Method of manufacturing electrodes by gas atomisation of molten metals

Flat negative electrodes for nickel metal hydride batteries are conventionally manufactured by the following process. An ingot is cast of the appropriate nickel hydride alloy. Powder is then produced from the ingot by one or more of grinding, crushing, milling or decrepitation. The powder is then mixed with a binder such as a suitable polymer material, and a conducting medium such as carbon. The mixture is then pressed or rolled onto a perforated nickel sheet and formed into a sandwich with a further such sheet. A method of forming an electrode is characterized in that the method comprising forming a porous coating of an alloy by gas atomisation on a substrate. The porosity of the coating is provided by controlling one or more conditions selected from the group consisting of the height and duration of deposition of the spray onto the substrate, the rate deposition, the speed of the atomized particles impacting on the substrate size distribution of the spray droplets, the temperature above melting, the substrate temperature, the substrate thermal conductivity, the conductivity of the gas, and the temperature of the gas.