摘要 |
<p>Copper based substrates for use at high temperatures in oxidizing atmospheres are made up of a copper core overlaid with a protective nickel oxide barrier layer formed in situ and an external protective layer of nickel. The process for forming the protective nickel oxide barrier layer comprises the steps of subjecting the copper core to oxidation to form a cuprous oxide surface layer over the copper core, reducing the surface of the cuprous oxide layer to regenerate copper to regain conductivity, plating a surface layer of nickel over the copper layer, and annealing the coated copper core to scavenge at least some of the oxygen from the cuprous oxide layer and react it at the interface with the plated nickel layer to form the protective nickel oxide barrier layer. The oxidation reduction steps may be carried continuously on a copper core which is moved through a reactor having an oxidation zone fed with oxygen, a reduction zone fed with hydrogen and a stabilizer zone separating the oxidation and reduction zones and fed with an inert gas. The reactor is maintained at a temperature such as to allow the oxidation and reduction reactions.</p> |