Abstract: Protection of a metal surface is carried out by applying a coating of vitreous enamel to the surface so that the enamel forms a strong bond with the metal and then spraying a coating of an atomized protective metal on the enamel. Preferably a peening operation is carried out on the surface of the sprayed metal simultaneously with or immediately after the spraying of the metal. The method is particularly advantageous in protecting steel marine structures against corrosion and, where the protective metal is cupro-nickel, fouling by marine creatures. The vitreous enamel forms an electrically insulating layer preventing galvanic action between the steel and the cupro-nickel in the presence of sea water.

Abstract: In order to deposit metal onto a surface such as a cylindrical surface, an arc spraying method is used with a consumable electrode (16), a non-consumable electrode (18) and a jet of atomising gas (22) blown through the arc (20) in a radial direction to propel the molten metal of the consumable electrode from the acr to the cylinder wall (12). The non-consumable electrode and the atomising gas jet both rotate about the cylinder axis so that the entire surface can be covered. The supply for the consumable electrode will normally come from a reel which can be stationary such that the consumable electrode does not rotate about its own axis.

Abstract: For uniformly coating a substrate with a spray, a stream of liquid falls past a point towards which a plurality of nozzles in a bank are all directed but at different angles. Bursts of atomising gas are sprayed through the respective nozzles in a repeated sequence, such as to cause a repeated sequence of equal durations of spray in a plurality of directions.