Titanium Compounds Research Articles

Features of the Ion Mobility and Phase Transitions in Hexafluoro Complex Compounds of Tantalum(V), Niobium(V), and Titanium(IV) with a Tetramethyl Ammonium Cation

Features of the Ion Mobility and Phase Transitions in Hexafluoro Complex Compounds of Tantalum(V), Niobium(V), and Titanium(IV) with a Tetramethyl Ammonium Cation

Variation of energy absorption build-up factor with penetration depth for some titanium compounds

The buildup factor is an important characteristic that need to be studied and determined prior to using a material clinically in radiation treatment and protection. Energy absorption buildup factors for some titanium compounds like Titanium dioxide (TiO 2 ), Titanium Carbide (TiC), Titanium Nitride (TiN) and Titanium Silicate (TiSi 2 ) has been calculated using the G.P. fitting technique upto penetration depth of 40 mean free path (mfp) and in an energy range from 0.015 to 15.0 MeV. The variation of absorption buildup factors with penetration depth for the selected compounds of titanium has been studied. It has been found that the maximum value of energy absorption buildup factors shifts to the intermediate incident photon energy regions with the increase in penetration depth of the selected compounds of titanium.

Recovery of Titanium Compounds from Ti-enriched Product of Alkali Melting Ti-bearing Blast Furnace Slag by Dilute Sulfuric Acid Leaching

The extraction of titanium from the Ti-enriched product which was prepared from Ti-bearing blast furnace slag by alkali roasting and water leaching, was investigated by dilute sulfuric acid leaching. The effects of sulfuric acid mass fraction, the ratio of acid to slag, reaction temperature and time on the extraction rate of titanium were studied in this paper. The results show that titanium recovery of 92.62 pct was obtained under the conditions of sulfuric acid mass fraction of 50 pct, ratio of acid to slag of 1.5:1, reaction temperature of 160°C and reaction time of 2.5hours. The kinetic study indicates that the acid leaching reaction was controlled by the rate of diffusion, and kinetics equation of drozdov can be described the acid leaching reaction.

Titanates and Titanate-Metal Compounds in Biological Contexts.

Metal ions are notorious environmental contaminants, some causing toxicity at exquisitely low (ppm-level) concentrations. Yet, the redox properties of metal ions make them attractive candidates for bio-therapeutics. Titanates are insoluble particulate compounds of titanium and oxygen with crystalline surfaces that bind metal ions; these compounds offer a means to scavenge metal ions in environmental contexts or deliver them in therapeutic contexts while limiting systemic exposure and toxicity. In either application, the toxicological properties of titanates are crucial. To date, the accurate measurement of the in vitro toxicity of titanates has been complicated by their particulate nature, which interferes with many assays that are optical density (OD)-dependent, and at present, little to no in vivo titanate toxicity data exist. Compatibility data garnered thus far for native titanates in vitro are inconsistent and lacking in mechanistic understanding. These data suggest that native titanates have little toxicity toward several oral and skin bacteria species, but do suppress mammalian cell metabolism in a cells-pecific manner. Titanate compounds bind several types of metal ions, including some common environmental toxins, and enhance delivery to bacteria or cells. Substantial work remains to address the practical applicability of titanates. Nevertheless, titanates have promise to serve as novel vehicles for metal-based therapeutics or as a new class of metal scavengers for environmental applications.

MATHEMATICAL MODELING OF LEACHING PROCESS OF RED MUD IN ORDER TO OBTAIN THE KINETICS PARAMETERS

The use of the waste of the Bayer process, red mud, is due to its chemical and mineralogical composition that shows a material rich in oxides of iron, titanium and aluminum. Some studies conducted show that this waste can be applied as a source of alternative raw material for concentration and subsequent recovery of titanium compounds from an iron leaching process, which is present in higher amounts, about 30% by weight. To obtain a greater understanding about the leaching kinetics, the information of the kinetic data of this process is very important. In this context, the main objective of this work is the development of a mathematical model that is able to fit the experimental data (conversion / extraction iron, titanium and aluminum) of the leaching process by which is possible to obtain the main kinetic parameters such as the activation energy and the velocity of chemical reactions as well as the controlling step of the process. The development of the mathematical model was based on the model of core decreasing. The obtained model system of ordinary differential equations was able to fit the experimental data obtained from the leaching process, enabling the determination of the controlling step, the rate constants and the activation energies of the leaching process.

The Structure and Protective Properties of Complex Chromium, Ti-tanium, Aluminum Based Diffusion Coatings on U8A Steel

Background. Modern materials work under stringent conditions of simultaneous action of high production speeds, high temperatures, aggressive environments, and therefore the materials they are made of must have an integrated protective properties: to combine wear resistance, high crack resistance, chemical stability at elevated temperatures, high corrosion resistance. Despite the large number of known types of coatings and their methods of obtaining scientific aspects of creation of coatings with a wide range of protective properties is not sufficiently developed.Objective. Study of phase and chemical compositions, structure and protective properties of coatings on U8A steel, obtained by combining of diffusion chromium plating with the subsequent titanium aluminizing.Methods. The coating was applied on the surface of the U8A steel. On the first stage, the gas plating at a temperature of 1050 °C for 4 hours was carried out. On the second stage titanium aluminizing of powder coat at a temperature of 1050 °C for 4 hours was carried out. X-ray diffraction, electron-probe, metallographic, durometric studies were conducted using known methods of physical materials science. Corrosion tests by gasometrical method were carried out.Results. It is shown that as a result of saturation on the steel surface a multilayer coating is formed consisting of carbides of chromium, titanium, intermetallic compounds of titanium, aluminum, chromium. It has been established that the microhardness of multilayer coatings based on chromium carbides, titanium carbides, intermetallic metals is 5.8–34.0 GPA. It is shown that the application of complex coatings based on chromium, titanium, aluminum increases the resistance of U8A steel in many aggressive environments.Conclusions. Complex chromium, titanium, aluminum saturation of U8A steel allows obtaining coatings with a total width of 27.5–30.5 µm, which ensures high corrosion resistance in various industrially important aqueous corrosive solutions.

Production of intense metal ion beams from ECR ion sources using the MIVOC method

The production of metal ion beams by electron cyclotron resonance (ECR) ion sources using the MIVOC (Metal Ions from Volatile Compounds) method is described. The method is based on the use of metal compounds which have high vapor pressure at room temperature, e.g., C2B10H12, Fe(C5H5)2, etc. Intense ion beams of B and Fe were produced using this method at the FLNR JINR cyclotrons. Experiments on the production of cobalt, chromium, vanadium, germanium, and hafnium ion beams were performed at the test bench of ECR ion sources. Main efforts were put into production and acceleration of 50Ti ion beams at the U-400 cyclotron. The experiments on the production of 50Ti ion beams were performed at the test bench using natural and enriched compounds of titanium (CH3)5C5Ti(CH3)3. In these experiments, 80 μA 48Ti5+ and 70 μA 48Ti11+ beam currents were obtained at different settings of the source. Following successful tests, two 3-week runs were performed with 50Ti beams at the U-400 cyclotron aimed to perform experiments on the spectroscopy of superheavy elements. The intensity of the injected 50Ti5+ beam was 50–60 μA. The source worked stably during experiments. The compound consumption rate was determined at about 2.4 mg/h, which corresponded to the 50Ti consumption of 0.6 mg/h.

Spectroscopic characterization of some new coordination compounds of titanium(IV) with Schiff bases of amino acids

Spectroscopic characterization of some new coordination compounds of titanium(IV) with Schiff bases of amino acids

Coordination compounds of titanium (IV) and 2-hydroxymethyl-phenol derivatives: Their synthesis, structure and catalytic activity in ethylene and 1-hexene polymerization

A series of titanium complexes LTiCl2·(iPrOH)212-18 and heterobimetallic complex L2Ti·iPrOLi·THF 19 bearing saligenin-type [O,O]2- ligands 6-11 were synthesized in high yields from Cl2Ti(OiPr)2 or LiTi(OiPr)5. X-ray structure analyses for 15 and 19 revealed that these complexes adopt a distorted octahedron or distorted tetragonal pyramid geometry. When activated by binary activator {3Et2AlCl + Bu2Mg}, complexes 12-19 exhibited moderate to high activities toward ethylene and 1-hexene polymerization, giving high molecular weight polymers with broad molecular weight distributions. The results of this study show the unique ability of Li and Mg chlorides to improve the catalytic ability of post-metallocene pre-catalysts.

Thermo-stable carbon nanotube-TiO2 nanocompsite as electron highways in dye-sensitized solar cell produced by bio-nano-process

We produced a thermostable TiO2-(anatase)-coated multi-walled-carbon-nanotube (MWNT) nanocomposite for use in dye-sensitized solar cells (DSSCs) using biological supuramolecules as catalysts. We synthesized two different sizes of iron oxide nanoparticles (NPs) and arrayed the NPs on a silicon substrate utilizing two kinds of genetically modified cage-shaped proteins with silicon-binding peptide aptamers on their outer surfaces. Chemical vapor deposition (CVD) with the vapor–liquid-solid phase (VLS) method was applied to the substrate, and thermostable MWNTs with a diameter of 6 ± 1 nm were produced. Using a genetically modified cage-shaped protein with carbon-nanomaterials binding and Ti-mineralizing peptides as a catalyst, we were able to mineralize a titanium compound around the surface of the MWNT. The products were sintered, and thin TiO2-layer-coated MWNTs nanocomoposites were successfully produced. Addition of a 0.2 wt% TiO2-coated MWNT nanocomposite to a DSSC photoelectrode improved current density by 11% and decreased electric resistance by 20% compared to MWNT-free reference DSSCs. These results indicate that a nanoscale TiO2-layer-coated thermostable MWNT structure produced by our mutant proteins works as a superior electron transfer highway within TiO2 photoelectrodes.

Investigation into Compacting the Nanopowders and Micropowders of Tungsten Carbide in a High-Pressure Apparatus

The results of the investigation into compacting (sintering) in high-pressure apparatus of the DO-138 model of nanopowders and micropowders of silicon carbide are presented. Compacting modes for both types of materials were identical (pressure of 3.5–4.0 GPa, temperature of 1600–1700 °C, and holding time of 10 s). The influence of cladding the SiC nanopowders and micropowders with titanium and titanium nitride on the properties of compacts (cakes) fabricated in the same sintering modes is also considered. It is established that when compacting the silicon carbide nanopowder, the formed cakes differ by the higher density, hardness, and lower porosity compared with the samples of finely dispersed silicon carbide of technical grade. High activity of titanium with respect to SiC allows one to bond chemically the grains of the latter due to the formation of intermediate layers of titanium compounds between them. This is resulted in that the formed ceramics possesses high density, hardness, and wear resistance. Wear resistance of synthesized composites based on nano-SiC is higher by a factor of 4.5 than that one of polycrystalline material made of silicon carbide micropowder.

High-Temperatures Rheometric Analysis Of Selected Heterogeneous Slag Systems

Abstract It is known that the dynamic viscosity coefficient of slag – with an increased titanium compounds content in the reducing conditions of the blast furnace - may rapidly change. The products of the reduction reaction, precipitation and separation of titanium compounds are responsible for the thickening effect of the slag and the problems of permeability of blast furnace, causing anomalies in the dipping zone. The presence of solid components (particles) in the melts determines the rheological character of the entire system. Identifying the rheological character of semi-solid slag systems provides opportunities for the development of mathematical modeling of liquid phase flows in a dripping zone of the blast furnace, allowing e.g to indentify the unstable parts of a metallurgical aggregate. Author have performed study of synthetic aluminosilicates slag concentration of TiO2 in the range up to 30%, systems were doped solids TiN also, it was made in order to assess the impact of the type forming areas/units of the SRO nature on the rheological identification mentioned systems. The high-temp rheometric measurements were performed at temperatures in the range between 1310-1490°C. The obtained results made it possible to carry out the rheological characteristics of analyzed liquid and semi-solid slag systems.

Study of Sintering Polycrystalline and Composite Materials Based on Silicon Carbide in High-Pressure Equipment

Results are provided for a study of sintering and some properties of new SiC-sintered polycrystalline and SiC-composite materials. Materials are prepared by sintering silicon carbide nano- and micropowders in high-pressure equipment. SiC powders are used both in pure form and with titanium compound nanocoatings applied to them.

A Career in Catalysis: John E. Bercaw

On the occasion of Professor John Bercaw’s 70th birthday, we reflect and highlight his distinguished career in organometallic chemistry and homogeneous catalysis. What began as a fundamental interest in the chemistry of bis(cyclopentadienyl)titanium compounds and their interaction with molecular nitrogen evolved into a vibrant and diverse program tackling some of the most important problems in catalysis. Using well-defined organometallic compounds, fundamental insights were gained in the mechanism of CO reduction; basic transformations of organometallic chemistry, such as alkene insertion and alkyl β-hydrogen elimination; the origin of stereocontrol in metallocene-catalyzed polymerization; and in the activation of hydrocarbons by electrophilic late transition metals.

Composition, structure, and properties of SHS-compacted cathodes of the Ti–C–Al–Si system and vacuum-arc coatings produced from them

The phase composition, structure and properties of SHS-compacted materials of the Ti-C-Al-Si system have been investigated. It is shown that metal- like titanium compounds can be used as cathodes of vacuum-arc evaporators. The coatings obtained from SHS-cathodes are of single-phase and re- present cubic titanium nitride of the (Ti, Al, Si) N composition. Their microdrop phase volume is 2,5-3,0 times lesser compared with TiN, and their micro- structure is not fragmented into low-strength columnar elements; the body-centered cubic lattice size is two times lesser than that of titanium nitride. Approximately given equal hardness and at the cost of lower elastic modulus, (Ti, Al, Si) N coatings essentially exceed TiN coatings in durability to elas- tic failure strain and plastic resistance. When milling tungsten-copper alloy, the lifetime of (Ti, Al, Si)N coated carbide cutters is 2,4 times more than that of cutters with TiN coating produced from titanium cathode with magnetic separation of plasma flow.

Numerical Analysis of Titanium Compounds in Blast Furnace Hearth During Titania Addition

The longevity of an iron making blast furnace is largely limited by the erosion of hearth refractory. The addition of titanium (Ti)‐bearing materials into the furnace may promote so‐called Ti‐rich scaffolds along the damaged hearth lining. A Computational Fluid Dynamics model is used to investigate the complex transport phenomena associated with the formation and dissolution of solid particles. Based on the modeling results, the isotherm of the equilibrium temperature of the incoming hot metal solution can be used as an indicator for the extent and phase of Ti compounds. It is proposed that the particles can be managed by controlling the location of this isotherm. This can be conducted by either (a) altering the Ti dosage and concentration or (b) altering the hot metal pool temperature. The effects of these parameters on the solids holdup along the hearth refractory linings are investigated. The equilibrium isotherm concept may provide a more suitable way to control the location of Ti‐based particles for furnace operators.

Possible connection between nodule development and presence of niobium and/or titanium during short time thermal oxidation of AISI 441 stainless steel in wet atmosphere

AISI 441 ferritic stainless steel is a good candidate for metallic interconnects of solid oxide fuel cells (SOFCs). In this alloy, the minor elements Ti and Nb are used to stabilise the ferritic structure but their influence on steel durability is not well understood. This study focuses on the early stages of oxidation (24 h) at 800°C of AISI 441 under 5%H2O in O2 following the cathodic SOFCs conditions. The typical duplex oxide scale, composed of a (Mn,Cr)3O4 spinel top layer and a Cr2O3 rich sublayer is observed, with oxide nodules growing in places. These objects, in the micrometre range in size, are studied by FIB tomography. The analyses reveal a complex structure and a development strongly linked to the presence of niobium and/or titanium compound(s) in the subjacent substrate.

Titanium compounds and their impact on the transformation of air pollutants

Titanium as transition metal is demonstrating the high mechanical strength, is light and corrosion resistant. The estimation of environmental impact of use of machine parts thats grains are freed from contact surface of titanium alloys by wear is buffling. Due to its catalytic action TiO 2 is nowadays added to: asphalt, concrete, exterior paints for elevation, self-cleaning glass and protective coatings. It is also present by clothes, food (E171), cosmetics (CI 77891) and textiles. The research on toxicity of titanium and its compounds is pointing at their neutral character, however an adverse impact is also being observed by nature. TiO 2 may affect air quality – it promotes free radicals and ozone origination. Properties and directions of titanium compounds use and their influence on pollutants circulation were described.

Thermodynamic model of high-temperature synthesis of oxygen-free titanium compounds from titanium tetrachloride

Thermodynamic model of high-temperature synthesis of oxygen-free titanium compounds from titanium tetrachloride

A Precipitation Phenomenon of Titanium Compounds in Aluminum Melts and the Refinement Fading Mechanism of the Al-5Ti-0.62C Master Alloy

The Al-5Ti-0.62C master alloy was prepared through a method of thermal explosion in molten aluminum. The process of remelting and refining of commercially pure aluminum was conducted, and precipitation samples with different heat-treatment times were obtained. Scanning electron microscopy (SEM), X-ray diffraction (XRD), optical microscopy (OM), and other techniques were used to analyze the microstructure of the precipitates at the bottom of the samples so as to explore the fading mechanism of Al-Ti-C alloy refinement. The results showed that an obvious precipitation phenomenon of titanium compounds existed in the remelted Al-5Ti-0.62C master alloy and that there were both TiC compounds and TiAl3compounds in the precipitates; in the refined pure aluminum samples, the precipitates were mainly TiC compounds. Precipitation of titanium compounds in aluminum melting is the main cause of fading in the refinement effect of an Al-Ti-C master alloy.