Pyrolitic carbon

On the microstructural level, several types of pyrolytic carbons may be deposited each with one of four distinctly different structures, ranging from layered, highly anisotropic forms to structures with very small, randomly-oriented crystallites with no preferred orientation. All of these structural variations are a result of modifications in processing conditions. In this particular study, only the isotropic forms of both pure LTI carbon and co-deposited LTI carbon-silicon alloyed carbon (Pyrolite registered trademark of Carbo-Medics, Inc., San Diego, California) were investigated. 

Chemical erosion can be suppressed by doping with substitutional elements such as boron. This is demonstrated in Fig. 14 [47] which shows data for undoped pyrolitic graphite and several grades of boron doped graphite. The mechanism responsible for this suppression may include the reduced chemical activity of the boronized material, as demonstrated by the increased oxidation resistance of B doped carbons [48] or the suppressed diffusion caused by the interstitial trapping at boron sites. 

Highly oriented pyrolitic graphite Glassy carbon -Pyrocarbon Graphite monocrystal Doped graphite (C,6 AsF5 )... 

The most common overcoats, however, are sputtered carbons. Their role in disk corrosion has been described in contradicting ways. Whereas Garrison [141] clearly observed that carbon, like Rh, can enhance galvanic corrosion, Smallen et al. [131] believe that carbon decreases corrosion by preventing lateral growth of corrosion products. Results of similar tests are sometimes contradictory Nagao et al. [145] have shown an improvement of the corrosion resistance of carbon-coated CoCr alloys on T/H test (with either SOz gas or NaCl mist), whereas Black [146] finds that pyrolitic carbon over a CoCrMo alloy results in elevated corrosion rates. 

Wang Z., Huang X., Xue R., Chen L. A new possible mechanism of lithium insertion and extraction in low-temperature pyrolitic carbon electrode. Carbon 1999 37 685-92. 

Figure 22 Cyclic voltammograms recorded in aqueous solutions of Rieske fragments from (a) bci complex glassy carbon working electrode pH 7.2 (b) (recombinant) biphenyldioxygenase (basal) pyrolitic graphite working electrode (in the presence of the positively charged additive neomycin) pH 7.0. Scan rate 0.01 V s ...

Since rusticyanin is positively charged (p/=9.1), its electrochemical response should be tested at negatively charged electrodes (namely, edge-plane pyrolitic graphite or glassy carbon electrodes). As a matter of fact, no positive response is obtained at a carbon paste electrode, but in the presence of a promoter such as 4,4/-bipyridyl a sufficiently resolved cyclic voltammetric response is obtained, Figure 37.67... 

Concerning the substrate, practically any material can be used to form a modified electrode, although the most used are gold, silver, platinum, mercury, and carbon (in its different variants, like glassy carbon, Highly Oriented Pyrolitic Graphite (HOPG), or Boron-Doped Diamond (BDD) electrodes [39]). 

For example, SEM examination of carbon surfaces has shown considerable difference between those of polished glassy carbon (GC) and pyrolytic graphite. The surface of pyrolitic graphite is "pebbled" and uneven (32) while the glassy carbon can be... 

This study shows the possibilities and specific feature of IR-pyrolysis for the formation of nanostructured carbon. In such way PAN, thermal transformations of which have been studied in detail [8-11], was chosen as the precursor for preparation of nanostructured carbon materials by carbonization of PAN and its composites with gadolinium chloride under non-coherent IR radiation. Specific action of IR-radiation on vibrational energy of PAN bands macromolecules allows one to decrease extremely time treatment and as a result to make simple, low energy and cost-effective pyrolitic method. 

With the purpose of increase in a specific surface and electroconductivity of GPSi the technology of gas-phase pyrolitic sedimentation of a layer carbon fibrous nanomaterial on a surface of macropores is developed [8]. Process of sedimentation carbon fibrous nanomaterial at catalytic decomposition of the ethanol steam proceeds strictly selectively, and the received material practically does not contain some soot. The nano-fibrous layer of carbon is homogeneously enough located on all surface of macropores (Fig. 8), thickness of a layer makes about 0,1-0,4 microns and depends basically on modes of sedimentation. The layer represents a mix nano-... 

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