The Susceptibility to Surface Corrosion in Acidic Fluoride Media: A Comparison of Diamond, HOPG, and Glassy Carbon Electrodes

The chemical inertness and corrosion resistance of a boron‐doped diamond thin film electrode, grown by chemical vapor deposition (CVD), have been studied during potential cycling (PC) for 2 h in a solution of at 50°C. Similar experiments were performed on highly ordered pyrolytic graphite (HOPG) and glassy carbon (GC), for comparison. The physicochemical properties of the electrode surface were characterized before and after PC by cyclic voltammetry, optical and scanning electron microscopy, Raman spectroscopy, and ac impedance spectroscopy. The results indicated that the diamond electrode possesses a superior degree of chemical inertness and corrosion resistance, has no microstructural damage nor was surface oxidation observed after PC. HOPG and GC surfaces, on the other hand, exhibited severe corrosion in the form of surface cavitation, pitting, and oxidation. The relative degree of microstructural damage and surface oxidation increased in the order of diamond . This work represents some of the initial efforts at systematically characterizing how the physical, chemical, and electronic properties of conductive diamond thin films are affected during exposure to electrochemical conditions ( i.e. , solvent, electrolyte, and applied potential).