US3578439A - Amalgamation process - Google Patents

Abstract

METHODS FOR AMALGAMATING IRON, PLATINUM, AND FERROUS ALLOYS, BY ACID CLEANING THE MATERIAL TO BE AMALGAMATED AND PERMITTING MOISTURE TO REMAIN OR FORM ON THE CLEANED METAL PRIOR TO DIPPING IN AMALGAM.

Description

United States Patent 3,578,439 AMALGAMATION PROCESS Maximillian R. Merriman, Upper Hibernia Road, Rockaway, NJ. 07866 No Drawing. Filed July 2, 1968, Ser. No. 741,891 Int. Cl. 'C22c 5/00, 7/00, 35/00 U.S. Cl. 75-129 10 Claims ABSTRACT OF THE DISCLOSURE Methods for amalgamating iron, platinum, and ferrous alloys, by acid cleaning the material to be amalgamated and permitting moisture to remain or form on the cleaned metal prior to dipping in amalgam.

The invention described herein may be manufactured, used, and licensed by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to electrical contact devices and is directed to improved methods for producing such devices by amalgamation, and particularly, the amalgamation of ferrous materials.

It is well recognized that mercury has certain advantages over solid contacts for opening and closing electric circuits. Being a fluid, it presents a fresh surface for each contact closure and does not become corroded and pitted as a result of successive circuit interruptions. On the other hand, solid contacts have certain advantages. They can be made of materials that are lighter than mercury and can be moved at higher speeds. Also, it is possible to apply the forces of a magnetic field more directly to solid contactoperating elements than to a mass of mercury for ef fecting the desired circuit closures and openings.

Accordingly, it is common practice in the prior art manufacture of switches and relay contacts to employ solid contact-operating elements and to provide means for covering the solid elements with a thin liquid coating of mercury. However, when electrical contacts employing substantially pure iron or platinum are desired for use and hermetically sealed devices, such, for example, as in glass to metal or ceramic to metal applications, no known procedures are available for amalgamating these metals.

Accordingly, it is an object of this invention to provide improved methods of forming electrical contacts for use in hermetically sealed devices.

Another object of this invention is to provide improved methods for forming such contacts wherein platinum, or iron, or ferrous alloys are employed.

Other objects and features of the invention will become apparent as the invention is more fully hereinafter disclosed.

In accordance with these objects, I have discovered that iron and platinum metals, and alloys of iron, may readily be amalgamated by anodically etching or dipping the metal or alloy in a suitable acid for cleaning thereof, and then amalgamating the metal or material in a suitable amalgam. Additionally, ferrous alloys may be amalgamated readily and economically by alloying with nickel or copper, for example, and then applying the steps of my invention to form the desired electrical contacts.

More specifically, I have discovered that pure iron or platinum, heretofore unwettable by mercury to form amalgam, may be wetted by mercury by cleaning the metal as aforedescribed and then treating the cleaned metal so as to permit a film of moisture to remain or form on the material before dipping into an amalgam containing a minor portion of an alkali metal.

Although it is not intended that the invention be limited thereto, there is set forth herein below for purposes of Patented May 11, 1971 illustration, examples of procedures and values which may suitably be employed in practicing my invention:

EXAMPLE I A stainless steel rod was placed in a beaker containing a 1% H01 solution for about 10 minutes. The rod was removed from the dilute acid and placed in an amalgam consisting of 0.4% by weight of potassium, the balance being substantially mercury. The moisture from the dilute acid, present on the steel rod, reacted with the alkali metal of the amalgam as evidenced by the evolution of bubbles, which was determined to be nascent hydrogen which immediately reduced any undesirable oxides formed on the steel rod while undergoing amalgamation. The rod was maintained in the amalgam for about 25 seconds and the resultant amalgam on the piece was adherent and could not be wiped off with a cloth with vigorous rubbing.

EXAMPLE II The procedure was generally similar to that described under Example I except high carbon steel drill was used. The resultant amalgamated piece was satisfactory.

EXAMPLE III platinum was dipped into an amalgam as described under' Example I and the resultant amalgamated piece was very satisfactory.

EXAMPLE IV An alloy comprising 45 nickel and 55 iron was anodically etched in 10% nitric acid, the alloy being made the positive electrode and platinum being made the cathode, although the metal used for the cathode is not critical. An anodic current was applied to the nitric acid until the alloy was cleaned. The cleaned alloy was immediately rinsed in distilled water and much of the excess moisture wiped off. A small amount of moisture was permitted to remain on the cleaned alloy surface. The alloy, with moisture on its surface, was then dipped into an amalgam containing 0.5% of an alkali metal, sodium, for a period of about 20 seconds. An amalgam formed, the alkali metal contained within the amalgam reacting with the moisture on the alloy surfaces to release hydrogen. An extremely shock-resistant and adhering amalgam resulted.

EXAMPLE V The procedure used was similar to that described in Example IV except the alloy was 52 nickel-48 iron and a 25% nitric acid anodic solution was used.

The concentration of the acid used is not critical. Concentrated acid may even be used so long as the cleaned alloy is immediately rinsed in distilled waterv and the excess water shaken off the piece to be amalgamated. The piece to be amalgamated cannot be completely free from moisture as abovedescribed.

Sulphuric acid may be substituted for nitric acid or hydrochloric acid, the solubility of the cathode in the acid being a major consideration. Since I have provided means for amalgamating substantially pure iron, the nickel in the nickel-iron alloy can range from a trace amount all the way up to Several examples of other ferrous alloys amalgamated in accordance with my invention are presented below:

EXAMPLE VI A 9.5 nickel-balance substantially iron (about 1% of carbon, manganese, chromium, copper, and molybdenum) alloy wire was cleaned by dipping in 50% nitric acid,

EXAMPLE VII The procedure used here was generally similar to that described under Example VI except the alloy comprised 77.4% copper, 13.3% iron, 3.7% molybdenum, 5.0% copper, and 0.4% of trace metals.

EXAMPLE VIII The procedure used was substantially identical to that described under Example VI except the alloy used was a 3%97% iron alloy. The alkali metals to be used with the amalgam are not limited to sodium and potassium. For example, cesium and rubidium in the range of about 0.01 to 1.0% by weight of the mercury may successfully be used. If excess alkali metal is present in the amalgam, it will either float to the top of the mercury or precipitate. In either case, the amalgam is not deleteriously effected.

From the data above, it is expected that iron-nickel and iron copper alloys may readily be amalgamated wherein the iron content varies from 100% to only a trace amount of either copper or nickel or both.

In all examples, the amalgam is desirably covered with kerosene, or the like, to prevent the alkali metal in the amalgam from oxidizing, or the amalgam is maintained in contact with an inert gas. Further, in the event the acidcleaned alloy is inadvertently dried completely, it is only necessary to re-dip it in distilled water and Wipe off the excess water before immersion into the amalgam.

I claim:

1. Process for amalgamating a metallic material selected from the group consisting of iron, platinum, and iron alloys, comprising the steps of:

cleaning said material with acid;

wetting said cleaned material to insure presence of moisture on surfaces thereof;

dipping said material having moistened surfaces into an amalgamated comprising an alkali metal and mercury to produce said amalgamated material.

2. The process as described in claim 1 wherein said metallic material is substantially pure iron.

3. The process as described in claim 1 wherein said metallic material is substantially pure platinum.

4. The process as described in claim 1 wherein said metallic material is a ferrous alloy.

5. The process as described in claim 1 wherein said acid is selected from the group consisting of hydrochloric, nitric, and sulphuric, and the concentration of said acids range from about 1% to concentrated.

6. The process as described in claim 1 wherein said amalgam comprises about 0.01 to 1.0 weight percent of said alkali metal and wherein said alkali metal is selected from the group consisting of sodium, potassium, cesium and rubidium.

7. The process as described in claim 1 wherein said iron alloy comprises only trace amounts of a metal selected from the group consisting of nickel, copper, and nickel and copper.

8. The process as described in claim 1 wherein said iron alloy is selected from the group consisting essentially of, by weight percent, 45 nickel and iron; 52 nickel and 48 iron; 9.5 nickel, balance substantially iron; and 77.4 copper, 13.3 iron, 3.7 molybdenum, 5.0 copper and 0.4 trace metals.

9. The process as described in claim 1, wherein said wetting step comprises allowing at least a trace of the moisture adhering on said material from said cleaning step to remain thereon prior to said dipping step.

10. The process as described in claim 1, wherein said wetting step comprises contacting said material with distilled water and allowing at least a trace of said water to remain thereon prior to said dipping step.

References Cited UNITED STATES PATENTS 71,307 11/1867 Johnston -169X 2,547,536 4/1951 Pollard 148-16X 2,784,061 3/1957 Cunningham 75--169X 2,850,382 9/1958 Kelly 75-169 3,154,413 10/1964 Dow 75-135 3,182,984 5/1965 Gilbert 75-l69X HYLAND BIZOT, Primary Examiner J. E. LEGRU, Assistant Examiner U.S. c1. X.R 75-135, 169, 172; 14816