Reduction of metal oxides by electron cyclotron resonance (ECR) plasma of hydrogen

A reduction experiment on oxides of Cu, Ni, Fe, Mo and Ti was carried out, using a low electron temperature ECR plasma of hydrogen. Reduction rates of these oxides were estimated by observing the disappearance of interference rings of oxide layers. The reduction efficiency eta of H+ flux was evaluated; eta = 0.4 for copper oxide and 10-3 < eta < 10-2 for other oxides. Roughly, the reduction rate decreased with an increase in the metal-oxygen binding energy. It was shown that oxide layers with a thickness in the order of magnitude 10-1 μm were reduced without difficulty. It is of interest from the viewpoint of discharge cleaning of fusion-oriented machines. (author)