Graphite content

As a generahty, porous metal sleeve bearings tolerate Pp levels up to 1.8 MN/(m-s) (50, 000 psift/min). Pp levels for thmst bearings should not exceed about 20% of the sleeve bearing limit. Variations of oil viscosity, oil content, graphite content, and other material and property details also influence the approximate operating limits given in Table 7. 

Affected metal is converted to a very soft material that can be dislodged with a sharp metal probe or cut with a knife. Graphitically corroded metal frequently has an oily, shppery feel, especially after surface deposits are scraped away. Because of its graphite content, chunks of corroded metal can be used as writing implements in the absence of a pencil (Fig. 17.4). Graphitically corroded metal will produce a dull thud rather than a metallic sound when struck with a hammer. 

A new series of sulfur lignin-graphite samples with known graphite content were treated with bromine in the vapor phase (doped). After measuring the conductivities, we recorded the curve shown in Figure 4b (Kuusela, T. A., The University of Helsinki, Finland, to be published). 

Effect of de-sintering observed during two-step sintering process (without and with pressure applied) on reference sample, two samples with 0.1 wt% carbon content after oxidation at 800°C from batch with carbon black, and one sample from batch with graphite and with no graphite content after oxidation at 800°C. 

Traditional materials are carbon brushes against copper commutators or sliprings, but carbon brushes rely on graphite content for lubrication of the sliding contact, and graphite requires the presence of moisture or other vapours, or sometimes more exotic materials, to ensure low friction. They cannot therefore be used in vacuum or... 

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