Characteristics Of TiC Research Articles

Wear characteristics of TiC, Ti(C,N), TiN and Al 2O 3 coatings in the turning of conventional and Ca-treated steels

The wear characteristics of single layers of TiC, Ti(C,N), TiN and Al 2O 3 were investigated during turning of conventional and Ca-treated quenched and tempered Al-killed steels. The experimental coatings were deposited using chemical vapour deposition (CVD) or moderate temperature CVD (MTCVD) on cemented carbide substrates of a single composition and the coatings were of similar thicknesses (7 ± 1 μm). The wear mechanisms and layer formation were studied using scanning electron microscopy, optical microscopy and X-ray diffraction. Inclusion modification appeared to be an effective means of enhancing machinability and all experimental coatings exhibited about 20% better performance as a result of Ca-treatment. In particular, the crater wear of the experimental coatings — excluding Al 2O 3 — was clearly reduced. Comparative cutting tests revealed important differences between the coating materials. Wear mechanisms of the experimental coatings are discussed in detail.

A controlled study of sensory tics in Gilles de 1a Tourette syndrome and obsessive-compulsive disorder using a structured interview.

OBJECTIVE: To determine the prevalence and characteristics of sensory tics in the Gilles de la Tourette syndrome (GTS), and a matched population of patients with obsessive-compulsive disorder (OCD) using a...

Tourette's syndrome: a disorder of cingulate and orbitofrontal function?

We discuss the clinical characteristics of tics and Tourette's syndrome (TS) and also possible treatment options. Based upon an overview of published pathophysiological and PET data, and the results of a recent PET study of changes in opioid receptor binding in TS, we hypothesize that the disease arises due to dysfunction within the cingulate and orbitofrontal cortex. The beneficial effects of dopamine receptor antagonists and dopamine-depleting agents in TS are suggested to be mediated via basal ganglia-thalamofrontal circuits, while opioid agents may act directly on the cingulate.

合金工具鋼ＳＫＤ１１にＣＶＤ処理したＴｉＣ被膜の特性

This paper deals with the characteristics of TiC coated on the tool steel of SKD11 by CVD method. The surface residual stress was measured by the X-ray stress measuring method. Also the characteristics of adhesion by the scratch test and wear resistance by the wear test were evaluated. Furthermore, the effect of heat treatment (quenched at 1020°Cand then at 450°C or 520°C) after CVD on these characteristics was considered. The results are as follows : (1) The residual stresses of TiC layer are compressive. However there is difference in values between after quenching and after tempering, and further there is also difference in values between in case of tempering at 450°C and tempering at 520°C. The stresses were -3.17GPa and -2.94GPa, respectively. These values were nearly equivalent to the calculated values of thermal stress. (2) Acoustic emission signal was detected corresponding with peeling off or damage of TiC layer. Also the critical load is subjected to the influence of substrate. The harder the substrate, the larger the critical load. (3) Wear resistance of SKD11 is extremely improved by means of coating CVD-TiC. When OHGOSHI type wear test is applied and TiC layer is very thin, not only the wear resistance of TiC layer but also the substrate of SKD11 is evaluated.

Effect of chromium in substrate steel on the chemical vapour deposition of TiC

TiC coatings on tools are widely used in order to increase their wear resistance. Chemical vapour deposition of TiC was performed on steels having different chromium contents in order to find a relationship between the chromium content in steel and the deposition characteristics of TiC. In the initial growth stage, the nucleation and growth was found to be strongly affected by the chromium content of the substrate steel. This result was attributed to the diffusion of carbon through the chromium-rich phase. Chromium element which increases the activation energy of carbon diffusion through the substrate steel reduces the deposition rate. A strongly preferred orientation of the (2 2 0) axis in the growth direction was found. Scanning electron micrographs showed that the grain was equiaxed for all experimental deposition conditions. They also showed that the grain size became finer with increasing chromium content in the substrate steels. Wear-resistance was improved with decreasing TiC grain size.

Outgassing characteristics of TiC coated materials

Outgassing characteristics of TiC coated materials

Outgassing characteristics of TiC and TiB2 coated graphite

Outgassing characteristics of TiC and TiB2 coated graphite

Outgassing characteristics of TiC and TiB2 coated graphite

Two coatings to minimize high-Z contaminant release in plasma devices are TiB2 and TiC chemically vapor deposited on Poco graphite. Total outgassing rate and mass spectra measurements have been conducted on the materials at room temperature, 100°C and 250°C.(AIP)

Some structural and mechanical characteristics of aqueous TiC- and ZrC-base suspensions

1. The viscosity of a slip depends on its solid phase content; the best properties are exhibited at a solid phase concentration of 70% for titanium carbide slips and 75% for zirconium carbide slips. 2. The addition of an acid or an alkali to a slip with the aim of decreasing its viscosity is not recommended, because it reduces the viscosity of the dispersing medium (Na-CMC solution), as a result of which the suspension becomes unstable. 3. Titanium and zirconium carbide slips based on a Na-CMC solution are “liquid-like” systems. 4. Titanium and zirconium carbide slips are thixotropic, but the thixotropic structure can easily be destroyed by mechanical mixing in a ball mill, as a result of which the slips become suitable for production purposes.

Automatic measurement of secondary electron emission characteristics of TaC, TiC and ZrC

A method and apparatus for plotting automatically the secondary electron emission yield curves from metals in an ultra-high vacuum environment are described. The yield curves from metals can be plotted in times of only a few seconds before the surfaces become contaminated. In addition, both the variation of the back-scattering coefficient with primary energy and the yield with angle of incidence of primaries may be plotted. Typical curves from Ni, Pt and Ta are presented to indicate the performance of the apparatus. Measurements using the apparatus are reported on the secondary electron emission characteristics of the three carbides TaC, TiC and ZrC as a function of primary energy and angle of incidence. In addition the yield curves are correlated with a theoretical universal yield curve.