Compacts of Boron-Doped Synthetic Diamond: Lowering of Synthesis Temperature and Its Effect on the Doping Level and Electrochemical Behavior

Substituting of metal (Co, Ni) borides for boron carbide in the boron carbide–graphite growth system for the process of diamond growth in the region of diamond thermodynamic stability allowed lowering the synthesis temperature for the electrodes of this new electrode material―boron-doped diamond compacts―significantly (by ~1000°C) without any deterioration of their electrochemical properties. On the other hand, using of amorphous boron with finer grain as compared with the boron carbide, mixed with graphite, results in a marked increase of the electrodes’ electrochemical efficiency, due to increase in their roughness after the chemical removing of boron-containing inclusions from their surfaces. Thus obtained compact electrodes have wide potential window and low background current in supporting electrolytes, they are well reproducible. Special features of their electrochemical impedance spectroscopy are similar to those of the recently studied compacts synthesized on the basis of boron carbide.