IMPROVEMENTS IN THE PROCESSING OF METALS AND ALLOYS

摘要

Metal spraying apparatus for forming metal as a powder or as a coating on a substrate comprises a mesh (12) formed from two mutually transversely extending layers (13, 14) of spaced refractory filaments under tension. The filaments of the upper layer are in contact with those of the lower layer. The mesh constitutes the bottom wall of a vessel in which the molten metal is disposed. The molten metal in the vessel is subjected to a pressure pulsating between upper and lower values which are respectively above and below the value at which the pressure is sufficient to overcome the forces of surface tension resisting the flow of the metal through the apertures of the mesh. A piston (26) slidable in a vertical cylinder (25) is reciprocated to cause gas above the molten metal in the vessel (10) to apply the pulsating pressure to the surface of the metal. The droplets (30) of molten metal fall through an enclosed space on to a cool substrate (23) to form a coating on the substrate.