GB444723A - Improvements in or relating to methods of applying a top layer to an article, more particularly to the surface of an electric device - Google Patents

Abstract

444,723. Coating by electrophoresis; static contact rectifiers ; electric discharge apparatus; electric incandescent lamps. NAAMLOOZE VENNOOTSCHAP PHILIPS' GLOEILAMPENFABRIEKEN, Emmasingel, Eindhoven, Holland. June 7, 1935, No. 16622. Convention date, Aug. 8, 1934. [Classes 37 and 41] [See also Groups XI and XL] The coating substances are deposited by cataphoresis without electrolysis from a mechanically obtained suspension in a non-aqueous medium such as alcohol, acetone or methylethyl ketone. The suspended material is finely divided but is not in the colloidal state ; shaking or stirring is necessary before cataphoresis. The following articles may be coated according to the invention, viz. : (i) electrodes of electric discharge tubes with zirconium or zirconium oxide or carbon or with emitting or intensely radiating materials such as barium carbonate, magnesium carbonate or magnesium oxide ; (ii) the heater of an indirectly heated cathode with insulating material; (iii) the filament of an incandescent electric lamp with a getter or with calcium fluoride; (iv) the plates of a condenser with dielectric material; (v) the inner wall of an Ulbrichts ball for photometry with magnesium oxide ; (vi) the inner walls of photo-electric cells. Fluorescent or phosphorescent substances such as calcium sulphide may be deposited over a conductive foundation. Varnish may be deposited. In the manufacture of dry rectifiers, tungsten sulphide is deposited over a thin insulating film present on the electrode. Two or more layers of different materials may be deposited successively. Mixed crystals may be deposited.