US2504238A

US2504238A - Anode assembly

Info

Publication number: US2504238A
Application number: US614626A
Authority: US
Inventors: Wesley Andrew
Original assignee: International Nickel Co Inc
Current assignee: Huntington Alloys Corp
Priority date: 1945-07-13
Filing date: 1945-09-06
Publication date: 1950-04-18
Anticipated expiration: 1967-04-18
Also published as: GB613244A; CH263666A; FR930181A

Description

A ril 18, 1950 A. WESLEY ANODE ASSEMBLY 3 Sheets-Sheet 1 Filed Sept. 6. 1945 11W 'EN 1 'OR. ANDREW WE8LEY ATTORNEY A. WESLEY ANODE ASSEMBLY April 18, 1950 2,504,238

Filed Sept. 6, 1945 3 Sheets-Sheet 2 +02 +0.4 +0.6 +0.8 ANODE POTENTIAL //v VOLTS saga 400.4 3a v00: asa saasdwv L/SN3C7 JNEHH/ID INVENTOR. ANDREW WESLEY A TTOR/VEY Filed Sept. 6, 1945 3 Sheets$heet 3 INVENTOR. All DREW WESL E) Patented Apr. 18, 1950 UNITED STATES TENT OFFICE AN ODE ASSEMBLY Andrew Wesley, Plainfield, N. J., assignor to The International Nickel Company, Inc., New York, N. Y., a corporation of Delaware Application September 6, 1945, Serial No. 614,626

In Canada July 13, 1945 The present invention relates to anode assemblies, and, more particularly, to anode assemthat Of the nickel anode material. Thus, for instance, difliculty has been encountered with nickel weld metal used in welding together lengths or parts of nickel, particularly electrolytic nickel, to produce anodes or parts thereof that exceed in length the available nickel anode stock. Similarly, difiiculty has been encountered with nickel weld metals used in welding together pieces of nickel to produce anodes having some particular or desired configuration, as it has been found that when nickel is used to weld together pieces of nickel to form anodes or parts thereof the nickel weld metal is subject to preferential corrosion often resulting in severance of the anodes along the weld joint. Many proposals and attempts have been made to solve this problem of preferential corrosion and of providing a welded anode or parts thereof. Thus, for example, in Canadian Patent No. 392,783 it is proposed to make an anode by connecting together several pieces of electrolytic nickel by means of a dovetailed joint protected against electrolytic attack by a rubber band covering the joint. This method has not proven entirely satisfactory because the anode corrodes preferentially due to an increase in current density at the edges of the rubber band thereby eventually causing the anode to be severed along one edge of the rubber band.

When severance of the anode occurs due to preferential corrosion of the joint, irrespective of the proposed prior art methods used for jointing,

the portion of the anode below the line of severance drops to the bottom of the bath, thereby greatly diminishing the amount of anode remaining for further plating. The portion of the anode that drops results in a substantial economic loss and possible damage to the work in progress. Furthermore, if an anode bag is used, the dropping of the severed portion of the anode often ruptures the bag. releasing particles enclosed 4 Claims. (Cl. 204-286) therein into the plating bath thereby adversely affecting the deposit on the cathode due to the physical inclusion of the particles in the deposit. Similarly, preferential corrosion of weld joints has also been an obstacle to the use of nickel anodes to which connections, including hooks, electrical connections, etc., are welded and which connection cannot be submerged or otherwise subjected to the electrolytic effect of the plating bath without showing preferential corrosion at the weld. When a connection or supporting means, such as a hook, was welded to a nickel anode, preferential corrosion at the Weld joint occurred when the weld joint and anode were submerged or otherwise subjected to the electrolytic action especially of a sulfate-containing nickel plating bath. Therefore, it was common practice in the nickel electroplating industry not to submerge the entire nickel anode, but to maintain the plating bath level at a sufficient distance below the top of the suspended anode in order that preferential corrosion would not occur at the weld jointing the connection to the anode proper. Such practice results in an economic loss as a substantial amount of the anode is not used and becomes anode scrap. Moreover, preferential corrosion of the weld joint, in many cases, tends to contaminate the plating bath by introducing materials which adversely affect the nickel deposit.

Furthermore, when unprotected supports for nickel anodes have been used in plating baths, such as in sulfate-containing nickel plating baths, and such supports have been subjected in ,contact with the nickel anode material proper,

, material and subjected to'the electrolytic and/or corrosive effects of the plating bath. Preferential corrosion of the anode supports often results in contamination of the plating bath by introducing materials which adversely affect the nickel deposit. In order to prevent such preferential corrosion of the anode supports, it has been found necessary, in the nickel electroplating industry, to use protective means, such as coatings which are oftentimes expensive, to protect the nickel anode supports from exhibiting objection- 3 abie preferential corrosion when used in nickel plating baths and subjected to the electrolytic action thereof.

As will be readily appreciated from the foregoing, there is a well recognized need in the art of nickel electroplating for electroplating articles and assemblies thereof comprising in whole or in part a metal composition dissimilar to that of the nickel anode material proper, so that preferential corrosion of the dissimilar metal will not occur when in contact with the nickel anode material and subjected to the electrolytic and corrosive effects of a nickel plating bath. Many attempts and proposals have been made to overcome the foregoing and other difiiculties and problems, but as far as is known, such attempts and proposals have not been completely satisfactory when carried into practice in overcoming the obstacle of preferential corrosion.

I have discovered that undesirable preferential corrosion of a dissimilar composition, as for example a welded joint in a nickel anode or a welded connection to a nickel anode or an unprotected support portion for a nickel anode, in contact with the nickel anode material proper, i. e. the body portion, at the anodic terminal of a nickel plating bath, especially a sulfate-com taining nickel plating bath, and subjected to the electrolytic action of such bath in plating therefrom, is overcome when said dissimilar metal composition contains nickel and a controlled amount of chromium. Although it has been found that the chromium-containing composition employed in the present invention is less noble than nickel itself, I have discovered that the chromium-containing composition does not corrode preferentially when in contact with nickel and subjected to the combined electrolytic and corrosive action of a nickel plating bath and this discovery has been applied to electroplating articles and assemblies thereof provided by the present invention as herein described.

It is an object of the present invention to provide welded nickel anodes in which the weld metal is not subject to preferential corrosion when subjected with the nickel anode material proper to the electrolytic, corrosive, and/or other detrimental action of a nickel plating bath, particularly sulfate-containing nickel plating baths; and to provide a method for producing such welded nickel anodes, particularly of electrolytic nickel, wrought nickel or cast nickel, that do not fail or exhibit preferential corrosion at the weld joint or joints when subjected with the nickel anode material proper to the electrolytic, corrosive, and/ or other detrimental action of a nickel plating bath.

It is another object of the present invention to provide an elongated nickel anode by welding together members of nickel so that the weld joint or joints will not fail or show preferential corrosion when subjected with the anode material proper to the electrolytic, corrosive, and/ or other detrimental action of a nickel plating bath, particularly a sulfate-containing nickel plating bath; and to provide a method for producing such an elongated anode, particularly from electrolytic, wrought, or cast nickel.

t is still another object of the present invention to provide welded nickel anodes shaped to conform, or to approximately conform, with the cathode, which anodes do not fail or exhibit preferential corrosion at the weld joint or joints when subjected to the electrolytic, corrosive, and/ or other detrimental action of a nickel plata ing bath, particularly a sulfate-containing nickel plating bath; and to provide a method for producing such anodes, particularly from electrolytic, wrought or cast nickel.

The present invention also contemplates the provision of nickel anodes with welded connection portions including welded hooks, welded rods, etc, which connections may be submerged in a nickel plating bath without showing preferential corrosion at the weld joint when subjected in contact with the nickel anode material proper to the electrolytic, corrosive, and/or other detrimental action of the bath; and to provide a method for producing such welded nickel anodes, particularly from electrolytic, wrought, or cast nickel.

Furthermore, it is within the purview of the present invention to provide electroplating assemblies containing a metal composition dissimilar to nickel anode material, and which dissimilarcomposition does not fail or exhibit preferential corrosion when in contact with the nickel anode material and subjected to the electrolytic, corrosive, and/or other detrimental action of a nickel plating bath; and to provide a method for making such electroplating assemblies.

Still another object of the present invention is to provide unprotected supports for nickel anodes and assemblies thereof, which supports may be welded or otherwise in electrically conductive contact with the nickel anode material proper, so that the supports, and any welded joints therein or with the anode, do not fail or show preferential corrosion when submerged in 01' otherwise subjected while in contact with the anode material proper, to the electrolytic, corrosive, and/or other detrimental action of a nickel plating bath; and to provide a method for producing such anode supports.

Various other objects, advantages and features of the present invention will become apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which:

Fig. 1 illustrates an elongated welded anode embodying the present invention;

Fig. 2 is a welded anode, having an irregular shape, produced in accordance with the present invention;

Fig. 3 shows an anode with welded connections which are submerged in the plating bath;

Fig. 4 illustrates an unprotected quoit anode holder, such as provided by the present invention;

Fig. 5 shows an unprotected basket type holder for nickel anode materials, contemplated by the present invention;

Fig. 6 depicts curves showing anode polarization for various anode and weld materials;

Fig. *7 is a reproduction of a photograph showing a front view of an anodically corroded electrolytic nickel anode containing a weld joint of nickel, such as proposed by the prior art;

Fig. 8 is a reproduction of a photograph showing a side view of the anode depicted in '1;

Fig. 9 is a reproduction of a photograph illustrating a front view of an anodically corroded electrolytic nickel anode containing a weld joint of the metal composition employed by the present invention; and

Fig. 10 is a reproduction of a photograph illustrating a side view of the anode depicted in Fig. 9.

Generally speaking, the present invention provides anode assemblies and component elements thereof, comprising a composition dissimilar to the nickel anode material proper, i. e., the nickel portion, and in contact therewith at the anodic terminal, which dissimilar composition does not show preferential corrosion when subjected with the anode material proper to the electrolytic, corrosive, and/or other detrimental action of a nickel plating bath in plating therefrom. The invention particularly includes improved assemblies such as nickel anodes having at least one welded joint made of a dissimilar metal having a critical composition, and provides a method for producing such nickel anodes that do not fail or exhibit preferential corrosion at the weld joint or joints. It also includes supports for and assemblies thereof with nickel anodes wherein the support portions comprise the dissimilar metal having a critical composition, and provides a method for producing such supports which are to be welded or otherwise in contact with the nickel anode material, that do not show preferential corrosion. In the electroplating articles and assemblies thereof, including the welded anodes, contemplated by the present invention, the dissimilar composition in contact with the nickel anode material proper contains nickel and a critical amount of chromium not less than about 8%. For the purpose of obtaining satisfactory results, the dissimilar metal composition employed in the present invention, which composition is used in contact with the nickel portion of the anode in an electroplating bath, is controlled within the following ranges:

Nickel at least about 8% Chromium about 8 to about 30% Iron up to about 74% The sum of the nickel, chromium and anyiron in the aforementioned composition employed in the present invention totals at least about 90%. Thus, when iron is not present in the composition, the nickel content thereof can be as much as about 92%.

In producing a welded nickel anode in accordance with the present invention, the weld metal comprises a composition within the aforementioned ranges, and such a welded nickel anode does not fail and is not subject to preferential corrosion at the weld when used in a nickel plating solution, particularly of the sulfate-containing type, at current densities from 3 to 120 am'-.

peres per square foot; e. g., 30 amperes per square foot. Similarly, supports for and assemblies thereof with nickel anodes, wherein said supports comprise a metal composition within the aforementioned ranges, do not fail and are not subject to preferential corrosion when subjected in electrically conductive contact with the anode material proper to the electrolytic, corrosive, and/or other detrimental action of a nickel plating bath, particularly of the sulfate-containing type.

While the composition given hereinbefore has been found satisfactory, in carrying the present invention into practice, I prefer to employ a composition comprised predominantly of nickel and preferably maintained within the following ranges:

Chromium about 8 to about 30% Iron up to about 10% Nickel balance A satisfactory composition, falling within the preferred range, contains about 80% nickel and about chromium. Another suitable composition contains about 80% nickel, about 14% chromium and about 6% iron. It is preferable, for improved results, that the iron content of the metal composition given herinbefore be maintained as low as practicable, as when a percentage of iron greater than about 50% is included, pitting of the; metal composition tends to begin when subjected, in contact with the nickel anode material proper, to the electrolytic, corrosive, and/or other detrimental action of a nickel plating bath. The occurrence of pitting in the metal composition is an indication that some of the iron has gone into solution in the plating bath. While minor amounts of pitting are not detrimental, if the pitting is excessive, the plating bath may become deleteriously contaminated with iron. I have found that when the iron content in the metal composition does not exceed about 74% it is not excessive so as to result in deleterious contamination of the plating bath with iron. Nevertheless, it is pre- 1" erred that the composition be substantially ironfree or that the iron content be kept as low as practicable in order to minimize any tendency to contaminate the plating bath with iron due to pitting. In actual practice a small amount of iron, generally in excess of 0.1%, e. g., about 2% or more, usually will be present in the compositions given hereinbefore, wherein the iron content does not exceed 74%, and is preferably maintained as low as practicable, exhibit satisfactory performance when employed in the e1ectroplating apparatus of the present invention and subjected, in contact with the nickel portion of the anode to the electrolytic, corrosive and/or other detrimental effect of a nickel plating bath.

When it is stated herein that nickel constitutes the balance of the composition, it is to be understood that small amounts up to about 10%, and preferably not more than about 4% of minor constituents, impurities and incidental elements may be present, although not essential for obtaining the desired results. Thus, the metal composition can contain small amounts of carbon, aluminum, columbium, titanium, silicon, manganese, boron, magnesium, sulfur and phosphorous. The carbon content of the composition is preferably kept as low as possible in order to obtain most satisfactory results, as presence of carbon in the composition tends to decrease resistance to preferential corrosion of the composition and-also causes formation of carbides that result in inter-granular corrosion and weakening of the metal composition when subjected in contact with the nickel anode material proper to the electrolytic action of a nickel plating bath. In general, if carbon is present in the composition, it should preferably not be present in amounts exceeding about 0.2%. The maximum content for any other elements in the composition should preferably not exceed about 2%.

When reference is made herein to nickel anode material, it is intended to mean the nickel anodes, including electrolytic, wrought and cast nickel anodes commonly used in electroplating of. nickel. The commonly used nickel anodes contain at least about 99% of nickel.

For the purpose of giving those skilled in the art a better understanding of the present invention and the improved results obtained thereby, the following illustrative examples are given:

Example 1 A nickel anode was prepared in accordance with the present invention by jointing together members of electrolytic nickel with a weld comprosing about nickel and about 20% chro- It was used as an anode in a Watts-type grams .per{ liter iof.'nickel.s'ulfate,,45 grams per liter of .nickel chloride vand about 30 ,gramsper liter of boric acid at .pI-Iof about.2.0.at 130 F. andat a current density ofabout 3.0.amperes ,per square foot. The weld joint wasso resistant to preferential corrosion that substantially no. attack thereon was observed whereas the electrolytic nickel of the anode-proper was consumed in asatisfactory manner.

' .These resultsare depicted bythephotographs .in Figs. 9 and 10 wherein'it will be clearly observed that practically no corrosionof the weld occurred,- whereas the nickel of theanodeproper was consumed in the usualmanner.

Emaml le .2

Anickel anode such ascontemplated by the present invention was prepared by jointing together pieces of-electrolytic nickel sheet with a weld comprising about 80% nickel, about 14% chromium and about 6% iron; such acomposition is sold under the trade-mark Incone1." Under the same conditions as in Example 1, there rosion' at the weld joint, although there was minor evidence of slight isolated pitting in some cases. .The pitting was not, however, in suflicient quantityto significantly affect the strength of the weld or. to deleteriously contaminate the bath with iron. The electrolytic nickel of the anode'proper was consumed in the usual manner.

- Example 3 A'nickel anode was prepared by jointing together pieces of electrolytic nickel sheets with a weld having acomposition employed in the present invention and comprising about 25% nickel, about 20% chromium and about 55% iron. Under the same conditions as in Example 1, the weld did not show preferential corrosion, 'although the weld joint showed more evidence of pitting than in Example 2. In the weldcomposition of Example 3, the presence of pits in the weld indicated that some iron had gone into solution but the amount was not so great as to excessively contaminate the plating bath with iron. The electrolytic nickel-of the anode proper was consumed in the usualmanner.

Example 4 For comparative purposes, a nickel anode was prepared by jointing together pieces of electro- :l-ytic nickel sheets with a weld of nickel, such as proposed prior to the present invention. Under the same conditions as in Example 1, the weld showed very marked preferential corrosion. These results are shown by Figs. '7 and 8 wherein it will be noted that marked preferential corrosion of the weld joint occurred at such a faster rate than the nickel of the anode that severance at the weld joint would occur long before the anode material was consumed.

'- Ezvample 5 For further comparison, anickelanodewas prepared by jointing together pieces of electrolytic nickel sheets with a weld made of a nickelcopper alloy containing about two-thirds nickel and one-third copper, e. g., about 67% nickel and about 30% copper; such compositions are sold under the trade-mark Monel. Under the same conditions as in Example 1, activecorrosion was exhibited by the weld joint. and like was substantially noffailure or preferential corthe weld of Example 4, did not possess resistance to. preferential corrosion.

Example 6 For still a further comparison, to indicate the unsatisfactory results obtained with a nickelface weld composition that is not within the range contemplated by the present invention, a nickel anode was prepared by jointing 'together pieces of electrolytic nickel sheets with a weldcomprising about 18% chromium and about 80% iron. Under the same test conditions as in Example 1, this weld suffered severe intergranular attack and badly contaminated the plating solution with dissolved iron.

Although the exact nature of the phenomena, explaining the improved resistance to preferential corrosion exhibited by the metal composition employed by the present invention, has not been definitely ascertained, it is believed that the'following theory, discussed in connection with welding ,of nickel anodes, will be helpful in understanding the principles underlying the present invention. In the welding of nickel anodes, as proposed by the prior art, it is believed that preferential corrosion of the nickel weld metal occurred because the anode polarization of the nickel weld metal is lower than that of the nickel anode material proper. The lower anode polarization of the nickel weld metal is believed to be caused by presence of impurities in the weld together with the cast structure of the weld. Therefore, as the anode polarization of the weld metal .is lower, the current density eifective thereon is higher than on the nickel of the anode, and preferential corrosion is exhibited by the nickel weld metal when in contact with nickel of the anode and subjected to the electrolytic, corrosive and/or other detrimental effects of the plating bath, as depicted in Figs. 7 and 8. If the weld metal contains nickel and a critical amount of chromium, as contemplated by the present invention, the weld metal has a higher .anode polarization than the nickel of the anode proper. Thus, the current density effective upon the weld metal is less than .upon the nickel of the anode proper, and preferential corrosion of the weld metal does not occur, as shown in Figs. 9 and 10.

Inasmuch as chromium is less noble than; nickel, it would be expected, by those skilled in the .art,.that addition of chromium to nickel would result in an alloy that preferentially corrodes when in contact with nickel and subjected to the electrolytic, corrosive, and/or other detrimental effects of a nickel plating bath. Although I have, by actual test, found that the chromiumcontaining alloy employed by the present invention is less noble than nickel itself, nevertheless, 0 it has been discovered that the chromium-containing .alloy does not preferentially corrode when in contact with nickel and subjected .to the electrolytic, corrosive and/or other detrimental effects of the plating bath. This improved result is believed to be due to the higher anode polarization of the chromium-containing alloy as compared to nickel, such as commonly used in nickel anodes. In this connection Fig. 6 is a graph showing polarization curves, by'plotl0 ting current density vs. anode potential in volts of various anode and weld metals. Curve A designates the polarization curve for the chromium-containing composition employed by the present invention. Curve B shows the polariza- 7.5 tion-curve for electrolytic nickel, a common type iii) 9 of nickel anode material. Curve depicts the approximate relative position for nickel weld metal such as proposed in the art prior to the present invention. As will be noted from the curves in Fig. 6, the anode polarization of the chromium-containing alloy employed by the present invention is higher than that for electrolytic nickel and cast nickel. Because the chromium-containing alloy employed by the present invention does not corrode preferentially when in contact with electrolytic and cast nickel and subjected to the electrolytic effects of a nickel plating bath, it is believed that the resistance to preferential corrosion of the chromium-containing alloy is due to its higher anode polarization. Similarly, it can be noted from the curves in Fig. 6 that nickel weld metal, curve C, proposed by the prior art, has a lower anode potential than electrolytic nickel, shown by curve B, and therefore, the nickel weld metal would preferentially corrode if used to weld electrolytic nickel and subjected in contact therewith to the electrolytic, corrosive and/or other detrimental effects of nickel plating baths. Although the believed reasons for the improved resistance to preferential corrosion exhibited by the chromium-containing alloy employed by the present invention are recited hereinbefore, it is to be understood that the theory underlying the improved performance of the chromium-containing alloy may be difierent than that recited hereinbefore. However, regardless of the reasons underlying the improved results obtained with the present invention, it has been found that preferential corrosion of the chromium-containing alloy employed by the present invention does not occur when such alloy is in contact with nickel oi the anode proper and subjected to the electrolytic, corrosive and/or other detrimental effects of a nickel plating bath.

The principles of the present invention can be used to produce electrolytic nickel anodes, wrought nickel anodes and cast nickel anodes of any desired size or shape. Thus, as shown in Fig. 1, two members of nickel anode material, 1. e., the nickel portions, designated by the reference characters I and 2 respectively, are welded together at weld 3 with the chromium-containing metal contemplated by the present invention and described hereinbefore to produce an assembly for use as an anode. Disposed at the top of the assembled anode is a connecting portion, such as hook 4 which may also be welded to the anode by means of the chromium-containing metal, for example, as indicated at weld 5. Thus, by welding, nickel anodes of any desired length that are resistant to preferential corrosion at the weld joint or weld joints may be obtained regardless of the original size of the pieces of nickel to be jointed in preparing the anode.

The present invention is also applicable to the production or anodes having an irregular shape;

for example, a shape conforming approximately to that of the cathode. Such anodes are desired for use in the plating of articles which themselves have an irregular shape whereby the effect of current density upon the surface of the-arti ole to be plated is equalized, and the throwing power increased. Thus, as illustrated in Fig. 2, the anode assembly may comprise several differently shaped members of nickel, i. e., the body portions, designated as 6 and, 1 respectively. As shown, members 6 and I are jointed together at weld. 8 with the chromium-containing metal em ployed in the present invention. In this case,

10 the assembled anode is provided with a comiection portion, such as hook 9 which is welded at Weld ill with the same chromium-containing composition. Thus, it will be readily appreciated that the principles of the present invention are applicable to the production of nickel anodes having any desired shape and configuration without exhibiting preferential corrosion at the weld joint or weld joints when the Whole of the anode body is subjected to the electrolytic, corrosive and/or other detrimental action of a nickel plating bath.

By applying the principles of the present invention, it will be readily understood that welded connections, which may be submerged in the plating bath, can be made to the nickel anode by using the chromium containing composition contemplated by the present invention. For example, a hook by which the anode is hung may be jointed to the anode by a weld having the composition contemplated by the present invention. In this manner, anodes may be provided which can be completely submerged in or otherwise subjected to the electrolytic, corrosive and/or other detrimental action of the nickel plating bath without exhibitin preferential corrosion at the joint of the hook and anode material proper. Hooks jointed to the anode by welding with the chromium-containing composition employed in the present invention are shown in Figs. 1 and 2 wherein hooks d and 9 are welded to the anodes at weld 5 and weld i ll respectively. Suitable protective means or coatings, such as normally used in the art of electroplating, may be used to prevent attack of the hook itself, or the like, by the plating bath. Typical examples of such protective means are stop ofi lacquers or rubber tape.

Another specific application of the invention in making submerged welded connections is the plating of nickel on a drum wherein the anode is completely submerged in the plating bath below the cathode drum. Fig. 3 depicts the application of such an embodiment of the present invention. As shown, reference character H illustrates a nickel anode completely submerged in the plating bath in which a cathode drum l2 isalso partly submerged. In practice under the prior art, the connecting rods, usually made of copper.

support the anode and are protected from attack of the nickel plating bath by means of a protective covering, but nevertheless, diii'iculty is encountered because of preferential corrosion at the weld jointing the connecting rods to the anode. By use of the chromium-containing metal contemplated by the present invention, the nickel anode member Ii is welded to connection per-- tions, such as connecting rods Hi at welds l3. In this manner, nickel anode assembhes can be pro-" vided which may be completely submerged in the plating bath without exhibiting preferential corrosion at the weld joint bonding the nickel anode to the connection portion, i. e., connecting rods. The connecting rods can be coated with a suitable protective coating or can be made to comprise, or be sheathedwlth, the metal composition contemplated by the present'invention whereby no preierentialcorrosion of the weld joints or connecting rods" will be exhibited when subjectedto the electrolytic, corrosive and/or other detrimental action of a nickel'plating' bath,'particu larly a sulfate-containing nickel plating bath.

In still another application, the chromiumcont'aining metal employed in the present inven-- tion may be used to produce anode supports, such as anode holders, anode hooks, anode boxes, anode baskets, quoit anode holders, holding-frames and similar articles "well. known xinrthe; art of. nickel electroplating. Use of the.chromiumecontainlng metal contemplated in the present. invent1on for nickel anode materials proper and subjected to the electrolyticaction of a nickel plating bath, particularly a sulfate-containing nickel plating bath,

will enable more efficient. utilization of" nickelanodes by making it possible'to completelyv submerge theanodes in the plating bath. As an example to illustrate this embodiment. of the present invention, Fig. 4 shows a quoit' anode holder i5 such as used in current practicefor anode materials. When it is desirable toxemploy-anodic material such" as in the 'form of plates, sheets or quoits;-isuch'forms may 'be strung uponanode material holder l5' in Fig. 4, which holder may be providediwith athook: IG'at; one end and provided at theiother extremitywith a removable. or. fired discor base I12 InFiga l quoits l8 arestrung on theanode holder l 51-" In practice under the prior art',.th'e anode materialholder 15 was provided withi a protective coveringzsuch as lead or rubber,"

in order-to prevent preferential corrosion of the anode material holder; By utilizing the principle ofthe present invention, and producing the anode material holder l5, including-'its'base' l 1, from the chromium=containingmetal contemplated in the present invention;.theiiholder will not fail orshow preferential corrosion when subjected; in assembly and incont'actiwiththe nickel anode material proper, toxtherelectrolytic, corrosive and/or other detrimental action: of anickel plating'bath, par-' ticularly a sulfate-containing nickel plating bath. Thus, it is unnecessary touse a coating of lead,

rubber or other: material to protect the. anode hol'derfrom preferential corrosion in:the plating bath.- Still another example illustrating 'thisembodimentof the present invention is Fig; 5 which shows an: anodic material holder: of the'basket type used in: the" electroplating industry. A

holderzof this type comprisesyertical members: I9; 20, 21 and 22 and horizontal.

members

3, 24;"

25, 26; 21,523, 29 and othersnot shown. Upon this frame-is mountedpreferably a perforated metal sheet 30. The basket is suspended in the bath by means of members Hand 32. In the prior art, the basket was'generally protected from the electrolytic'action of the plating'bath by-protective means, suchias a vulcanized rubber coatingr Use. of the chromium-containing alloycontemplated in the presentinvention for'producing the complete basket, including-the hooks -3l and 32, willl provide-an unprotectedzanode support that will not show. preferential corrosionwhen in. assembly and in contact. with: the nickel anode material proper, and submerged: in, or otherwise.

subjected to the: electrolytic, corrosive and/or other detrimental. .action: of a. nickel platingbath, particularly the; sulphate containing-rnickel platingbaths. As a result, it is not necessary to use theprotective means required heretofore to proteot' such. anodic support from the electrolytic action of the bath. Likewise anode supports such, as hooksiAandfl, shown inFi'gs. l. and 2 respectively, maybe made of the'chromiumecontaining metal contemplated in the present invention. Availability of such unprotected anode supports that do not show preferential corrosion will enable I more eifective utilization of nickel anodes by making it possible to subject the Whole of the unprotected anode supports, including holders and hooks, to the electrolytic action of'the plating.

facial relationship by-the chromium-containing composition 'employe'drby the present invention.

Thus, the laminated-body portion may be sup-- ported by a hook-like member having a bent threaded shank, e. g.,,bent at about degrees,-.

said threaded shankpassing through holes inzthe laminations of the body portion and having-abolt to fasten together the laminationsonto the support. In-order to support theanodein a vertical position-in the plating bath, another hook-like support can-be fittedonto the bent shank-between the laminated body portion and the bolt. The" supports, e. g;, hook-like members and the shanksthereof, as Wellas the bolt, in accordance withthe present invention, are made. of the chromiumcontaining compositiondescribed'herein.

It should. also be understood thatlthe principle of the present invention isapplicable tothe. welding of any component partsof. anodes and anode;-

supports and assemblies. thereof. that areto besubjected to the electrolytic and/oricorrosive action of a nickelplating. bath,.especially. of the sulphate-containing nickel plating bathsr The term anode supports. usedherein is in-.

tended to include electroplating articlessuchas. anode hooks, anode holders, anode boxes,.anode. baskets, quoit anode holders, holdin hooks, and

similar anodic articles well knownintheartof electroplating which aresubjectedin contact with the nickel anode materials proper to the electrolytic, corrosive and/or. other detrimental. action of the nickel plating bath.

Although the present invention .has been described. in conjunction with certain preferred embodiments, those skilled in theart will understand that variations and modifications thereof can be made. Thus, generally speaking, cobalt is for practical purposes considered interchangeable with respect to.nickel to make the anodes and parts thereof such as described herein, and the present invention is intendedto applywhen cobalt isusedto replace in part, the nickel content of the chromium-containing.metal composirtion employed in the present invention. Variations and modifications-are consideredto bewithr in the purview and the scope of the specification. and appended claims.

I claim:

1. A new articleof manufacture comprising a plurality of nickel; members. a,.supporting memher and a plurality of weldmetal jointsjoining saidnickel membersand said supporting member. into. the structural form of, an. electroplating. anode suspended inuse by saidsupporting member, said weld .metal joints and saidsupporting member having controlled metal compositions containing 8% to 30% chromium, at least 8%- nickel, and 0.1% to 74% iron, the sum of the chromium, nickel and iron contents being at least 90%, saidanode being characterized by'improved resistance to preferential attack-at thewelds and upporting member when. subjected to anodic- 13 attack during electroplating from a sulfate-containing nickel electroplating bath.

2. A new article of manufacture comprising a plurality of electrolytic nickel members, a suspension member and a plurality of weld metal joints joining said electrolytic nickelmembers and said suspension member to structurally form an electroplating anode suspended in use by said suspension member, said weld metal joints and said suspension member having controlled metal compositions containing 8% to 30% chromium, at least 8% nickel, and 0.1% to 74% iron, the sum of the chromium, nickel, and iron contents being at least 96%, said anode being characterized by improved resistance to preferential attack at the welds and suspension member when subjected to anodic attack during electroplating from a sulfate-containing nickel electroplating bath.

3. As a new article of manufacture, a welded nickel electroplating anode comprising a plurality of electrolytic nickel sheet members, a sus' pension member, and a plurality of weld metal joints joining said electrolytic nickel sheet members and said suspension member into the structural form of an electroplating anode longer than said electrolytic nickel sheet members and suspended in use by said suspension member, said weld metal joints being exposed in use to a sulfate-containing nickel electroplating bath and having a controlled metal composition containing 8% to 30% chromium, at least 8% nickel, and up to 74% iron, the sum of the chromium, nickel and iron contents being at least 90%, said welded anode being immersed in use in a sulfate-containing nickel electroplating bath and being characterized by improved resistance to preferential corrosion at the weld when subjected to anodic corrosion therein.

4. As a new article of manufacture, a welded nickel electroplating anode comprising a plurality of electrolytic nickel sheet members, at

least one weld metal joint joining said electrolytic nickel sheet members into the structural form of an electroplating anode longer than said electrolytic nickel sheet members and suspending means to suspend said welded anode in a sulfatecontaining nickel electrolyte and to provide the sole electrical connection to said anode, said weld metal joint having a controlled metal composition containing 8% to 30% chromium, up to 10% iron, and the balance essentially nickel, said welded anode being suspended in use to immerse substantially the whole of said nickel members and said weld metal joint in a sulfate-containing nickel electroplating bath and being characterized by improved resistance to preferential corrosion at the weld when subjected to anodic corrosion therein.

ANDREW WESLEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS OTHER REFERENCES "Corrosion Resistance of Metals and Alloys, McKay, Reinhold Publishing Corp., New York, 1936, pp. 32, 33 and 358.

Certificate of Correction Patent No. 2,504,238 April 18, 1950 ANDREW WESLEY It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 1, line 3, for nicked read nickel; column 6, line 26, for the syllable and Words positions given hereinbeforo, wherein the iron" read position. The metal compositions given herein/before, wherein the iron; lines 73 and 74, for comprosing read comprising; column 11, line 53, for members 3 read members 23;

and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Oifice.

Signed and sealed this 8th day of August, A. D. 1950.

THOMAS F. MURPHY,

Assistant Gammissioner of Patents.

Claims

1. A NEW ARTICLE OF MANUFACTURE COMPRISING A PLURALITY OF NICKEL MEMBES, A SUPPORTING MEMBER AND A PLURALITY OF WELD METAL JOINTS JOINING SAID NICKEL MEMBERS AND SAID SUPPORTING MEMBER INTO THE STRUCTURAL FORM OF AN ELECTROPLATING ANODE SUSPENDED IN USE BY SAID SUPPORTING MEMBER, SAID WELD METAL JOINTS AND SAID SUPPORTING MEMBER HAVING CONTROLLED METAL COMPOSITIONS CONTAINING 8% TO 30% CHROMIUM, AT LEAST 8% NICKEL, AND 0.1% TO 74% IRON, THE SUM OF THE CHROMIUM, NICKEL AND IRON CONTENTS BEING AT LEAST 90%, SAID ANODE BEING CHARACTERIZED BY IMPROVED RESISTANCE TO PREFERENTIAL ATTACK AT THE WELDS AND SUPPORTING MEMBER WHEN SUBJECTED TO ANODIC ATTACK DURING ELECTROPLATING FROM A SULFATE-CONTAINING NICKEL ELECTROPLATING BATH.