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Publication numberUS2819982 A
Publication typeGrant
Publication dateJan 14, 1958
Filing dateOct 29, 1953
Priority dateNov 15, 1952
Also published asDE928807C
Publication numberUS 2819982 A, US 2819982A, US-A-2819982, US2819982 A, US2819982A
InventorsHaes Bartholomeus, Jan Willem Van Tyen, Westerveld Willem
Original AssigneePhilips Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Production of silver mirrors by volatilisation
US 2819982 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

Unite States PRODUCTION OF SILVER MIRRORS BY VOLATILISATION No Drawing. Application October 29, 1953 Serial No. 389,156

Claims priority, application Netherlands November 15, 1952 3 Claims. (Cl. 117-35) It has been suggested before to provide a method of producing silver mirrors by silver-coating and rendering incandescent a filament made of a metal having a very high melting point, such as tungsten or molybdenum. The article required to be coated with silver is then placed near the filament.

This methods permits of providing, for example, glass bulbs for electric incandescent lamps or bowls for reflectors with a reflecting surface.

A known limitation consists in that silver wets the filament poorly and contracts in drops so that the silver drops from the wire. It was suggested before to add to the filament or to the silver a third metal apt to improve the adherence of the silver and to cause it to flow out about the filament. It was suggested to use as the flux the metals of the eighth group and more particularly platinum, palladium, iridium, rhodium, iron, nickel and cobalt and also beryllium.

Even the use of these metals gives rise to difiiculties. It is true that precious metals, such as platinum have the desired effect, but the precentage to be added to the silver is comparatively high. The best results are obtained with a silver alloy containing from 5 to 15% of these metals. However, such alloys are far more expensive than the silver itself. Of the other metals a quantity of the order of 1% is added to the silver. The adherence of such alloys is comparatively poor and it may be necessary previously to coat thefilament entirely with such an alloy by galvanic means.

According to the invention the flux used is silicon and this has the advantage that minute quantities, in the order ent of 0.1%, are sufficient, the wetting of the filament being quite satisfactory. In addition, silicon satisfies the requirement that on volatisation it does not bring about any change in colour of the silver mirror.

For carrying out the method according to the invention pieces of a silver alloy containing for example 0.1% silicon may be introduced into a filament of tungsten, molybdenum or similar high melting point metal. When glowing this alloy will spread quite evenly throughout the surface of the filament.

What is claimed is:

1. A method of producing silver mirrors comprising the steps, introducing an alloy of silver and a minute amount of silicon into a metallic filament consisting essentially of a refractory metal having a high melting point, and heating to incandescence said filament to evaporate the silver therefrom and deposit said silver on the surface of a body placed in the vicinity of said filament thereby to form a silve mirror on said body.

2. A method of producing silver mirrors comprising the steps, introducing an alloy of silver and about 0.1% of silicon into a metallic filament consisting essentially of a refractory metal having a high melting point, and heating to incandescence said filament to evaporate the silver therefrom and deposit said silver on the surface of a body placed in the vicinity of said filament thereby to form a silver mirror on said body.

3. A method of producing silver mirrors comprising the steps, introducing an alloy of silver and about 0.1% of silicon into a metalic filament consisting essentially of a refractory metal selected from the group consisting of tungsten and molybdenum, and heating to incandescence said filament to evaporate the silver therefrom and deposit said silver on the surface of a body placed in the vicinity of said filament thereby to form a silver mirror on said body.

References Cited in the file of this patent UNITED STATES PATENTS 2,079,784 Williams May 11, 1937 2,138,637 Leach Nov. 29, 1938 2,386,876 Ogle et al Oct. 16, 1945 2,424,085 Bergsteinsson July 15, 1947 2,450,340 Hensel et al. Sept. 28, 1948 2,450,850 Colbert et al. Oct. 5, 1948 2,450,856 Colbert et a1. Oct. 5, 1948

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2079784 *Jan 19, 1933May 11, 1937Robley C WilliamsPlating by thermal evaporation
US2138637 *Apr 23, 1938Nov 29, 1938Handy & HarmanAlloys
US2386876 *Nov 30, 1943Oct 16, 1945Libbey Owens Ford Glass CoMethod of coating surfaces with quartz
US2424085 *Aug 11, 1943Jul 15, 1947Shell DevSupported silver catalyst and its preparation
US2450340 *Feb 3, 1944Sep 28, 1948Mallory & Co Inc P RSilver base alloy for metal evaporation
US2450850 *Dec 3, 1946Oct 5, 1948Libbey Owens Ford Glass CoMethod of coating by evaporating metals
US2450856 *Dec 3, 1946Oct 5, 1948Libbey Owens Ford Glass CoMethod of coating by evaporating metals
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2904451 *Dec 5, 1957Sep 15, 1959Gen ElectricVaporization coating process and alloy therefor
US5493170 *Sep 9, 1994Feb 20, 1996Philips Electronics North America CorporationHigh efficiency sealed beam reflector lamp
US5789847 *Oct 24, 1995Aug 4, 1998Philips Electronics North America CorporationHigh efficiency sealed beam reflector lamp with reflective surface of heat treated silver
Classifications
U.S. Classification427/593, 427/162, 427/107, 427/166, 445/9, 420/501
International ClassificationC23C14/26, C03C17/09
Cooperative ClassificationC03C2217/251, C23C14/26, C03C2218/15, C03C17/09
European ClassificationC03C17/09, C23C14/26