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Tin
Terms modified by Tin Selected AbstractsOn the effects of triangulated terrain resolution on distributed hydrologic model responseHYDROLOGICAL PROCESSES, Issue 11 2005Enrique R. Vivoni Abstract Distributed hydrologic models based on triangulated irregular networks (TIN) provide a means for computational efficiency in small to large-scale watershed modelling through an adaptive, multiple resolution representation of complex basin topography. Despite previous research with TIN-based hydrology models, the effect of triangulated terrain resolution on basin hydrologic response has received surprisingly little attention. Evaluating the impact of adaptive gridding on hydrologic response is important for determining the level of detail required in a terrain model. In this study, we address the spatial sensitivity of the TIN-based Real-time Integrated Basin Simulator (tRIBS) in order to assess the variability in the basin-averaged and distributed hydrologic response (water balance, runoff mechanisms, surface saturation, groundwater dynamics) with respect to changes in topographic resolution. Prior to hydrologic simulations, we describe the generation of TIN models that effectively capture topographic and hydrographic variability from grid digital elevation models. In addition, we discuss the sampling methods and performance metrics utilized in the spatial aggregation of triangulated terrain models. For a 64 km2 catchment in northeastern Oklahoma, we conduct a multiple resolution validation experiment by utilizing the tRIBS model over a wide range of spatial aggregation levels. Hydrologic performance is assessed as a function of the terrain resolution, with the variability in basin response attributed to variations in the coupled surface,subsurface dynamics. In particular, resolving the near-stream, variable source area is found to be a key determinant of model behaviour as it controls the dynamic saturation pattern and its effect on rainfall partitioning. A relationship between the hydrologic sensitivity to resolution and the spatial aggregation of terrain attributes is presented as an effective means for selecting the model resolution. Finally, the study highlights the important effects of terrain resolution on distributed hydrologic model response and provides insight into the multiple resolution calibration and validation of TIN-based hydrology models. Copyright © 2005 John Wiley & Sons, Ltd. [source] Paclitaxel, ifosfamide, and nedaplatin (TIN) salvage chemotherapy for patients with advanced germ cell tumorsINTERNATIONAL JOURNAL OF UROLOGY, Issue 6 2007Norio Nonomura Background: The paclitaxel, ifosfamide, and cisplatin regimen has been used to treat metastatic testicular cancer with successful results. We investigated the usefulness of a paclitaxel, ifosfamide, and nedaplatin (TIN) regimen as salvage therapy for patients with advanced testicular germ cell tumors (GCTs). Methods: Eight patients with advanced GCTs were treated with TIN. The treatment was performed as salvage therapy for cases refractory to therapies, such as bleomycin, etoposide and cisplatin, and irinotecan with nedaplatin. The TIN regimen consisted of paclitaxel (200 mg/m2) by 24-h infusion on day 1, followed by ifosfamide (1.2 g/m2) infusions over 2 h on days 2,6, and nedaplatin (100 mg/m2) given over 2 h on day 2. Results: Seven out of eight patients achieved a disease-free status after chemotherapy, followed by surgical resection of the residual tumor. Six of the seven patients have continued to show no evidence of disease after salvage therapy, with a median follow-up period of 27 months, but one patient developed a ,growing teratoma syndrome' in the mediastinum 31 months after TIN chemotherapy. All patients developed grade 4 leukocytopenia. However, it could be managed by using granulocyte colony-stimulating factor. Only one patient developed grade 2 sensory neuropathy and no patient developed nephrotoxicity. Conclusion: The TIN regimen was efficacious and well-tolerated as salvage chemotherapy for Japanese patients with advanced GCTs. [source] Clinicopathology of childhood-onset renal systemic lupus erythematosusNEPHROLOGY, Issue 4 2007WASIU A OLOWU SUMMARY: Aims: To determine the clinicolaboratory renal manifestations; glomerular, extra-glomerular histopathologic lesions; renal tubular dysfunction (RTD) frequency and outcome of a short-term renal follow up in Nigerian children with systemic lupus erythematosus (SLE). Methods: A non-randomized prospective study of consecutive cases of childhood-onset SLE with nephropathy was conducted. Baseline/follow-up clinicolaboratory data were collected. Each patient was followed up for 12 months. Results: Seven of the 11 children studied were girls. The median age at diagnosis was 11.0 years. Median diagnosis time interval (1.9 years) and median time of renal disease onset (1.0 year) were similar. Hypertension, nephrotic syndrome and acute renal failure (ARF) occurred in 45.5%, 54.5% and 63.7% of the patients, respectively. The glomerular lesions were non-proliferative lupus nephritis (LN) in 9.0% (class II LN); focal (class III LN) and diffuse (class IV LN) proliferative LN (PLN) in 27.0% and 64.0%, respectively. Tubulointerstitial nephritis (TIN, 91.0%) and RTD (64.0%) were common. ARF (P = 0.033) and RTD (P = 0.015) were significantly associated with severe TIN. Complete renal remission rate at end-point was 71.4%. Relapse and renal survival rates were 14.3% and 86.0%, respectively. RTD was persistent in 43.0%. Conclusion: Renal function disorders, diffuse PLN and extra-glomerular lesions were frequent. Significant association of ARF and RTD with severe TIN in this series suggests the need for early renal tubular function (RTF) assessment in our SLE patients. Deranged RTF may be marker of severe TIN in SLE warranting early confirmatory renal biopsy and aggressive interventional treatment. [source] Use of average value of Langmuir probe characteristic for characterization of pulsed dischargesCONTRIBUTIONS TO PLASMA PHYSICS, Issue 7 2003J. Bla Abstract Based on numerical calculations a new method has been developed, which enables plasma analysis from the average value of the Langmuir probe current measured in pulsed discharge. The application of this method for characterization of a planar reactor used for plasma enhanced chemical vapor deposition of TiN and (TiAl)N hard coatings is described as an example. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Renewable Ceramic (TiN) Ring Electrode in Stripping Voltammetry.ELECTROANALYSIS, Issue 16 2009Determination of Pb(II) Without Removal of Oxygen Abstract Characteristic features of the process of Pb(II) reduction and oxidation at a renewable ceramic ring electrode (RCRE) were studied by stripping voltammetry. The main constituents of the RCRE are: a specially constructed TiN ring electrode, a silver sheet used as silver counter/quasi-reference electrode and a silicon O-ring are fastened together in a polypropylene body. The renovation of this electrode is carried out through mechanical removal of solid contaminants and electrochemical activation in the electrolyte which fills the RCRE body. The optimal measurement conditions, composition of supporting electrolyte and procedures of the electrode activation were selected. The measurements were carried out from nondeaerated solutions. As shown on selected examples, RCRE exhibits good performance in underpotential deposition stripping voltammetry (UPD-SV) applied for the determination of lead(II) in synthetic solutions with and without surfactants and in certified reference materials. The peak current is proportional to the concentration of lead(II) over the range 2×10,9,1×10,7,mol L,1, with a 3, detection limit of 1×10,9,mol L,1 with an accumulation time of 30,s. The obtained results showed good reproducibility, (RSD=2,5%; n=5) and reliability. [source] Evaluation of Thin Film Titanium Nitride Electrodes for Electroanalytical ApplicationsELECTROANALYSIS, Issue 10 2007Carolina Nunes, Kirchner Abstract Titanium nitride is a hard and inert conducting material that has yet not been widely used as electrode material for electroanalytical applications although there are highly developed protocols available to produce well adherent micro and nanostructured electrodes. In this paper the possibilities of using titanium nitride thin films for electroanalytical applications is investigated. Scanning electrochemical microscope (SECM) was used for analysis of the redox kinetics of a selected fast redox couple at thin films of titanium nitride (TiN) in different thicknesses. The investigation was carried out by approaching an amperometric ultramicroelectrode (UME) to the TiN film while the soluble redox couple (ferrocenemethanol/ferrociniummethanol) served as mediator in a SECM configuration. The substrate was biased at a potential so that it rereduces the species being produced at the UME, thus controlling the feedback effect. Normalized current,distance curves were fitted to the theoretical model in order to find the apparent heterogeneous standard rate constant (k°) at the sample. The data are further supported by structural investigation of the TiN films using scanning force microscopy and X-ray photoelectron spectroscopy. It was found that the kinetics are little influenced by prolonged storage in air. The heterogeneous standard rate constants in 2,mM ferrocenemethanol were (0.73±0.05)×10,3,cm s,1 for 20,nm TiN thin layer, (1.5±0.2)×10,3,cm s,1 for 100,nm TiN thin layer and (1.3±0.2)×10,3,cm s,1 for 300,nm TiN thin layer after prolonged storage in air. Oxidative surface treatment (in order to remove organic adsorbates) decreased the kinetics in agreement with a thicker oxide layer on the material. The results suggest that their direct use for amperometric detection of reversible redox systems in particular at miniaturized configurations may be advantageous. [source] Fabrication of Load-Bearing NiTi Scaffolds for Bone Ingrowth by Ni Foam Conversion,ADVANCED ENGINEERING MATERIALS, Issue 7 2010Irena Gotman Highly porous NiTi scaffolds for bone ingrowth were fabricated by reactive conversion (PIRAC) of commercially available Ni foams. These open cell ,trabecular NiTi' scaffolds possess high strength and ductility and exhibit low Ni ion release. PIRAC deposition of a thin titanium nitride (TiN) layer further improves the corrosion characteristics of "trabecular NiTi" and allows for material bioactivation by alkali treatment or biomimetic Ca phosphate deposition. [source] Multifunctional FeCo/TiN Multilayer Thin Films with Combined Magnetic and Protective Properties,ADVANCED ENGINEERING MATERIALS, Issue 12 2009Christian Klever Abstract Coatings with thicknesses ranging from a few nanometer up to several micrometer produced by physical vapor deposition (PVD) processes have been established in engineering technologies since the early 1980s. In particular, magnetron sputtered wear resistance coatings are industrially established and capable to enhance tool lifetimes significantly. However, in cases where optical inspection of a coating in use is not possible, an intrinsic sensor function of the film would be beneficial. Therefore, the development of wear resistant coatings with an integrated sensor functionality based on the insertion of a magnetoelastic ferromagnetic phase is suggested. In combination with appropriate read-out electronics such a film system would be ready for online monitoring of the coatings' actual state (e.g., strain, temperature, volume loss). This paper focuses on the development of wear resistance coatings which simultaneously supply beneficial mechanical properties as well as ferromagnetic properties optimized for online non-contact read-out applications. Multilayer coatings obtained through alternate stacking of magnetron sputtered TiN and FeCo layers with a nominal total thickness of 1000,nm were produced as a model system meeting the above conditions. The bilayer period was varied down to 2.6,nm while the individual layer thickness ratio tTiN/tFeCo was determined by the deposition rates and maintained constant at a value of about 3/1. The films were vacuum annealed ex situ in a static magnetic field subsequent to the deposition. The constitution of the as-deposited and annealed coatings as well as their mechanical (nanohardness, Young's modulus) and magnetic properties (magnetization hysteresis, frequency-dependent permeability) are described. Finally, the suitability of the coatings for the use in remote-interrogable wear sensor applications is briefly discussed. [source] Nanocomposite Hard Coatings: Deposition Issues and Validation of their Mechanical Properties,ADVANCED ENGINEERING MATERIALS, Issue 5 2005P. Schwaller Abstract The limitations of conventional coatings due to inferior hardness or poor oxidation stability can be overcome by nanocomposite hard coatings such as nc-TiN/a-SiNx, which consists of nanocrystalline TiN and a non-crystalline tissue phase of SiNx which are mutually immiscible. The properties of nanocomposite coatings, especially their increased hardness, can be explained by their nanostructure, which leads to a maximum hardness at typically 80 atomic percent of the crystalline phase. We show that enhanced hardness can only be attained when the silicon nitride phase is sufficiently nitrided. The accurate and reliable measurement of the hardness and elastic modulus requires the use of appropriate nanoindentation equipment and a careful tip correction with periodical validation. It is shown that for a correct hardness determination of a few microns thick nanocomposite coatings, an indentation depth of 100,nm is sufficient. The maximum hardness of our nc-TiN/a-SiNx coatings deposited by a hybrid UBM/arc-PVD process is about 40,GPa. This value represents a global hardness value, due to the nanocomposite structure there may be a local hardness variation of about ±10,%. [source] Nanostructured Titanium Oxynitride Porous Thin Films as Efficient Visible-Active Photocatalysts,ADVANCED FUNCTIONAL MATERIALS, Issue 16 2007E. Martínez-Ferrero Abstract Nanocrystalline mesoporous N-doped titania films have been prepared for the first time. The introduction of nitrogen into the anatase structure starts at 500,°C, with N bonding to titanium via oxygen substitution. Increasing the treatment temperature leads to the formation of TiN (TiN1,xOx) and N-doped rutile showing mixed-valence Ti states. Microstructural characterization shows that the ordered mesoporosity is maintained until 700,°C, where TiN (TiN1,xOx) begins to form. Optical characterization shows that the discrete introduction of N is able to shift the titania absorption edge. The photocatalytic tests give the best results under visible light excitation for the film nitrided at 500,°C. At this temperature the concentration of nitrogen in the structure is optimal since oxygen vacancies are still not important enough to promote the recombination of the photogenerated electrons and holes. [source] A Chemical Solution Approach to Epitaxial Metal Nitride Thin Films,ADVANCED MATERIALS, Issue 2 2009Hongmei Luo Epitaxial metal nitride films are prepared using a general chemical solution approach. A polymer-assisted deposition to prepare epitaxial cubic TiN, metastable AlN, and ternary nitride Ti1,xAlxN films is demonstrated. The structural, optical and electrical properties of the films are investigated, and may be of interest for many technological applications. [source] Rapid determination of stress factors and absolute residual stresses in thin filmsJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 6 2006E. Eiper A methodology is presented that allows the determination of experimental stress factors in thin films on the basis of static diffraction measurements. The approach relies on the characterization of thin films deposited on a monocrystalline substrate serving as a mechanical sensor. Rocking-curve measurements of the symmetrical reflections of the substrate are used to determine the substrate curvature and subsequently the macroscopic stress imposed on the film. The elastic strain in the film is determined by lattice-spacing measurement at different sample tilt angles. The calculated experimental stress factors are applied to thin films deposited on other types of substrates and are used to determine the absolute magnitude of the residual stress. The approach is applied to nanocrystalline TiN and CrN thin films deposited on Si(100) and steel substrates, characterized using a laboratory-type ,/, goniometer. [source] A theoretical study on the structures and energetics of hypothetical TiM(NCN)3 compounds of the 3d transition metalsJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 11 2005Maxence Launay Abstract Quasi-ternary cyanamides and carbodiimides of general formula AB(NCN)3 with A , B have neither been predicted nor synthesized. Thus, hypothetical compounds of that kind containing 3d transition metals were considered (A = Ti, B = Mn, Fe, Co, Ni, Cu) by means of density-functional calculations on 34 structural models, most of which were derived from chemically related phases. After performing structure optimizations based on the local-density approximation, the relative energetic orderings are rationalized in terms of geometrical factors such as molar volumes and polyhedral connections. Total-energy generalized-gradient calculations evidence that the most stable models are enthalpically favored with respect to the elements. Even at ambient temperatures, the ternary phases are predicted as being thermodynamically stable in terms of their Gibbs free formation energies, especially if energetically competing and low-lying binaries (TiC, TiN) can be excluded by a kinetic reaction control. The best models are characterized by low-spin magnetic transition metals found in octahedral coordination, and the TiN6 and MN6 polyhedra either share faces or edges. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 1180,1188, 2005 [source] Abrasion resistance of titanium nitride coatings formed on titanium by ion-beam-assisted depositionJOURNAL OF ORAL REHABILITATION, Issue 2 2005T. SAWASE summary, To improve the physical properties of the pure titanium surface, thin titanium nitride (TiN) films were deposited by means of ion-beam-assisted deposition. Film structure was confirmed as TiN by X-ray diffraction analysis. Surface hardness and abrasion resistance were significantly improved on TiN-coated specimens. Five combinations of oral hygiene instruments and materials were applied to the specimens as simulations of the oral environment. Treatment with the metal scaler and ultrasonic scaler severely changed the surface features and significantly increased the surface roughness parameters on pure titanium controls, whereas only small scratches and dull undulations were seen on the TiN-coated specimens. Profilometric tracings and scanning electron micrographs demonstrated the improved abrasion resistance of the TiN-coated specimens. [source] Titanium Silicon Carbide Pest Induced by NitridationJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 2 2008Haibin Zhang The thermal stability of bulk Ti3SiC2 in high-purity nitrogen was investigated. It was surprising to observe that Ti3SiC2 underwent rapid and catastrophic disintegration above 1300°C, although this material was thermally stable below this temperature. This degradation was unexpected and extremely serious, and has been termed "Ti3SiC2 pest." This phenomenon was related to the volume change associated with the formation of mixtures of TiCx, Ti(C, N)x, and TiN, which caused internal tensile stresses and cracked the resulting layers. "Ti3SiC2 pest" could be prevented by increasing oxygen partial pressure in nitrogen. [source] Novel Method to Prepare Electroconductive Titanium Nitride,Aluminum Oxide NanocompositesJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 3 2002Jingguo Li A novel method for the preparation of TiN,Al2O3nanocomposites was developed. TiN,Al2O3nanocomposite powders were prepared by the direct nitridation of TiO2,Al2O3nanocomposite powders that were derived from the simultaneous hydrolysis of tetra-butyl titanate and precipitation of aluminum nitrate. Dense sintered bodies of these TiN,Al2O3nanocomposite powders were obtained by hot pressing at 1450°,1650°C and 30 MPa for 60 min. The resistivity of nanocomposite reaches a minimum (1.5 × 10,3,·cm) at 25 vol% TiN additions. The percolation concentration of nanocomposite is ,10 vol% TiN. [source] Synthesis of Dense TiB2 -TiN Nanocrystalline Composites through Mechanical and Field ActivationJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 6 2001Jae Won Lee The synthesis of dense nanometric composites of TiN-TiB2 by mechanical and field activation was investigated. Powder mixtures of Ti, BN, and B were mechanically activated through ball milling. Some powders were milled to reduce crystallite size but to avoid initiating a reaction. In other cases powders were milled and allowed to partially react. All these were subsequently reacted in a spark plasma synthesis (SPS) apparatus. The products were composites with equimolar nitride and boride components with relative densities ranging from 90.1% to 97.2%. Crystallite size analyses using the XRD treatments of Williamson-Hall and Halder-Wagner gave crystallite sizes for the TiN and TiB2 components in the range 38.5,62.5 and 31.2,58.8 nm, respectively. Vickers microhardness measurements (at 2 N force) on the dense samples gave values ranging from 14.8 to 21.8 GPa and fracture toughness determinations (at 20 N) resulted in values ranging from 3.32 to 6.50 MPa·m1/2. [source] Mechanochemical Formation of Metal,Ceramic CompositesJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 1 2000Nicholas J. Welham A mechanical activation technique has been used to form composites of alumina with titanium carbide, nitride, or carbonitride, both with and without elemental iron. The composites were formed by reacting elemental aluminum with either ilmenite (FeTiO3) or rutile (TiO2) concentrates in the presence of carbon and/or nitrogen in a ball-mill at ambient temperature. The reaction was complete for the ilmenite samples after milling but was completed only for rutile under hot pressing conditions. Microhardness measurements indicated that the composites had hardnesses in the range 19,30 GPa (1740,2750 VHN), with only a small variation within each sample. Elemental mapping of the pressed pellets indicated that titanium and aluminum were evenly distributed on a submicrometer level whereas iron tended to coalesce into <20 ,m particles in the presence of TiC. The coalescence decreased with the carbon content of the hard material until iron was evenly distributed with TiN. A superstoichiometric amount of aluminum led to the formation of iron,aluminum phases which decreased the iron coalescence. The XRD crystallite size of the alumina was 30,50 nm and was 25,50 nm for the titanium phases, confirming the extremely fine microstructure. [source] Reciprocative sliding friction and wear properties of electrical discharge machined ZrO2 -based compositesLUBRICATION SCIENCE, Issue 9 2009Koenraad Bonny Abstract Hot-pressed, laboratory-made, ZrO2 -based composites with 40 vol. % WC, TiCN or TiN were surface finished by electrical discharge machining in order to compare their reciprocating sliding friction and wear response against WC,6wt%Co cemented carbide in unlubricated conditions. Sliding experiments were performed using a Plint TE77 pin-on-flat wear test rig, revealing a strong impact of the secondary phase on the tribological behaviour of the ZrO2 -based composites. The worn surfaces and wear debris were characterised by scanning electron microscopy, energy dispersive X-ray analysis and surface topography scanning, pointing out abrasion, polishing and adhesion as main wear mechanisms. The most favourable friction and wear characteristics were encountered with ZrO2,WC composites compared to the other grades with equal amount of volumetric secondary phase. Copyright © 2009 John Wiley & Sons, Ltd. [source] Tribological characterisation of hard coatings with and without DLC top layer in fretting testsLUBRICATION SCIENCE, Issue 1 2006D. KlaffkeArticle first published online: 14 DEC 200 Abstract The potential of coatings to protect components against wear and to reduce friction has led to a large variety of protective coatings. In order to check the success of coating modifications and to find solutions for different purposes, initial tests with laboratory tribometers are usually done to give information about the performance of a coating. Different Ti-based coatings (TiN, Ti(C,N), and TiAlN) and NiP were tested in comparison to coatings with an additional diamond-like carbon (DLC) top coating. Tests were done in laboratory air at room temperature with oscillating sliding (gross slip fretting) with a ball-on-disc arrangement against a ceramic ball (Al2O3). Special attention was paid to possible effects of moisture (relative humidity). The coefficient of friction was measured on line, and the volumetric wear at the disc was determined after the test from microscopic measurements of the wear scar and additional profiles. The friction and wear behaviour is quite different for the different coatings and depends more or less on the relative humidity. The DLC coating on top of the other coatings reduces friction and wear considerably. In normal and in moist air the coefficient of wear of the DLC top-layer coating is significantly less than 10,6,mm3/Nm and the coefficient of friction is below 0.1. In dry air, however, there is a certain tendency to high wear and high friction. Copyright © 2006 John Wiley & Sons, Ltd. [source] Abrasive Wear of DLC/PVD Multilayer Coatings: AFM StudiesLUBRICATION SCIENCE, Issue 3 2004C. Martini Abstract The tribological behaviour of multilayered coatings deposited on plain carbon steel was investigated by microscale abrasion tests (MSATs). The multilayered coatings consisted of an outer diamond-like carbon (DLC) layer, a physical vapour deposition (PVD) nitride-based interlayer, and an inner electroless Ni-P layer. PVD TiN- and Ti(C,N)-coated samples with and without the DLC outer layer were studied in order to evaluate the influence of each layer on the tribological behaviour of the multilayer-coated system. The MSATs were carried out using a device based on ball-cratering geometry: a hard steel sphere was rotated against the coated specimen in the presence of an aqueous suspension of SiC particles. The wear coefficients of the multilayers were calculated from the diameter of the wear craters. The morphology of the wear scars produced by the MSATs was studied by atomic force microscopy (AFM). The wear damage was described by measuring the r.m.s. roughness (Sq) on the sides of the wear craters. Roughness values were related to the wear coefficients (kc) for the different multilayers on the basis of mathematical elaboration typical of the ,design of experiment' (DOE) statistical technique. The presence of the DLC outer layer reduced the roughness of the crater sides and significantly increased the wear resistance of the multilayer only in the case of the PVD TiN sublayer. [source] A method for the tribological testing of thin, hard coatingsLUBRICATION SCIENCE, Issue 2 2002R. Michalczewski Abstract A new method has been developed for tribological testing of thin, hard antiwear coatings, using a ball-on-disc tribosystem, under conditions of dry sliding. In this, an Al2O3 ball is pressed against a coated steel disc. Wear debris is removed from the contact zone by a stream of dry argon in this novel method. This improves the stability of the tribological properties and the repeatability of the test results. All test conditions are precisely defined, in particular: the type of motion, air relative humidity, ambient temperature, sliding speed, load, tribosystem spatial configuration, substrate material, substrate hardness and roughness, and coating thickness. The method developed has been used to test various physical vapour deposition coatings (deposited by the vacuum arc method), i. e., single-layer TiN, Ti(C,N), CrN, and Cr(C,N), and multilayer Cr(C,N)/CrN/Cr and Cr(C,N)/(CrN+Cr2N)/CrN/Cr. It is shown that CrN coatings exhibit the best antiwear properties, and Ti(C,N) the worst. Friction coefficients for CrN and Cr(C,N) coatings are much lower than for the more commonly used TiN. Multilayer coatings have better antiwear properties than single-layer ones. [source] Coating and near-surface modification design strategies for protective and functional surfacesMATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 11 2005M.P. Brady Abstract This paper discusses strategies for controlling the surface chemistry and microstructure of materials to form protective and functional surfaces through controlled gas-metal reactions. Potential applications range from oxidation, corrosion, and wear resistance to electrochemical devices such as fuel cells to catalysts. Phenomenological examples are presented for coatings designed to self-grade under oxidizing conditions, and for the growth of simple and complex (binary and ternary) nitride and carbide phase surface layers by nitridation and carburization reactions. Specific systems discussed include environmental barrier coatings (EBCs) for Si-based ceramics such as Si3N4 and SiC, the growth of continuous, protective CrN/Cr2N, TiN, VN, NiNbVN, and related simple nitride layers on Fe- and Ni-base alloys, the possible formation of ternary nitride and carbide surface phases (e.g. Ti3AlC2 and related MAX-phases) on intermetallic surfaces to improve oxidation resistance, and the formation of composite near-surface structures in Ag-SiO2 and Co(Mo)-Co6Mo6C2 systems. [source] Trace element studies of silicate-rich inclusions in the Guin (UNGR) and Kodaikanal (IIE) iron meteoritesMETEORITICS & PLANETARY SCIENCE, Issue 7-8 2007Gero Kurat It contains a rutile grain and is in contact with a large Cl apatite. The latter is very rich in rare earth elements (REEs) (,80 × CI), which display a flat abundance pattern, except for Eu and Yb, which are underabundant. The devitrified glass is very poor in REEs (<0.1 × CI), except for Eu and Yb, which have positive abundance anomalies. Devitrified glass and Cl apatite are out of chemical equilibrium and their complementary REE patterns indicate a genesis via condensation under reducing conditions. Inclusion 1 in the Kodaikanal (IIE) iron consists of glass only, whereas inclusion 2 consists of clinopyroxene, which is partly overgrown by low-Ca pyroxene, and apatite embedded in devitrified glass. All minerals are euhedral or have skeletal habits indicating crystallization from the liquid precursor of the glass. Pyroxenes and the apatite are rich in trace elements, indicating crystallization from a liquid that had 10,50 × CI abundances of REEs and refractory lithophile elements (RLEs). The co-existing glass is poor in REEs (,0.1,1 × CI) and, consequently, a liquid of such chemical composition cannot have crystallized the phenocrysts. Glasses have variable chemical compositions but are rich in SiO2, Al2O3, Na2O, and K2O as well as in HFSEs, Be, B, and Rb. The REE abundance patterns are mostly flat, except for the glass-only inclusion, which has heavy rare earth elements (HREEs) > light rare earth elements (LREEs) and deficits in Eu and Yb,an ultrarefractory pattern. The genetic models suggested so far cannot explain what is observed and, consequently, we offer a new model for silicate inclusion formation in IIE and related irons. Nebular processes and a relationship with E meteorites (Guin) or Ca-Al-rich inclusions (CAIs) (Kodaikanal) are indicated. A sequence of condensation (CaS, TiN or refractory pyroxene-rich liquids) and vapor-solid elemental exchange can be identified that took place beginning under reducing and ending at oxidizing conditions (phosphate, rutile formation, alkali and Fe2+ metasomatism, metasomatic loss of REEs from glass). [source] Intraoperative Study of Polarization and Evoked Response Signals in Different Endocardial Electrode DesignsPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 7 2001CHING LAU LAU, C., et al.: Intraoperative Study of Polarization and Evoked Response Signals in Different Endocardial Electrode Designs. Some new generation pacemakers use an algorithm based on evoked response (ER) detection to verify beat-to-beat capture and to enable automatic adjustment of output. This is a prospective acute study of polarization signal (PS) and ER in nine currently available electrodes. Intraoperative testing of ventricular bipolar electrodes used the Autocapture (AC) algorithm. The intrinsic R wave, PS, ER, acceptance of AC function, and stimulation thresholds (STs) were obtained. Ventricular electrodes were categorized as follows: titanium nitride (TiN)-coated passive and active fixation, high impedance (HI), passive fixation (VP), iridium oxide-coated titanium (IROX) (VI), and platinum helix (PH) active fixation. Acute testing was performed in 217 patients with an average age of 74.26 years, 59.6% were men with primary pacing indication-SSS (46.3%). There were no significant differences found with respect to R wave and threshold between the various electrodes. PH active-fixation electrodes had significantly higher ER and PS than other groups including the TiN-coated active-fixation electrodes. TiNcoated electrodes (active and passive fixation) had significantly lower PS than other electrodes. As a result, TiN electrodes had a significantly higher functional rate of AC (91.7%), whereas PH had the lowest rate (0%). In conclusion, (1) polarization characteristics are significantly different for commercially available ventricular electrodes, (2) certain physical features at the tissue to electrode interface like TiN coating appears to be more important in determining PS than electrode tip size and fixation method, and (3) the current algorithm for AC requires electrodes that provide low polarization for satisfactory performance. [source] Effects of substrate bias and argon flux on the structure of titanium nitride films deposited by filtered cathodic arc plasmaPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 1 2005Y. J. Zhang Abstract High-quality titanium nitride (TiN) films with nano-structure were prepared at ambient temperature on (111) silicon substrates by filtered cathodic arc plasma (FCAP) technology with an in-plane "S" filter. The effects of substrate bias and argon flux on the crystal grain size, roughness and preferred orientation were systematically investigated. It was found that the substrate bias and argon flux can affect the properties of TiN films effectively. Transmission electron microscope images showed that the crystal grain size was uniform and ranged from 10 nm to 5 nm. The results of X-ray diffraction and electron diffraction indicated that the degree of preferred orientation was more evident under high substrate bias and high argon flux. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Deposition of TiN,WS2 Nanocomposite Coatings by a Hybrid Process: Reactive Sputtering and Clusters GunPLASMA PROCESSES AND POLYMERS, Issue S1 2009D. Bharathi Mohan Abstract A dc magnetron reactive sputtering equipment connected with a homemade clusters gun was used to deposit a series of TiN,WS2 nanocomposite coatings with different magnetron power values and different argon pressures in the clusters gun. The original idea was to achieve from the TiN matrix, originated from the normal running of the magnetron system, the high wear resistance property, whereas the pre-formed IF,WS2 nanospheres introduced by the clusters gun would provide the low friction coefficient. A small peak detected at low diffraction angles by X-ray diffraction in two of the produced samples gave the first evidence of the WS2 nanospheres incorporation in the TiN matrix. Then, scanning electron microscopy was used for observing very small grain features which were identified as the WS2 nanospheres by energy dispersive analysis of X-rays, demonstrating the feasibility of this hybrid technique for the deposition of nanocomposite coatings. [source] Effect of Ion Bombardment on the Characteristics of Ti Based Biocompatible CoatingsPLASMA PROCESSES AND POLYMERS, Issue S1 2007Alina Vladescu Abstract TiN and TiAlN coatings were deposited on CoCr alloy, 316L stainless steel, and Si substrates by cathodic arc method. Various ion bombardment conditions were obtained by different DC and pulsed bias voltages applied on the substrates. A comparative analysis of the coating characteristics for different substrate biasing conditions was performed. [source] Electrospray ionization and atmospheric pressure matrix-assisted laser desorption/ionization mass spectrometry of antioxidants applied in lubricants,RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 24 2009Alexander Kassler The aim of this study was to investigate the utility of ion trap mass spectrometry (ITMS) in combination with the two desorption/ionization methods, electrospray (ESI) and atmospheric pressure matrix-assisted laser desorption/ionization (AP-MALDI), for the detection of antioxidants which are applied in lubricants. These experiments should form the base for future investigations of antioxidants in tribologically formed thin layers on the surface of frictional systems. Seventeen different antioxidants were selected out of the group of hindered phenolic and aromatic aminic compounds. Practically all antioxidants could be characterized by positive ion ESI- and AP-MALDI-ITMS, forming various types/species of molecular ions (e.g. [M]+., [M+H]+, [M+Na]+ or [M,2H+H]+). A few compounds could be analyzed by negative ion ESI-MS, too, but none by negative ion AP-MALDI-MS. The influence of target materials in AP-MALDI-MS (gold- and titanium nitride (TiN)-covered stainless steel, micro-diamond-covered hard metal, hand-polished and sand-blasted stainless steel targets) with respect to the molecular ion intensity and type of molecular ion of two selected antioxidants was evaluated. The surface properties are of particular interest because in friction tests different materials with different surface characteristics are used. However, the MS results indicate that optimal target surfaces have to be found for individual antioxidants in AP-MALDI-MS but in general smooth surfaces were superior to rough surfaces. Finally the gold-covered stainless steel MALDI target provided the best mass spectra and was selected for all the antioxidants investigated. Copyright © 2009 John Wiley & Sons, Ltd. [source] Synthesis of ultrafine titanium carbonitride powders,APPLIED ORGANOMETALLIC CHEMISTRY, Issue 5 2001Frederic Monteverde Abstract Titanium-carbonitride-based materials are very hard materials with increasing technical importance. They are mainly used in composites with various metal carbides and/or metallic binders (cermets) for metal cutting operations. These applications call for the synthesis of titanium carbonitride powders with homogeneous chemical composition, as small as possible grain size and narrower grain size distribution. Nowadays on the market, only commercial submicrometric (0.5,2,,m) powders are available. Starting from blends of nanosize commercial TiN or TiO2 powders mixed with different carbon powders (carbon black, active carbon), this study aimed to set up a low-cost process to synthesize fine and pure TiC1,X,NX powders with an X value close to 0.5. The morphology of the as-obtained powders and the progress of the reaction were investigated by scanning electron microscopy and X-ray diffraction. The stoichiometric parameter X was estimated on the basis of a TiC1,X,NX Raoultian solid solution together with Vegard's rule. The results are presented and discussed to assess relations between powder characteristics and processing conditions. The most encouraging results were obtained using a mixture TiN,+,10,wt%C (carbon black) processed at 1430,°C for 3,h under flowing argon. Regularly shaped particles with limited agglomeration ranged from 100 to 300,nm and an X value close to 0.5 Copyright © 2001 John Wiley & Sons, Ltd. [source] | ||||||||||||||||||||||||||||||||||||||||||||||