Patent GB-755758-A (GB)
Title: Method and apparatus for manufacture of metal films
Inventor: BELITZ HANS GUENTHER
IPC: C23C16/01
Filed: 1954-03-17
Abstract: 755,758. Coating with metals. COMMONWEALTH ENGINEERING CO. OF OHIO. March 17, 1954, No. 7813/54. Class 82(2). [Also in Group XXII] A process for preparing metal foil by the heat decomposition of metal-bearing vapours consists in rotating a roll within a chamber, with the roll surface heated to the decomposition temperature of said vapours, contacting the surface of the roll with the vapours, and continuously stripping the thin film of metal deposited on the roll therefrom. Two types of foil may be produced. One type is produced by depositing upon the roll a thin insulating coating of material which prevents the deposited metal from adhering tightly to the roll, and the other type by depositing metal upon a roll having a surface coating composed of thermoplastic resin, e.g. polyethylene, that is carried off with the metal foil as it is stripped from the roll. The resin may be applied to the surface of the roll by spraying or by use of an auxiliary roller which dips into a trough containing the molten resin, and it may be desirable to coat the roll with insulating material before coating it with thermoplastic resin. The insulating material may be applied by blowing powdered graphite on to the roll, which is preferably made of ground glass, by rotating the roll in a smokey acetylene flame which deposits carbon soot, or by continuously sizing the roll with a wax or resin which does not soften appreciably at the decomposition temperature used. The metals which may be deposited are nickel, chromium, copper, tungsten, tin, zinc, lead, iron, molybdenum, cobalt, antimony, osmium and ruthenium and they may be introduced as their carbonyls, nitrosyl carbonyls, carbonyl halides, hydrides, halides, nitroxyl compounds and alkyls. Specific examples given of such compounds are nickel, chromium, iron, molybdenum and cobalt carbonyls, cobalt nitrosyl carbonyl, osmium carbonyl bromide, ruthenium carbonyl chloride, chromium, tin and antimony hydrides, chromium chloride, copper nitroxyl and lead tetraethyl. The metal-bearing vapours may be mixed with a carrier gas such as an inert gas, carbon dioxide, hydrogen or oxygen-free combustion gases, or their liquid phase may be sprayed into the carrier gas which is heated so as to vaporise the liquid droplets. As shown, metal-bearing gases are introduced into the chamber 10 through conduit 21, the said chamber being provided with a jacket 11 containing a cooling medium and the said conduit being provided with a hood-like portion 22 adapted to direct inflowing gases into contact with a large area of the surface of the roll 16 which is provided internally with heating means 20 such as electrical resistance or induction coils. Tangentially positioned in contact with the exterior of the roll 16 is a doctor blade 23 which strips the coated deposit from the roll. Strip 36 issues between rollers 25, traverses the chamber 28, which contains an inert gas atmosphere, and passes between rollers 31 to reel winding equipment. As the roll rotates a layer of wax, for example, is deposited by an auxiliary feeder roller 35 which dips into a trough containing the molten wax, and if a layer of thermoplastic resin is to be provided it may be formed by replacing the molten wax in the trough by molten thermoplastic resin or, if necessary, a further trough and feeder roller may be provided for the resin.