Diamond-Carbon Composites. Physico-Chemical Properties, New Areas of Their Application

Abstract

The physico-chemical principles of high-temperature compacting of micro- and nanopowders of synthetic diamond within the pressure range of 100–200 mm Hg (25–35 kPa) have been developed and the diamond-carbon composites with regulated porosity of 2–75% have been received for the first time. High-porosity composites have been obtained on the base of chemically modified nanodiamond powders and low-porosity composites have been obtained on the base of statically synthesized micropowders of various granularities. The object of this work was to investigate hydrogen adsorption and catalytic reaction of oxidation and reduction of hydrogen and oxygen on the surface of diamondcarbon composites, their corrosion resistance in aggressive media depending on material porosity.

It has been established that the composites obtained on the base of nanodiamond powders have the highest adsorptive and catalytic activity as regards hydrogen. The catalytic activity of these diamond-carbon composites is maximal for materials with 50–75% porosity.

It has been shown that high-porosity diamond-carbon composites being investigated can be recommended as catalysts of hydrogen reaction (for example in fuel elements) or adsorbents of organic compounds.

The low-porosity diamond-carbon composites owing to their increased corrosion resistance in aggressive media can be used as insoluble electrodes in hydroelectrometallurgy.