Titanium Pellets Research Articles

An optimized process of drying titanium pellets in a tunnel kiln

This paper examines the problem of modelling the titanium pellets drying process with the aim to find an optimum processing mode. For this, a mathematical operator was built that can translate the starting representation point in the parameter space into the end point along a given path. The key regularities of the titanium pellets drying process were examined, and conditions — defined that would allow to minimize the moisture content in the product over a time period specified in the statement of work avoiding consuming more power. A mathematical and computer models were developed to optimize the process of drying a flowing dense multi-layered mass of titanium pellets. These models helped optimize the energy and resource efficiency of this complex dynamic thermal process. The obtained results were applied when calculating a pellets drying process that would be energy efficient in a tunnel kiln. It was found that the optimum multi-layer drying mode is associated with a reduced energy consumption, a higher quality of the final product, and a lower return rate. This resulted in a minimum moisture content in titanium pellets reached in the time period as specified in the statement of work, with no need for additional power.

Bone-Miniscrew Contact and Surface Element Deposition on Orthodontic Miniscrews After Ultraviolet Photofunctionalization.

The aim of this study was to evaluate the effect of ultraviolet (UV) photofunctionalization on peri-implant osteogenesis of miniscrews. Titanium orthodontic miniscrews were placed in the maxillary premolar-molar region of 17 patients undergoing fixed orthodontic treatment. This was a split-mouth study wherein the miniscrews on one side were treated with UV photofunctionalization and those on the other side were left untreated. Photofunctionalization was performed by placing the miniscrews in a chamber consisting of UV-A and UV-C lights for 15 minutes immediately prior to implantation. Efficacy of the UV chamber was assessed by examining stereomicroscopic images of a 10-μL droplet of double-distilled water placed on a UV-treated titanium pellet. Retrieved miniscrews were evaluated for bone-miniscrew contact (BMSC) using scanning electron microscopy (SEM) based on a custom-devised 4-point objective scoring system. Surface element deposition of miniscrews was estimated using energy-dispersive x-ray spectrometry (EDX). Ratios of Ca/Ti and Ca/P were calculated for upper, middle, and lower regions of all miniscrews. Increased spread of the water droplet over the UV-treated pellet showed that photofunctionalization converted the titanium surface from hydrophobic to superhydrophilic. SEM imaging revealed that BMSC was greater in the photofunctionalized group, but only in the lower third of miniscrews, and this was not statistically significant. EDX analysis revealed that Ca/Ti and Ca/P ratios in both groups were similar. Thus, there was no significant difference between peri-implant osteogenesis of UV-treated and untreated miniscrews. These results suggest that UV photofunctionalization did not enhance the biologic potential of titanium orthodontic miniscrews in clinical application.

Metallurgical properties and furnace protection practice of different titanium-bearing burdens

ABSTRACT The excellent properties of titanium pellet Z in the blast furnace hearth protection were determined by studying the composition, metallurgical properties and a over four years period of application practice of titanium-containing pellets(C&Z) and ores (J, G&D) in a domestic blast furnace. The reduction and softening-melting properties of titanium pellet Z were better than those of titanium lump ore G, D and J, and titanium pellet C. Under the condition of a titanium load of 7–8 kg TiO2/tHM, the fuel rate, pressure drop and slag ratio of the blast furnace using titanium pellet Z were better than that for the titanium-bearing resources. Using pellet Z had an obvious effect on the decrease of the hearth temperature and sustained stability. It was concluded that pellet Z was an excellent titanium-bearing burden for both laboratory research and industrial trial.

Preparing high-strength titanium pellets for ironmaking as furnace protector: Optimum route for ilmenite oxidation and consolidation

High-quality titanium pellets were prepared through applying the optimum path for ilmenite oxidization and consolidation in present investigation. The elucidated oxidization behaviors of ilmenite indicated that Fe2O3 and Fe2Ti3O9 were formed below 800 °C, and the process was controlled by interface chemical reactions. At 825 °C, Fe2O3 became the mainly formed mineral, while it could combine with TiO2 to form Fe2TiO5 if the oxidizing time was long enough. Increasing the temperature further considerably enhanced the percentage of Fe2TiO5. The effects of minerals formed during oxidation process on pellets consolidation indicated that the recrystallization of Fe2O3 in subsequent roasting process improved the mechanical strength of pellets, while Fe2TiO5 impaired pellets consolidation. The revealed optimum route was to improve the formation, enrichment and recrystallization of Fe2O3 at particle edge, and the recommended preheating parameters were 825 °C and 34 min, respectively. The strength of roasted pellets reached 2169 N/P (Newton per pellet), which can be used as the protector for blast furnace.

Reduction kinetics and mechanism of pellets prepared from high chromium vanadium–titanium magnetite concentrate

High chromium vanadium–titanium magnetite has not been exploited and made full use of on a large scale so far due to the immature utilisation technology and the reality that the utilisation efficiency of valuable metals still urgently needs to be improved. In the present paper, the isothermal reduction kinetics and mechanism of high chromium vanadium–titanium pellets were studied at 800–1100°C. The microstructures were examined by a SEM equipped with EDX capabilities to reveal the elemental distributions. The effect of reduction temperature on the volumetric swelling degree and cold crushing strength was also studied. It was found that reduction temperature has a large effect on the reduction rate of pellets, and the increase in reduction rate is more obvious in the range 1000–1100°C than 800–1000°C. The volumetric swelling degree of pellets increased with increasing reduction temperature, while the cold crushing strength decreased. The apparent activation energy of the reduction reaction was calculated to be 44.3 kJ mol−1, and the reduction rate is controlled by the combined effect of interfacial chemical reaction and gas diffusion through the porous product layer. The rate controlling steps were further studied by calculating the resistance percentages. The interfacial chemical reaction was found to be predominant in the initial reduction stage, with the percentage effect of gas diffusion through the porous product layer gradually increasing during reduction.

Study of the Antibacterial Activity by using Titanium Dioxide Nanoparticles

The study was the effectiveness of the microbial activity by using titanium dioxide nanoparticles which are prepared by using laser ablation of titanium pellet immersed in de-ionzed water. Palsed Nd: YAG laser with 1064nm wavelength and laser energy 250 mJ was used to irradiate the target for ablation time 15 min, 200 pulses. Where studied synthetic characteristics of the sample prepared using the X-ray diffraction pattern of nanoparticles proved the presence Alatanas planes. A scanning electron microscope measurement appearance Tio2 nanoparticle of structures with cube shapes , while the results of Zeta potential was the values being equal to (34) are located within the range of suspension potential Stability. The results of antimicrobial activity of Tio2 nanoparticle against bacterial stratin S.aureus, C .albicans, and E.coli with antibiotic at concentration .1000 mg/ml (AMC, DO10 and CN10) using well diffusion assay showed. The best concentration of 1000 mg /ml of antibiotics give us with dioxide nanoparticles to inhibition bacterial growth .The results showed that the nanoparticles with antibiotics inhibition the growth of S.aureus then C.albicans which is more sensitive than E.coli .Our results showed that dioxide nanoparticles have synergistic effect with (CN10& DO10) .And there is no any synergistic effect with (AMC).

The role of the domain size and titanium dopant in nanocrystalline hematite thin films for water photolysis.

Here we develop a novel technique for preparing high quality Ti-doped hematite thin films for photoelectrochemical (PEC) water splitting, through sputtering deposition of metallic iron films from an iron target embedded with titanium (dopants) pellets, followed by a thermal oxidation step that turns the metal films into doped hematite. It is found that the hematite domain size can be tuned from ∼10 nm to over 100 nm by adjusting the sputtering atmosphere from more oxidative to mostly inert. The better crystallinity at a larger domain size ensures excellent PEC water splitting performance, leading to record high photocurrent from pure planar hematite thin films on FTO substrates. Titanium doping further enhances the PEC performance of hematite photoanodes. The photocurrent is improved by 50%, with a titanium dopant concentration as low as 0.5 atom%. It is also found that the role of the titanium dopant in improving the PEC performance is not apparently related to the films' electrical conductivity which had been widely believed, but is more likely due to the passivation of surface defects by the titanium dopants.

New potential for preparation of performing h-BN coatings via polymer pyrolysis in RTA furnace

Abstract An innovative IR irradiation annealing process is used to increase the crystallization ratio of hexagonal boron nitride (h-BN) coatings on pure titanium pellets. Since the polymer pyrolysis route requires heating the green polymer at high temperature to convert it into a ceramic, the use of IR radiation furnace (compared to a resistive furnace) allows achievement of better crystallized h-BN while the substrate remains at relatively low temperature (

O-(2-[18F]fluoroethyl)-L-tyrosine PET combined with MRI improves the diagnostic assessment of cerebral gliomas

MRI is commonly used to determine the location and extent of cerebral gliomas. We investigated whether the diagnostic accuracy of MRI could be improved by the additional use of PET with the amino acid O-(2-[18F]fluoroethyl)-l-tyrosine (FET). In a prospective study, PET with FET and MRI was performed in 31 patients with suspected cerebral gliomas. PET and MRIs were co-registered and 52 neuronavigated tissue biopsies were taken from lesions with both abnormal MRI signal and increased FET uptake (match), as well as from areas with abnormal MR signal but normal FET uptake or vice versa (mismatch). Biopsy sites were labelled by intracerebral titanium pellets. The diagnostic performance for the identification of cellular tumour tissue was analysed for either MRI alone or MRI combined with FET PET using alternative free response receiver operating characteristic curves (ROCs). Histologically, 26 biopsy samples corresponded to cellular glioma tissue and 26 to peritumoral brain tissue. The diagnostic performance, as determined by the area under the ROC curve (Az), was Az = 0.80 for MRI alone and Az = 0.98 for the combined MRI and FET PET approach (P < 0.001). MRI yielded a sensitivity of 96% for the detection of tumour tissue but a specificity of only 53%, and combined use of MRI and FET PET yielded a sensitivity of 93% and a specificity of 94%. Combined use of MRI and FET PET in patients with cerebral gliomas significantly improves the identification of cellular glioma tissue and allows definite histological tumour diagnosis. Thus, our findings may have considerable impact on target selection for diagnostic biopsies as well as therapy planning.

Titanium-dioxide film formation using gas cluster ion beam assisted deposition technique

Gas cluster ion beam (GCIB) assisted deposition technique has been applied to form titanium-dioxide films. When oxygen cluster ions collide on solid surfaces, oxygen molecules in the clusters enhance oxidation due to high density energy deposition. Metal titanium pellets were used as source material for EB evaporation, because evaporation with metal pellets is much stable than that of oxide pellets. Films were deposited on sapphire (0 0 0 1) substrates with various conditions. Characteristics of the films were examined by use of XRD, RBS and AFM. When film was deposited with the acceleration voltage of 7 kV at 473 K, the well c-oriented rutile TiO 2 film was formed with average roughness of 0.4 nm. Without assistance of GCIB rough amorphous film was formed in an atmosphere of oxygen. Very smooth surface films with good crystallinity were formed by GCIB assisted deposition technique.

Mathematical model of reaction between titanium pellet and nitrogen

The reaction between titanium pellet and nitrogen was investigated, under a regime in which both chemical reaction and gas pore diffusion were important, and on the basis of this study a physicochemical model was formulated to describe the reaction system. T he chemical reaction rate expressions, determined in the chemical reaction control region, were used to interpret the experimental data in the light of the model. T he expression for effective gas diffusivity De, which was used as a fitting parameter for calculation of the theoretical predictions, was determined to be 1·37 × 10 - 5 exp(-13000/RT) m2 s - 1. Deviation was found between the predictions of the model and the experimental data as the pellet thickness was increased. This is explained by the geometrical difference between the mathematical model, with flat surfaces only, and the actual pellet with both flat and circumferential surfaces. A geometrical factor g was introduced to compensate for this difference, the value of which was calculated to be 1/( 1 + 11·47L), where L is the half thickness of the sample.

A Novel Method of X-Ray Diffraction to Analyze Paritally Nitrided Titanium Pellet

The purpose of this paper is to introduce a new X-ray diffraction (XRD) method. Using this new analysis method, the component of partially nitrided titanium pellet for different positions in the direction of pellet thickness can be determined and the reaction model for the nitridation of titanium pellet can be predicted.

Morphological Study on Direct Nitridation of Titanium Pellet.

Dissections of solid samples partially reacted under different conditions were examined to determine the control region of the reaction between titanium pellet and nitrogen gas. The thickness of the pellet studied was varied from 0.0012 to 0.00638 m while temperature was varied from 1, 173 to 1, 473 K. Experimental results indicate that the system is in the chemical reaction control region as the pellet thickness is 0.0012 m for all temperatures studied. The system is in the gas-pore-diffusion control region when the thickness is 0.00638 m and the temperature is 1, 373 or 1, 473 K. For other cases, the system is in both control region.

Preparation and Electrical Properties of Rhombohedral Pb(ZrxTi1-x)O3 Thin Films by RF Magnetron Sputtering Method

Rhombohedral lead zirconate titanate (PZT) thin films with a thickness of 0.3–1.2 µm were successfully grown on (111)Pb(La,Ti)O3/Pt/Ti/SiO2/Si and (111)Ir/SiO2/Si substrates by an RF magnetron sputtering method using a multi-target consisting of calcinated PbO and metal titanium pellets on a zirconium metal plate. The composition of the films could be controlled by adjusting the area ratio of PbO/Zr/Ti. The crystal structures of the films were sensitive to the area of PbO and the substrate temperature. The pyroelectric current, relative dielectric constant, Curie temperature, remanent polarization (Pr) and coercive field dependence on the Zr content of the films are described. The pyroelectric coefficient of the as-prepared PZT films showed a peak from 94°C [for Pb(Zr0.91Ti0.09)O3] to 36°C [for Pb(Zr0.97Ti0.03)O3], which corresponded to the phase transition from the low-temperature to high-temperature rhombohedral ferroelectric phase. The fatigue characteristic was also measured using a double bipolar pulse. The PZT films preserved an initial switching charge value over a switching cycle of 1012.

Preparation of Titanium Nitride from Direct Nitridation of Titanium.

The reaction between titanium pellet and flowing nitrogen under 1 atm over the temperature range 973 to 1373 K was investigated by thermogravimetric analysis system, scanning electron microscope and X-ray diffractometer. α-Ti → TiN0.3 → TiN0.5 → TiN was found to be the sequence of transformation of solid sample. Experimental results indicated that the reaction rate could be increased by increasing the gas flow rate, nitrogen concentration or reaction temperature. The rate was also found to be increased by decreasing the thickness of titanium pellet. The smaller the titanium grain, the faster the reaction. The effect of forming pressure of pellet on the reaction rate was found to be insignificant. Effects of additives such as Al, B, Fe, Si, TiN and Y2O3 were found to be negative on the reaction rate. Empirical expression of conversion of titanium has been determined.

Synthesis of titanium nitride by a spark-discharge method in liquid ammonia

Titanium nitride powders were synthesized by the spark-discharge method in liquid ammonia at — 78 to 130 °C and 3.5–10.5 kV discharge voltage using titanium pellets as the starting materials. Titanium nitride possessing nitrogen defect, TiN1−x(x≃0.5), was obtained as the main product, together with small amounts of α-Ti alloyed with nitrogen. The increase in temperature of the liquid ammonia resulted in an increase in the titanium nitride content in the product but a decrease in the powder production rate. By calcining the mixed powders of TiN1−xand α-Ti in a nitrogen atmosphere around 1200 °C, stoichiometric TiN was obtained as single phase.

Reaction-bonded titanium nitride ceramics

Reaction-bonded titanium nitride (RBTN) ceramics were formed using high surface area titanium powder (surface area 20 m 2 g −1), and nitrogen gas as precursor reactants. The titanium precursor was made by the combustion synthesis technique. 1 Owing to their microstructure and internal porosity, the metal particles are highly reactive towards nitrogen, and can be fully converted to the mononitride at comparatively low temperatures and short reaction times. Nitridation kinetics of these powders were determined at temperatures of up to 1000 °C by means of insitu gravimetry. Dry-pressed binderless porous titanium pellets were heat-treated in pure nitrogen at temperatures of up to 1000 °C, and fully converted to the porous TiN compacts with dimensional changes less than 5%. A reaction mechanism is proposed. The difference between the relative density of the final product and the packing density of the green body was negligibly small, but there is a considerable increase in the gas permeability and mechanical strength during nitridation. The porous end product is a suitable matrix for further applications and for making composites by infiltration deposition.

A Low Temperature CVD Process for TiN Coatings

AbstractA novel low temperature process for the chemical vapour deposition of titanium nitride films has been developed. Titanium sub-halides generated “in situ” by chlorination of titanium pellets are subsequently reacted with ammonia at reduced pressure and temperatures of 450–600° C. The coatings have excellent adhesion and wear resistance. A description of the process and the properties of the coatings produced by it will be presented.

Simultaneous electrochemical removal of copper and chemical oxygen demand using a packed-bed electrode cell

Copper ions and chelating agents in water were treated simultaneously by using a packed-bed electrode cell. The cathode packings were graphite particles or graphite felt; the anode packings were platinum-plated titanium pellets, β-PbO2 particles or oxidized lead spheres. The catholyte contained ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), iminodiacetic acid (IDA) or glycine chelate of copper, while the anolyte contained the corresponding chelating agents. The initial concentration of chelating agents was 0.01 M in each experiment. The electrowinning of copper and the removal of chemical oxygen demand (COD) were achieved in the cathodic and the anodic chamber, respectively, under galvanostatic conditions. The COD was determined by the standard KMnO4 method. Of the cathodic packings, the graphite felt gave better results than the graphite particles because of the large surface area of the felt. Of the anodic packings, the platinum-plated titanium pellets and the β-PbO2 particles showed equal suitability for COD removal. In the case of the platinum-plated titanium pellets, the current efficiency for COD removal of EDTA, NTA and IDA was 1.4, 0.7 and 0.32, respectively, in the range 0–12 kC. The removal of COD for EDTA, NTA and IDA under the same conditions was 41, 36 and 25%, respectively. In the lower pH range the electro-oxidation of EDTA proceeded more efficiently.

Anodic oxidation of coal slurries in flow-through packed bed electrodes

Experimental studies were made to determine the characteristics of anode systems depolarized by coal slurries. The anode was a packed bed of platinum-plated titanium pellets, through which the slurries were recirculated. This flow system increased collisions between coal particles and the anode surfaces so that the anodic oxidation of the coal was enhanced. At the same time, soluble organic compounds and Fe 2+ ions dissolved from the coal were oxidized at the anode, and Fe 3+ was reduced by thermochemical reactions with reducing compounds in the coal; this reduction was important in maintaining the current density in long-term electrolysis.