Brief description of the coating of a substrate made of metal or alloy to be passivated, by a layer of oxide, and a cladding tube and the fuel assembly spacer grid - covered products of a layer of oxide

摘要

A superficial preoxydation of the substrate (2) is effected by placing it in contact with an oxidant gas excited by a cool plasma of the substrate (2) situated in the flow post-discharge of the cool plasma used to the oxidant element and heated to an oxidation temperature lower than 500 DEG C. At the surface of the preoxidized substrate (2), a metal oxide is provided by heterogenous oxidation of a metal halide by using a gas mixture comprising an oxidant element activated by a cool plasma. The oxidant gas mixture is set in contact with the halide at the closest vicinity of the substrate arranged in the remote flow post-discharge of the cool plasma. Preferably, the cool plasma is generated by micro-waves. The process may be used particularly for forming a protection coating on a casing tube of a nuclear fuel rod.