CA1232227A - Manufacturing electrode by immersing substrate in aluminium halide and other metal solution and electroplating - Google Patents
Manufacturing electrode by immersing substrate in aluminium halide and other metal solution and electroplatingInfo
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- CA1232227A CA1232227A CA000419585A CA419585A CA1232227A CA 1232227 A CA1232227 A CA 1232227A CA 000419585 A CA000419585 A CA 000419585A CA 419585 A CA419585 A CA 419585A CA 1232227 A CA1232227 A CA 1232227A
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D3/00—Electroplating: Baths therefor
- C25D3/02—Electroplating: Baths therefor from solutions
- C25D3/56—Electroplating: Baths therefor from solutions of alloys
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
- C25B11/042—Electrodes formed of a single material
- C25B11/046—Alloys
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
- C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
- C25C7/00—Constructional parts, or assemblies thereof, of cells; Servicing or operating of cells
- C25C7/02—Electrodes; Connections thereof
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D3/00—Electroplating: Baths therefor
- C25D3/02—Electroplating: Baths therefor from solutions
- C25D3/34—Electroplating: Baths therefor from solutions of lead
- C25D3/36—Electroplating: Baths therefor from solutions of lead characterised by the organic bath constituents used
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
- C25D5/34—Pretreatment of metallic surfaces to be electroplated
- C25D5/38—Pretreatment of metallic surfaces to be electroplated of refractory metals or nickel
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
- C25D5/34—Pretreatment of metallic surfaces to be electroplated
- C25D5/42—Pretreatment of metallic surfaces to be electroplated of light metals
- C25D5/44—Aluminium
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/64—Carriers or collectors
- H01M4/66—Selection of materials
- H01M4/665—Composites
- H01M4/667—Composites in the form of layers, e.g. coatings
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/64—Carriers or collectors
- H01M4/70—Carriers or collectors characterised by shape or form
- H01M4/72—Grids
- H01M4/73—Grids for lead-acid accumulators, e.g. frame plates
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Composite Materials (AREA)
- Electrolytic Production Of Metals (AREA)
- Electroplating Methods And Accessories (AREA)
Abstract
ELECTRODE COATED WITH LEAD OR A LEAD ALLOY
AND METHOD OF MANUFACTURE
ABSTRACT
An electrode in particular an oxygen-evolving anode for metal electrowinning from an acid electrolyte comprises a body of aluminium or other metal coated with lead or a lead alloy by electroplating preferably from a non-aqueous electrolyte. The substrate can be a sheet of aluminium or compacted particles of aluminium plated with lead or a lead alloy. A sheet of lead or lead alloy is clad to the electroplated substrate and advantageously an electrocatalytic material such as surface-activated valve metal sponge is applied to the surface of the lead or lead alloy sheet.
AND METHOD OF MANUFACTURE
ABSTRACT
An electrode in particular an oxygen-evolving anode for metal electrowinning from an acid electrolyte comprises a body of aluminium or other metal coated with lead or a lead alloy by electroplating preferably from a non-aqueous electrolyte. The substrate can be a sheet of aluminium or compacted particles of aluminium plated with lead or a lead alloy. A sheet of lead or lead alloy is clad to the electroplated substrate and advantageously an electrocatalytic material such as surface-activated valve metal sponge is applied to the surface of the lead or lead alloy sheet.
Description
Case 3483/33~8/FF
~23Z'~7 ELECIRODL Kettle WITH LEA OR
A LEAD ALLOY AND METHOD OF MANUFACTURE
, TIC Nikolai Fled The invention relates to electrolysis electrodes which are foaled with read or a lead alloy, as well as to methods of manufacturing the electrodes. The electrodes are useful as anodes, cathodes and bipolar electrodes in various electrolysis processes, one advantageous use being as oxygen evolving anode in metal electrowinning from an acid electrolyte.
BACKGROUND ART
At present, probably the best anode for oxygen-evolution is that described in UK patent specify cation No. 1.399.576, having a coating containing a mixed crystal of tantalum oxide and iridium oxide. However, neural electrodes of this type contain at least about 7.5 g/m2 of iridium so that despite their excellent performance in terms of over voltage and lifetime, the high cost of iridium makes these electrodes less attractive and in order to be competitive with cheaper anodes they must be operated at a relatively high anodic current density which necessitates various expedients in the cell design. Consequently, anodes made of solid lead, lead alloys, cobalt-silicon alloys and so forth are still used in many electrowinning plants despite the known disadvantages of such neutrals.
Massive anodes of issued and lead alloys such as lead-silver thus ~,~
~23Z~7 remain the most widely used anodes in metal electrowinning from sulfite electrolytes despite problems of weight, poor mechanical strength and high over-voltage. Lead-silver alloys offer a lower Dyer-voltage and are less subject to corrosion in zinc electrowinning, but massive anodes of these alloys are very expensive.
EGOS 28 33 439 to Noah Spa opened Eyebrow 15, 1979 has proposed an elec~traw~n~ng anode consisting of tubes of aluminum coated with an extrusion drawn lead-silver alloy; this seeks to provide a lightweight and relatively inexpensive structure compared to conventional massive lead-silver anodes, but is subject to nutrias drawbacks. Firstly, the extrusion drawing process is expensive, does not provide an excellent electrical contact and is limited to tubular and rod-like sections. Secondly, in electrowinning applications the rod-like configuration results in a voltage penalty of about 350mV compared to massive anodes, as well as a greater dissolution of lead leading to increased contamination of the catholically deposited metal, e.g. zinc.
DISCLOSURE OF INVENTION
A main aspect of the invention, as set out in the claims, is an electrolysis electrode comprising an electrically conductive body of aluminum, titanium, zirconium, niobium, molybdenum, tungsten, tantalum, magnesium alloys, iron, steel, nickel, copper or alloys of these metals or graphite, coated with an electroplated layer of lead or a lead alloy to which a sheet of lead or lead alloy is bonded. In many instances, aluminum will be very advantageous as the electrically conductive body or substrate, and the invention will be more particularly described by way of example with aluminum as the substrate material.
Thus, the invention more specify icily provides an electrolysis electrode, primarily an improved oxygen-evolving anode, in the form of a light and mechanically strong structure comprising a body of aluminum coated with an electroplated layer of lead or a lead alloy to which a sheet of lead or lead alloy is bonded, which will advantageously replace the massive lead or lead alloy electrodes heretofore used in metal ;~32' I:
electrowinning, and is also useful in other processes, e.g. organic Electra-synthesis, in which toad anodes have been used. Other uses such as cathodes for some processes, or bipolar electrodes or battery electrodes are also envisaged.
The lead or lead alloy is preferably electroplated directly on the substrate material, e.g. aluminum, this advantageously being achieved by removing oxide skin from the aluminum and electroplating lead or a lead alloy directly onto the aluminum from a non-aqueous electrolyte based on an aluminum halide dissolved in an aromatic hydrocarbon. Alternatively, lead can be electroplated from an aqueous plating bath in which case, after removal of its oxide skin, the aluminum must be replated with thin protective layers of, for example, zinc or tin covered with copper.
Electroplating of lead from a molten salt electrolyte is another possibility. In these manners, but preferably by the direct, non-aqueous plating method, a well adherent and pore-free coating of lead or lead alloy can be built up to a desired thickness.
In one particular embodiment of the invention, the anode is composed of aluminum particles electroplated with a coating of lead or à
lead alloy, preferably by non-aqueous electroplating, and then consolidated into a body by pressing the coated particles together; the body thus formed may be further coated with an additional electroplated layer of lead or a lead alloy, if desired, before bonding the outer sheet of lead or lead alloy. This embodiment has the advantage that when the anode is used in a corrosive environment and is liable to damage, as for example by short-circuiting due to dendrite formation of a catholically deposited metal such as zinc, corrosion of the aluminum will be strictly localized to the damaged part. Thus, the composite anode body takes maximum advantage of the excellent corrosion resistance of lead while benefiting from the lightness and good conductivity of aluminum.
In a modification of this embodiment, aluminum particles electrocuted with lead or a lead alloy can be deposited onto an aluminum sheet pre-coated with an electroplated lead or lead alloy layer; a further layer of lead or lead alloy can then be electroplated on top if desired, Jo I
and finally a sheet of lead or lead alloy is bonded onto the composite.
Bonding a sheet of lead or lead alloy onto an electroplated lead or lead alloy underplayer on a sheet aluminum substrate, or a composite substrate comprising aluminum particles coated with lead, avoids long plating times for the production of a thick, protective lewd en lead alloy coating and the bond can be achieved with a negligible ohmic loss at the interface. Such a bonding of sheet lead directly onto aluminhJm and other valve metals is not feasible, and the propelled electroplated layer serves to provide an excellent bond using conventional cladding techniques employing heat and prowar, in particular rolling techniques. Conveniently, after rolling lead or lead alloy sheets onto either side of a lead plated aluminum sheet, protruding edges of the sheets are simply folded over and sealed by applying heat and pressure.
The operative surface of the electrode may be that of the sheet of bonded or clad lead, or it can be advantageous to use sheets of lead-silver, lead-calcium or lead-antimony alloy as the active surface to provide an anode which replaces massive lead-silver, lead-calcium or lead-antimony anodes but at a fraction of the cost and with improved mechanical strength and conductivity.
However, in many instances it will be advantageous to apply an electrocatalytic material to the surface of the bonded sheet of lead or lead alloy. The electrocatalytic material my consist for example of electroplated lead dioxide or manganese dioxide, or can be a coating formed by applying a solution of a compound which decompose to form an electrocatalyst at a temperature preferably below about 325~C, and heating to decompose the compound. Alternatively, the electrocatalyst can consist of a powder which is pressed, hammered or rolled into the lead surface, or is applied in a binder. For example, prP-prepared powders of solid solutions of ruthenium-titanium dioxide, ruthenium-manganese dioxide or iridium-tantalum oxide can be used, or powders of ruthenium dioxides, manganese dioxides or magnetites as well as mixtures of these powders.
I, A particularly preferred electrocatalytic material consists of surface-ac~ivated particulate valve metal, in particular a flattened sponge such as titanium sponge. The particulate valve metal is surface-activated with a suitable electrocatalytic material typically the platinum-group metals platinum, palladium, rhodium, iridium and ruthenium or their oxides possibly in combination with other oxides such as the oxides of tin, manganese, cobalt, chromium, antimony, molybdenum, iron, nickel, tungsten, vanadium, silicon, lanthanum, tellurium, phosphorus, boron, beryllium, sodium, lithium, calcium, strontium, lead and copper, these other oxides usually being present in minor or trace amounts. This surface activation of the valve metal particles can take place prior to or after applying the particles onto the lead surface of the composite anode; it may also be convenient to do a preliminary activation of the particles with a high-temperature bake (i.e. above ~5C) and a final activation once the particles have been applied to the lead surface, followed by baking at a temperature below 325C. Typically, these valve metal particles will have a size from about 75-85û micron, usually from owe micron; however, after pressing, particles of sponge will be deformed into flattened shapes which may be bigger. Usually, the loading of particles will be from about 50-2000 g/m2 of the anode surface area, 300-800 g/m2 generally being adequate, the electrocatalyst (calculated as platinum-group metal) usually corresponding to 0.3 - 6% by weight of the valve metal of the particles. The particles can be applied by hammering, pressing, rolling or in any other convenient manner. The preparation and application of such surface-activated particles-to a lead substrate is more fully described in European patent application No. 46727 published 1982.
The provision of a surface electrocatalyst is advantageous in that the lead or lead alloy remains electrochemically inactive and simply acts as a conductive and relatively corrosion-resistant support for the active electrocatalyst where the oxygen evolution reaction takes place.
Consequently, corrosion of the lead or lead alloy, which would take place when the lead or lead alloy is used as the active electrode surface, is virtually eliminated and therefore relative thin layers of lead can be I
~3;2~7 , I, used without fear of corrosion of the lead or lead alloy producing holes exposing the aluminum substrate.
The various described anodes are particularly advantageous when used for the electrowinning of metals such as zinc, copper, cobalt or nickel from a sulfite electrolyte. In zinc electrowinning with conventional massive lead or lead alloy electrodes, zinc dendrites grow on the cathode and may come to touch the anode, this causing short-circuits which melt lead or lead alloy at the surface and burn holes in the anode.
However, with anodes according to the invention this problem is considerably diminished because of the excellent heat conductivity of the aluminum core. This is illustrated by the following simple test. Sheets of (a) lead (b) zinc and (c) aluminum plated and clad with lead in accordance with the invention were exposed to a flame at approx.
1500~C, and the lime for the surface to begin melting was measured. This was: (a) lead 9 seconds; (b) zinc 15 seconds; (c) aluminium/lead 30 seconds. These test data can be extrapolated to commercial zinc electrowinning practice as follows. When a zinc dendrite touches a lead electrode, the zinc dendrite conducts away heat better than the lead electrode, and the surface of the lead electrode overheats and is burnt.
However, when a zinc dendrite touches an aluminium/lead electrode according to the invention, the aluminum core conducts heat away rapidly so that the lead surface does not overheat, whereas the zinc dendrite conducts away heat less well and will be preferentially burnt away.
This excellent resistance of the composite electrodes according to the invention to damage by short-circuiting is further enhanced when a suitable electrocatalyst is provided on the lead or lead alloy surface, in particular a surface-activated particulate valve metal, the best protection effect being obtained with flattened surface-activated valve metal sponge.
By suitably choosing the lead electroplatinglcladding conditions as well as preferably including a surface electrocatalyst, it is possible to virtually eliminate any risk of damage to the lead coating which would be ~3~227 followed by corrosion of the aJuminium substrate. However, if corrosion of the aluminiurn does take place, this is by no means a serious problem in metal electrowinning since the aluminum does not plate out with and contaminate the catholically deposit metal, but either precipitates out or remains in solution. To avoid any problems of contamination of the catholically deposited metal or of reduction of the current efficiency, the aluminum will either be essentially pure or may be alloyed with metals which are harmless in the electrowinning environment, for example magnesium, silicon or in some instances copper (e.g. in copper electrowinning~. To the contrary, it should not contain any appreciable amount of metals which are poisons in the environment such as tin, antimony, cobalt or copper for zinc electrowinning. Similar considerations apply to the alloying elements for the lead alloys. The most usual alloys will be lead-siJver for zinc electrowinning, and lead-calcium and lead-antimony for copper electrowinning.
The aluminum substrate will usually be in the form of a solid sheet, this being particularly advantageous for metal electrowinning applications, but it is also possible to use sheets of an expanded aluminum mesh or grid which are abated e.g. by the non-aqueous plating method and then bonded to a lead sheet and possibly coated with a catalyst. As previously mentioned, aluminum powder coated with lead can also be used as the substrate to which the lead or lead alloy sheet is bonded.
For some processes, for example for the synthesis of adiponitrile, it is possible to incorporate the lead-coated and clad aluminum anode into a bipolar electrode. For instance an alurninium substrate could be electroplated and clouded with lead or a lead alloy (e.g. lead-silver) on its anode side, and optionally carry an electrocatalyst such as magnetize mixed with platinum, or a mixed ruthenium-titanium oxide, or silver. The cathode side would carry a suitable cathodic material, e.g. it could be plated/clad with lead or cadmium. Such bipolar electrodes are also useful for water electrolysis to produce hydrogen and oxygen from a sulfuric acid based electrolyte; in this instance the cathode face can incorporate any suitable hydrogen evolution catalyst, a layer of nickel-aluminium-molybdenum (from which the aluminum is leached) being one possibility.
` ~232~2~
_ 8 -In some processes, the substrate material, e.g. iron, steel or nickel could operate as the cathodic surface of the bipolar electrode.
In the other applications, the lead-coated and clad side could act as cathode of a bipolar electrode with an appropriate anodic material as the other side of the substrate.
.
Although the invention has been described mainly with reference to en aluminum substrate, as a modification it is possible to use a substrate of titanium, zirconium, niobium, molybdenum tungsten, tantalum, magnesium alloy, iron, steel, nickel, copper or alloys or these metals or graphite. The substrates titanium through magnesium alloys may advantageously be incorporated in bipolar electrodes. Nickel and copper substrates can be advantageous respectively for nickel and copper electrowinning anodes.
.
ELECTROPLATING METHOD
Manufacture of the composite anodes preferably includes the step of electrocuting onto the aluminum or other substrate from a non-aqueous electrolyte. This is advantageously carried out by a novel method in which etching of the aluminum or another valve metal substrate and subsequent electroplating with lead or lead alloy is carried out in a single bath of suitable composition, instead of the conventional process in which the aluminum or other substrate is etched in a first bath and then transferred to a separate plating bath.
In effect, an oxide-free surface of aluminum can be obtained by etching in a solution of an aluminum halide (Alex) and an aromatic hydrocarbon (ah), the Aye film being dissolved in this medium by formation of soluble oxy-halide complexes with Alex. This etching step can be accelerated by anodization of the aluminum substrate. A very clean surface of aluminum can be obtained rapidly by this method if the AXE ah solution contains a certain quantity alkali metal-and/or other metal-halides. The presence of a minimum quantity of alkali and/or metallic go ~23~ 7 _ 9 _ halides is necessary to dissolve the AXE formed by anodization of the Al substrate, by the formation of [Mn+.nAlX4-] or Nooks complexes which are more soluble than Alex in ah-By using an appropriate metallic halide Men as the complexingagent in solution, the electrode position of M can be obtained directly on an aluminum substrate by a subsequent cathodic polarization in the same solution. The surface treatment of the aluminum substrate is preferably carried out with an acidic composition of the bath, because the dissolution of the al~Jminium oxide film is only possible in the presence of AXE or AXE- forms. Consequently, this process applies mainly to metals which are deposited at a potential more positive than aluminum and, because of the potential leveling effect of Alex ah medium, an alloy deposit can be obtained by using a mixture of metallic halides. In particular the process applies to the electrode position of lead and alloys such as Bag Pica Pb-Sb.
A very adherent Pub deposit may be obtained directly onto an I
substrate from a solution of AlC13-PbC12-LiCI in Tulane. AWOKE is preferable to AlBr3 or Aye because of its stronger affinity to form the oxyhalide complexes. AIF3 is not soluble in ah. Tulane is the preferred ah solvent because its busiest is weak enough not to decrease the etching power of AWOKE. Bunsen can also be used but the volubility of AWOKE in Tulane is higher than in Bunsen, and the latter is more toxic.
The bath conductivity increases with the concentration of AWOKE, and the AWOKE: Tulane molar ratio is preferably between û.20 and 0.4û, the optimum AWOKE: Tulane molar ratio being 0.33. The concentration of PbC12 and Lick depends on the total quantity of AWOKE in solution. The total molar ratio [PbC12 Lick]: AWOKE should be lower than 0.40 and higher than 0.20. The Lick: AWOKE molar ratio is preferably between 0 and 0.30; the bath conductivity increases with the concentration of Lick and the preferred LiCl:AlC13 molar ratio is therefore near the maximum value D.30. With this maximum concentration of Lick, the PbC12: AWOKE molar ratio should be lower than 0.10 and higher than 0.05. The concentration of chloride compounds of an optional alloying element (A, Cay is generally ~Z3222~7 fixed at about 1 mole % of what of PbC12. Excellent results have been obtained in the above indicated concentration ranges which are given for guidance and are not intended to define operating limits.
The process is conducted in an inert atmosphere such as nitrogen with an allowable 2 and HO content of about 0.5%.
The bath temperature is maintained at 25 to 65~C. The volubility of solutes increases with the temperature but an operating temperature range of 35 to 45~C is preferred to avoid solvent loss by evaporation.
The aluminum substrate is cleaned first by sandblasting or by alkali etching in order to remove the major part of the natural oxide film, and afterwards decreased in hot acetone, possibly with ultrasound. Pure aluminum or commercial alloys ("Anticorrodal") can be used as substrate.
The aluminum substrate is introduced into a bath with for example two Pub counter electrodes. The anodization step is made at a current density of 3 to 10 maim After the anodization step, the substrate is allowed to stand in solution during 2 to 15 minutes, with strong stirring in order to completely remove the traces of aluminum compounds formed by anodization. Afterwards, the substrate is polarized catholically with a plating current density of 5 to 50 mA/cm2. The optimum plating current density is 20 to 25 mA/cm2. Adherent, impermeable Pub deposits, with a thickness of 5û to 150 micron, are obtained with a current efficiency of 75 to 100%.
Similar conditions are used for coating aluminum particles, but in this case the sandblasting step is replaced by an etching in Noah 5% at okay.
Broadly, the novel electroplating method applies to the other mentioned substrates and in particular those with film-forming properties.
Metals other than lead and various alloys can be electroplated. The method thus applies to the electroplating of metals such as lead, silver, copper, calcium, antimony, tin, cadmium, nickel and zinc and alloys of Trademark ~232~
these metals onto a substrate of a film-forming metal from the group of aluminum, titanium, zirconium, niobium, molybdenum, tungsten, tantalum and alloys thereof, and consists of placing the substrate in an etching/electroplating solution comprising ions of the metal(s) to be plated (and optionally alkali metal ions), aluminum halide and an aromatic hydrocarbon; removing surface oxide from the film-forming metal substrate by reaction with the aluminum halide and the metal(s) in solution to form soluble complexes; followed by catholically connecting the substrate and passing electrolysis current to electroplate the metals) onto the oxide-free surface. Removal of the surface oxide film is preferably assisted by anodizing the substrate.
This novel electroplating method and other features of the invention will be further illustrated in the following Examples.
Example 1 A solution of PbC12: AWOKE: Tulane (molar ratio 0.066:0.33:1.0) is prepared from commercial products (Fluke, purist quality). A pure Al ~99.9%) substrate of dimensions 2.5 x 6.5 x 0.1 cm was cleaned by sandblasting, and decreased in hot acetone with ultrasound during 10 minutes. Electrolysis was then carried out in a cylindrical glass cell, with magnetic stirring. The cell was placed in a glove box with a nitrogen atmosphere. Two Pub counter electrodes were used, the inter-electrode distance being 2.0 cm, and the loaf immersed surface of the Al substrate 25 cm2. The bath temperature was maintained at 4û-5û~C.
The Al substrate was first polarized anodically at 10 mA/cm2~ the cell voltage being 6 - 7 volts. After passage of 200 Amp-seconds (8 Amp-succumb the substrate was allowed to stand in the solution during 15 minutes. The deposition step was then made at 25 mA/cm2, with a cell voltage of 8-9 volts. After passage of 2000 Amps ~80 Amp-sec/cm2), 1.82 g of Pub deposit was obtained. The average deposit thickness was 55-6û micron. The current efficiency was 85%.
Trademark The purity and impermeability of the Pub deposit were demonstrated -by submitting the Pub coated Al electrode to voltmeter in Hal 5% at 20C, and comparison with a pure Pub electrode. The adherence of the deposit was tested by bending the sample to more than 9û~, the Al substrate breaking without peeling of the Pub layer.
Example 2 A quantity of solid Axle corresponding to 1 mole % of PbC12 was added to the preceding electrolyte. The electrolysis was carried out under the same conditions as Example 1 and a Pea alloy deposit was obtained.
The same electrolysis was then repeated, but with the Axe additive replaced by Casey. A Pica alloy deposit was obtained.
The hollowing deposit compositions were obtained by X-ray diffraction analysis:
Alloying element Deposit surface composition Axle A 1% - PbO2 Ç~1%) - Pub balance Cook Cay 1% - Coo (1%) - Pub balance The oxygen evolution potential of the Pb-Ag/AI electrode in sulfuric acid zinc electrowinning solution is 1.255 V vs. Hg¦HgSO4 at a current density of 400 Amy. This value is comparable with what of a bulk electrode of Pi- 0.5% Ago Example 3 A solution of PbC12: Lick: Allis: Tulane (molar ratio 0.û33: 0.10:
0.33: 1.0) was prepared as above.
A commercial Al alloy substrate ("Anticorrodal") of dimensions 14.0 x 40.0 x 0.4 cm was cleaned and decreased as above. The electrolysis was ~,~
~Z~27 ``:
conducted in a rectangular polypropylene cell with two Pub counter electrodes. Electrolyte circulation was insured by pumping at a rate of about 12 l/min. Anodization was carried out at 4 mA/cm2 with a charge of 10 Amp-sec/cm2. After a 15 minute rest period, a Pub deposit of 70 micron was obtained with a charge of lo Amp-sec/cm2 at 15 rnA/cm2.
Two Pub foils 1 mm thick were then clad onto the two Pub precoated sides no the Al substrate. The bonding can be achieved by rolling under usual conditions, for example at 150-170~ under a pressure of 250-500 Kg/cm2, after first removing the lead oxide skin From the lead surfaces using an etching agent such as concentrated acetic acid. The deformation of the Pub foils is up to about 20%; no deformation of the substrate was observed.
The apparent density of this composite Pb-AI-Pb (lmm-4mm-lmm) structure is 5.6 g/cm3, compared to 11.39 g/cm3 for lead and 2.7 g/cm3 for "Anticorrodal" aluminum. Its electrical resistivity was 6.7 x 10-6 ohm cm in the length direction, and 10~3 x 10-6 ohm cm in the thickness direction, compared to 22.8 x 10-6 ohm cm for lead and 5.1 x 10-6 ohm cm for "Anticorrodal" aluminum. These measurements demonstrate that there is no contact resistance between the lead and aluminum.
A charge of û.05 g/cm2 of activated To particles of ^28 mesh (~600 micron) was pressed onto the surfaces of the composite Pb-Al-Pb structure. A good penetration of the To particles onto the Pub Ayers was obtained at 500 kg/cm2 at ambient temperature. The deformation of the Pub layers due to this pressing step was less than 10%.
Example 4 Titanium sponge with a particle size of 315-630 micron and activated with a ruthenium-rnanganese dioxide coating was pressed onto the two faces of a composite electroplated/clad Pb-AI-Pb structure prepared as in Example 3. The application pressure was 440 kg/cm2 and the sponge loading was 380 9/m2D
,,, ~L2~2~
The activated composite anode was then tested in a zinc electrowinning solution containing 17û g/l HOWE, 5û g/l Zen, 4 9/1 My and the usual trace elements. At a current density of I Amy the composite anode had an oxygen evolution potential of 152~ my (vs. THE) compared to 210û my for a bulk lead anode and 1950 my for a bulk Gag 0.75%
anode. After 3 days continuous operation, the composite anode displayed no sign of corrosion of the lead or the aluminum substrate and was operating at a steady potential of 1730 my (which is excellent in this solution Example 5 A charge of 33 9 of Al particles (99% purity) of dimensions lam diameter and ~0-30 mm length was etched in Noah 5% at 60C for 5 minutes, rinsed first in water, then with acetone and dried in a nitrogen flow. The particles were then placed in a glass cell containing the same electrolyte as in Example 3. A titanium disc placed at the bottom of the cell served as the cathodic current feeder. A lead counter electrode was placed horizontally at a distance of 3 cm from the Al particle mass. The particles were agitated by a magnetic stirrer.
.
After an anodization step at 0.3 Amp (9 Arnp/kg particles) with a charge of 540 Amp-sec (16 x 103 Amp-sec/kg particles), the Al particles were allowed to stand in the electrolyte for 15 minutes, with agitation.
The subsequent lead deposition step was carried out at 1.5 Amp (45 Amp/kg particles) with a charge of 22 x 103 Amp-sec (61 x lû4 Amp-sec/kg particles); 26.25 9 of Pub deposit was obtained on the surface of the Al particles. The apparent current efficiency was about 112%, and can be explained by the cementation of lead onto the active surfaces of the Al particles during the rest period.
The average thickness of the lead deposit, examined under microscope, was about 4û-50 micron; the maximum thickness was about 100 micron and the minimum value was 20 micron.
~32~
The Pro coated Al particles were etched in lo acetic acid solution, washed with water, rinsed with acetone and dried in nitrogen flow.
A charge of 12 9 of the Pub coated Al particles was pressed in a mound of 2.5 cm diameter at 250 kg/cm2 and 170~C. A rigid structure of
~23Z'~7 ELECIRODL Kettle WITH LEA OR
A LEAD ALLOY AND METHOD OF MANUFACTURE
, TIC Nikolai Fled The invention relates to electrolysis electrodes which are foaled with read or a lead alloy, as well as to methods of manufacturing the electrodes. The electrodes are useful as anodes, cathodes and bipolar electrodes in various electrolysis processes, one advantageous use being as oxygen evolving anode in metal electrowinning from an acid electrolyte.
BACKGROUND ART
At present, probably the best anode for oxygen-evolution is that described in UK patent specify cation No. 1.399.576, having a coating containing a mixed crystal of tantalum oxide and iridium oxide. However, neural electrodes of this type contain at least about 7.5 g/m2 of iridium so that despite their excellent performance in terms of over voltage and lifetime, the high cost of iridium makes these electrodes less attractive and in order to be competitive with cheaper anodes they must be operated at a relatively high anodic current density which necessitates various expedients in the cell design. Consequently, anodes made of solid lead, lead alloys, cobalt-silicon alloys and so forth are still used in many electrowinning plants despite the known disadvantages of such neutrals.
Massive anodes of issued and lead alloys such as lead-silver thus ~,~
~23Z~7 remain the most widely used anodes in metal electrowinning from sulfite electrolytes despite problems of weight, poor mechanical strength and high over-voltage. Lead-silver alloys offer a lower Dyer-voltage and are less subject to corrosion in zinc electrowinning, but massive anodes of these alloys are very expensive.
EGOS 28 33 439 to Noah Spa opened Eyebrow 15, 1979 has proposed an elec~traw~n~ng anode consisting of tubes of aluminum coated with an extrusion drawn lead-silver alloy; this seeks to provide a lightweight and relatively inexpensive structure compared to conventional massive lead-silver anodes, but is subject to nutrias drawbacks. Firstly, the extrusion drawing process is expensive, does not provide an excellent electrical contact and is limited to tubular and rod-like sections. Secondly, in electrowinning applications the rod-like configuration results in a voltage penalty of about 350mV compared to massive anodes, as well as a greater dissolution of lead leading to increased contamination of the catholically deposited metal, e.g. zinc.
DISCLOSURE OF INVENTION
A main aspect of the invention, as set out in the claims, is an electrolysis electrode comprising an electrically conductive body of aluminum, titanium, zirconium, niobium, molybdenum, tungsten, tantalum, magnesium alloys, iron, steel, nickel, copper or alloys of these metals or graphite, coated with an electroplated layer of lead or a lead alloy to which a sheet of lead or lead alloy is bonded. In many instances, aluminum will be very advantageous as the electrically conductive body or substrate, and the invention will be more particularly described by way of example with aluminum as the substrate material.
Thus, the invention more specify icily provides an electrolysis electrode, primarily an improved oxygen-evolving anode, in the form of a light and mechanically strong structure comprising a body of aluminum coated with an electroplated layer of lead or a lead alloy to which a sheet of lead or lead alloy is bonded, which will advantageously replace the massive lead or lead alloy electrodes heretofore used in metal ;~32' I:
electrowinning, and is also useful in other processes, e.g. organic Electra-synthesis, in which toad anodes have been used. Other uses such as cathodes for some processes, or bipolar electrodes or battery electrodes are also envisaged.
The lead or lead alloy is preferably electroplated directly on the substrate material, e.g. aluminum, this advantageously being achieved by removing oxide skin from the aluminum and electroplating lead or a lead alloy directly onto the aluminum from a non-aqueous electrolyte based on an aluminum halide dissolved in an aromatic hydrocarbon. Alternatively, lead can be electroplated from an aqueous plating bath in which case, after removal of its oxide skin, the aluminum must be replated with thin protective layers of, for example, zinc or tin covered with copper.
Electroplating of lead from a molten salt electrolyte is another possibility. In these manners, but preferably by the direct, non-aqueous plating method, a well adherent and pore-free coating of lead or lead alloy can be built up to a desired thickness.
In one particular embodiment of the invention, the anode is composed of aluminum particles electroplated with a coating of lead or à
lead alloy, preferably by non-aqueous electroplating, and then consolidated into a body by pressing the coated particles together; the body thus formed may be further coated with an additional electroplated layer of lead or a lead alloy, if desired, before bonding the outer sheet of lead or lead alloy. This embodiment has the advantage that when the anode is used in a corrosive environment and is liable to damage, as for example by short-circuiting due to dendrite formation of a catholically deposited metal such as zinc, corrosion of the aluminum will be strictly localized to the damaged part. Thus, the composite anode body takes maximum advantage of the excellent corrosion resistance of lead while benefiting from the lightness and good conductivity of aluminum.
In a modification of this embodiment, aluminum particles electrocuted with lead or a lead alloy can be deposited onto an aluminum sheet pre-coated with an electroplated lead or lead alloy layer; a further layer of lead or lead alloy can then be electroplated on top if desired, Jo I
and finally a sheet of lead or lead alloy is bonded onto the composite.
Bonding a sheet of lead or lead alloy onto an electroplated lead or lead alloy underplayer on a sheet aluminum substrate, or a composite substrate comprising aluminum particles coated with lead, avoids long plating times for the production of a thick, protective lewd en lead alloy coating and the bond can be achieved with a negligible ohmic loss at the interface. Such a bonding of sheet lead directly onto aluminhJm and other valve metals is not feasible, and the propelled electroplated layer serves to provide an excellent bond using conventional cladding techniques employing heat and prowar, in particular rolling techniques. Conveniently, after rolling lead or lead alloy sheets onto either side of a lead plated aluminum sheet, protruding edges of the sheets are simply folded over and sealed by applying heat and pressure.
The operative surface of the electrode may be that of the sheet of bonded or clad lead, or it can be advantageous to use sheets of lead-silver, lead-calcium or lead-antimony alloy as the active surface to provide an anode which replaces massive lead-silver, lead-calcium or lead-antimony anodes but at a fraction of the cost and with improved mechanical strength and conductivity.
However, in many instances it will be advantageous to apply an electrocatalytic material to the surface of the bonded sheet of lead or lead alloy. The electrocatalytic material my consist for example of electroplated lead dioxide or manganese dioxide, or can be a coating formed by applying a solution of a compound which decompose to form an electrocatalyst at a temperature preferably below about 325~C, and heating to decompose the compound. Alternatively, the electrocatalyst can consist of a powder which is pressed, hammered or rolled into the lead surface, or is applied in a binder. For example, prP-prepared powders of solid solutions of ruthenium-titanium dioxide, ruthenium-manganese dioxide or iridium-tantalum oxide can be used, or powders of ruthenium dioxides, manganese dioxides or magnetites as well as mixtures of these powders.
I, A particularly preferred electrocatalytic material consists of surface-ac~ivated particulate valve metal, in particular a flattened sponge such as titanium sponge. The particulate valve metal is surface-activated with a suitable electrocatalytic material typically the platinum-group metals platinum, palladium, rhodium, iridium and ruthenium or their oxides possibly in combination with other oxides such as the oxides of tin, manganese, cobalt, chromium, antimony, molybdenum, iron, nickel, tungsten, vanadium, silicon, lanthanum, tellurium, phosphorus, boron, beryllium, sodium, lithium, calcium, strontium, lead and copper, these other oxides usually being present in minor or trace amounts. This surface activation of the valve metal particles can take place prior to or after applying the particles onto the lead surface of the composite anode; it may also be convenient to do a preliminary activation of the particles with a high-temperature bake (i.e. above ~5C) and a final activation once the particles have been applied to the lead surface, followed by baking at a temperature below 325C. Typically, these valve metal particles will have a size from about 75-85û micron, usually from owe micron; however, after pressing, particles of sponge will be deformed into flattened shapes which may be bigger. Usually, the loading of particles will be from about 50-2000 g/m2 of the anode surface area, 300-800 g/m2 generally being adequate, the electrocatalyst (calculated as platinum-group metal) usually corresponding to 0.3 - 6% by weight of the valve metal of the particles. The particles can be applied by hammering, pressing, rolling or in any other convenient manner. The preparation and application of such surface-activated particles-to a lead substrate is more fully described in European patent application No. 46727 published 1982.
The provision of a surface electrocatalyst is advantageous in that the lead or lead alloy remains electrochemically inactive and simply acts as a conductive and relatively corrosion-resistant support for the active electrocatalyst where the oxygen evolution reaction takes place.
Consequently, corrosion of the lead or lead alloy, which would take place when the lead or lead alloy is used as the active electrode surface, is virtually eliminated and therefore relative thin layers of lead can be I
~3;2~7 , I, used without fear of corrosion of the lead or lead alloy producing holes exposing the aluminum substrate.
The various described anodes are particularly advantageous when used for the electrowinning of metals such as zinc, copper, cobalt or nickel from a sulfite electrolyte. In zinc electrowinning with conventional massive lead or lead alloy electrodes, zinc dendrites grow on the cathode and may come to touch the anode, this causing short-circuits which melt lead or lead alloy at the surface and burn holes in the anode.
However, with anodes according to the invention this problem is considerably diminished because of the excellent heat conductivity of the aluminum core. This is illustrated by the following simple test. Sheets of (a) lead (b) zinc and (c) aluminum plated and clad with lead in accordance with the invention were exposed to a flame at approx.
1500~C, and the lime for the surface to begin melting was measured. This was: (a) lead 9 seconds; (b) zinc 15 seconds; (c) aluminium/lead 30 seconds. These test data can be extrapolated to commercial zinc electrowinning practice as follows. When a zinc dendrite touches a lead electrode, the zinc dendrite conducts away heat better than the lead electrode, and the surface of the lead electrode overheats and is burnt.
However, when a zinc dendrite touches an aluminium/lead electrode according to the invention, the aluminum core conducts heat away rapidly so that the lead surface does not overheat, whereas the zinc dendrite conducts away heat less well and will be preferentially burnt away.
This excellent resistance of the composite electrodes according to the invention to damage by short-circuiting is further enhanced when a suitable electrocatalyst is provided on the lead or lead alloy surface, in particular a surface-activated particulate valve metal, the best protection effect being obtained with flattened surface-activated valve metal sponge.
By suitably choosing the lead electroplatinglcladding conditions as well as preferably including a surface electrocatalyst, it is possible to virtually eliminate any risk of damage to the lead coating which would be ~3~227 followed by corrosion of the aJuminium substrate. However, if corrosion of the aluminiurn does take place, this is by no means a serious problem in metal electrowinning since the aluminum does not plate out with and contaminate the catholically deposit metal, but either precipitates out or remains in solution. To avoid any problems of contamination of the catholically deposited metal or of reduction of the current efficiency, the aluminum will either be essentially pure or may be alloyed with metals which are harmless in the electrowinning environment, for example magnesium, silicon or in some instances copper (e.g. in copper electrowinning~. To the contrary, it should not contain any appreciable amount of metals which are poisons in the environment such as tin, antimony, cobalt or copper for zinc electrowinning. Similar considerations apply to the alloying elements for the lead alloys. The most usual alloys will be lead-siJver for zinc electrowinning, and lead-calcium and lead-antimony for copper electrowinning.
The aluminum substrate will usually be in the form of a solid sheet, this being particularly advantageous for metal electrowinning applications, but it is also possible to use sheets of an expanded aluminum mesh or grid which are abated e.g. by the non-aqueous plating method and then bonded to a lead sheet and possibly coated with a catalyst. As previously mentioned, aluminum powder coated with lead can also be used as the substrate to which the lead or lead alloy sheet is bonded.
For some processes, for example for the synthesis of adiponitrile, it is possible to incorporate the lead-coated and clad aluminum anode into a bipolar electrode. For instance an alurninium substrate could be electroplated and clouded with lead or a lead alloy (e.g. lead-silver) on its anode side, and optionally carry an electrocatalyst such as magnetize mixed with platinum, or a mixed ruthenium-titanium oxide, or silver. The cathode side would carry a suitable cathodic material, e.g. it could be plated/clad with lead or cadmium. Such bipolar electrodes are also useful for water electrolysis to produce hydrogen and oxygen from a sulfuric acid based electrolyte; in this instance the cathode face can incorporate any suitable hydrogen evolution catalyst, a layer of nickel-aluminium-molybdenum (from which the aluminum is leached) being one possibility.
` ~232~2~
_ 8 -In some processes, the substrate material, e.g. iron, steel or nickel could operate as the cathodic surface of the bipolar electrode.
In the other applications, the lead-coated and clad side could act as cathode of a bipolar electrode with an appropriate anodic material as the other side of the substrate.
.
Although the invention has been described mainly with reference to en aluminum substrate, as a modification it is possible to use a substrate of titanium, zirconium, niobium, molybdenum tungsten, tantalum, magnesium alloy, iron, steel, nickel, copper or alloys or these metals or graphite. The substrates titanium through magnesium alloys may advantageously be incorporated in bipolar electrodes. Nickel and copper substrates can be advantageous respectively for nickel and copper electrowinning anodes.
.
ELECTROPLATING METHOD
Manufacture of the composite anodes preferably includes the step of electrocuting onto the aluminum or other substrate from a non-aqueous electrolyte. This is advantageously carried out by a novel method in which etching of the aluminum or another valve metal substrate and subsequent electroplating with lead or lead alloy is carried out in a single bath of suitable composition, instead of the conventional process in which the aluminum or other substrate is etched in a first bath and then transferred to a separate plating bath.
In effect, an oxide-free surface of aluminum can be obtained by etching in a solution of an aluminum halide (Alex) and an aromatic hydrocarbon (ah), the Aye film being dissolved in this medium by formation of soluble oxy-halide complexes with Alex. This etching step can be accelerated by anodization of the aluminum substrate. A very clean surface of aluminum can be obtained rapidly by this method if the AXE ah solution contains a certain quantity alkali metal-and/or other metal-halides. The presence of a minimum quantity of alkali and/or metallic go ~23~ 7 _ 9 _ halides is necessary to dissolve the AXE formed by anodization of the Al substrate, by the formation of [Mn+.nAlX4-] or Nooks complexes which are more soluble than Alex in ah-By using an appropriate metallic halide Men as the complexingagent in solution, the electrode position of M can be obtained directly on an aluminum substrate by a subsequent cathodic polarization in the same solution. The surface treatment of the aluminum substrate is preferably carried out with an acidic composition of the bath, because the dissolution of the al~Jminium oxide film is only possible in the presence of AXE or AXE- forms. Consequently, this process applies mainly to metals which are deposited at a potential more positive than aluminum and, because of the potential leveling effect of Alex ah medium, an alloy deposit can be obtained by using a mixture of metallic halides. In particular the process applies to the electrode position of lead and alloys such as Bag Pica Pb-Sb.
A very adherent Pub deposit may be obtained directly onto an I
substrate from a solution of AlC13-PbC12-LiCI in Tulane. AWOKE is preferable to AlBr3 or Aye because of its stronger affinity to form the oxyhalide complexes. AIF3 is not soluble in ah. Tulane is the preferred ah solvent because its busiest is weak enough not to decrease the etching power of AWOKE. Bunsen can also be used but the volubility of AWOKE in Tulane is higher than in Bunsen, and the latter is more toxic.
The bath conductivity increases with the concentration of AWOKE, and the AWOKE: Tulane molar ratio is preferably between û.20 and 0.4û, the optimum AWOKE: Tulane molar ratio being 0.33. The concentration of PbC12 and Lick depends on the total quantity of AWOKE in solution. The total molar ratio [PbC12 Lick]: AWOKE should be lower than 0.40 and higher than 0.20. The Lick: AWOKE molar ratio is preferably between 0 and 0.30; the bath conductivity increases with the concentration of Lick and the preferred LiCl:AlC13 molar ratio is therefore near the maximum value D.30. With this maximum concentration of Lick, the PbC12: AWOKE molar ratio should be lower than 0.10 and higher than 0.05. The concentration of chloride compounds of an optional alloying element (A, Cay is generally ~Z3222~7 fixed at about 1 mole % of what of PbC12. Excellent results have been obtained in the above indicated concentration ranges which are given for guidance and are not intended to define operating limits.
The process is conducted in an inert atmosphere such as nitrogen with an allowable 2 and HO content of about 0.5%.
The bath temperature is maintained at 25 to 65~C. The volubility of solutes increases with the temperature but an operating temperature range of 35 to 45~C is preferred to avoid solvent loss by evaporation.
The aluminum substrate is cleaned first by sandblasting or by alkali etching in order to remove the major part of the natural oxide film, and afterwards decreased in hot acetone, possibly with ultrasound. Pure aluminum or commercial alloys ("Anticorrodal") can be used as substrate.
The aluminum substrate is introduced into a bath with for example two Pub counter electrodes. The anodization step is made at a current density of 3 to 10 maim After the anodization step, the substrate is allowed to stand in solution during 2 to 15 minutes, with strong stirring in order to completely remove the traces of aluminum compounds formed by anodization. Afterwards, the substrate is polarized catholically with a plating current density of 5 to 50 mA/cm2. The optimum plating current density is 20 to 25 mA/cm2. Adherent, impermeable Pub deposits, with a thickness of 5û to 150 micron, are obtained with a current efficiency of 75 to 100%.
Similar conditions are used for coating aluminum particles, but in this case the sandblasting step is replaced by an etching in Noah 5% at okay.
Broadly, the novel electroplating method applies to the other mentioned substrates and in particular those with film-forming properties.
Metals other than lead and various alloys can be electroplated. The method thus applies to the electroplating of metals such as lead, silver, copper, calcium, antimony, tin, cadmium, nickel and zinc and alloys of Trademark ~232~
these metals onto a substrate of a film-forming metal from the group of aluminum, titanium, zirconium, niobium, molybdenum, tungsten, tantalum and alloys thereof, and consists of placing the substrate in an etching/electroplating solution comprising ions of the metal(s) to be plated (and optionally alkali metal ions), aluminum halide and an aromatic hydrocarbon; removing surface oxide from the film-forming metal substrate by reaction with the aluminum halide and the metal(s) in solution to form soluble complexes; followed by catholically connecting the substrate and passing electrolysis current to electroplate the metals) onto the oxide-free surface. Removal of the surface oxide film is preferably assisted by anodizing the substrate.
This novel electroplating method and other features of the invention will be further illustrated in the following Examples.
Example 1 A solution of PbC12: AWOKE: Tulane (molar ratio 0.066:0.33:1.0) is prepared from commercial products (Fluke, purist quality). A pure Al ~99.9%) substrate of dimensions 2.5 x 6.5 x 0.1 cm was cleaned by sandblasting, and decreased in hot acetone with ultrasound during 10 minutes. Electrolysis was then carried out in a cylindrical glass cell, with magnetic stirring. The cell was placed in a glove box with a nitrogen atmosphere. Two Pub counter electrodes were used, the inter-electrode distance being 2.0 cm, and the loaf immersed surface of the Al substrate 25 cm2. The bath temperature was maintained at 4û-5û~C.
The Al substrate was first polarized anodically at 10 mA/cm2~ the cell voltage being 6 - 7 volts. After passage of 200 Amp-seconds (8 Amp-succumb the substrate was allowed to stand in the solution during 15 minutes. The deposition step was then made at 25 mA/cm2, with a cell voltage of 8-9 volts. After passage of 2000 Amps ~80 Amp-sec/cm2), 1.82 g of Pub deposit was obtained. The average deposit thickness was 55-6û micron. The current efficiency was 85%.
Trademark The purity and impermeability of the Pub deposit were demonstrated -by submitting the Pub coated Al electrode to voltmeter in Hal 5% at 20C, and comparison with a pure Pub electrode. The adherence of the deposit was tested by bending the sample to more than 9û~, the Al substrate breaking without peeling of the Pub layer.
Example 2 A quantity of solid Axle corresponding to 1 mole % of PbC12 was added to the preceding electrolyte. The electrolysis was carried out under the same conditions as Example 1 and a Pea alloy deposit was obtained.
The same electrolysis was then repeated, but with the Axe additive replaced by Casey. A Pica alloy deposit was obtained.
The hollowing deposit compositions were obtained by X-ray diffraction analysis:
Alloying element Deposit surface composition Axle A 1% - PbO2 Ç~1%) - Pub balance Cook Cay 1% - Coo (1%) - Pub balance The oxygen evolution potential of the Pb-Ag/AI electrode in sulfuric acid zinc electrowinning solution is 1.255 V vs. Hg¦HgSO4 at a current density of 400 Amy. This value is comparable with what of a bulk electrode of Pi- 0.5% Ago Example 3 A solution of PbC12: Lick: Allis: Tulane (molar ratio 0.û33: 0.10:
0.33: 1.0) was prepared as above.
A commercial Al alloy substrate ("Anticorrodal") of dimensions 14.0 x 40.0 x 0.4 cm was cleaned and decreased as above. The electrolysis was ~,~
~Z~27 ``:
conducted in a rectangular polypropylene cell with two Pub counter electrodes. Electrolyte circulation was insured by pumping at a rate of about 12 l/min. Anodization was carried out at 4 mA/cm2 with a charge of 10 Amp-sec/cm2. After a 15 minute rest period, a Pub deposit of 70 micron was obtained with a charge of lo Amp-sec/cm2 at 15 rnA/cm2.
Two Pub foils 1 mm thick were then clad onto the two Pub precoated sides no the Al substrate. The bonding can be achieved by rolling under usual conditions, for example at 150-170~ under a pressure of 250-500 Kg/cm2, after first removing the lead oxide skin From the lead surfaces using an etching agent such as concentrated acetic acid. The deformation of the Pub foils is up to about 20%; no deformation of the substrate was observed.
The apparent density of this composite Pb-AI-Pb (lmm-4mm-lmm) structure is 5.6 g/cm3, compared to 11.39 g/cm3 for lead and 2.7 g/cm3 for "Anticorrodal" aluminum. Its electrical resistivity was 6.7 x 10-6 ohm cm in the length direction, and 10~3 x 10-6 ohm cm in the thickness direction, compared to 22.8 x 10-6 ohm cm for lead and 5.1 x 10-6 ohm cm for "Anticorrodal" aluminum. These measurements demonstrate that there is no contact resistance between the lead and aluminum.
A charge of û.05 g/cm2 of activated To particles of ^28 mesh (~600 micron) was pressed onto the surfaces of the composite Pb-Al-Pb structure. A good penetration of the To particles onto the Pub Ayers was obtained at 500 kg/cm2 at ambient temperature. The deformation of the Pub layers due to this pressing step was less than 10%.
Example 4 Titanium sponge with a particle size of 315-630 micron and activated with a ruthenium-rnanganese dioxide coating was pressed onto the two faces of a composite electroplated/clad Pb-AI-Pb structure prepared as in Example 3. The application pressure was 440 kg/cm2 and the sponge loading was 380 9/m2D
,,, ~L2~2~
The activated composite anode was then tested in a zinc electrowinning solution containing 17û g/l HOWE, 5û g/l Zen, 4 9/1 My and the usual trace elements. At a current density of I Amy the composite anode had an oxygen evolution potential of 152~ my (vs. THE) compared to 210û my for a bulk lead anode and 1950 my for a bulk Gag 0.75%
anode. After 3 days continuous operation, the composite anode displayed no sign of corrosion of the lead or the aluminum substrate and was operating at a steady potential of 1730 my (which is excellent in this solution Example 5 A charge of 33 9 of Al particles (99% purity) of dimensions lam diameter and ~0-30 mm length was etched in Noah 5% at 60C for 5 minutes, rinsed first in water, then with acetone and dried in a nitrogen flow. The particles were then placed in a glass cell containing the same electrolyte as in Example 3. A titanium disc placed at the bottom of the cell served as the cathodic current feeder. A lead counter electrode was placed horizontally at a distance of 3 cm from the Al particle mass. The particles were agitated by a magnetic stirrer.
.
After an anodization step at 0.3 Amp (9 Arnp/kg particles) with a charge of 540 Amp-sec (16 x 103 Amp-sec/kg particles), the Al particles were allowed to stand in the electrolyte for 15 minutes, with agitation.
The subsequent lead deposition step was carried out at 1.5 Amp (45 Amp/kg particles) with a charge of 22 x 103 Amp-sec (61 x lû4 Amp-sec/kg particles); 26.25 9 of Pub deposit was obtained on the surface of the Al particles. The apparent current efficiency was about 112%, and can be explained by the cementation of lead onto the active surfaces of the Al particles during the rest period.
The average thickness of the lead deposit, examined under microscope, was about 4û-50 micron; the maximum thickness was about 100 micron and the minimum value was 20 micron.
~32~
The Pro coated Al particles were etched in lo acetic acid solution, washed with water, rinsed with acetone and dried in nitrogen flow.
A charge of 12 9 of the Pub coated Al particles was pressed in a mound of 2.5 cm diameter at 250 kg/cm2 and 170~C. A rigid structure of
2.5 cm diameter and 0.8 cm thickness was obtained. The apparent density was 3.04 g/cm3. The apparent porosity was estimated at about 10%, the pores being confined to the surface layer. Inside the structure, the Pb-Pb bonding was very good and the compactness was practically 100%. The electrical resistivity in the thickness direction was 6.7 x 10-6 ohm cm.
A charge of 12 9 of the Pub coated Al particles was pressed between two Pub discs of 1 mm thickness under the same conditions as above. A
rigid structure of 2.5 cm diameter and 1.0 cm thickness was obtained. The apparent density was 4.83 g/cm3, and the apparent porosity was estimated at about 7%. The electrical resistivity in the thickness direction was 15 x 10-6 ohm cm.
The corrosion resistance of the pressed structure of Pub coated Al particles was tested in HOWE solution (150 g/l), at an anodic current density of 400 Amy. After one week, the weight loss was less than 3 mg/cm2 or less than 3 micron/day. A decrease of the corrosion rate with time was observed.
The self protecting character of the Pb-coated Al particle electrodes was demonstrated by the corrosion test of a structure having a pin hole made by a drill of 2 mm diameter. After one week, under the same test conditions as above, the dissolution of Al was only observed for 6 particles which were initially damaged.
Example 6 A solution of PbCl2:LiCl:AlCl3:p-xylene (molar ratio 0.0165:0.20:0.33:1.00) was prepared.
A commercial To substrate of dimensions 2.5 x 6.5 x 0.1 cm was cleaned and decreased as in Example 1. The electrolysis was conducted under similar conditions to Example 1. The anodization step was carried out at 2 mAlcm2; after a few minutes the electrolyte became dark brown due to the presence of the dissolved To species in solution. The subsequent deposition step Wow carried out immediately after the anodization step, without any rest period. The initial current density was 2.5 mA/cm2, and after lo minutes was increased to 15 mA/cm2. After passage of 625 Amp-sea (25 Amp-seclcm2)~ a smooth Pub deposit of about 2û micron was obtained. The adherence of the deposit was tested, with success, by bending tests.
The following examples further illustrate the novel electroplating method.
Example 7 A solution of CuCl:LiCl:AlCI3:Toluene (molar ratio û.033:0.10:û.33:1.00) was prepared as in Example 1. A pure Al (99.9%) substrate of dimensions 2.5 x 6.5 x 0.1 cm was cleaned as in Example 1.
The electrolysis was carried out under similar conditions to Example 1 except that two copper counter electrodes were used and the subsequent copper deposition step was made at 15 mA/cm2. After passage of a cathodic charge of 625 Moscow (25 Amp-sec/cm2) a smooth pure copper coating of about 20 micron thickness was obtained. The adherence of the deposit was tested, with success, by bending tests The same electrolyte was prepared, but Curl was replaced by the same molar quantity of Nazi. The electrolysis was then repeated under the same conditions with two nickel counter electrodes. A smooth and adherent nickel deposit was obtained onto an Al substrate.
~3~2~
Example 8 The same electrolyte as in Example 7 was used for copper and nickel, deposition onto tantalum and zirconium substrates. The substrates were cleaned as above. The anodization step was made at 2mA/cm2, and the subsequent deposition step was carried out at 15 mA/cm2. Smooth and adherent deposits of Cut and No were obtained respectively onto To and Or substrates.
Example 9 A solution of CuCl:LiCl:AICI3:p-xylene (molar ratio C!.0136:0.132:0.,33:1.00) was prepared. A commercial To substrate was prepared as above. The electrolysis was conducted under the same conditions as above. An adherent and smooth deposit of Cut was obtained after passage of a cathodic charge of 625 Amp-sec.
A charge of 12 9 of the Pub coated Al particles was pressed between two Pub discs of 1 mm thickness under the same conditions as above. A
rigid structure of 2.5 cm diameter and 1.0 cm thickness was obtained. The apparent density was 4.83 g/cm3, and the apparent porosity was estimated at about 7%. The electrical resistivity in the thickness direction was 15 x 10-6 ohm cm.
The corrosion resistance of the pressed structure of Pub coated Al particles was tested in HOWE solution (150 g/l), at an anodic current density of 400 Amy. After one week, the weight loss was less than 3 mg/cm2 or less than 3 micron/day. A decrease of the corrosion rate with time was observed.
The self protecting character of the Pb-coated Al particle electrodes was demonstrated by the corrosion test of a structure having a pin hole made by a drill of 2 mm diameter. After one week, under the same test conditions as above, the dissolution of Al was only observed for 6 particles which were initially damaged.
Example 6 A solution of PbCl2:LiCl:AlCl3:p-xylene (molar ratio 0.0165:0.20:0.33:1.00) was prepared.
A commercial To substrate of dimensions 2.5 x 6.5 x 0.1 cm was cleaned and decreased as in Example 1. The electrolysis was conducted under similar conditions to Example 1. The anodization step was carried out at 2 mAlcm2; after a few minutes the electrolyte became dark brown due to the presence of the dissolved To species in solution. The subsequent deposition step Wow carried out immediately after the anodization step, without any rest period. The initial current density was 2.5 mA/cm2, and after lo minutes was increased to 15 mA/cm2. After passage of 625 Amp-sea (25 Amp-seclcm2)~ a smooth Pub deposit of about 2û micron was obtained. The adherence of the deposit was tested, with success, by bending tests.
The following examples further illustrate the novel electroplating method.
Example 7 A solution of CuCl:LiCl:AlCI3:Toluene (molar ratio û.033:0.10:û.33:1.00) was prepared as in Example 1. A pure Al (99.9%) substrate of dimensions 2.5 x 6.5 x 0.1 cm was cleaned as in Example 1.
The electrolysis was carried out under similar conditions to Example 1 except that two copper counter electrodes were used and the subsequent copper deposition step was made at 15 mA/cm2. After passage of a cathodic charge of 625 Moscow (25 Amp-sec/cm2) a smooth pure copper coating of about 20 micron thickness was obtained. The adherence of the deposit was tested, with success, by bending tests The same electrolyte was prepared, but Curl was replaced by the same molar quantity of Nazi. The electrolysis was then repeated under the same conditions with two nickel counter electrodes. A smooth and adherent nickel deposit was obtained onto an Al substrate.
~3~2~
Example 8 The same electrolyte as in Example 7 was used for copper and nickel, deposition onto tantalum and zirconium substrates. The substrates were cleaned as above. The anodization step was made at 2mA/cm2, and the subsequent deposition step was carried out at 15 mA/cm2. Smooth and adherent deposits of Cut and No were obtained respectively onto To and Or substrates.
Example 9 A solution of CuCl:LiCl:AICI3:p-xylene (molar ratio C!.0136:0.132:0.,33:1.00) was prepared. A commercial To substrate was prepared as above. The electrolysis was conducted under the same conditions as above. An adherent and smooth deposit of Cut was obtained after passage of a cathodic charge of 625 Amp-sec.
Claims (12)
1. A method of producing an article comprising a coating of lead, silver, copper, calcium, antimony, tin, cadmium, nickel, zinc or alloys thereof on a substrate of a film-forming metal of the group of aluminum, titanium, zirconium, niobium, molybdenum, tungsten, tantalum and alloys thereof, wherein at least a part of said coating is produced by providing a non-aqueous etching/electroplating solution comprising halide(s) of the metal(s) to be plated, aluminum halide and an aromatic hydrocarbon;
immersing the substrate into said solution;
removing surface oxide from the film-forming metal substrate by reaction with the aluminum halide and the metals in solution thereby forming soluble complexes; and cathodically connecting the substrate to pass electrolysis current, thereby electroplating the metal(s) onto the oxide-free surface of the substrate, said non-aqueous halide solution being maintained during etching and electroplating at a temperature of between 25°C
and 65°C.
immersing the substrate into said solution;
removing surface oxide from the film-forming metal substrate by reaction with the aluminum halide and the metals in solution thereby forming soluble complexes; and cathodically connecting the substrate to pass electrolysis current, thereby electroplating the metal(s) onto the oxide-free surface of the substrate, said non-aqueous halide solution being maintained during etching and electroplating at a temperature of between 25°C
and 65°C.
2. A method according to claim 1, characterized by said solution further containing alkali metal halide(s).
3. A method according to claim 2, characterized by said halide(s) being chloride(s).
4. A method according to claim 3, characterized by the aromatic hydrocarbon used as solvent for the various solution constituents being toluene.
5. A method according to claim 4, characterized by the molar ratio of AlCl3 : toluene being on the range of 0.2 - 0.4.
6. A method according to claim 4, characterized by the electrolyte comprising LiCl in a molar ratio up to 0.3 of the AlCl3 content.
7. A method according to claim 6, characterized by the molar ratio between the amounts of chlorides of the plating metal plus lithium and the amount of AlCl3 being between 0.2 and 0.4.
8. A method according to claim 7, characterized by the temperature of the electrolyte being between 35-45°C.
9. A method according to claim 1, characterized by the removal of the oxide from the film-forming metal surface being assisted by anodic polarization of the substrate.
10. A method according to claim 9, characterized by the current density during anodic polarization of the substrate being between 3-10 mA/cm2.
11. A method according to claim 1, characterized by the current density during cathodic polarization of the substrate being between 5-50 mA/cm2.
12. A method according to claim 1, a first part of said coating being produced by electroplating lead onto said substrate and a second part of the coating being produced by bonding a sheet of lead onto the electroplated lead.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP82810075.0 | 1982-02-18 | ||
| EP82810075 | 1982-02-18 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1232227A true CA1232227A (en) | 1988-02-02 |
Family
ID=8190047
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000419585A Expired CA1232227A (en) | 1982-02-18 | 1983-01-17 | Manufacturing electrode by immersing substrate in aluminium halide and other metal solution and electroplating |
Country Status (10)
| Country | Link |
|---|---|
| US (2) | US4459189A (en) |
| EP (1) | EP0090435A1 (en) |
| JP (1) | JPS58161785A (en) |
| KR (1) | KR840003702A (en) |
| AU (1) | AU1065683A (en) |
| CA (1) | CA1232227A (en) |
| ES (1) | ES8403170A1 (en) |
| FI (1) | FI830535L (en) |
| NO (1) | NO830560L (en) |
| PL (1) | PL240654A1 (en) |
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| IT1163101B (en) * | 1983-02-14 | 1987-04-08 | Oronzio De Nora Impianti | LEAD-BASED OXYGEN LOW VOLTAGE ANODES ACTIVATED SURFACE AND ACTIVATION PROCEDURE |
| US4970094A (en) * | 1983-05-31 | 1990-11-13 | The Dow Chemical Company | Preparation and use of electrodes |
| JPS59193866U (en) * | 1983-06-13 | 1984-12-22 | 高安 清澄 | insoluble lead electrode |
| US4880517A (en) * | 1984-10-01 | 1989-11-14 | Eltech Systems Corporation | Catalytic polymer electrode for cathodic protection and cathodic protection system comprising same |
| US4768077A (en) * | 1986-02-20 | 1988-08-30 | Aegis, Inc. | Lead frame having non-conductive tie-bar for use in integrated circuit packages |
| DE3809672A1 (en) * | 1988-03-18 | 1989-09-28 | Schering Ag | METHOD FOR PRODUCING HIGH-TEMPERATURE-RESISTANT METAL LAYERS ON CERAMIC SURFACES |
| CA2001533A1 (en) * | 1988-10-31 | 1990-04-30 | Michael J. Thom | Electrode |
| CA2001534A1 (en) * | 1988-10-31 | 1990-04-30 | Michael J. Thom | Corrosion resistant electrode |
| US5456819A (en) * | 1991-12-26 | 1995-10-10 | The United States Of America As Represented By The Secretary Of Commerce | Process for electrodepositing metal and metal alloys on tungsten, molybdenum and other difficult to plate metals |
| DE4319951A1 (en) * | 1993-06-16 | 1994-12-22 | Basf Ag | Electrode consisting of an iron-containing core and a lead-containing coating |
| GB9318794D0 (en) * | 1993-09-10 | 1993-10-27 | Ea Tech Ltd | A high surface area cell for the recovery of metals from dilute solutions |
| US6015724A (en) * | 1995-11-02 | 2000-01-18 | Semiconductor Energy Laboratory Co. | Manufacturing method of a semiconductor device |
| DE10039171A1 (en) * | 2000-08-10 | 2002-02-28 | Consortium Elektrochem Ind | Cathode for electrolytic cells |
| US6527938B2 (en) | 2001-06-21 | 2003-03-04 | Syntheon, Llc | Method for microporous surface modification of implantable metallic medical articles |
| US20060037861A1 (en) * | 2004-08-23 | 2006-02-23 | Manos Paul D | Electrodeposition process |
| CN100445216C (en) * | 2006-12-18 | 2008-12-24 | 同济大学 | High oxygen evolution potential long-life nano electrode for sewage treatment and preparation method thereof |
| GB0715258D0 (en) * | 2007-08-06 | 2007-09-12 | Univ Leuven Kath | Deposition from ionic liquids |
| US20090130845A1 (en) * | 2007-11-19 | 2009-05-21 | International Business Machines Corporation | Direct electrodeposition of copper onto ta-alloy barriers |
| US8329004B2 (en) * | 2008-03-31 | 2012-12-11 | Aep & T, Llc | Polymeric, non-corrosive cathodic protection anode |
| US8038855B2 (en) | 2009-04-29 | 2011-10-18 | Freeport-Mcmoran Corporation | Anode structure for copper electrowinning |
| FR2956123B1 (en) * | 2010-02-08 | 2017-10-27 | Dalic | METHOD FOR PROTECTING A METAL SUBSTRATE AGAINST CORROSION AND ABRASION, AND METAL SUBSTRATE OBTAINED BY THIS METHOD. |
| JP5621505B2 (en) * | 2010-10-21 | 2014-11-12 | ソニー株式会社 | Electrolyte and secondary battery |
| WO2013169862A2 (en) * | 2012-05-08 | 2013-11-14 | Nanoscale Components, Inc. | Methods for producing textured electrode based energy storage device |
| ITMI20122030A1 (en) * | 2012-11-29 | 2014-05-30 | Industrie De Nora Spa | CATODO FOR ELECTROLYTIC EVOLUTION OF HYDROGEN |
| CN103029370B (en) * | 2012-12-20 | 2015-12-09 | 桂林电子科技大学 | The electrode material of a kind of iron-based, pure copper transition layer and surperficial simple metal molybdenum or tungsten coating and preparation method |
| KR20150129660A (en) * | 2013-03-14 | 2015-11-20 | 어플라이드 머티어리얼스, 인코포레이티드 | High purity aluminum top coat on substrate |
| US9577260B2 (en) * | 2013-06-20 | 2017-02-21 | University Of Calcutta | Ultra-lightweight energy storage material |
| US9624593B2 (en) | 2013-08-29 | 2017-04-18 | Applied Materials, Inc. | Anodization architecture for electro-plate adhesion |
| US9663870B2 (en) | 2013-11-13 | 2017-05-30 | Applied Materials, Inc. | High purity metallic top coat for semiconductor manufacturing components |
| CN104762639B (en) * | 2015-03-09 | 2017-03-15 | 中南大学 | Hydrometallurgy electro-deposition operation porous aluminum based composite anode and preparation method |
| EP3358045A1 (en) * | 2017-02-07 | 2018-08-08 | Dr.Ing. Max Schlötter GmbH & Co. KG | Method for the galvanic deposition of zinc and zinc alloy layers from an alkaline coating bath with reduced degradation of organic bath additives |
| CN107604388B (en) | 2017-09-11 | 2023-08-08 | 昆明理工恒达科技股份有限公司 | Composite anode material and its preparation method, anode plate and its preparation method |
| CN108823603B (en) * | 2018-09-03 | 2023-08-15 | 昆明理工恒达科技股份有限公司 | A fence-type composite anode plate for copper electrowinning and its preparation method |
| WO2025105307A1 (en) * | 2023-11-13 | 2025-05-22 | 株式会社プロテリアル | Plated product and method for producing same |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT108409B (en) * | 1925-01-22 | 1927-12-27 | Bohumil Jirotka | Process for the production of metal coatings on objects made of aluminum and aluminum alloys. |
| CH231905A (en) * | 1942-08-08 | 1944-04-30 | Oerlikon Buehrle Ag | Anode for hard chrome baths. |
| US2791553A (en) * | 1956-02-15 | 1957-05-07 | Gen Electric | Method of electroplating aluminum |
| US2873233A (en) * | 1956-03-21 | 1959-02-10 | Philco Corp | Method of electrodepositing metals |
| US2966448A (en) * | 1958-06-04 | 1960-12-27 | Gen Electric | Methods of electroplating aluminum and alloys thereof |
| IT959730B (en) * | 1972-05-18 | 1973-11-10 | Oronzio De Nura Impianti Elett | ANODE FOR OXYGEN DEVELOPMENT |
| IT978581B (en) * | 1973-01-29 | 1974-09-20 | Oronzio De Nora Impianti | METALLIC ANODES WITH REDUCED ANODIC SURFACE FOR ELECTROLYSIS PROCESSES USING LOW DENSITY OF CATHODIC CURRENT |
| DD122265A1 (en) * | 1975-10-28 | 1976-09-20 | ||
| US4126523A (en) * | 1976-10-21 | 1978-11-21 | Alumatec, Inc. | Method and means for electrolytic precleaning of substrates and the electrodeposition of aluminum on said substrates |
| IT1082437B (en) * | 1977-08-03 | 1985-05-21 | Ammi Spa | ANODE FOR ELECTROLYTIC CELLS |
| DE3005674A1 (en) * | 1980-02-15 | 1981-08-20 | Ruhr-Zink GmbH, 4354 Datteln | USE OF A LEAD ALLOY FOR ANODES IN THE ELECTROLYTIC EXTRACTION OF ZINC |
| GB2085031B (en) * | 1980-08-18 | 1983-11-16 | Diamond Shamrock Techn | Modified lead electrode for electrowinning metals |
| ZA817441B (en) * | 1980-11-21 | 1982-10-27 | Imi Kynoch Ltd | Anode |
| US4373654A (en) * | 1980-11-28 | 1983-02-15 | Rsr Corporation | Method of manufacturing electrowinning anode |
| GB2096643A (en) * | 1981-04-09 | 1982-10-20 | Diamond Shamrock Corp | Electrocatalytic protective coating on lead or lead alloy electrodes |
| US4388159A (en) * | 1981-05-18 | 1983-06-14 | Borg-Warner Corporation | Surface preparation of aluminum articles |
-
1983
- 1983-01-17 CA CA000419585A patent/CA1232227A/en not_active Expired
- 1983-01-20 AU AU10656/83A patent/AU1065683A/en not_active Abandoned
- 1983-02-08 EP EP83200194A patent/EP0090435A1/en not_active Ceased
- 1983-02-16 US US06/467,088 patent/US4459189A/en not_active Expired - Fee Related
- 1983-02-16 US US06/467,153 patent/US4465561A/en not_active Expired - Fee Related
- 1983-02-17 KR KR1019830000642A patent/KR840003702A/en not_active Withdrawn
- 1983-02-17 NO NO830560A patent/NO830560L/en unknown
- 1983-02-17 FI FI830535A patent/FI830535L/en not_active Application Discontinuation
- 1983-02-17 ES ES519883A patent/ES8403170A1/en not_active Expired
- 1983-02-18 PL PL24065483A patent/PL240654A1/en unknown
- 1983-02-18 JP JP58026143A patent/JPS58161785A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| US4465561A (en) | 1984-08-14 |
| ES519883A0 (en) | 1984-03-01 |
| FI830535A7 (en) | 1983-08-19 |
| US4459189A (en) | 1984-07-10 |
| NO830560L (en) | 1983-08-19 |
| KR840003702A (en) | 1984-09-15 |
| EP0090435A1 (en) | 1983-10-05 |
| AU1065683A (en) | 1983-08-25 |
| ES8403170A1 (en) | 1984-03-01 |
| FI830535L (en) | 1983-08-19 |
| JPS58161785A (en) | 1983-09-26 |
| PL240654A1 (en) | 1984-03-26 |
| FI830535A0 (en) | 1983-02-17 |
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