US2071645A - Electrode and electrical contact - Google Patents

Description

Feb. 23, 1937. J. MCNEIL ELECTRODE AND ELECTRICAL CONTACT Filed Jan. 5, 1935 M'ckel Alloy 011 or 0.1 in 8.0% Al taing 0.1 to 8.0%ALuminug-n murum up in 20% Chromzum lnv'enior,

(.7 57? Mc/Vi] A tor/76 3 lead sulphate.

Patented Feb. 23, 1937 UNITED STATES PATENT orrica ELECTRODE AND ELECTRICAL CONTACT John McNeil, London, England, assignor to The International Nickel Company, Inc., New York, N. Y., a corporation of Delaware Application January 3, 1935, Serial No. 241 In Great Britain December 29, 1933 2 Claims.

The present invention relates to electrical contacts or electrodes subjected in use to the action of electric sparks, especially in corrosive atmospheres, and more particularly, to electrodes for spark plugs for internal combustion engines.

It is well known that electrodes subjected to the action of electric sparks when used at high temperatures deteriorate rapidly, especially in the presence of corrosive atmospheres. Thus, in the case, of internal combustion engines and high duty engines, especially of the high compression type, the deterioration of the electrodes of the spark plugs, particularly the central electrode, is sufliciently rapid to necessitate frequent renewals, especially for good efliciencies.

not been fully explained, but it appears to be due to a combination of the disintegrating effects of the spark and the corrosive action of thesurrounding atmosphere at the high temperature of working. In particular, in the case of doped fuels, the deterioration may be accelerated on account of the presence of ,lead compounds including lead bromide, lead sulphide and Heretofore, spark plugs have been chiefly made from nickel,

manganese-nickel alloys, nickel-chromium alloys,

may .be obtained by criticallamounts of aluminum.

improved electrode or electrical contact .constituted of nickel or nickel alloys and containing It is a further object of the invention to provide animproved' electrode or electrical contact containing aluminum which has superior resistance to the action of electric sparks in corrosive atmospheres and/or at high temperatures.

- The invention also contemplates the provision of. an improved electrode or electrical contact constituted of nickel or nickel alloys and containing 0.1 to 8% aluminum whereby increasedresistance is exhibited towards deleterious actions, especially .thm present in high-compres- As yet the exact cause of this rapid deterioration has the electrodes of It is an object of the invention to provide an sion internal combustion engines using doped fuels.

Other objects and advantages of the invention will become apparent from the following description taken in conjunction with the accompanying drawing which depicts an illustrative embodiment of the present invention.

According to the present invention, increased life is obtained from electrodes and electrical contacts constituted of an alloy containing from 0.1 to 8% aluminum together with nickel or nickel alloyed with one or more of the metals comprising chromium, manganese and iron. When any substantial proportion (i. e. about 2% to about or so) of iron is present, the aluminum may be wholly or in part replaced by silicon. With the lower contents of nickel, relatively low aluminum contents have been generally found to be desirable. Thus, with alloys containing about 15% nickel, the aluminum content should be kept below about 4%.

In the manufacture of a spark plug electrode,.

a binary aluminum-nickel alloy may be 'employed. Thus, an alloy may be used containing, besides aluminum and nickel, only the normal amounts of impurities that are'found' in metallic aluminum and malleable" nickel, respectively. For instance, satisfactory'results have been obtained with an alloy comprising approximately 96% nickel and 4% aluminum.

Ternary alloys of special composition have also been found to give new results when used as electrodes or electrical contacts. Thus, a nickelmanganese alloy containing for instance, about 93% nickel, about 4% manganese, and about 3% aluminum has given satisfactory results. An

electrode of the foregoing composition has a.

superior and increased resistance to the type of action which heretofore has caused rapiddete rioration with the known alloys containing 96% nickel and 4% manganese.

In the case of the nickel-chromium alloys, it C content is limited to 6%. An example of this class of alloy is one comprising about 77% nickel, about-20% chromium and'abou't 3% aluminum which is superiorlto prior. alloys containing 80% nickel and 20% chromium which have been used aselectrodes.

other alloys embodying the present invention that may be employed as electrodes and electrical contacts are' nickel-iron-alloyscontaining from about 2% up to 80% iron and complex-alloys, suchas, nickel-chromium-iron alloys, containing has been foundthat the chromium content should not exceed30%, while the permissible-aluminum from about 8% to about 95% nickel, from about 2% to about chromium, and from about 2% to about 75% iron. In these ferrous alloys, the aluminum may, as mentioned hereinabove, be wholly or partly replaced by silicon.

The accompanying drawing illustrates a standard spark plug. Reference characters I and 2 designate electrodes which are constituted of my improved nickelalloy set forth hereinabove. It is to be observed that the electrode in the illustrative embodiment is a round rod or wire. As those skilled in the art can readily understand, an electrode will have the same or substantially the same composition throughout its cross section from the most interior region to the most exterior region. It is to be understood that no claim is made for the structural features of the standard spark plug illustrated in the drawing as such structural features are old in the art.

Generally speaking, in all of the present alloys, there may be present other elements which would not deleteriously affect the life or render the working of the material impracticable. In particular, if desired the alloys may contain small quantities of molybdenum, titanium, zirconium, tungsten, vanadium, tantalum, copper and berryllium not only without deleterious effect but with improvement of the properties of the alloys in particular directions, while the non-ferrous alloys may contain small quantities of iron. The presence of small quantities of carbon with or without other elements such as tungsten is sometimes desirable forgpurposes of hardening and strengthening the alloy. In general, the amount of carbon added for this purpose should not exceed about 0.25%.

' It is to be observed that any of the additions commonly made to alloys for the purpose of improving their properties may be included. Calcium is of especial value on account of its desulphurizing properties and consequent power I of increasing the forgeability of the alloy. The

other alkaline earth metals, barium and strontium, may also be used for this purpose. As examples of other additions which may be made may be mentioned lithium, which is of value in fiuxing non-metallic inclusions and thereby improving the quality .of the alloy.

What is claimed is:

1. As an article of manufacture, a spark plug electrode adapted to resist corrosion and having improved resistance to erosion by the electric arc in the presence of corrosive products of combustion and constituted of a nickel alloy comprising about 0.1% to about 8% of aluminum diifused throughout the alloy, and the balance consisting essentially of nickel, said electrode having substantially the same composition throughout its cross section from the most interior region to the most exterior region.

2. As an article of manufacture, a spark plug electrode adapted to resist corrosion and having improved resistance to erosion by the electric arc in the presence of corrosive products of combustion and constituted of a nickel alloy comprising about 0.1% to about 8% of aluminum diffused throughout the alloy, an effective amount up to about 20% chromium, and the balance consisting essentially of nickel within a range of about 77% to about JOHN Mom

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