A nodic oxidation of graphitic materials in aqueous electrolytes is a com plex process which may yield e.g. higher stage intercalation com pounds and lamellar graphite oxides, acidic surface or defect oxides and gaseous or colloidal decom position products. Kind and concentration o f the electrolyte solution are the most important parameters to control this wide-spread distribution of products. Based on electrochem ical and m icroscopic studies on H O PG and carbon fibres, a mechanistic concept o f electrolyte effects is proposed:In dilute aqueous solutions, attack of OH* radicals formed in the primary electrochem ical step is the dom inant reaction pathway leading to formation o f covalent carbon-oxygen bonds. Due to their reactivity, OH* radicals are able to attack basal plane carbon sites and also to create 3-dim ensional defect oxides. D issociation or capture o f OH* radicals -which is favoured in basic and in most concentrated neutral solutions, respectively, -results in less active radical species and limits the attack to thermodynam ically less stable carbon atoms at edge sites which may be either oxidized or rem oved. Due to acidification o f the diffusion layer of anodes even in neutral aqueous electrolytes, direct current oxidation always yields higher stage acid intercalation com pounds and lamellar graphite oxide as by-products. This can be almost prevented by alternating current oxidation.

Scanning tunneling microscopF (STM) is a powerful tool for atomic resolution imaging of the topography of electronically conductive samples: Highly dispersed Pd is a preferred catalyst for electroless formaldehyde-driven Cu deposition on glass fiber reinforced epoxy printed circuit boards. Using surface oxidized highly oriented pyrolytic graphite (HOPG) as a model substrate, it was possible to obtain STM images of Pd clusters (typical size 1-5 nm). An electrochemical mechanism with separation of anode reaction (oxidation of formaldehyde on Pd) and cathode reaction (deposition of Cu on graphite) is proposed for electroless Cu plating.Electroless deposition of Cu from Cu2+/HCHO solutions onto nonconductive substrates and in particular onto printed circuit boards is of considerable technical importance. It requires catalytically active surfaces to initiate the Cu nucleation process. Activation can be performed by impregnation with solutions of Pd complexes and their subsequent chemical reduction (1). Factors like particle size, distribution, and anchorage of Pd clusters, of course, strongly affect quality and deposition rate of electroless Cu platings. Unfortunately, conventional imaging of these nuclei requires transition electron microscopy (TEM) techniques (2) since the resolution of scanning electron microscopy (SEM) is not sufficient. By the same token, STM has several important advantages over TEM: (i) higher resolution, (ii) most simple sample preparation, (iii) almost free choice of sample environment (e.g., air liquids), and (iv)

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