DE4018649A1 - METHOD AND DEVICES FOR ELECTROLYTIC ZINCING - Google Patents

Abstract

In order to avoid corrosion damage in the non-bath galvanizing , using hand-held electrodes, of e.g. iron adjacent to masonry, aqueous ammonia is used as the starting electrolyte and zinc as the cathode, so that only inert zinc oxide and no corrosive salts remain behind after drying. Several hand-held rub electrodes are described which render possible the use in practice of the new, simple, low-conductivity electrolyte. In the simplest case, the hand-held electrode comprises a piece of zinc wire (1) 3 mm in diameter and 40 mm long, one half of which passes hermetically (3) through the bottom of a soft plastics beaker (2) 5 mm wide so that the rim of the beaker extends 2 mm beyond the end of the wire, the free end of the wire being connected to positive (4), and the beaker holding the electrolyte (E). The electrode with its bevelled mouth can be used equally well in any position. It gives about 40 mA at 12 V, and one fill lasts for more than 5 min. Zinc plated on to polished iron (5) adheres and covers well, is ductile and is suitable for the direct application of a paint coating.

Description

The subject of the present invention is a method and are associated apparatus for electrolytic Ab Separate adherent and opaque coatings of metal metallic zinc, in particular iron or on zinc and on galvanized iron, in this case galvanizing called. The galvanizing produced on iron is mainly neuter and especially painted the corrosion protection against atmospheric influences. Galvanizing closes following the deposition and impure or alloy zinc.

There are numerous formulations for the aqueous electro lytlösungen, here briefly called electrolysis, known, the serve as a bath, in which the negatively poled, verzin kenden objects and the positively polarized electrodes dip in zinc. Suggested for a bath free galvanizing by hand guided electrodes, so-called Hand electrodes in which brushes, sponges, felts and paste-forming agents as carriers for the aqueous elec serve trolytes. Allen has become known electrolyte together the use of non-volatile acids or the non-volatile alkali metal bases and of electrolytically special these are well-conductive salts, so-called conductive salts. The Tendency of zinc only needle-like deposition (dendrites) is due to the special recipe (material composition tion of many components, distance and area behavior of the electrodes, voltage and current density, Acidity, temperature, etc.) and the movement of the bath or the electrodes, during bath-free galvanizing by rubbing movement of the hand electrodes (so-called Frictional electrodes) on the surface to be galvanized, entge counteracted.

For the repair of damaged areas on galvanized or painted iron sheets, in particular on motor vehicles, such electrolytes and hand electrodes are recommended Service. The strong acid or alkaline attack Electrolytes still existing galvanizing quickly and lead as well as even the smallest remnants of the salts to rust  education in unprotected places, where the electrolyte runs out of control. Furthermore, the well-known hand Electrodes not for every surface contour and spatial position and not suitable for bottlenecks, they mechanically injure the paint in the vicinity of the repair and Decimate the galvanizing produced. Also grab the electrolytes the zinc electrode in the de-energized state on.

Object of the present invention is to provide a korro sion-free electrolytes. In particular, should be for Repair purposes a bath-free primer galvanizing ge that will not find the aforementioned evils having. As a very special task, which so far has not been asked, should be a repair galvanizing Such iron parts are made possible on concrete or Borders border. For this are the known electrolytes completely unsuitable because they are concrete or masonry mortar destroy and be absorbed by them so that one non-removable reservoir of rust-forming salts ent would.

It has now been found that an aqueous solution of Ammonia, so-called Salmiakgeist, as an electrolyte at Use of zinc as positively polarized electrode, short positive, suitable and the signs ten evils can be overcome.

If, according to the invention, z. B. 15 ° C in the bathroom 10% aqueous ammonia of a vertical iron wire 3 mm diameter at a distance of 2 mm parallel a zinc wire positive from a pair of wires of 3 mm each Diameter opposite and electrolyzed at about 1 volt with 6 mA corresponding to an electric current density of 0.3 A / dm² zinc longitudinal cutting surface, so after an An Running time of a few seconds, with a clear Hydrogen evolution is connected to the negatives, a light gray zinc plating formed on the negatives. Here is the great uniformity and the big litter the deposition, which is also used for galvanizing the Rücksei te negatives in a few minutes leads, impressive. However, then occurs after a total of about 15 minutes  Polarization with current standstill by increasing the voltage can be corrected to 2V.

In the electrolysis of the invention, zinc goes from the positive into solution and precipitates on the negative. In the solution are after passage of the current known Zinkamminohydroxide Zn (NH₃) _n (OH) ₂ with n = 4 or 6 before. Instead of starting with pure aqueous ammonia, one can accordingly start trolyten with already used Elek. Another possibility is it according to mix in before or during the electrolytic galvanizing Zinkamminohydroxide. Instead, you can also just finely divided zinc oxide, z. As zinc white, or salt-free zinc hydroxide, since these compounds slowly dissolve in aqueous ammonia moderately to form the zinc ammonium hydroxide. Powdered zinc can also be mixed, since it also reacts with aqueous ammonia with the evolution of hydrogen to give zinc aminophy droxides.

Another way, the electrolyte with zinc To enrich amino hydroxides, according to the invention in a previous electrolysis of the aqueous Ammoniaklö solution between zinc electrodes with the largest possible current density, which is a major hydrogen evolution on the Ne gatives, and a repeated reversal of polarity the electrodes. In each period as a result of the same goes generate more zinc in solution than hydrogen itself separates.

Finally, the electrolyte according to the invention can also by reaction of zinc nitride with water or aqueous Ammonia are produced.

The process of the invention requires no Leitsal ze and no alkali bases. Of course, there are traces of ammonium carbonate or other reaction products of aqueous ammonia with the carbon dioxide of the air not as To address conductive salt content.

Incidentally, the above-mentioned salt-free zinc hydroxide through laborious washing of zinc salt solution, precipitate zinc hydroxide only approximate. The Solubility of the same in aqueous ammonia increases with the Residual salt content too.  

The electrolyte according to the invention can be soluble therein Contain zinc phosphates, which are added or from a coating of the galvanized iron materials come with zinc phosphates. Zinc phosphate is not a salt, which leads to corrosion, but is called corrosion protective pigment known.

The above aggregates all increase the elek trolytic conductivity of aqueous ammonia and allow higher electricity under otherwise identical circumstances tight. Zinc phosphate is stronger in aqueous ammonia soluble and may be the viscosity of the electrolyte be increase significantly.

The admixture of the zinc oxide and / or zinc hydroxide can go to paste making, in particular one Leakage of the electrolyte from the damaged area to prevent bad galvanizing.

To increase the rate of electrolytic dissolution The ability of the positively poled zinc is according to the invention Zinc in granular form, in particular from the melt flow produced roundish granules or in the form of a lot number of small wire sections, used. Grains out Fine zinc (99.99% Zn) greater than 0.5 mm, be at room temperature or below of aqueous Ammonia was not appreciably attacked, as long as no electrical external current flows. These forms of zinc allow the construction of advantageous hand electrodes.

The low electrolytic conductivity of he according to the invention electrolytes is thereby taken into account, that between the electrodes - deviating from the bis previous practice, in particular with hand electrodes - preferential There are no electrolyte carriers, the whole Take power cross section and a considerable Have thickness. It will only be in certain cases thin fabrics, knitted fabrics, nets, sieves, perforated films, Nonwovens o. The like. As far as possible electrolytdurch casual, electrolyte-compatible, by the electrolyte wettable, electrically non-conductive, abrasion as possible solid and soft-elastic materials, here Sepa for short  called, which are the electrolytic Leit ability between positive and negative not essential because they also have a particularly small size Allow electrode spacing. Provided wicks as an electrolyte carriers are used, these cover the main one current conducting cross section between the electrodes possible not off.

It was found that the known particularly star The tendency of zinc in electrolytic galvanizing not adherent from ammoniacal solutions and not Growing up layered, but loose dendrites or to form a black sponge, and the tendency for polarization until the current stoppage, which otherwise only for a limited time due to a powerful surge remedy in the simplest and safest way can be encountered, that rubbing body on the separator glide surface, with the necessary Bewegungsgeschwin they tend to increase with the current density takes. By tuning of applied electrical span tion, the current density, the distance and the area behavior ness of the electrodes, the ammonia content, if necessary the electrolyte movement and this rubbing movement succeeds it that on the metal documents, in particular on Iron and zinc or the already existing Galvanizing, no black and loose zinc forms or already formed - if necessary at increased movement speed - again detached and largely dissolves. In this way you can festhaf galvanizing up to such high current densities whose further overrun for reasons of Electricity overheating is no longer possible.

Without the use of rubbing bodies, the Ver zincing only at very low current densities. But also then finally, though only after hours, Den third growth and / or polarization until stagnation stood up.

The zinc as a deposition pad will be lower Requirements placed as to the iron: a thin coating of zinc with weathering products such as zinc oxide or  basic zinc carbonate does not interfere with the deposition because the aqueous ammonia exposes the metallic zinc. egg Senrost, on the other hand, can only be used to a limited extent by the Galvanization are covered, with the adhesive strength suffers. Zinc-phosphated iron can be dissolved Go the electrically insulating coating in the aqueous Galvanize ammonia without further ado.

Prerequisite for the flow of electricity and the area-wide Deposition is that the electrolyte the negative Unterla wetted. It has an advantageous effect that aq ammonia grease and remove greasy soils can wash. Aqueous ammonia is a good wetting agent medium. It can, for. B. polyethylene, so that this material for the production of hand electrodes can be used. The rest is the rubbing Be to make a difference. In principle, however, the iron surface must be clean to a firm, uniform ge and nationwide galvanization to achieve.

Without the rubbing motion sets at the larger Current density immediately deposited black zinc spontaneously a strong evolution of hydrogen. Through it reaching movement, the black zinc dissolves completely or almost completely up. A hydrogen evolution means Stromaus Loot loss and danger of hydrogen embrittlement egg ner steel pad. By fast movement, the what hydrogen evolution avoided or at least minimized.

As a rubbing body z. B. felt-free fen, in the rotating drum also a galvanizing, moving bulk material, eg. Iron wire pins, even we ken. For bath-free galvanizing with electrolyte-filled Hand electrodes are preferably the mouthpieces of same as rubbing bodies that do not conduct from electrical consist of the material.

For carrying out the method according to the invention and in particular the task of repair Ver In zinc, various hand electrodes have been found. All have in common an integrated space, which is a be limited amount of the electrolyte absorbs. This one is like this designed that as little ammonia can outgas.  In addition, if the evolution of hydrogen kept low is, then the consumption or loss of electrolyte small. Therefore, the electrolyte filling amount and the Electrolyte space be small. Otherwise, they are present the hand electrodes easily refillable.

After the hand electrode is filled to the brim with electrolyte is filled, the mouthpiece is the same with light tem pressure as flush as possible on the surface to be galvanized put on, so that these from the electrolyte to the touchdown is wetted. Limited, the current density on un dangerous 3 A / dm² zinc face of the positive, so can be galvanized without movement for a long time. To this Purposes can be the hand electrode with an iron bandage wire and with the help of a permanent magnet in the richti be fixed in position.

At larger current densities, the hand electrode becomes dage immediately after switching on the electric current quickly in frictional contact over the area to be galvanized The result is no black zinc on the surface forms or this at least as far as possible again dissolves.

Preferably, the electrolyte vessels of the Handelek They are so well designed that they are - apart from the open Mouthpiece - hermetically sealed. You have it the general form of a mug, without that term to restrict to the circular cylindrical shape. At Begren The width of the cup mouth is approximately 8 mm it is possible with such hand electrodes, in every room the same, d. H. also subpages and vertical pages zinc surfaces, because the electrolyte does not run when handling after filling still after flush Put it on because it is a surface tension and free-hanging liquid held at atmospheric pressure represents the power column. Has the mouthpiece oval shape, so By "width" is meant the smaller diameter become.

The electrolyte vessel does not only encompass the space between the electrodes, but also a reserve space, the same if electrolyte can absorb and release.  

This reserve space is - also without the use of carriers for the electrolyte - mainly slit-shaped and the columns are up to 3 mm wide. At the Galvanizing surfaces with mouth down pieces, may accumulate in the top of this gap ascending small hydrogen bubbles or the at Put on trapped air (for non-brimful fill ment), without the inner zinc positive contact with the Electrolyte loses.

The electrolyte loss of the hand electrodes is limited on the amount to be crossed while running over the entire zincing surface on this as a wetting layer behind stays and more or less evaporates, as well as on the usually very small amount, that of a repression of the Electrolytes by the usually very low Wasserstoffent winding originates. When galvanizing sub-views, d. H. with mouthpiece up, leave the water Substance bubbles the mouthpiece laterally outward. At the Galvanizing vertical surfaces is the current-conducting cross cut accordingly by gas accumulation, and only with larger gas accumulation, the current flow under binds or diminishes too much, a refill is necessary manoeuvrable. It is therefore advantageous for the galvanizing lot Right surfaces, the mouthpiece beveled and so auf put the gas bubbles up into the open or into the Removing reserve space from the mouthpiece space.

The hydrogen evolution can - as already mentioned - through faster movement of the hand electrode and through Throttling the current, z. B. by enlargement of Electrode spacing can be minimized. It was festge Make sure that the rubbing motion is a strong one mixture in the electrolyte space, the yes preferably no Flow resistances in the form of the known electrolyte carrier, but is free, causing the the zinc ion transport serves and thus the competing Counteracts hydrogen separation.

If the mouthpiece of a sufficiently fine-meshed Separator covered, so finds a leakage of the electrolyte th also at some cm diameter of the mouthpiece unab  not depending on the space situation, not even if put the mouthpiece on the surface to be galvanized and then being moved. The retention of the Separa The better the wetting and the better mechanical stress of the separator is. For example, a can stretched over the edge of a cylindrical cup Nylon stocking knit hanging column of 10% aq ammonia of more than 9 cm diameter of the cup rim carry. However, such large diameters are prohibited in practice for reasons of power supply and drainage the current heat and shock sensitivity.

The separators can also ensure that the filled granular zinc as little as the electrolyte fall out. Of course, the separators must made of non - conductive material when combined with the Positive and at the same time come in contact with the negatives.

If the zinc positive has the shape of a mug, like they z. B. of dry batteries ago, then can it directly serve as an electrolyte vessel. Thus the of fene side of the cup can serve as a mouthpiece, le just another border of electrically nonconductive Material needs something that protrudes. At least from ei The mouthpiece width of about 8 mm is the covering by a separator necessary, which is itself the elek can represent electrically insulating border. The cup can then contain granular zinc without losing it. Of course, the cup - also to Vergrö erosion of the zinc solution surface - also other loose or solid, in electrical contact with the cup Included zinc internals.

If the electrolyte space not only below, but also open at the top, slit-shaped, free and so narrow, that he is already shut down owing to his capillarity after dipping in the electrolyte with this to considerable filling level, so the electrolyte runs at the bün wetting contact with the mouth directed downwards piece on the surface to be galvanized not son The gap capillarity ensures a retention to like. Such electrodes can be built very narrow  and are therefore ge for galvanizing in narrow places suitable. Gas bubbles can escape upwards to the outside. As the movement wetting and Ausgasungsverlu They are produced at intervals of a few minutes refilled by a brief dunk.

It has been found that mouthpieces made of soft-elastic Shem and abrasion resistant material, in the Verwen As a friction electrode very good galvanizing results result. The paint in the vicinity of the damaged area will not be damaged. Already precipitated zinc is not abraded. In the simplest case, that is Mouthpiece of this type from a tube of ammonia firm and abrasion-resistant soft rubber. Rubber slides on the wetted surfaces gently and effortlessly. It will be for the production of the mouthpiece edges no porous Ma terialien used because these insufficiently resistant to abrasion and are too dull in the movement and because they are an off favoring gassing of ammonia.

For processing larger, wavy and curved ter surfaces, several small hand electrodes are bundled in this way delt that the mouthpieces of each hand-held electrode too immediately sit on the surface to be galvanized and closed at least in the case of curved and wavy surfaces too so are mutually parallel movable, that at the same time all mouthpieces with the surface in constant contact stay. This can in the simplest case through the frets be achieved with a rubber band, on the one hand as tightly stretched around the entirety of the individual electrodes that they experience the necessary concentration, that others on the other hand, the rubber band but also enough loose, so that each individual electrode in the bundle is the Flächenkon due to gravity, manual operation, pressing a foam pad, etc. can adapt. Is the Radius of curvature not too small and will only 5 Einzelelek combined troden, so z. B. a spherical surface also to be worked with a rigid bundle.

The simplest, cheapest and most common usable hand electrode of the present invention be stands out from a section of a zinc wire, the one  on the other hand with a soft-elastic sleeve one slit-shaped reserve storage space for the electrolyte forms and protrudes over the end of the wire and here forms the mouthpiece, and the cavity on the other hand, d. H, closed between the outer tube and the zinc wire, and the other end of the zinc wire with the electric Supply line and the positive pole of the DC power source verbun that is. The conclusion and the sealing of the gap space preferably takes place in the simplest way by a second hose on which the buffer tube and in the the zinc wire are difficult to move. This second one Hose can at the same time in its extension the Kon Timing of the clamped stripped end of Zu get lead wire with the zinc wire and continue to Serve support the supply line. The tightness and a Adjustability of the electrode spacing can be achieved by additional Medium means such as a screw clamp or a gum miband, which you can loosen or tighten as needed can be guaranteed. The two tubes can even in a uniform rubber molded body, the z. B. equipped with sealing lips against the zinc wire can be summarized.

Instead of fixed fittings made of zinc, the Zinkbecherelek also grainy zinc or parallel to its coat Easily movably arranged zinc wire or wall Zinc tube sections of approximately the same length enthal th, in electrically conductive contact with the cup stand. A fe on the inner cup bottom fe reducing material, e.g. B. polyurethane foam larger Density, ensures that the mouthpiece-side forehead surfaces of the inserts against the mouthpiece separator drüc ken, so that this the contour of the surface to be galvanized automatically follows.

To damage the over the sharp edge of the Zinc beaker electrode pulled separator through this The latter can be avoided by wrapping with the edge an aluminum foil of z. B. defused 0.1 mm thickness become. It has been found that in the case of lee ren, d. H. only electrolyte-filled zinc beaker electrode no wear of the separator fabric occurs when  its protruding edge between zinc bucket outer wall and Mouthpiece tube is squeezed and the latter little projects.

In another embodiment, there is the electrolyte made of a soft rubber or soft plastic body, the not just a zinc wire positive and the supply ent but also granular zinc or longer Zinc wire sections provides space in the electric Contact with the supply line, and the latter below are movable in parallel and via a separator can follow the surface contour. Advantageous compared the cylindrical zinc beaker electrode is that the Elek trolytic vessel in the case of zinc grain filling to the gap can be reversibly deformed, so that too close to galvanizing throats or gaps can be achieved and that a special external insulation is unnecessary. In case of filling with the longer zinc wire section th the elastic vessel, the function of the Federein able to take over. For this filling is enough a gröbe sieve bottom as a separator. The one for a finer one Zinc grain filling required finer mesh separator can with the more wear-resistant sieve bottom, in shape z. B. a perforated vessel bottom, who combined the, wherein the feinmaschigere separator preferably is arranged inside.

The finer-meshed separator can also be bottom of a beu which contains the granular zinc and into which the Feed line, preferably a zinc wire, is introduced and the bag has room in the electrolyte vessel. The Zulei tion is introduced airtight in the vessel. The container can be composed of several parts.

Those in claims 33 and 34 in detail Handheld electrodes described except by great performance through flexibility and fast replacement the separability of Separatorgewebe.

The already mentioned capillary electrode with free, only electrolyte-filled crevices and uncovered mouth piece is advantageously made of a piece of zinc Sheet as positive, partially with an electric  surrounded by insulating sheath, which kapil with the sheet metal lare wetting gap forms. The shell towers over the sheet metal down slightly and forms the narrow gap-shaped mouth piece. The sheath is preferably made of hard Polyvi nylchloride and gets up against the protruding metal sheet preferably by self-vulcanizing Si in the air licon mass made airtight. Through this seal is achieved that the electrode for galvanizing Soffits can be used, because without the Abdich The wettable aqueous ammonia passes Following gravity. When filling by dunking one must provide for the escape of the air by the Mouthpiece obliquely eintunkend in between upwards rich tet.

In German Patent 34 400 is a brush described electrode from a narrow gap aufgewic celt zinc plate, the gap distance through inlaid bristles is given, which from the winding roll emerge like a brush. By incorporation in a Zinkbe It is useful for under-surface galvanizing makes.

Contains the electrolyte vessel, preferably a zinc cup, zinc in the form of mutually parallel move zinc tubes, whose mouthpiece-side openings slightly projecting insulating wear, so can these as spacers and as friction elements opposite serve the area to be galvanized, so that a Separa gate is unnecessary.

Finally, a solution was found by the Mög porous and capillary active electrolyte carrier such as soft-elastic open-pore foams, fabric pac kung and the like makes use, but without this little abrasion resistant materials too much by friction to bean speak and without affecting the current path too much and without forming zinc shorts in them: In a zinc cup, its insulating mouthpiece again by a covered and slightly over the edge of the cup protruding hose is formed are located fits such support materials that project something that  but when contacting the hose nozzle on the compressed area to be galvanized and ge in the cup be urged. These wick-like materials adapt the surface contour and provide the annulus between the zinc beaker edge as positive and the zinc-plated Surface as negative with electrolyte. The main one Conductive annulus is made of these substrates essentially not used. Despite the low electrode spacing, the foam height ins Overall very large and thus the electrolyte absorption capacity as well as the softness and conformability be very big without the electrolytic conductivity and the corpse Noteworthy activity of the frictional movement of the mouthpiece is impaired.

The galvanizing according to the invention is not the Einhal certain formulas and limited work conditions. So the ammonia content of the fluctuate aqueous solution within wide limits. The maximum the electrolytic conductivity is about 10% by weight ammonia content. The handling with aqueous Am This concentration of ammonia can be odorless respectively. The applicable current densities are not critical and variable within wide limits. Current densities from 5 to 50 A / dm² of active zinc surface are at moving electrodes practical. At higher current densities problems arise with the dissipation of the current heat. The electrode distance results from the separator thickness and the unbe Covered hand electrodes in that short circuit avoided should be. Is worked with 12 volts and is the Current density in stationary operation to a maximum of 3 A / dm² to limit, so an electrode distance of about 25 mm necessary, if you do not have a special series resistor wants to turn on. The inventive method functio at every room and outside temperature.

To limit the current at a given voltage The car battery can be the long line wire that is necessary to all parts of the vehicle to be able to reach, in whole or in part by one Replace resistance wire to create a special pre-resistor saved up.  

An environmentally friendly simplification is that the Ver not washed off after completion of the electrolysis but it is enough to wipe dry or dry leave in the air.

The properties of the galvanizing according to the invention fine zinc on iron and on zinc are in the patent Speech 45 summarized.

All mentioned zinc parts can be made of fine zinc or / and made of impure zinc and / or alloyed zinc.

The described embodiments of the devices and of the method can be analogous as for iron, zinc and galvanized iron on other metallic substrates such as Apply copper, nickel and tin. The copper can be similar like the zinc also used with oxidized surface become.

The particular achieved by the present method ductile and wetting-friendly galvanizing are as lubricant and lubricant carrier for mechanical Deformations of the metal pad suitable.

Examples

In the following examples, the invention to explain further without restricting it to them ken are functionally analogous parts with the same number designation provided. This should be the common prin zip be clarified.

It means

1 zinc parts = positive
2 = parts of the cup-shaped electrolyte vessel
3 = parts to seal 1 to 2
4 = supply line with fixing parts
5 = surface to be galvanized = negative
6 = separator and mounting hardware
7 = paint layer
8 = iron wire
9 = permanent magnet
10 = rubber band
11 = wetting gusset
12 = springs buffer
13 = adhesive film
14 = wick

Example 1 Galvanizing steel with staid, smaller, very one simple hand electrode and with aqueous ammonia as a start electrolytes

The hand electrode according to Fig. 1 consists of a wire section ( 1 ) of fine zinc (99.99%) of 3 mm diameter and 40 mm in length, a soft-elastic and durchsichti gene shaped body ( 2 , 3 ) and a stranded wire ( 4 ) , The molding projects beyond the one hand, the one end of the zinc wire to an adjustable length (d) and here forms the open and 5 mm wide mouthpiece through the commercial Liche aqueous ammonia as starting electrolyte with an ammonia content of 10 wt .-% is filled and the zinc wire and the shaped body formed cylindrical and gap-cylindrical cavity fills. On the other hand, the molded body tightly and hermetically encloses the zinc wire, and its extension ( 4 ' ) presses the abraded bare metal end of the strand against the zinc wire. The extension further supports the insulated strand from ela stic and prevents them from kinking. The molding can also be replaced by 2 matching hose sections ( 2 and 3 ) of Ø 2.8 × 1.3 × 25 and Ø 5 × 0.4 × 35 mm.

Surface tension and air pressure as well as capillarity ensure that the electrolyte when handling in any The position of the electrode expires, except in the case of a jerky one Acceleration, very strong deformation of the electrolyte vessel or when sucking with z. B. absorbent paper.

The electrode, which has been filled to the edge and free from air, is placed on the damaged area ( 5 ) of a lacquered ( 7 ) steel sheet, which has been freed of rust and paint residues by scratching with a steel nail and made bright metal, with a slight pressure by hand, vertically and mouth-flush , whereby the electrolyte wets the bare spot. An integrally formed iron wire ( 8 ) and a permanent magnet ( 9 ) hold the electrode in this position.

The wire is with the positive pole and the steel sheet with the negative terminal of a dry battery of about 1.5 volts Terminal voltage conductively connected. If d = 4.5 mm,  so immediately flows a current of 1.4 mA and remains over the whole electrolysis period of 1 hour quite kon constant. The current flow is also by means of a magnifying glass to recognize that small gas bubbles from the damaged area rising up. They collect at the top of the gap raumes and take after 1 h 5 mm height, accordingly 62 mm³ of hydrogen gas. The temperature is 15 ° C. The Power loss through hydrogen gasification is thus 62/602 10%, because the 1.4 mA by 3600 s would be calculated Develop 602 mm³ H₂ of 15 ° C. The current density is, based on the end face of the zinc solution electrode, 1.4 mA / 7.0 mm² = 2.0 A / dm².

During the electrolysis period that of the formed Amount of hydrogen corresponding small amount of electrolyte on Mouthpiece edge out. A refill of electrolyte not done. Apart from this small drainage There is no loss of electrolyte. Because the mouthpiece closes pretty tight, no NEN evaporates noteworthy amount of ammonia. There is therefore no Ge ruchsbelästigungen.

After removal of the electrode, the site with suction dry wiped paper. The galvanizing is bright gray, matt, fine-grained when viewed microscopically metallic-crystalline and full-opaque as well as glittering, she is ductile and after rubbing with a rounded steel Fully polished tool, can be carved with a steel stylus, high adhesion firm (bending and shear test), sharply delimited by mouth piece edge or through the paint edge. The separation Thickness is 10 microns, they can by extension the electrolysis period are increased, but eventually Dendrite growth or polarization with current arrest may occur.

The electrode can be applied not only on horizontal but on surfaces of every contour and spatial position. Fig. 2 illustrates the application on a bottom view throat ( 5 ), wherein the mouthpiece of 2 adapts and allows galvanizing into the depth of the throat. All recently must be placed in this case carefully air-free. Gas bubbles can leave the mouthpiece and throat sideways outward. If the zinc wire pushed back further, so that d is larger, which is favorable in the Geome, the current flow and the Gasentwick ment and the power loss is lower.

In particular, when repair galvanizing the motor vehicle can use the existing 12 volt battery as a power source be used to the advantage that each damaged spot with the Negative pole is connected. By a series resistor of 10 kOhm, the current can be limited to 1.2 mA.

example 2 Galvanizing iron with moving, small, hand-operated lever and 10% aqueous ammonia

Greater currents than about 2 mA, according to 3 A / dm² zinc front surface are attached to the stationary th trading electrode described in detail in Example 1 Ben is unreachable, because spongy black or dendritic zinc precipitates and the Wasserstoffent winding up considerably. Much higher currents and Separation capacities are possible if the hand electrode is moved, the mouthpiece of the electrode easily rubbing over the surface to be galvanized on wetting the The same thing by the electrolyte as flush as possible aufit Zend is moved back and forth or rotating. To one equally good galvanizing as on horizontal supervision and to achieve sub-views even on vertical walls, a bevel of the mouthpiece is practical. Thereby can the gas bubbles in this spatial position from the Mouthpiece are made to disappear, in which this to the outside (strand end facing downwards) or - preferably - inwards at the top (wire connection upwards directed) are derived.

Table 1 gives guideline data on the achieb Ren current strengths I as a function of the electrode spacing d at 12 volts applied voltage, use of aq ammonia as starting electrolyte with an ammonia content of about 10% by weight, and at a temperature of 15 ° C. In addition, the time t is given in minutes, after the refilling of the aqueous ammonia necessary or opportune.

Table 1

The highest achievable current of 100 mA is not  recommended because the heat is so great that a mouthpiece made of soft PVC its elasticity and Strength loses and becomes sticky. In addition, the Refill time and the galvanizing current yield poor. A d = 2 to 4 mm is practically advantageous.

It is necessary, the hand electrode immediately to move after switching on the current. Because otherwise the black zinc forms, at first in thinner Coating the iron, but then to voluminous sponge and sometimes coniferous trees growing to short conclusion between the electrodes. This is a very strong hydrogen evolution associated. By the proofs These complications remain. Black and dendritic zinc can be completely avoided and the Reduce hydrogen evolution so that the in the tabel 1 refill times specified. By Short standstill or inadequate movement arose Fresh black zinc can be replaced by - if necessary only temporary - increasing the speed of movement be brought back into solution. The formation of black zinc, as well as hydrogen evolution ment a loss of electricity yield for galvanizing.

The necessary speed of movement increases with the Current density. With d = 2 to 4 mm and 40 to 10 mA leave achieve high quality galvanizing, if sufficient is moved by hand. The soft mouthpiece calls at the Movement no damage to the intact paint of the order  the galvanizing. In addition, the 10% engages Ammonia synthetic resin paints not at all and an existing Ver Zincung only as far as it is for the liability of the new Deposition is favorable.

The galvanizing achieved can be after the Ab dry without further ado.

The minimum electrolysis time should be about 1 minute per cm².

As the zinc electrode is encapsulated and the strand insulated is there is no danger of an external short circuit. The inner short circuit is reliably ver by the movement ver avoided. A series resistor is therefore not required.

To make repair galvanizing the vehicle can, is about 8 m long, thin, flexible wire used with the positive pole of the vehicle battery there is connected by that their stripped bare end between the iron pole clamp and an applied one Clamping magnets is clamped.

example 3 Bundling of hand electrodes

In Fig. 3, four electrodes are shown in plan view and in side view, which by the rubber band ( 10 ) loosely bundled gebün and placed on the curved surface ( 5 ). When light pressure is exerted on the electrodes by hand, the electrodes conform to the curvature by making the mouthpieces of the electrodes 2 and 2 'deeper than those of 2 ''and 2 '''. The mouthpieces deform on the one hand something, on the other hand, they form Wetzzwic kel ( 11 ) with the filled electrolyte.

A spherical surface can with 3 bundled electrodes galvanized, whose mouthpieces lie on the same level gene; they can therefore be bundled immovably.

Such bundling makes faster galvanizing as possible with single electrodes and are therefore Ver tines of larger areas advantageous.

example 4 Zinc Granule Separator Hand Held Electrode With Soft PVC Form body

In Fig. 4 is a zinc wire section ( 1 ) of 3 mm diameter airtight and tight in a molded body ( 2 , 3 ) made of soft polyvinyl chloride. The 16 mm wide circular mouthpiece of the molding is covered with 2 layers of polyester fabric ( 6 ) as a separator, which is attached to the outside of the molding with adhesive tape and has a layer thickness of 2 times 0.125 mm. The interior of the molded body is filled with zinc granules ( 1 ') of fine zinc (99.99% Zn) of 0.5 to 2 mm grain size.

On the upwardly directed mouthpiece is 10% aqueous ammonia pipetted until the same he the edge is enough and has wetted the separator fully (1.6 ml).

The electrode can be used in any position. Under Current flow must be moved quickly immediately. The Current density at 12 volts is approx. 50 A / dm² mouthpiece surface. A 3 × 3 cm² area is in 3 minutes provided with 8 μm zinc coating. A refill takes place not here. The thin iron sheet pad heats up strong.

The electrode becomes with the mouthpiece after the use deposited on absorbent paper, the remaining Electrolytes sucks. The electrode is immediately at any time again operational. The fabric is however wear spare parts.

For the purpose of galvanizing very narrow and wavy surfaces of the molding can be compressed at the mouthpiece with your fingers to form a gap, see longitudinal section and outline in the lower part of Fig. 4. In this Sepa occur rator and granules bead-like.

When the electrode is first used on the horizontal and has already lost electrolyte for wetting and then for a bottom view galvanizing without refilling is to be used, the compression is recommended The mouthpiece also, because this electrolyte out is pressed and this on the mouthpiece ample Ver must be available.

Also for galvanizing small holes is recommended the narrow gap mouthpiece, with one of the two Corners is placed on the hole.

Otherwise fits the loosely clamped tissue  each mountainous and mature surface contour easily, and the large dispersion also ensures the galvanizing in the Depth of z. B. threading, in the no electrode down fits.

With only one layer of polyester fabric of 0.125 mm Normal layer thickness is reached 100 A / dm². Then but the warming by the current so strong that the Ver tines must be interrupted after 1 minute.

As a result of the use of zinc granules, which is a large Have surface, and the strong power heating will be with such electrodes the highest galvanizing performance achieved.

example 5 Granule Doppelseparator-hand electrode

In Fig. 5, the thin-walled, slightly conical, cup-shaped rubber container ( 2 ) together with the soft, matching rubber stopper ( 3 ) forms the electrolyte container, inner diameter 26 mm. The bottom of the rubber cup is durchlö chert. On the inside is the textile fabric ( 6 ), which is fixed by the rubber stopper. The zinc wire ( 1 ) is airtight through the plug, which is in electrical contact with the Granoli filling ( 1 ') and is positively poled. The electrolyte is applied with the Polyethylfla rule pipette on a bottom hole to the edge fullness.

When Untersichtverzinken the cup is something zusam together Pressed to good wetting contact between the Produce electrodes. The movement of the cup bottom as a mouthpiece is flush on the negative, the mouth piece can follow the surface contour and becomes light Spirigotierend led with direction changes.

It will be 150 mA at 12 V, corresponding to 105 A / dm² Area sum of the hole cross sections reaches at a Bo thickness of just under 2 mm and a fabric thickness of 0.13 mm. The separators are wear-free.

example 6 Power-hand electrode

An electrode which brings 1.5 amperes at 12 V with 10% aqueous ammonia is drawn in FIG . It consists of a rubber hose ( 2 ) Ø 28 mm by 2 mm wall thickness, which forms with the two-ply fabric separator ( 6 ) and the rubber plug ( 3 ) the electrolyte vessel in which the granules ( 1 ') and the zinc wire ( 1 ) are located. The tissue separator is clamped between the tube 2 and a rubber tube ( 6 ') Ø 28 times 0.5 mm. Flat textiles can be used as a separator, diameter 95 mm. The electrode is very poisonous and suitable for rough hands.

example 7 Zinc can wire bundle-hand electrode

In Fig. 7, the separator ( 6 ) of strong, soft elastic, coarse-meshed polyamide knitted fabric (Lycra fibers) of 0.6 mm layer thickness by means of rubber hose ( 4 ', 6 ') via the mouthpiece of a cup of zinc alloy (0, 3% lead and cadmium) of 13 mm diameter and 48 mm length. The hose is also used for external elec trical insulation and the contacting of the cable strand ( 4 ). The sharp edge of the mouthpiece is coated with aluminum foil of 0.1 mm thickness, so that the Separatorgewirke ( 6 ) can not hurt. On the cup bottom is a tight polyurethane foam cushion ( 12 ), which cushions 10 zinc wire sections Ø 3 mm ( 1 ') against the separator, so that this ren the Flächenkontu ( 5 , 5 ', 5 '') can follow. ( 13 ) is an insulating adhesive film.

With 10% aqueous ammonia are at 12 V applied Voltage 200 to 300 mA (42 A / dm² face total of Zinc wires). One-time filling of the electrolyte enough for 5 min. Galvanization. For the introduction of the electrolyte, a hypodermic syringe is practical.

With zinc granules (fine zinc 0.5 to 2 mm grain size) instead of zinc wires and three-ply fine-meshed Polyester fabrics of 0.4 mm total thickness will be 400 to 600 mA (100 A / dm² mouthpiece cross-section) achieved.

Instead of the zinc wire sections ( 1 ) and zinc sheet tubes can be used and in particular those in the mouthpiece sides plastic souls are constrained, which as well as the buffer tube ( 4 ', 6 ') protrude beyond the zinc front surfaces and the distance to galvanize the surface ( 5 ) and to this extent make a separator superfluous.

example 8 wick electrode

Over a cup of alloyed zinc (0.3% lead and cadmium) Ø _a 13.3 mm × 0.4 × 46, Fig. 8 (1,2), is a soft PVC hose ( 2 ') Ø _i = 13, wall thickness 1.5 mm, length 50 mm, drawn, which presses the stripped end of the supply line ( 4 ) against the cup, the cup electrically insulated to the outside, serves as a handle, and especially the mouthpiece edge forms by the Hose surmounted the edge of the cup by almost 1 mm.

In the cup of soft elastic, open-cell foam ( 12 , 14 ) is movably fitted, which protrudes in the decompressed state over the mouthpiece edge. The foam absorbs wicked the introduced Elek trolyte. When placing the mouthpiece on the surface to be galvanized, the foam of this surface conforms to its contour by correspondingly receding, Fig. 8 below, flat surface ( 5 ).

The wetted by the electrolyte foam wets the surface to be galvanized and the zinc wall, in particular the zinc beaker edge, and provides electrolytic Lei direction between the Becherpositiven and the negatives ( 5 ).

It is advantageous over the known foam Tampon electrode, in which a thinner foam layer as electrolyte carrier between parallel Elek trodenflächen is arranged, that the foam here is much less stressed by the rubbing motion, that the current paths through the foam in the edge region not at all and less covered inside, that the foam thickness is not equal to the electric the distance is, and that fasteners omitted.

The electrode is suitable in every location. With 10% aqueous ammonia is achieved at 15 ° C 125 mA.

Instead of the foam can also be a Wick from textile fibers, in particular in the form of a  rectangular fabric piece made of cotton, which becomes one matching cylindrical wick is tightly wound, use. Such a wick has an unsurpassed Absorbing and holding capacity for the electrolyte.

But with such a wick is not only a special long galvanizing with a filling of 4 ml Elek trolyt possible in any position and on edges, etc., son This electrode construction shows a special Ability to cover rust marks on sheet steel, which is the largest when looking over the rusty spot with the electrode a few seconds rest, so that a circular full spot of black zinc was visible becomes bar, and then continues with the movement that the black deposit mark then visually to Verschwin that brings. However, the adhesive strength is such Galvanizing on such not completely pure metal Substrates lower.

example 9 Zinc beaker electrode without internals

In Fig. 9 is compared with Fig. 8, the wick weggelas sen and the zinc cane mouth covered with a textile fabric (polyester, polyamide), the protruding edge wall for fixing this separator between cup outer wall and tube inner wall is squeezed by slipping the Unte ren 17 mm high tube section , Tube overhang d = 0.2 mm, fabric thickness 0.1 mm. The cup is conveniently filled before electrolyte.

It has been surprisingly found that a such separator after prolonged use no Shows signs of wear and not by the unprocessed edge of the extrusion process ago has been injured.

With 12 V, after a start-up time up to 300 mA in reached every spatial position. Soffit and vertical Astonishingly, tines can also be partially filled take place when the separator every now and then by briefly early turning of the mouthpiece downwardly rewetted becomes.  

It is favorable, the circular mouthpiece to an oval to displace, as well as narrow areas accessible become. The current does not decrease, the current density is increasing. Because at short standstill of the electrode A black ring of the oval-shaped zinc-ring forms with a width of about 2 mm on the negative Un from.

Example 10 Granulated zinc double cup-hand electrodes

In Fig. 10, the zinc wire ( 1 ) is airtightly passed through the bottom ( 3 ) of a soft rubber cup ( 2 , 6 '). The cup contains a stiffer soft PVC hose ( 2 ', 6 '') of 20 mm inner diameter, 2 mm wall thickness and 20 mm height, the mouthpiece is slightly opposite to the rubber disc edge, and with the moss rubber washer ( 12 ) forms an inner cup. The bulky filling with 12 g zinc granules ( 1 ', 99.99% Zn, 0.5 to 2 mm grain size) is covered and prevented from falling out by a four-ply polyester fabric ( 6 ), Ø = 58 mm, total layer thickness = 0.5 mm , whose edges are squeezed and fixed with a screwdriver into the narrow gap between the cup wall and the tube, which is easy to do by pressing the thumb on the tissue and the granules.

The electrode delivers 0.8 A. After every 1 minute Electrolysis time must be inserted a cooling off.

The electrolyte content is good and galvanizing in each the spatial situation equally well possible.

The inner cup can also be a second rubber cup used, which is similar to the outer.

example 11 Capillary-hand electrode

A hard polyvinyl pipe piece of 15 mm in height and diameter and a wall thickness of 0.8 mm is pressed together in the heat to a gap of 1 mm width and fixed by cooling in this form, Fig. 11 ( 2 ). Zinc sheet (titanium zinc) of 40 mm in length, 17 mm in width and 0.8 mm in thickness ( 1 ) is tightly inserted into the gap, so that on both sides of the zinc sheet free gaps of 0.2 mm width are formed, which are still some bumps on the Zinc sheet are stabilized. The protruding end of the positively poled sheet which is electrically insulated by adhesive film ( 4 ) ', 13 ) is sealed against the shell by self-vulcanizing silicone composition ( 3 ). The shell projects from the other end of the zinc sheet by d = 0.5 mm and forms the mouthpiece of the electrode. The shell, together with the silicone seal, the cup-shaped electrolyte vessel is to be refilled by obliquely drowning and air release with upwardly directed mouthpiece about every 2 minutes.

The lower part of Fig. 11 represents a cross section through the electrode.

The maximum current is at filling with 25% aqueous ammonia 150 mA.

This electrode is especially suitable for galvanizing tight throats and columns and suitable for any location.

example 12 Galvanizing steel with aqueous ammonia-zinc phosphate electrolytes

14 g of metaphosphoric acid HPO₃ and 50 g of water are converted by heating to 80 ° C in orthophosphoric H₃PO₄ and then 23 g of zinc oxide (zinc white red seal quality) dissolved, finally mixed with 52 g of 25% aqueous ammonia, creating a clear dickflüssi ge solution which is used as an electrolyte in the commercial, construction as in Example 1, Fig. 1, is used, see Table 2.

It can be seen that working conditions were found those in which no hydrogen evolution at the negative ge polten steel takes place. This process variant is like this with suitable, z. B. spring steel, easily by water fabric pickup brittle, to galvanize. It can be at the same time minimizes oxygen evolution at the zinc positive so that long galvanizing times at stationary Operation can be achieved.

Washing off after galvanizing is no longer necessary This electrolyte also because zinc phosphate in Ge Substitute to the known conductive salts (mostly chlorides and sulfates) is not a corrosive salt.  

Table 2

example 13 Badverzinken

A negatively poled horizontal iron axle carries a perforated drum made of non-conductive plastic. The drum rotates in an iron trough, the Elek contains trolytes. To the trough are zinc sheets as solid standing positives arranged. The encapsulation has a Gas vent on. The drum is fresh with hydrochloric acid stained and water-washed iron wire pen (nails) filled to 3/4. Galvanizing with 10% ammonia as the starting electrolyte is more moderate Current density almost without gas evolution and very much the same moderate. The zinc coating is matt light gray. The getrock Neten wire pins are dipped in mineral oil and from centrifuged. They are so durable against rusting preserved.

example 14 Periodic pre-enrichment electrolysis

In a test tube is 10% aqueous Ammonia, in the 2 Zinkelektroden in the form of one each Wire double, wire diameter 3 mm, vertical and paral Immerse each other. It starts with 12 volts electrolyzed. The current rises from 75 in 7 minutes 230 mA. On the negative, zinc separates as  black sponge off. The voltage is at 10 volts and withdrawn after 2 minutes to 5 volts, because the Tempe rises in temperature. After another 10 minutes is the Current 300 mA, and the sponge is about to fall off or one Shorting bridge to form. It is reversed, after which the Zinc sponge goes into solution and a new zinc sponge at the new negatives forms. This periodic DC electrolysis will still be several periods, the getting shorter, continued, with a strong Hydrogen evolution takes place at the respective negatives place. Eventually the electrolytic becomes conductive measured speed and other Elek invention trolytes, see Table 3.

product conductivity 25% ammonia 2.0 10% ammonia 6.6 Present experiment 29 Zinc white red seal plus 10% aqueous ammonia after 8 days of service life 38

Advantages of the invention

After the above detailed description of the invention Finally, partly in summary, partly in supplement They will discuss the benefits they have in life Compared to the prior art offers.

By the invention has been shown that the elec trolytic galvanizing on corrosive salts, Alkaliba sen and acids can be dispensed with altogether, in the simplest way. This is the application of an elek trolytic galvanizing has become practicable by Iron parts connected to masonry, masonry mortar, concrete and other porous materials border as it is inevitable that they are wetted by the electrolyte and soaked up An electrolyte, the corrosive nonvolatile Contains ingredients - and this applies to all known Galvanizing electrolytes - would be the source for one Sub-grate that can not be turned off. But also at Repair galvanizing on motor vehicles can not be ruled out  conclude that the electrolyte gets into cracks where it does Can cause rust damage if it corrosive Bestandtei contains le, which are non-volatile, and if a continuation len is not guaranteed to the smallest traces. With the electrolyte according to the invention is a first time Electrolytic galvanizing has been described, the only volatile (water and ammonia) and inert (zinc oxide, Zinc hydroxide) and rust-protective (zinc phosphate) Be contains constituents.

Although it is known (W.S. Sebborn, Transactions Faraday Society (J. of Chem. Soc.) 29 (1933) 659-663) that a dilute solution of zinc oxide in excess Ammonium hydroxide solution "on electrolysis with" ho "Current density" between stationary zinc sheet electrodes Zinc sponge deposits, whose presentation and sub are the subject of the publication. There are but no evidence that or how a Verzin kung can be achieved.

With ammoniacal zinc salt solutions are experiments for deposition on zinc. The dendri Table growth that interfered with the application was not possible very low current densities and addition of cresolsul fonat avoided for a longer electrolysis duration who (F. Foerster and K. Klemm, Z. Elektrochemie 35 (1929) 409 to 426). There is also no indication how a perfect galvanizing without salts and additives or can be achieved at higher current densities. in the the rest, the adhesion to zinc says nothing about iron and other metals.

In the special literature on hand electrodes is not called a special electrolyte. True, this is in this the rubbing motion is known ("rubbing electrodes"), but in that and in combination with the aqueous ammonia the key for galvanizing without salt application lies, apparently has not been recognized yet.

In fact, so far only a single hand electrode for electrolytic repair galvanizing by force vehicle recently appeared on the market. You ent speaks the DE OS 36 30 919 A1 (C 25 D 19/00), wherein  the positive is not zinc and no solution electrode, but consists of charcoal, about 0.3 mm lags behind over the abrasive ring surrounding it. It is with Zinc chloride-containing, strongly acidic electrolyte ge works, which is thickened. When moving this Rei A considerable part of the electrode is deposited zinc - for the purpose of smoothing - sanded off, so that the current efficiency is poor. A short circuit will Prevented by a built-in series resistor, the but the usable amperage when applying the force Vehicle battery with 12 Volt terminal voltage on approx 100 mA limited. For this performance is the electrode quite large (outer diameter 15 mm, carbon diameter 6.5 mm, length 110 mm) and not suitable for bottlenecks. Since there is no zinc solution electrode, the klei ne amount of electrolyte between the electrodes extremely quickly electrolyzed, and you always have to worry about it for carry, fresh electrolyte under the coal posi tive. The passage of electricity is through the strong gas formation (hydrogen and chlorine) makes it difficult A tough foam quickly forms. The zinc chloride is the most corrosive of all zinc salts. A fresh one Electrolyte portion is required after just 1 minute.

In contrast, the electrode according to the invention works before preferably with a soft-elastic mouthpiece, the no zinc abrades and the paint environment of the repair do not damage it. The new electrolyte is not only free of salt and corrosion, it does not develop poison chlorine, but at most little hydrogen. The Electrolyte hardly consumes, and in principle is only a very thin electrolyte layer as a vehicle for the Absorption and release of zinc ions required. On Series resistor is unnecessary. The current efficiency is over 90%. The refill times are usually longer than the Ver zinkungszeiten.

For the first time by the inventive method a perfect galvanizing without observing a achieved specific recipe and temperature, and this even alone with the han in every drugstore 10% aqueous ammonia and simplest  Electrodes. Although it is about 10% aqueous ammonia optimal, but it can also be much more concentrated or be weaker, so that the process insensitive to a Outgassing of ammonia reacts. The outgassing is also through the flush mouthpiece constructions very much limited. Equally variable is the electrode spacing, the Current density, the voltage, the temperature, the area ver ratio of positive to negative, all parameters that otherwise exactly prescribed.

Galvanizing without the application of corrosive Substances not only brings to the galvanizing, but also for the bath galvanizing advantages. For the galvanized good no longer has to go to liberation to be washed from minute traces of these substances. The inventive method is therefore environmentally friendly and cheaper. There is also no danger that corrosive substances in the galvanization included sen and later cause mischief. In many cases it is sufficient to drain the galvanized material only and in the air to dry. Environmentally friendly and cost-effective Also, that the electrolyte consumption is minimal, because the Production of every chemical is harmful to the environment. The extremely small amount of ammonia that enters the atmosphere Sphere escapes, agriculture comes as fertilizer benefits over the rain and reduces the acidity thereof.

That the low electrolytic conductivity of the aqueous ammonia is not a handicap, they show numerous electrolysis devices described here and that enable competitive current densities. Aqueous ammonia and these devices form one uniform solution of the asked inventive reproducing.

Conversely, the novel devices but also adaptable and suitable for other electrolytes.

As little as aqueous ammonia from the solution electrode Fine zinc attacks in the currentless state of rest, so little it also attacks existing and already generated interest kungen, while the known electrolytes all ag  are gressive.

The aqueous ammonia dissolves the weathering products of zinc, copper and nickel and thereby sets the for the Electrolytic deposition required metal substrate free. Because copper and nickel as well as zinc metal ammino form hydroxide, these metals are analogous to zinc deposited. Without additional oxidants such. B. Air, hydrogen peroxide u. a. m. become copper and nickel but not attacked by ammonia, to the sub also did not differ to zinc with electrolytic current River.

In general, it is not necessary, the inventive Rinse electrodes after use. At the one Precipitation Zinc Oxide and Hydroxide so dry such as zinc phosphate if necessary go with renewed Ge with the filled aqueous ammonia back in Solution. You can insert the electrodes with the mouthpiece fold onto absorbent paper containing the electrolyte then sucks. When storing in the air makes rest ammonia with the carbon dioxide of the air ammonium carbonate, which, however, is a volatile and decomposable one Salt and therefore not from sustainable corrosive Effect is.

The life of the electrodes is either only through the consumption of zinc parts for the galvanizing itself or determined by the life of the separator, the However, it is easily replaceable.

Compared to the short bristle brush electrodes, the little cuddly and halting work, glide the plastic or rubber mouthpieces according to the invention very wet and wet on the wetted, wet surface participating. In the densest and thus capillary active Pac cover the uniformly thick, round bristles this geometrically 91% of the free cross section that the present invention not or only as little as possible limits.

Long-haired brush electrodes that are softer than short ones and stiff bristles work, are less durable capable and by the way also for highly conductive electrolytes  hardly practicable. It has therefore been suggested, Bür to use stenelektroden whose bristles z. T. shorter and are electrically conductive (US PS 41 59 934).

Instead of fine zinc can also impure and alloy used zinc. Whether a zinc alloy suitable for the present process, can quickly through to be decided on a preliminary test.

Compared to the known sponges and foams with open pore structure as the electrolyte carrier, the whole Use a cable cross-section with a large thickness (Tampon electrodes), are the advantages of the invention The electrodes are unimpeded or only slightly hindered Continuity, abrasion resistance and avoidance of shorting bridges, as caused by zinc deposition in the pore courses of the tampon electrodes occur.

As the training of the hand electrode according to claim As far as 32 is concerned, it has decreased with respect to the hand electrode the German PS 6 73 190 the advantages that the electrolyte carrier does not cover the whole positives in a thick layer, the electrolyte carrier nevertheless much thicker and adaptable is more capable, the electrode spacing is lower and the spei is greater for the electrolyte because the Electrolytic vessel - except for the mouthpiece - airtight ver is closed, and that no shorting bridges Training zinc in the vehicle, probably because of this does not cover the annular main flow path and the soft-elastic foam carrier in the mouthpiece area is in strong motion.

The construction of a brush electrode, in which the hair bundle is located in a platinum cup and beyond the edge of it is in German GM 81 29 270.8 described. In comparison to the hand electrodes z. B. according to claims 28 and 32 to notice that the protruding brush hair no ensure constant electrode spacing, because they are depending on the pressure exerted by hand more or less crooked and wear, except that the Vo Lumenbeanspruchung the hair bundle and the strong gas Development of the inert positive to disorders of the  Current flow leads.

An open mouthpiece with otherwise airtight electric Lytgefäß has already become known in a hand electrode those for "point-like electrolytic treatment metallic objects, in particular for polishing and Ätzen "serves (German PS 11 30 245), but it is only around the narrow mouth through which the spent Elek trolyte, driven by gas generated during the process, should leak constantly. It is not one Traveling friction electrode, and she has no solution positives. The nature of the mouthpiece is a. a. O. only the requirements made that it does not lei electrically tend to be tight and pointy tight. The invention Mouthpiece should be as far as possible, and the width is limited only by the conflicting specification that if possible, no electrolyte should leak.

If a comparison between the capillary gap Electrode according to the above claim 26 with the pin selelektrode after the German PS 34 400 employed It will be noted that the zinc wound up sheet formed gap is filled by brush bristles, which guarantee the gap width and the electrode gap and the rubbing effect, while said Ausbil tion of the electrodes according to the invention free capillary split and only a rubbing mouthpiece on the circumference has. Further, the electrode according to claim 26 is for Galvanizing in any location suitable, which in the known is not correct, because with her - similar to the An Paint a blanket with a brush - the electrolyte can flow out on the handling side, because the pin sel is not encapsulated. Finally, the well-known Electrode suitable only for larger flat surfaces while the inventive both for tight column and - bundled according to claim 38 - for contoured surfaces is usable.

Claim 27 includes an improvement the electrode according to the aforementioned DE PS 34 400 by Encapsulation of the same with a zinc cup, so that they are in Any space situation can be used. Here are enough  bristles as gap width holders, and the bristle projections are in the use of the protruding Isolierstoffum Edge of the zinc beaker edge as a means of preserving the Electrode distance and dispensable as friction elements.

Listed below are further advantages of the present invention The present invention have already been described in detail above been:

• 1. Unsurpassed simple electrolyte and easy hand electrodes.
• 2. No electrolyte flow, but lowest consumption.
• 3. Typical application: repair galvanizing garage door sleepers whose galvanization has worn down or Be tone borders.
• 4. Hand electrodes applicable in any location.
• 5. Essentially free electrolyte space, so no He the material exchange and current flow through inert electrolyte carrier.
• 6. Hand electrodes adaptable to each surface contour.
• 7. Thin separators allow a very low Elek electrode gap and the use of granular zinc, which has a high dissolution activity.
• 8. Very good current scattering, so that galvanizing z. B. Thread depressions is possible.
• 9. The advantages of galvanizing as a paint carrier: no advance paint and no filler required.
• 10. No abrasive properties of soft mouthpieces.
• 11. Absorbent, nonwoven electrolyte carriers only to the extent that as the power line cross section between the Elek remains open, d. H. the electrodes in the most active area are not covered.
• 12. Use of foam as an electrolyte carrier, wherein this abrasion relieved and surface adaptive are, as well as a constant electrode gap through the Mouthpiece is given.
• 13. The good wetting ability of aqueous ammonia.
• 14. The minimization of hydrogen gasification.
• 15. High current efficiency.
• 16. No polarization with current standstill at Reibeelek trode.  
• 17. Galvanizing possible even at winter temperatures Stig.
• 18. Coverability of rust scars.
• 19. Immediate galvanizing phosphated iron sheets.
• 20. Capillary gap sucks faster than tampon, without the to increase electrolytic resistance.
• 21. Flexible bundling of hand electrodes for processing larger, even curved surfaces.
• 22. Use of galvanizing as a lubricant and Gleitmit carrier for mechanical deformation.
• 23. Use and separation of zinc alloys.
• 24. No resistor required, because no short risk of closure exists and the electrical resistance is selectable by the electrode spacing.

Reviewed literature

Pamphlets of the German Patent Office of the classes
48a 5/00, 5/10, 5/70, 5/72, 5/74, 5/76;
C 07 D 231/18;
C 25 D 3/02, 3/22, 5/00, 5/04, 5/06, 5/08, 5/10, 5/22, 17/14, 19/00.
Chemical Abstracts 1916 ff.
Gmelin, Handbook of Inorganic Chemistry, Volume Zinc, Hauptwerk 1924 and supplementary volume 1956, Verlag Chemie. U. on

Claims (49)

1. A process for the electrolytic production of adherent and covering coatings of zinc on negatively ge polten metals, in particular iron and zinc, by means of an aqueous ammoniacal electrolyte solution and a positive polarity electrode made of zinc, characterized in that an electrolyte is used, which at the start in consists essentially of pure ammonia, or that this already contains the electrolytic reaction products (zinc aminohydroxides), or that they are given before or during the electrolytic galvanizing, in particular by admixing zinc oxide and / or zinc hydroxide and / or powdered zinc, or be produced by prior electrolysis of the aqueous ammonia solution between zinc electrodes at high current density and large hydrogen evolution at the negatively poled Zinkelektrode and how umholter polarity reversal of the electrodes. 2. The method according to claim 1, characterized, that the electrolyte of zinc nitride and water or aqueous ammonia is produced. 3. Process according to claims 1 and 2, characterized, that the electrolyte no conductive salts or alkali bases contains. 4. The method according to claim 1, characterized, that the ammoniacal electrolyte additionally in the sem soluble zinc phosphates, either to be set and / or out of the coating to galvanizing iron materials with zinc phosphates come. 5. Process according to claims 1 to 4, characterized, that excess zinc oxide and / or zinc hydroxide for the sake of thickening, which go to paste consistency can, is mixed.   6. Process according to claims 1 to 5, characterized, that the electrical voltage, the electric current density, the electrode spacing, the area ratio the electrodes, the ammonia content and the size ren current densities required relative movement of the Electrolytes and / or Rubbers on the Nega tives or on the already formed Ver Zinkung, be adjusted so that on the Ne does not form black or loose zinc, or already formed - if necessary at increased movement - again detached and largely dissolves and on the negatives a stuck and covering galvanizing forms, and that preferential wise at the negatives in the case of iron and zinc as negative, no or very little hydrogen arises. 7. Process according to claims 1 to 6, characterized, that moved in the moving electrolytic bath to be galvanized Bulk material acts as a rubbing body. 8. Process according to claims 1 to 6, characterized, that in bath-free galvanizing with electrolyte-filled Hand electrodes whose mouthpieces are not electrically conductive material serve as a rubbing body. 9. Process according to claims 1 to 4, characterized, that a hand electrode is used whose space between the electrodes contains only the electrolyte, that the electrode so on the surface to be galvanized is placed on that wets the electrolyte is, and that the electrode ge in this position ge will hold, especially when galvanizing iron with the help of a magnet and an iron wire, where a current density of about 3 A / dm zinc front surface is not exceeded.   10. hand electrode for performing a bath-free electro-lytic galvanizing with the electrolyte according to claims 1 to 5, characterized in that at the same time

• a) the electrolyte vessel is cup-shaped,
• b) the cup-shaped vessel consists of positively polarized zinc and / or absorbs such
• c) the edge of the open cup mouth is made of electrically insulating material,
• d) the electrode spacing is 0.1 to 5 mm,
• e) the volume of the vessel is greater than the volume between the area of the open mouthpiece and the nearest zinc surface (electrolysis reserve and gas storage),
• f) the mouthpiece edge can be placed flush on the surface to be galvanized,
• g) the electrolyte wetted mouthpiece edge can serve as a gentle friction element,
• h) the electrolyte wetted surface of the positively poled zinc is larger than the area of the open mouthpiece,
• i) the cup-shaped vessel - apart from the open mouthpiece - is airtight,
• j) the electrolyte liquid is prevented from running down in mouthpiece mouthpiece, and preferably by the fact that the filled elec trolyte - in particular, without the use of voluminous absorbent Elektrolytträgersubstan zen - forms a freely suspended column of liquid, at least at open Mundstücksbreiten about mm with an electrolyte permeable, wettable by the electrolyte, thin Sepa rator such as fabric, knitted fabric, mesh, sieve, perforated film, nonwoven o. The like. From electrically insulating material for stabilization one or more layers is covered on the open mouthpiece.

11. The method according to claims 6 and 8 by hand Grinding electrode according to claim 10, characterized, that this filled with the electrolyte and on the zu galvanizing surface is placed so that these too is wetted next to the Aufsitzstelle, and that the Electrode after switching on the electric current moved so fast in frictional contact over the surface is that no black zinc on the surface from separates or this dissolves again as far as possible. 12. hand-held electrode according to claim 10, characterized, that the zinc relative to the mouthpiece by 0.1 to 5 mm ago. 13. Hand electrode for carrying out the method according to Claims 1 to 4, characterized, that the zinc wholly or partly in lumpy and free movable form is present and by a in the claim 10 defined separator falling out of the mouth piece is hindered. 14. hand electrode according to claim 13, characterized, that the zinc in granular form, in particular roundish Granules or edged, short wire sections before lies. 15. hand electrode according to claim 13, characterized, that the zinc in the form of mutually parallel ver sliding zinc wire or zinc tube sections is present. 16. hand electrode for performing the method according to to claims 1 to 5, characterized, that the electrolyte vessel zinc in the form of against each other contains parallel displaceable zinc tubes whose Orifice-side openings 0.1 to 5 mm protruding Insulator bear as a spacer and Serve friction elements.   17. hand electrode according to claims 10 to 16, characterized, that the electrolyte period at least in the range of eng not well filled with electrolyte carrier is filled and preferably at all no electrolyte carrier or only in claim 10 defined separators or in An contains 6 mentioned Isolierkörperchen. 18. hand electrode according to claims 10 to 17, characterized, that the edge of the mouthpiece of soft-elastic Material exists, which is electrically non-conductive. 19. hand electrode according to claims 10 to 18, characterized, that the electrolyte vessel from electrically do not conduct the material is formed and zinc as wire, rod or sheet contains, that these parts or their Zu lines through the wall of the vessel airtight are introduced. 20. hand-held electrode according to claim 19, characterized, that the electrolyte vessel of soft-elastic Mate exists. 21. Hand electrode according to claims 19 and 20, characterized, that in the cup-shaped electrolyte vessel, a zinc wire is inserted through the bottom of the cup that between the zinc wire and the side beaker Forming a gap is formed, that the gap up 3 mm and the open mouthpiece, preferably ange is oblique until 8 mm are wide, and that the mouth piece is uncovered. 22. hand electrode according to claim 21, characterized, that about a piece of a zinc wire approximately in the middle shorter piece of a tight fitting hose zoned gene is, and that a sleeve tube on the one hand on the sem seals and on the other hand, the one end of the Zinc wire towers over.   23. Hand electrode according to claims 21 and 22, characterized, that the zinc wire in the cup bottom or in the strammsitzenden hose piece is displaceable, and that the tightness by aids such as screw clamp, rubber band or the like can be ensured the ge for moving the wire as needed ge loosens or can be tightened. 24. hand electrode according to claims 13 to 15 and 19 and 20, characterized, that the mouthpiece carries a Separatorsieb, too Component of the electrolyte vessel may be by z. B. whose bottom is perforated, that the electric lytgefäß from a cup part and a plug part may exist that on the sieve bottom the end faces Of zinc wire sections store, each other arranged parallel and preferably against each other are movable in parallel and fill the free space len and whose diameters are larger than the Boh or mesh of the sieve, or that the Sieve bottom with a sufficiently fine-meshed sepia is occupied and the zinc filling is grainy. 25. Hand electrode according to claim 14, characterized, that the granular zinc in a textile bag together is taken, in the electrical supply into it leads, and that the bottom of the bag be separator can. 26. hand electrode according to claims 10 and 19, characterized, that zinc from narrow slit-shaped spaces around give is that in particular sheet-shaped zinc with the electrically non-conductive electrolyte vessel capillary active tight free column forms the mouthpiece side are not covered, and that as a sealing material for the site of introduction of zinc into the vessel preferably hard polyvinyl chloride, preferably at the Air self-vulcanizing silicone composition is used.   27. Hand electrode according to claims 10, 19 and 26, characterized, that a positively polarized zinc cup an electrode according to DE PS 34 400 receives, with the cup in electrical contact stands. 28. Hand electrode according to claims 10, 12 and 18, characterized, that the cup of zinc to be filled with electrolyte Mouthpiece with a separator, preferably Textilge Webe, which is fixed by his protruding edges between the zinc cups and the soft-elastic border squeezed on the mouthpiece are, and that the border is preferably opposite to the Separator surface slightly protrudes, so that the Separator to verzin at least on flat and concave kenden surfaces is protected against frictional closure. 29. Hand electrode according to claim 28, characterized, that the mouthpiece of a cylindrical zinc cup from Circle is deformed to the oval. 30. hand electrode according to claims 28 and 29, characterized, that the zinc cup contains additional zinc parts. 31. hand electrode according to claims 10, 15, 28 and 30, characterized, that in the zinc cup parallel to the wall of zinc Wire or tube sections loosely movable are in order and in electrically conductive contact Stand with the cup that feathers on the bottom of the cup the material is placed, and that the resilient Ma terial the wire and tube sections against the Separator presses. 32. hand electrode according to claims 10 and 12, characterized, that the zinc has the shape of a cylindrical cup, whose open side is the mouthpiece whose elek a trio of insulating edges project something that the cup contains a wick, preferably from soft-elastic open-pored foam or out  Textile aggregates, in particular of cotton, in that Wick in decompressed state over the mouthpiece Preferably something protrudes edge that the cup and the wick absorbs the electrolyte, and that the Wick when galvanizing the annulus between the zinc cup edge and the corresponding to be galvanized Preferably leaves counter-surface free. 33. Hand electrode according to claims 10, 14 and 20, characterized in that the cup-shaped Elek soft rubber gum with tightly inserted Zinc wire a fitted stiffer hose, z. B. made of soft polyvinyl chloride, whose mouthpiece slightly behind the mouthpiece of the rubber cup jumps, and the one with the inner rubber cup wall egg NEN gap forms that preferably on the Becherbo a disc of soft-elastic sponge rubber lies, that the remaining tube space up to its mouthpiece edge is filled with granular zinc, that this Mouthpiece covered with a textile fabric is that its protruding edge forced into the gap and is fixed with it. 34. Hand electrode according to claim 33, characterized, that the fitted hose through a fitted Rubber cup is replaced. 35. An electrode according to claims 10, 12, 18, 8, characterized, that over a zinc cup as an electrolyte vessel in full length one hose or several hose parts are pulled tight, the first is the zinc cup insulated electrically to the outside, secondly the over the edge of the cup something protruding Reibemund piece, which is also used to fix a Separa third, and the third contact with the supply line according to claim 36 allows. 36. Hand electrode according to claims 10 to 35, characterized, that the cylindrical, in particular wire-shaped or Cup-shaped zinc electrode or its supply line  is connected to the supply line by a Hose, over the stripped end of the strand and the zinc or the intermediate supply tight and in the case of the zinc wire in its extension as a flexible support for the after outside continuous strand can serve. 37. Hand electrode according to claims 21 to 23 and 36, characterized, that cups and tubes have a uniform shape per which the zinc wire is heavily displaced Bar is sealed, preferably by means of sealing lips in the molding. 38. The method according to claim 6, characterized, that several hand electrodes for the purpose of processing size rer, also wavy and curved surfaces bundled be, and that the bundling a Parallelbeweglich speed of the individual electrodes can allow, preferably by not too tight elastic bands. 39. The method according to claim 6, characterized, that the hand electrode so on the surface to be galvanized is placed and if necessary moved that the gas produced during the electrolysis either after Pull off the outside or in the mouthpiece-distant part of the vessel can collect the electrode. 40. Method and electrodes according to claims 1 until 39, characterized, that the zinc parts of fine zinc and / or of impure zinc and / or alloyed zinc. 41. Process according to claims 1 to 40, characterized, that with aqueous ammonia from 5 to 25 weight percent, preferably about 10 wt .-%, at current densities of 1 to 100 A / dm 2, preferably 10 to 50 A / dm 2 zinc end face, a distance between mouthpiece edge and zinc of 0.1 to 25 mm, preferably 0.2 to 0.5 mm in Separatorbetrieb and at the Kapillarspaltelek  electrode (claim 26) and approximately 3 mm with free mouthpiece, and at voltages of preferably around 12 volts is processed. 42. The method according to claim 41, characterized, that the electrode spacing depends on the applied elec tric voltage is adjusted so that the ge wished electrical current density is achieved and no resistor is required. 43. The method according to claim 41, characterized, that the z. B. for the repair directory on Kraftfahr zeug with the power source required long Lei wire wholly or partly made of insulated elec The resistance wire is a special one Save on series resistance. 44. Process according to claims 1 to 43, characterized in that the galvanization to Been the electrolysis is not washed off, but only is wiped dry or dried in air. 45. Galvanization of iron and zinc, produced according to the Claims 1 to 44, characterized, that they are of adherent, covering, shear and bending firmer, ductile, with Stahlstichel scratchable, weitge metallic, macroscopic on the surface mostly smoother and duller, with strong rubbing with steel tool to shine coming and such only micro skopisch rough texture is that they are made of varnishes Wetting penetrating on water and solvent base is, and that the paints - as well as melting and sintering lacquer coatings - are well anchored and none require further priming. 46. Method and devices according to claims 1 to 44, characterized, that they are based on the galvanizing of galvanized iron, copper, Nickel and tin are applied.   47. Process according to claims 1 to 46, characterized, that the galvanizing achieved as a lubricant or / and lubricant carrier for mechanical deformation be applied. 48. The method according to claim 4, characterized, that coated with zinc phosphate iron as uncoated tetes, metallic iron is treated, d. H. without previous mechanical removal of the phosphate coating tung. 49. Method and devices according to the claims 1 to 44, characterized, that an ammoniacal electrolyte is used, the except Zinkamminohydroxiden also Nickelammino hydroxide and / or copperamminohydroxide.