Coated carbon

Static SIMS is also capable of analyzing liquids and fine particles or powders. A liquid is ofren prepared by putting down an extremely thin layer on a flat substrate, such as a silicon wafer. Particles are easily prepared by pressing them onto doublesided tape. No further sample preparation, such as gold- or carbon-coating, is required. 

Majetich and coworkers have studied magnetic properties of carbon-coated Co[32], Gd2C3, and FIo2C3 nanocrystals[33] formed in the chamber soot. A brief account on the coated Co nanocrystals is given here. They extracted magnetic nanocrystals from the crude soot with a magnetic gradient field technique. 

A new form of carbon coating is now available which is neither diamond nor graphite and is known as diamond-like carbon (DLC).bl DLC can be considered as a metastable carbon produced as a thin coating with a broad range of structure and composition.l b[42]... 

The function of the carbon coating is to contain the byproducts of the fission reaction, thereby reducing the shielding requirements. It also protects the nuclear fuel from embrittlement and corrosive attack and from hydrolysis during subsequent processing steps. CVD coatings of alumina deposited at 1000°C and beryllia deposited at 1400°C have also been studied for that purpose.P l... 

Robertson, J., Requirements of Ultrathin Carbon Coatings for Magnetic Storage Technology," Trihol. Int.,VcA. 36,2003, pp. 405-415. 

Heimberg, J. A., Wahl, K. J., Singer, I. L., and Erdemir, A., "Friction Behavior of Diamond-like Carbon Coatings Time and Speed Effects, Appl. Phys. Lett., Vol. 78, 2001, pp. 2449-2451. 

Sundararajan, S., and Bhushan, B., Micro/Nanotribology of Ultra-thin Hard Amorphous Carbon Coatings Using Atomic Force/Friction Force Microscopy," Wear, Vol. 225-229, 1999, pp. 678-689. 

Bhushan, B., Chemical, Mechanical and Tribological Characterization of Ultra-Thin and Hard Amorphous Carbon Coatings as thin as 3.5 nm Recent Developments," Diamond Relat. Mater., Vol. 8,1999,pp. 1985-2015. 

Salt-inclusion solids described herein were synthesized at high temperature (>500°C) in the presence of reactive alkali and alkaline-earth metal halide salt media. For single crystal growth, an extra amount of molten salt is used, typically 3 5 times by weight of oxides. The reaction mixtures were placed in a carbon-coated silica ampoule, which was then sealed under vacuum. The reaction temperature was typically set at 100-150 °C above the melting point of employed salt. As shown in the schematic drawing in Fig. 16.2, the corresponding metal oxides were first dissolved conceivably via decomposition because of cor-... 

Magnetic hard discs are used in computers to store information in the form of magnetic bits on a ferromagnetic alloy film. To protect the magnetic medium, a hard carbon coating about... 

This paper describes the catalytic activity of nickel phosphide supported on silica, alumina, and carbon-coated alumina in the hydrodesulfurization of 4,6-dimethyldibenzothiophene. The catalysts are made by the reduction of phosphate precursors. On the silica support the phosphate is reduced easily to form nickel phosphide with hi catalytic activity, but on the alumina support interactions between the phosphate and the alumina hinder the reduction. The addition of a carbon overlayer on alumina decreases the interactions and leads to the formation of an active phosphide phase. 

It is thus likely that the carbon coating on the alumina support lessened the interaction between AI2O3 and P and inhibited the formation of nickel phosphate after calcination and also lowered the reduction temperature. Structural models of the supported Ni2P catalysts are shown in Figure 4. 

The primary consideration for all AEM analysis is that the specimen be thin (generally carbon coated electron microscope grid either dry or in a suitable liquid. If a liquid suspension is used in preparing the specimen, it is important that all elements of interest are insoluble in that liquid. Only particles thin enough to meet AEM thin-film criteria (15) should be analyzed quantitatively. Scraping surface particles from a catalyst pellet for specimen preparation may be more useful than grinding the entire pellet. 

Pd on Carbon. The catalyst analyzed here is a commercial hydrogenation catalyst with 5% Pd supported on activated carbon (Alfa). The catalyst was ground in a mortar and pestle and dispersed dry onto a carbon coated Cu grid. While x-ray spectra from heavy metal particles down to 2nm in diameter can be obtained (O by manually directing the electron beam to the particle, digital images of Pd particles at high resolution have not been obtained previously. 

Innocent surfaces do not allow formation of such extended 2D areas as has been demonstrated by using carbon coated copper grids (for TEM) or liquid surfaces as used for Langmuir-Blodgett techniques. Only islands... 

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