THE MODIFICATION OF GRAPHITE FELT WITH COBALT

Abstract

The feasibility of electrochemical modification of graphite felt fiber surface with cobalt was investigated under galvanostatic conditions in simple cobalt electrodeposition bath, containing Co²⁺ ions and boric acid as buffering agent. Electroless cobalt deposition on sensitized (with Sn²⁺ ions) and activated (with Pd) surface of graphite felt fibre was carried out in pyrophosphate bath containing hypophosphite as reducing agent. The composition and structure of electrodeposited and electrolles cobalt on the surface of modified graphite felt was confirmed by EDS and XRD analysis. The atomic concentration of Co on the surface of electrochemically and chemically modified with cobalt graphite felt fibres was about 0.3 % and 3.4 %, respectively. Such concentration of Co is sufficient for the modified graphite felt to interact with a permanent magnet. The morphology of electrodeposited and electrolles cobalt on the graphite felt fiber surface was demonstrated by SEM analysis. The nanometric surface elements (globular, flake-like, and needle-like crystallites) of cobalt were observed on the surface of modified graphite felt fibres. It should be noted, that proper pretreatment in NaOH and HCl solutions increases the quality and wettability of graphite felt fibre surface and it is a necessary operation before electrochemical and chemical modification of graphite felt with cobalt.

DOI: http://dx.doi.org/10.5755/j01.ct.60.2.1891