GB454919A - - Google Patents

Abstract

454,919. Depositing metals by electric discharge. TENNANT, W. J., 111, Hatton Garden, London.-(Grupe, W. F. ; Lyndhurst, New Jersey, U.S.A.) Jan. 4, 1935, No. 369. [Class 41] Gold leaf or like metal foil is made by depositing the metal on a. moving carrier-band by cathode dispersion in an atmosphere of an. inert gas such as argon and afterwards separating the foil by solution or melting of the band or of a superficial layer thereon. In the apparatus shown, the carrier band is passed in a curved path close to the cathode constituted by a gold lining 27 on the container 13. The conveyer comprises an endless band 45 moving over drums 31, 41, 46 and guide members 42 and and a band 47 moving over drums 32, 14, 48 and guides 142. The carrier band is unwound from a drum 128 passing over drums 129, 41 from whence it is carried by the outer limbs of the two conveyer bands passing on return close to the issuing material to be wound up on a drum 30. The drums 30, 31, 32 are driven from a shaft 56 by an electric motor 54. The carrier band divides the vacuum chamber substantially into two parts to the outer of which argon is supplied from a cylinder 53, the inner space being exhausted through a pipe 50. The supply of gas is controlled by a pressure gauge 62 through an electric relay 66. The container 13 is surrounded by a jacket 11 through which cooling liquid is circulated. It is provided with a cover and a base member which are also cooled. The carrier-band may be of metal ; in this case a paper band is applied to the deposited film by a heat-releasable material such as varnish or wax and the carrier band is removed by floating on a solvent liquid. The paper may be applied to the edges only after removal of the metal carrier the edges are removed by slitting, leaving the deposited metal as a free foil. Alternatively, the carrierband may be of cellulosic material, such as that known under the Registered Trade Mark " Cellophane," coated with suitable material. Specifications 333,246, [Class 41], and 367,074 are referred to. The Provisional Specification also describes the introduction into the apparatus of a minute quantity of the vapour of a metal such as mercury, sodium or magnesium having the property of diminishing the surface tension of gold ; Specifications 211,539, 252,710, 275,523, and 276,291, [all in Class 41], are referred to therein.