GB1247731A - Improvements relating to the electrical deposition of material - Google Patents

Abstract

1,247,731. Electrical deposition of insulating material. E.M.I. Ltd. Oct. 23, 1968 [Nov. 8, 1967], No. 50821/67. Heading C7B. Insulating particles 8 e.g. of a phosphor such as zinc silver sulphide are deposited on an insulating support 2, e.g. glass or a mica sheet, by providing one surface of the support with a thin electrically conductive film 4, e.g. of antimony, electrically connected to a further electrical conductor, e.g. ring 3, which can be seen from the opposite side of the support, placing the insulating support between an anode 5 and a cathode 6 in an electrically conducting solution, e.g. of aqueous zirconium nitrate in iso-propyl alcohol, containing the insulating particles in suspension so that the conductive film faces one of the electrodes and the further conductor faces the other electrode and applying a P.D. between anode and cathode to cause the particles to be deposited on the conductive film. When a single layer of particles has been deposited current flow ceases and the coated support is then washed in water which removes most of the antimony film. Thereafter the coated support is coated with a nitro-cellulose lacquer film and aluminized, and thereafter baked at 400‹C., removing the lacquer film and the remaining antimony. Instead of antimony aluminium may be used for the conducting film. To improve the deposition a stainless steel grid may be disposed between the anode 5 and the support 2, and in an alternative arrangement instead of ring 3 an annulus of conductive material may be provided on the face of the support directed to the cathode 6.