|Publication number||US2819982 A|
|Publication date||Jan 14, 1958|
|Filing date||Oct 29, 1953|
|Priority date||Nov 15, 1952|
|Also published as||DE928807C|
|Publication number||US 2819982 A, US 2819982A, US-A-2819982, US2819982 A, US2819982A|
|Inventors||Haes Bartholomeus, Jan Willem Van Tyen, Westerveld Willem|
|Original Assignee||Philips Corp|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (7), Referenced by (3), Classifications (14)|
|External Links: USPTO, USPTO Assignment, Espacenet|
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
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US2079784 *||Jan 19, 1933||May 11, 1937||Robley C Williams||Plating by thermal evaporation|
|US2138637 *||Apr 23, 1938||Nov 29, 1938||Handy & Harman||Alloys|
|US2386876 *||Nov 30, 1943||Oct 16, 1945||Libbey Owens Ford Glass Co||Method of coating surfaces with quartz|
|US2424085 *||Aug 11, 1943||Jul 15, 1947||Shell Dev||Supported silver catalyst and its preparation|
|US2450340 *||Feb 3, 1944||Sep 28, 1948||Mallory & Co Inc P R||Silver base alloy for metal evaporation|
|US2450850 *||Dec 3, 1946||Oct 5, 1948||Libbey Owens Ford Glass Co||Method of coating by evaporating metals|
|US2450856 *||Dec 3, 1946||Oct 5, 1948||Libbey Owens Ford Glass Co||Method of coating by evaporating metals|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US2904451 *||Dec 5, 1957||Sep 15, 1959||Gen Electric||Vaporization coating process and alloy therefor|
|US5493170 *||Sep 9, 1994||Feb 20, 1996||Philips Electronics North America Corporation||High efficiency sealed beam reflector lamp|
|US5789847 *||Oct 24, 1995||Aug 4, 1998||Philips Electronics North America Corporation||High efficiency sealed beam reflector lamp with reflective surface of heat treated silver|
|U.S. Classification||427/593, 427/162, 427/107, 427/166, 445/9, 420/501|
|International Classification||C23C14/26, C03C17/09|
|Cooperative Classification||C03C2217/251, C23C14/26, C03C2218/15, C03C17/09|
|European Classification||C03C17/09, C23C14/26|