Question

Graphite fiber is made by modifying the microstructure into long, thin ribbons, in which the carbon sheets parallel the plane of the ribbon. The ribbons are then rolled, somewhat as one would roll a newspaper, to form the graphite fiber. While normal graphite is weak, graphite fiber is extremely strong when pulled along the fiber axis. Explain in terms of the microstructure and the bonding in graphite.

Answer 1

In the sturucture of graphite carbon atoms forms sheets in which atoms are hexagonally configured.These sheets are stacked in configuration in which successive sheets are weakly bonded to one another.carbon is good conductor in the palne of its sheet, when assuming valence bond of carbon is in the plane of sheet only.

on other hand graphite is poor conductor in the direction perpendicular to the sheet., because the sheets are far apart the bonds between them and do not permit electrical conduction.

graphite in its usually microstructure small three dimensional particles made of stacked plannar sheets, and graphite defoems easily.

the flakes of graphite slide are easily over one another, so that graphite can easily deform. When graphite sheets are rolled in to tubes to create fibres they are very strong when pulled along the fibre axis.To deform a rolled sheet one must stretch the bonds in the sheet ,since the carbon atoms in the graphite are tightly bound in the sheet plane and it is difficult to do.