Abstract: Metallic articles having heat transfer channels are produced by solidification of molten metallic material about pre-formed channel defining members such that a solidified metallic deposit having heat transfer channels is formed. The channel defining members may be in the form of either solid elements (which are subsequently removed to leave the channels), or conduit elements (which may remain permanently embedded in the article). Moulds, dies, cores and other tools for use in moulding or casting of plastics and metals are particularly suitably formed by the process, the heat transfer channels being used for cooling of the respective articles during use. The molten metallic material is preferably deposited by spray forming utilizing one or more sprays of molten metallic material.

Abstract: An apparatus for mixing a particulate substance, which may be in chopped or short fibre form, with a matrix metal comprises a container (11) for molten metal (10) having an aperture (12) through which a stream of the metal can fall, a feed motor (20) for feeding the particulate substance into the metal stream, and one or more downwardly inclined nozzles (23) through which jets of atomizing gas are directed on to the combined flow of metal and particulate substance. The feed motor comprising a horizontal ring (20a) which extends about and is coaxial with the molten metal stream, and which has a radial vibration imparted to it so as to form a node on the axis of the ring. The upper surface of the ring may be horizontal or may be inclined downwardly towards the axis and may have annular grooves of ratchet tooth section with the steeper part of the section facing towards the axis.

Abstract: A scanning apparatus is provided for scanning a stream of atomized particles comprising a pneumatic valve through which gas can be routed to one or more nozzles to give a scanning action on the stream of atomized particles which routing is externally adjustable and externally programmable.

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: A stream of molten metal particles in a metal spraying apparatus is deflected from side to side by gas issuing from two nozzle blocks disposed at diametrically opposite sides of the stream. Gas is supplied to the two nozzle blocks (13) alternately under the control of a rotary valve (19) having a stator (18) and a cylindrical rotor (24). The rotor has two circumferentially extending grooves (26) whose cross-sectional area varies in predetermined manner and each of which serves to provide and cut off communication between an inlet port (21) for gas under pressure and an outlet port (23) which is circumferentially aligned with the inlet port and which leads to an associated one of the nozzle blocks. The areas of the inlet and outlet ports are each greater than the maximum cross-sectional area of the groove, so that the quantity of gas reaching the nozzles at each instant is determined by the instantaneous effective area of the groove (26).

Abstract: A method for the spray distribution of metals includes emitting a stream of molten metal particles and a gas nozzle which is rotated about the stream. The gas nozzle is inclined to the axis of the particle stream and in the direction of the stream in order to produce a required distribution of the particle stream on a workpiece.