiO2 powder. The phase obtained in this way was identified by X-ray diffraction. TiO2 synthesized by this method showed a unique flower-like assembly of nanotubes, very high surface area and high photocatalytic activity under visible light irradiation.展开更多
TiO2 was employed as the waste form for disposal of simulated nuclide Sr. Preparation of Sr bearing rutile was explored under different sintering temperatures and Sr contents. The optimal treatment temperature was con...TiO2 was employed as the waste form for disposal of simulated nuclide Sr. Preparation of Sr bearing rutile was explored under different sintering temperatures and Sr contents. The optimal treatment temperature was confirmed as 1300 ℃ for the incorporation of SrO in rutile Ti O2. Perovskite type Sr TiO3 was prepared as the resultant product. The limited containment capacity of SrO in rutile was speculated to be 56.5wt%. As the SrO content increases, the as-synthesized sample exhibits more porosity because Sr TiO3 phase demonstrates higher density than rutile and SrO. The 28 day normalized leaching rate(LRi) of Sr and Ti will decrease congruously as the SrO incorporation increases. The LRSr value is lower than 0.1g·m^-2·d^-1, which is about 3 orders of magnitude higher than the LR(Ti) value.展开更多
Remarkable room-temperature ferromagnetism was observed both in undoped and Cu-doped rutile TiO2 single crystals(SCs).To tune their magnetism,Ar ion irradiation was quantitatively performed on the two crystals in wh...Remarkable room-temperature ferromagnetism was observed both in undoped and Cu-doped rutile TiO2 single crystals(SCs).To tune their magnetism,Ar ion irradiation was quantitatively performed on the two crystals in which the saturation magnetizations for the samples were enhanced distinctively.The post-irradiation led to a spongelike layer in the near surface of the Cu-doped TiO2.Meanwhile,a new CuO-like species present in the sample was found to be dissolved after the post-irradiation.Analyzing the magnetization data unambiguously reveals that the experimentally observed ferromagnetism is related to the intrinsic defects rather than the exotic Cu ions,while these ions are directly involved in boosting the absorption in the visible region.展开更多
基金supported by the National Science Foundation of China(Grant Nos.92055202)the Second Tibetan Plateau Scientific Expedition and Research(Grant No.2019QZKK0702)the China Geological Survey(Grant Nos.DD20221817 and DD20221630)。
文摘The formation of titanite coronae after rutile is common in retrograde high-to ultrahigh-pressure meta-mafic rocks,which provides a good opportunity to address the geochemical behavior of HFSE in crustal environments.In the Sumdo eclogite,titanite occurs either as a corona around rutile grains or as semi-continuous veins cross-cutting the major foliation,whereas rutile grains occur either as inclusions in garnet or omphacite or as a relict core surrounded by titanite.Textural relationships and trace elements characteristics of rutile and titanite with different occurrences indicate that both minerals preferentially incorporate Nb and Hf over Ta and Zr in aqueous fluid.Moreover,the breakdown of omphacite and epidote could release substantial amounts of aqueous fluids enriched in Ca,Si,Fe and REE,which would react with rutile to form titanite coronae and veins.During this process,water-insoluble elements,like HFSE and HREE,behave like mobile elements,but they do not migrate substantially out of the system,instead,tending to react in situ.This suggests that the aqueous fluids released during the retrograde metamorphic reactions in mafic rocks could not substantially transfer fluidimmobile elements into the overlying mantle wedge in subduction environments.
文摘We report the discovery of TiO_(2)-Ⅱ in the unmelted rock of the shocked Suizhou L6 chondrite.Natural TiO_(2)-Ⅱ was previously found in ultrahigh-pressure metamorphic and mantle-derived rocks,terrestrial impact structures,and tektite.Our microscopic,Raman spectroscopic,electron microprobe and transmission electron microscopic investigations have revealed:(1) All observed TiO_(2)-Ⅱ grains are related with ilmenite and pyrophanite;(2) TiO_(2)-Ⅱ occurs as needle-and leaf-shaped inclusions in llmenite and patch-,tape-shaped body in pyrophanite;(3)The composition of TiO_(2)-Ⅱ is identical with that of its precursor rutile;(4) The Raman spectrum of TiO_(2)-Ⅱ is in good agreement with that of natural and synthesized α-PbO_(2)-type TiO_(2);(5) TiO_(2)-Ⅱ occurs mainly in the form of well-ordered nano-domains and small mis-orientation among the domains can be observed.(6) All electron diffraction reflections from TiO_(2)-Ⅱ can be indexed to α-PbO_(2)structure in space group Pbcn with lattice parameters of a=4.481 ?,b=5.578 A and c=4.921 A;(7) The exsolution inclusions of rutile from host ilmenite are mostly connected with an alternation process along the lamellar twinning plane of ilmenite induced by shockinduced high pressure and high temperature;(8) The P-T regime of 20-25 GPa and 1000 ℃ estimated for the Suizhou unmelted rock is suitable for phase transition of rutile into TiO_(2)-Ⅱ phase.
文摘Two non-destructive analytical techniques (gamma spectrometer and X-ray diffractometer) were employed in the analysis of bauxite and rutile ore and their vicinity soil and control sourced within the Kanam and Wase mineral exploration sites. The activity concentrations of natural radionuclides <sup>238</sup>U, <sup>232</sup>Th, and <sup>40</sup>K in the soil samples received from bauxite and rutile mineral mining vicinities revealed high concentrations of <sup>238</sup>U, <sup>232</sup>Th, and <sup>40</sup>K compared to the control soil samples sourced 500 m away from the mineral exploration vicinities. Radiological detriments RLI, AUI, Hin and Hex unveiled values exceeding the radiation standard concentration (>1) for soil. X-ray diffraction characterization of bauxite ore revealed the interlocking minerals of Bauxite (18)%, Albite (11)%, Garnet (15)%, Illite (6)% and Muscovite (43)% in various proportions obtained within the 2θ range (9.18 to 64.4) and a peak value (intensity, cps) of 3400. Pure bauxite percentage in the ore meets metallurgical grade (15 - 25)%. X-ray diffraction of rutile ore revealed the minerals of rutile (40)%, quartz (21.4)%, ilmenite (27)% and garnet (11.8)% found within the 2θ range (27.5 to 35.6) and a peak value intensity of 31.1 - 100.0 cps also meeting the metallurgical grade of 15% - 25%. The major environmental concern associated with the mineral-sands industry is the radiation hazards, pollution of ground-water sources from heavy metals, mineral transport with heavy equipment’s, dredging operations in fragile coastal area and clearing of vegetation.
基金financially supported by the National Natural Science Foundation of China(Nos.51734002 and51774027)。
文摘Rutile titania(TiO2)was successfully prepared via hydrolysis of TiCl4 in the presence of AlCl3.The powders were characterized by X-ray powder diffraction(XRD),scanning electron microscopy(SEM),and Brunauer-Emmett-Teller(BET)surface area analysis.In the present system,AlCl3 functions as a nucleating agent and induces the formation of rutile TiO2.The influences of HCl and isopropanol concentrations on the purity and morphology of the rutile TiO2 were investigated.The purity of the rutile TiO2 increased with increasing concentration of HCl.Evenly dispersed rutile TiO2 particles with a spherical morphology were obtained when the HCl and isopropanol concentrations were 0.5 and 1 mol·L-1,respectively.Furthermore,the prepared TiO2 powders were used in adsorption tests of the heavy metal pollutant Cr(Ⅵ).Rutile TiO2 sample S-9 demonstrated greater adsorption performance and a removal efficiency that was greater than 99.95%after60 min of adsorption when the Cr(Ⅵ)concentration was 200 mg·L-1.The maximum adsorption capacity on rutile TiO2 was 28.9 mg·g-1.This work provides an easy path to prepare a high-performance rutile TiO2 adsorbent with potential applications in water pollution treatment.
文摘Rutile separation from calcite, apatite and quartz by flotation was investigated. The results show that the rutile separation from calcium and silicon gangue minerals can be realized with alkyl-imino-bismethylene phosphoric acid (TF112) as a collector and sodium hexametaphosphate (SH) as a regulator.
文摘This study aims to prepare a composite polyurethane coating through a facile synthesis process. Titanium dioxide, which is a component of the prepared hydroxyl acrylic resin polyurethane varnish, was partially substituted by wollastonite, and an optimal substitution ratio was obtained. Analyses based on scanning electron microscope, powder X-ray diffraction, and Raman scattering measurements demonstrated that the addition of wollastonite caused nearly no change in the basic structure of the coating. Coating with a substitution ratio of 25% showed high thermal stability, good cover effect, considerable moisture-proof and water resistance ability, great acidic and basic resistance, and improved performance and hardness in performance tests. Furthermore, the production cost was reduced significantly at this substitution ratio.
基金The present research was supported by the High Technology and Development Project of the China (Grant:2003AA302320)National Natural Science Foundation of China (Grant:50021009)Basic Research Foundation of Tsinghua University (JC200206).
文摘Nanocrystalline titania was prepared by the homogeneous-precipitation method at temperature lower than 120℃. The properties of powders were identified by XRD,TEM and diffuse reflection spectra.The results showed that rutile titania formed at 70℃without calcination in air.Nanometer rutile TiO_2 had good crystalline and small particle size.The formation mechanism of rutile was also discussed.The photocatalytic activity of the prepared particles was tested for the degradation of methyl orange.The photocatalytic activity of rutile TiO_2 was higher than those obtained from Degussa P-25 TiO_2.The reasons for high photocatalytic activity of futile were discussed.
基金supported by the National Natural Science Foundation of China (No 20871027)the Program for New Century Excellent Talents in University (NCET-07-0169)
文摘A new zinc 1,3,5-benzenetricarboxylate Zn3(BTC)2(DMSO)4(BTC=1,3,5-benzenetricarboxylate) has been solvothermally synthesized in DMSO and structurally determined by X-ray single-crystal diffraction.It crystallizes in the monoclinic system,space group P21/c with a=10.0861(11),b=10.2527(11),c=16.4013(18),β=95.478(2)°,V=1688.3(3)3,Z=2,Zn3S4C26H30O16,Mr=922.85,Dc=1.815 g/cm3,F(000)=936,μ=2.434 mm-1,R=0.0319 and wR=0.0755.This compound consists of trimeric zinc clusters and BTC linkers.Alternate connection of these trimeric zinc clusters and BTC linkers results in a three-dimensional(3,6)-connected frame-work with rutile topology.
基金supported by the China Scholarship Council (CSC) and the National Natural Science Foundation of China (Grant Nos. 10676025 and 10574096)the Science-Technology Foundation for Young Scientist of Sichuan Province,China (Grant No. 09ZQ026-049)
文摘The systematic trends of electrionic structure and optical properties of rutile (P42/mnm) RuO2 have been cal- culated by using the plane-wave norm-conserving pseudopotential density functional theory (DFT) method within the generalised gradient approximation (GGA) for the exchange-correlation potential. The obtained equilibrium structure parameters are in excellent agreement with the experimental data. The calculated bulk modulus and elastic constants are also in good agreement with the experimental data and available theoretical calculations. Analysis based on elec- tronic structure and pseudogap reveals that the bonding nature in RuO2 is a combination of covalent, ionic and metallic bonds. Based on a Kramers Kronig analysis of the reflectivity, we have obtained the spectral dependence of the real and imaginary parts of the complex dielectric constant (~1 and z2, respectively) and the refractive index (n); and comparisons have shown that the theoretical results agree well with the experimental data as well. Meanwhile, we have also calculated the absorption coefficient, reflectivity index, electron energy loss function of RuO2 for radiation up to 30 eV. As a result, the predicted reflectivity index is in good agreement with the experimental data at low energies.
基金Project supported by the Natural Science Foundation of Xi'an Jiaotong University, China
文摘TiO2 coatings are of technical importance owing to their promising applications to photocatalytical, electrical, optical and tribological coatings. Thermal spraying process has been widely used to deposit both metallic and nonmetallic coatings. During thermal spraying, spray particle at fully or partially melted condition is projected to a substrate and subsequently flattens, rapidly cools and solidifies. Therefore, a coating in lamellar structure is usually formed as a quenched microstructure. TiO2 coatings were deposited on different substrates through plasma spraying with fused-crushed powder in rutile phase as feedstock to reveal the crystalline orientation in the coatings. XRD results show that the coatings consist of rutile phase with a fraction of anatase phase, and the rutile phase presents a preferable crystalline orientation along [101] direction. It is found that the orientation factors of rutile phase in the thin coatings are significantly influenced by substrate materials. The thick coatings yield the same orientation factors of 0.22 to 0.23 on all substrates in spite of substrate materials. It is considered that the thermal properties of substrate materials are the dominant factors for the preferable crystalline orientation in rutile phase within plasmasprayed TiO2 coating.
基金Project(09R23) supported by the Scientific Research Starting Foundation of Nantong UniversityProjects(50671100, 10604055) supported by the National Natural Science Foundation of China
文摘The laser ablation technique was employed to prepare TiO2 nanoparticles by pulsed laser ablation of a titanium target immersed in the poly-(vinylpyrrolidone) solution using wavelength of 1 064 nm. The as-prepared products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The results indicate that the rutile TiO2 nanoparticles are synthesized at room temperature and the average size is about 35 nm with narrow size distribution. A possible formation mechanism was discussed and the UV-vis absorption and photoluminescence were measured. The optical study shows that rutile nanoparticle possesses direct optical transition with band gap of 3.15 eV.
基金Funded by Hubei Natural Science Foundation (No. 99J118).
文摘The emulsifiable conditions of composite collector(FP-2)inindustry are systematically re- searched in the paper. It is foundthat types of the emulsifiers, emulsification temperature, the mixedproportion of FP-2 to emulsifier are the important parametersaffecting emulsification effect rutile flotation targets. When Theproportion of FP-2 to emulsifier(E-4)is 100, by means ofemulsification of mechanical stirring, the rutile Flotation recoveryis 85.6/100 and the grade is 75.3/100, which approach the flotationtargets of FP-2 used as col- Lector by ultrasonic emulsificationunit.
基金supported by the National Basic Research Program of China (Grant No 2009CB929201)the National Natural Science Foundation of China (Grant No 10774179)
文摘A Fe doped rutile TiO2 single crystal is grown in an O2 atmosphere by the floating zone technique. Electron spin resonance (ESR) spectra clearly demonstrate that Fe^3+ ions are substituted for the Ti^4+ ions in the rutile TiO2 matrix. Magnetization measurements reveal that the Fe:TiO2 crystal shows paramagnetic behaviour in a temperature range from 5 K to 350 K. The Fe^3+ ions possess weak magnetic anisotropy with an easy axis along the c axis. The annealed Fe:TiO2 crystal shows spin-glass-like behaviours due to the aggregation of the ferromagnetic clusters.
文摘Rutile phase exhibits higher refractive index and h id ing power, good chemical stability, and is becoming a candidate material for the high-temperature separation and catalysis applications. The thermodynamically stable feature of rutile among the three polymorphs of TiO 2 usually hinders ob taining nano-sized rutile phase by a conventional calcining way. However, acid peptization of amorphous TiO 2 is favorable to the formation of rutile phase. I n this work, well-crystallized and well-dispersed rod-like rutile particles w ith specific surface areas of 49.1 and 35.0 m 2/g were prepared by hydrothermal ly treating the acid peptized TiO 2 amorphous sols at relatively low temperatur es of 200 ℃ or 240 ℃, respectively. The formation of non-touching rutile part icles is attributed to high long-range electrostatic forces between particles i n the presence of the high concentration of the peptizer. The acid peptization w ould easily break the ≡Ti-O-Ti≡ bonds to form ≡Ti-OH or HO-Ti-OH species depending on the amount of acid, and create conditions for the formation of rut ile nuclei after structural rearrangements.
文摘Titanium oxide (rutile, TiO2) and zircon (ZrSiO4), known insoluble ceramic materials, are commonly used for coatings of implant materials. We investigate the release of zirconium, titanium, aluminum, iron, and silicon from different micron-sized powders of 6 powders of natural rutile (TiO2) and zircon (ZrSiO4) from a surface perspective. The investigation includes five different synthetic body fluids and two time periods of exposure, 2 and 24 hours. The solution chemicals rather than pH are important for the release of zirconium. When exceeding a critical amount of aluminum and silicon in the surface oxide, the particles seem to be protected from selective pH-specific release at neutral or weakly alkaline pH. The importance of bulk and surface composition and individual changes between different kinds of the same material is elucidated. Changes in material properties and metal release characteristics with particle size are presented for zircon.
文摘A green, rapid and facile method for synthesis of pure rutile TiO2 has been developed. Rutile TiO2 of high purity was synthesized by controlled hydrolysis of TiCl3 in aqueous medium at room temperature. Addition of nitric acid to TiCl3 greatly increased the rate of TiCl3 hydrolysis, crystallization and surface area of the prepared TiO2 powder. The phase obtained in this way was identified by X-ray diffraction. TiO2 synthesized by this method showed a unique flower-like assembly of nanotubes, very high surface area and high photocatalytic activity under visible light irradiation.
基金Funded by the National Natural Science Foundation of China(No.51202203)the Young Outstanding Scientist Fund(No.13zx9108)the Open Project of Southwest University of Science and Technology(No.14tdfk02)
文摘TiO2 was employed as the waste form for disposal of simulated nuclide Sr. Preparation of Sr bearing rutile was explored under different sintering temperatures and Sr contents. The optimal treatment temperature was confirmed as 1300 ℃ for the incorporation of SrO in rutile Ti O2. Perovskite type Sr TiO3 was prepared as the resultant product. The limited containment capacity of SrO in rutile was speculated to be 56.5wt%. As the SrO content increases, the as-synthesized sample exhibits more porosity because Sr TiO3 phase demonstrates higher density than rutile and SrO. The 28 day normalized leaching rate(LRi) of Sr and Ti will decrease congruously as the SrO incorporation increases. The LRSr value is lower than 0.1g·m^-2·d^-1, which is about 3 orders of magnitude higher than the LR(Ti) value.
基金Project supported by the National Natural Science Foundation of China(Grant No.11575074)the Open Project of State Key laboratory of Crystal Material,Shandong University,China(Grant No.KF1311)+2 种基金the Open Project of Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education,Lanzhou University,China(Grant No.LZUMMM2012003)the Open Project of Key Laboratory of Beam Technology and Material Modification of Ministry of Education,Beijing Normal University,China(Grant No.201204)the Fundamental Research Funds for the Central Universities,China(Grant No.lzujbky-2015-240)
文摘Remarkable room-temperature ferromagnetism was observed both in undoped and Cu-doped rutile TiO2 single crystals(SCs).To tune their magnetism,Ar ion irradiation was quantitatively performed on the two crystals in which the saturation magnetizations for the samples were enhanced distinctively.The post-irradiation led to a spongelike layer in the near surface of the Cu-doped TiO2.Meanwhile,a new CuO-like species present in the sample was found to be dissolved after the post-irradiation.Analyzing the magnetization data unambiguously reveals that the experimentally observed ferromagnetism is related to the intrinsic defects rather than the exotic Cu ions,while these ions are directly involved in boosting the absorption in the visible region.