US2046440A - Process for effecting the electrodeposition of metals - Google Patents

Description

July 7, 1936. 5 Ab 2,046,440

PROCESS FOR EFFECTING THE ELECTRODEPOSITION OF METALS Filed Sept. 20, 1933 rne/var Patented July 7, 1936 PROCESS FOR ammo-ram EFFECTIN I DEPOSITION DI -METALS Grace Ellen Adey, Totterldge, London, England Application September 20, 1933. Serial No. 699,258

' In Great Britain 21, 1-932 2 Claims. (carol-s) being of an extremely simple character results in the obtaining of electro-deposits of metal which are more satisfactory than those which have been obtained up to the present, such electro-deposits being in fact of much greater density, that is to say of a less porous nature, than deposits which have hitherto been obtained.

Although the process according to the invention is suitable for the electro-deposition oi metalsin so-called vats or baths, itis particularly applicable when the electro-deposition is eiiected by an apparatus which includes an electrode of the metal to be deposited 'and a sheath or pad of absorbent material enclosing said electrode, the electrode-depositing element thus constituted being adapted to be saturated with an I appropriate electrolyte and then passed over the v surface receiving the deposit.

The process for effecting the electrmdeposition of metals, according to the invention, is characterized by the fact that during the depositing operation the direct electric current supp y to the anode and cathode elements of the apparatus is interrupted intermittently.

The periodicity of such intermittent interruption can have any desired value, but inmost cases a value of between thirty and sixty interruptions' per second is satisfactory, although in other cases values lower or higher than these may be adopted, for instance several thousand interruptions per second or even higher.-

Many forms of apparatusv suitable for the practical realization. of the above process are possible. For example such apparatus according to preferred embodiments is characterized in that the intermittently interrupted direct current supply is obtained by the half-wave rectification of an alternating current supply. There is shown in Fig. 1 'of the accompanying drawing a diagram indicating the waveform of the intermittently interrupted direct current supply that is' obtained by the half-wave rectification of an alternating current, the intermittent direct cur: rent required for the process being shown by the shaded portions of tlie'diagram which are interrupted by the time interval indicated between the points A and B. r

An apparatus for obtainingsuch an intermittently interrupted direct current supply from an alternating current supply is shown diagramcan be obtained. In this case vthe direct current input circuit I includes a vibratory make matically in Fig. 2 wherein l indicates a transformer, of which is adapted to be connected to an alternating current supply when desired, whilst the secondary includes a halfwave rectifier 2 of any desiredtype, the interll mittently interrupted direct current supp y being obtained from the output circuit 3.

Another form of apparatus for obtaining the required intermittently interrupted direct current supply is diagrammatically shown-in Fig. 3 10 wherein a direct current input circuit 4 includes a rotary make and break switch device I, for example a commutator, the required intermittently interrupted vdirect'current supply being obtained from the output circuit 6. The rotary 15 make and break device 5 may of course be rotated in any desired manner, for instance by an electric motor operated from the direct current input circuit 4.

Fig. 4 shows in a diagrammatic manner a still further form of apparatus whereby the required intermittently interrupted directcurrent supply and break device 8 whilst'the intermittently interrupted direct current supply is'obtained from the output circuit 9.

' Other forms of apparatus can be provided in which thermionic-valve oscillators are arranged to control the intermittent interruption of a di-' rect current supply circuit.

As previously stated the process according to the invention is particularly applicable for effecting the electro-deposition of metals by cans of a device which comprises a sheath or 36 pad that encloses an electrode of the metal to be deposited, and in such casesthe entire apparatus necessary for electro-deposition operations can "be arranged so that it 'is readily portable;- whilst moreover it can be adapted for use with several different metals which require different electrical potentials in order to obtain the most satisfactory result. In addition such an appapanel iZ. Said power unitis constituted by the studs of an associated hand "dicated at l8. This secondary circuit also 'inating current,

, The part 24 I desired,

various accessories which containers for diilerent V instancaa copper electrolyte; a nickel electrolyte devices necessary for obtainingthe desired. intermittently interrupted direct-current supply from either alternating current or direct current public supply mains. These devices are showndiagrammatically in Fig. 6 and comprise an electric motor l3 of such a character as tooperate equally well from either alternating current or direct current public supply mains to which it is adapted to be connected when desired by means of a plug and socket fitting l4, this input cir-;

cuit also including an on and oil switch l5.

An alternating current generator I6 is arranged to be driven by the said motor, and the.

output circuit of this generator includes the pri-' mary circuit of a transformer I I, the secondary circuit of which is tapped at desired points, these tapping points being connected to the operable switch includes a half-wave rectifier. i9 oi'.any desired The direct current output, which has, byrea-J. son of the half-wave rectification of the ,alteran intermittently interrupted as indicated by the diagram 1, is fed by suitable conductors characteristic shown in Fig.

j and through the intermediary of an ampere meter 20 and a variable series resistance element 2| to one part of a plug and socket fitting 22, to which is adapted'to be detachably connected the other part of said fitting which is carried atone end of 'a pair oi! conducting wires 23. To the other ends of these two the parts 24 and'25 of plug and socket fittings.

is adapted to bedetachably connected to a metal clip device 26 which device is itselLdapted to be connected'when desired to the surface which is'to receive the deposit.

The part of the'said plug and socket fittings I is adapted to be detachably connected when desired to a depositing electrode element. Such a depositing electrode element for. use withthis apparatus consists of a tubularhandle portion 21 to which an electrode formed item the class ,of metal to be deposited lssecured, said electrode being enclosed withina sheath or pad 28, which, during the use of the device, is adapted to be maintained saturated with the required electrolyte, 'and for filled with the required electrolyte and to sub.- sequently discharge said electrolyte down the tubular handle on to the shea h 0 Dad when by pressing said bulb by hand. H

e, To complete the apparatus there is provided include three separate electrolyte solutions, for

and a chromiumelectrolyte. These containers are conveniently, comprised by glass Jars J0 "suitably supported within the rear portion oi the casing'and provided with removable stop- Dcrs or otherjclosure means. In addition the equipment also includes a desired'number of further depositing electrode elements similar to s. that above described but i'oruseiwhen depositing difi'erent metals, ior example three suchelements may be provided in all, n for copp the diflerent metals so :adoption, whilst in addition practical realization of the vthe invention, the intermittently interrupted di-= wires 23 there is secured this purpose the handle portion 21 can'ies a rubber bulb which is adapted to be circuits, each incorporating its own resistance and provided with means one for nickel and one for chromium, and when not in use are adapted to be accommodated within the lid or cover I i by suitable clip devices in the manner indicated at 33. Still further the accessories include cleaning brushes and scrap- 5 ers, such for instance as indicated at ,32 and in. addition so-called priming solutions, polishing solution or; cleaning acids contained in bottlesor tins as indicated at 33, as well as other accessories which it may be found desirable to incorporate in the apparatus such for instance as'polishing rags It willbe realized that such a can be readily transported.

Further withsu'ch an apparatus it is possible to effect, in a most eificient manner, the electrounit assembly and moreover by means of the switch-device I8 associated with the tappings of the secondary circuit of the transformer i1, the voltage of. the intermittently interrupteddirect current outbut can be adjusted to suit the requirements of p t optimumresults will at all times be possible. v v It be obvious that .such. an apparatus is 2 particularly useful and suitable ,for universal v to the improved quality of the electro-deposits obtained byadopting the process according to the invention, it is to be understood that the, electro-depositing 30 operation canbe fl'ec ed without in anyway interfering with the permanent position? of the surface receiving the deposit, ior instance the, fittings of an automobile vehicle can -be.readily electro-plated with nickel and/or chromium without removing such fittings from the vehicle. In other forms 01' apparatus'suitable for. the process according to rectcurrent supply can be obtained by means of an electric motor which can be operated from either alternating current or direct current public supply mains. a direct, current generatordriven by the said motor andaarotaryswitch device 7 adapted to be rotatedby the shaft oi'the motor 46 unit assembly, the-power unit maybe mounted ,within a casingot itsown. whilst the accessories' are arranged in a separate casing, thus two .co-operating portablevunits would be pro-' vided.'- '1 q Furthen-in some cases another portableunit maybe'provided, this unit containing meansior polishing the deposited metal and may comprisefor example a rotary polishing mop of any desired suitable form and construction and an electric motor for operating said mop. or as an alternative flexible shai'ting may be provided connecting the spindle oi the -mop to the shatter the electric motor provided in-the power unit aforesaid. t

, In some cases the apparatus may be-adapted to cited the simultaneous clectro-deposition 01' two or more din'erent metals. and for this purpose the intermittently interrupted direct cur- 7 rent output is divided into a number oi parallel regulatin whereby it can be connected to a separate depositing electrode. A similar arrangement would also enable 7 a number of persons to effect the electro-deposition of a single metal in cases where very large surfaces are to be treated, and it is desired to effect the depositing in as short a time as possible.

In other cases and where the apparatus is larger than that hereinbefore more particularly described, the power unit, the accessories and if desired, a polishing mop unit can be combined in a single unit assembly which may be mounted upon a wheeled trolley or the like so that it can be more readily transported. as a whole.

It is to be understood that as an alternative to providing a rubber bulb in association with the depositing element for discharging the required electrolyte on to the sheath or pad as hereinbefore more particularly described, other means such for example as a piston pump may be provided in association with the said depositing element to effect this purpose.

As previously stated the process the invention is equally suitable for the electrodeposition of metals in so-called vats or baths as distinguished from the particular form oi. "pad depositing as herein described, it only being necessary to provide suitable vats or baths for containing the desired electrolyte, in fact with the apparatus hereinbeiore more particularly described the jar-like containers for the various electrolytes can be conveniently used as vats for the electro-deposition of small articles.

The invention-is not limited to the precise according to forms or details of construction or arrangements described, as these may be varied to suit par! ticular cases.

- What I claim and desireto secure by Letters Patent oi. the United States of America is: 5 V 1. The hereindescribed process for effecting the electro-deposition of metals, consisting in passing over and in contact with the surface receiving the deposit a depositing element which comprises an electrode of the metal to-be de- 10 1 posited and an associated covering of absorbent material which is saturated with an appropriate electrolyte and conducting to said electrode and the surface receiving the deposit a periodically interrupted direct electric current, the periods15 of fiowof saidcurrent being equal to the periods of cessation.

2. The hereindescribed process for eflecting the electro-deposition of 'metals, consisting in passing over and in contact with the surface'go receiving the deposit a depositing element which comprises. an electrode of the metal to be deposited and an associated covering of absorbent material which is saturated with an appropriate electrolyte, and conducting to said electrode and 25 the surface receiving the deposit uniiormly spaced direct current impulses of symmetrical form, the periods of rest between said impulses being equal to the periods at which said impulses are impressed uponsaid electrode and said deposit receiving surface.

canon mm ADEY.

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