Hydro-Quebec

Sherbrooke University

Louis Brossard

Hugues Menard

Francois Morin

Yves Choquette

Guy Raynaud

A process and an apparatus for manufacturing electrocatalytic electrodes. The process comprises the steps of immersing a substrate in a plating bath containing metal ions and electrocatalytic material in particles form, such as Ni, NiAl, and CoAl, among others. Electric current is established in the bath inducing a deposition of metal on the substrate by reduction of metal ions and, simultaneously, the cell containing the plating bath is inverted periodically to cause a recurrent migration of the particles of electrocatalytic material, under the effect of gravity, toward the substrate, in order to build-up a layer of electrocatalytic material on the substrate, the particles of the electrocatalytic material being fixed on the substrate by the reduction of metal ions.

Process and apparatus for manufacturing an electrocatalytic electrode

Selective surfaces for photothermal solar collectors consisting of a nickel support, preferably commercial nickel of 99.5% purity, a layer of a porous nickel oxide of about 0.2 .mu.m covering the metallic support, the layer of porous nickel oxide being covered with asperities in the form of a network of nickel oxide discs in which the major portions are oriented at an angle with respect to the vertical. The network of discs has a thickness of about 2 .mu.m. The preparation of these selective surfaces is carried out in the following manner. Thin nickel plates are subjected to a heat treatment by heating and oxidizing in an oxidant gas during a short period of time at a temperature varying between about 1000.degree. C. and 1100.degree. C. The oxidized nickel plates are reduced at a temperature of about 1100.degree. C. in the presence of a reducing gas until the metallic state is obtained. The surrounding temperature is thereafter lowered between 810.degree. and 830.degree. C. and an oxidizing gas is circulated around the plates, at a rate of flow which is sufficient to flush away the reducing gas. The plates are rapidly cooled down to room temperature to give the intended selective surfaces.

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Ste-Julie, Canada

Louis Brossard