GB485965A

GB485965A - Process and apparatus for thermal deposition of metals or other materials

Info

Publication number: GB485965A
Application number: GB19772/37A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1936-07-17
Filing date: 1937-07-16
Publication date: 1938-05-27
Also published as: NL51379C; US2153786A; FR824423A; BE422666A

Abstract

485,965. Fusing and working silica. ALEXANDER, P. July 16, 1937, No. 19772. Convention date, July 17, 1936. [Class 56] [Also in Group II] In depositing coatings of metal or other material, e.g. quartz, by evaporation in vacuo, the rate at which the material to be evaporated is fed towards the heater is so low and the temperature of the heater is so high that the material is evaporated substantially as soon as it contacts with the heater. An inert gas, e.g. hydrogen, may be fed into the chamber to replace the residual air, and the residual gas may be ionized. In the form shown in Fig. 1, the material to be evaporated is in the form of a wire or strip 18 which is fed from a roll 19 so that its end contacts with the heater 16. The material is at once vaporized to form a coating on the surfaces 22 and 23. Inert gas may be introduced at 32 and the residual gas ionized by the electrodes 26, 27. In coating small surfaces a straight wire or strip may be placed in the guide 33 so as to rest on the heater, the wire or strip being fed down by its own weight. Fig. 2 shows a device, e.g. for use with quartz, where the material is fed in granular form, being carried from a hopper 34 at a predetermined rate by a conveyer 35 to a hopper 36 which feeds it on to a U-shaped heater 38. In another form, the heater may be a hollow body, e.g. a cylinder, made of wire gauze or perforated metal, a wire or strip of the material being fed into the body through a hole or slit. To coat large surfaces a plurality of heaters may be used, and Fig. 3 shows a device in which a plurality of heaters and feeding-devices is mounted on a bar 40 which can be moved up and down on guides 42, adjacent the surface 43 to be coated. In coating long flexible surfaces, such as paper strips, these may be contained on rolls which feed them past the source of vapour. The low density of the vapour enables a relative]y low vacuum to be used ; e.g. aluminium may be vaporixed in a vacuum of 10<-3> mm. of the temperature of the heater being about 1500 C.