JP2021533257A - Electrodes for electroplating or electrodeposition of metal - Google Patents

Abstract

The present invention relates to electrodes for electroplating or electrodeposition of metals and methods for obtaining them. The electrode comprises a conductive substrate, at least one layer of an electrochemically active coating placed on the substrate, and at least one top coating layer of valve metal. [Selection diagram] None

Description

The present invention relates to the field of electrodes for electroplating or electrodeposition of metals comprising at least one top coating layer and at least one electrochemically active coating layer, and methods thereof.

In electroplating, more commonly in the electrodeposition process, a thin metal coating is formed starting from the metal cations dissolved in the electrolytic bath and deposited above the designated cathode surface via an electrolytic reaction. NS. The reaction is carried out in an electrolytic cell containing at least an anode-cathode pair immersed in an electrolytic cell. The bath is often equipped with a dimensionally stable anode, such as an activated titanium anode, and the electrolyte typically contains a certain amount of added organic elements. These additives usually include brighteners, levelers, surfactants and inhibitors, for example promoting uniform deposition of metals and controlling their physical-mechanical properties, eg, their tensile strength and elongation. Used for. However, during operation, these organic components deteriorate over time, primarily due to the oxidation that occurs at the anode. The resulting additive consumption affects the quality of metal plating / deposits and also strongly affects the overall cost of the process.

In addition, the process conditions for electroplating and electrodeposition of metals can be very harsh on battery components, especially activated anodes. Corrosive electrolytes, and in certain applications, high current densities affect electrode life and performance by degrading the active coating layer, further exacerbating the amount of additives consumed.

Electrodes for electroplating or electrodeposition of metals that include at least one tantalum oxide-based top coating layer above the activation electrode, i.e., electrodes with at least an electrochemically active coating layer, have the above-mentioned problems. It is known to the applicant to partially deal with.

U.S. Pat. No. 6,527,939 and U.S. Patent Publication No. 2004031692 are provided to protect potential electrocatalyst coating layers in applications involving oxygen evolution and to prevent organic elements or other oxidizable species in the electrolyte from oxidation. It is taught to use a valve metal or tin top coating layer on the activation electrode. It is taught that the valve metal top coating layer is formed from the valve metal alkoxide in an alcohol solvent with or without the presence of an acid or with the use of dissolved metal salts. However, the preparation methods generally described in the art for valve metal topcoats, especially the Ta or Sn-based topcoat preparation methods taught in the embodiments of the prior art, are other valve metal topcoats. No works have been found to work well with compositions, especially Nb-based compositions.

Moreover, Sn-based top coatings are generally undesirable in applications such as copper foil, where even the slightest tin contamination of the electrolyte can adversely affect the quality of the deposited copper.

Therefore, it is desirable to provide alternative or improved electrodes for electroplating / electrodeposition processes that exhibit extended service life and limited additive consumption.

It is also desirable to provide an alternative and improved method for making electrodes containing Nb-based top coating layers for electroplating and electrodeposition processes.

The present invention relates to improved activated electrodes for electroplating and electrodeposition processes, and methods of manufacturing thereof. The electrodes are operated in an electrolyte environment containing organic additives, where the electrodes can reduce the amount of organic components via oxidation.

The activated electrode comprises at least one top coating layer containing niobium oxide that can induce an improvement in the barrier effect on the consumption of the additive, wherein the Nb-based top coating layer is an acid precursor, an acid precursor. That is, it can be obtained by thermal decomposition of an aqueous solution containing niobium oxalate in acetic acid.

Other benefits and advantages of the invention will be apparent to those skilled in the art based on the embodiments for carrying out the invention below.

Under one aspect, the invention is a conductive substrate, at least one top coating layer of the first composition and at least one electrochemically active coating of a second composition different from the first composition. For electrodes suitable for electroplating or electrodeposition of metal from an electrolyte solution in an electrolytic bath containing a layer, an electrochemically active coating layer is placed between the conductive substrate and the top coating layer, first. The composition of the above contains 90-100% niobium or an oxide thereof (represented in percent by weight relative to the metal).

In contrast to the electrodes obtained via the preparation methods disclosed in the prior art, an Nb-based top coating layer obtained via thermal decomposition of a precursor solution containing an aqueous solution of acetic acid containing niobium oxalate is added. The inventor surprisingly observed that it had a favorable effect on the consumption of the agent, thereby improving the quality of the electrodeposited / electroplated metal. In addition, Nb-based top coatings that can be obtained via the methods described above minimize exposure to electrolytes of any platinum group metal or oxide thereof that may be present in electrochemically active coatings. Allows the useful life of the electrode to be extended. The above can be achieved without adversely affecting the electrode potential of the battery.

Thus, the electrodes according to the invention may provide a viable and advantageous alternative for electrodes with Ta and Sn-based topcoats described in the prior art.

Nb-based top coating layer means a top coating layer (represented by weight percent relative to metal) containing 90-100% niobium or an oxide thereof.

Further, the electrode with the Nb-based top coating according to the present invention may also show an improved alternative to the electrode with the Nb-based top coating layer obtained by the preparation method described in the prior art. Such methods teach, for example, the use of alkoxides or chlorides of valve metals as precursors dissolved in alcohol solvents, regardless of the presence of acid. These known methods give good results when the valve metal is tantalum, but are less satisfying when the valve metal is niobium.

Normally, niobium chloride is hydrolyzed in the presence of water, even in the presence of trace amounts of water. As a result, chloride precipitates as niobium oxide, thereby hindering the application of the coating and causing problems with the stability of the coating solution.

As expected, the inventor has found that the tendency of these niobium precursors to hydrolyze adversely affects the performance of the resulting top coating. In fact, _{it has been found that the Nb-based topcoat layer obtained starting from a solution of NbCl 5} in hydrochloric acid or alcohol (such as butanol, isopropanol, and ethanol) does not provide a suitable and reproducible electrode.

In particular, the high evaporation rate of alcohol greatly affects the stability of the resulting solution, as can be observed, especially for ethanol and isopropanol.

In addition, since the top coating layer is thermally treated at temperatures well above 100 ° C., it is usually desirable not to use flammable solutions such as alcohol in the electrode preparation process.

The Nb-based top coating layer obtained starting from Nb alkoxide resulted in a highly porous electrode with a very low barrier effect on additive consumption.

Of all the solutions listed above, _{only those containing NbCl 5} in butanol were found to produce a working electrode, but the top of the Nb-based according to the invention in terms of additive consumption and service life. It fell short of both coats and Ta-based topcoats known in the art.

As far as the inventor knows, the above may explain why metal electroplating or electroplating electrodes with Nb-based top coatings are not commercially available and are not normally used in possible applications.

In general, the electrodes according to the invention are particularly useful as dimensionally stable anodes, especially when used for electrodeposition of copper foil from sulfate electrolytes, for example in the manufacture of printed circuit boards.

It is desirable that the electrodes according to the invention reduce the oxidation of oxidizable species in solution, for example in order to inhibit the production of chlorine and / or hypochlorite in systems containing low levels of chloride. It can also be used to advantage in electrochemical processes.

The electrodes according to the invention can be used, for example, in an undivided electrolytic cell in which opposing electrodes are separated by a physical gap containing an electrolyte. The battery may include a bag of insulating material such as a plastic material such as polypropylene that surrounds the anode.

In electroplating and electrodeposition of the metal of interest, the electrolyte is typically a water-based solution in which the electroplated / electrodeposited metal is dissolved.

Electrolytes usually contain additives such as brighteners, levelers, surfactants, and inhibitors. Additives may include disulfide compounds such as bis (sulfopropyl sodium) disulfide (SPS), polyethylene glycol or amines.

The conductive substrate of the electrode can be a valve metal such as titanium, tantalum, zirconium, niobium, and tungsten. Alternatively, tin or nickel may be used. Suitable metals for conductive substrates may include alloys and intermetal mixtures thereof, in addition to the elemental metals themselves described above. The preferred material for conductive substrates is titanium, which is due to the toughness, corrosion resistance and general availability of titanium.

The conductive substrate can be in any form suitable for performing its purpose. In particular, it can be in the form of plates, meshes, sheets, blades, tubes or wires.

By convention in the art, the latter is prophylactically cleaned prior to applying any of the coating layers over the substrate and, in some cases, known in the art such as intergranular etching, blasting or plasma spraying. It is treated by any conventional technique to enhance the adhesion, followed by a surface treatment to clean the substrate and remove any residue adhering to it.

In some cases, the surface of the substrate may be subjected to other preparation steps such as pretreatment before coating the coating layer. For example, the surface may be subjected to hydration or nitriding, or the substrate may be provided with an oxide layer by heating the substrate in air or by anodic oxidation.

The electrodes according to the invention are activated with an electrochemically active coating comprising at least one electrochemically active coating layer having a composition different from that of the top coating layer.

The electrochemically active coating is placed between the top coating and the conductive substrate. The top coating allows larger additive molecules in the electrolyte to reach the electrochemically active coating, while allowing other components of the electrolyte to adequately access the potentially electrochemically active coating. On top of that, it is likely to prevent oxidation.

Electrochemically active coating layer compositions include valve metals such as magnesium, thorium, cadmium, tungsten, tin, iron, silver, silicon, tantalum, titanium, aluminum, zirconium and niobium, as well as iridium, osmium, palladium and platinum. , Rhodium, ruthenium and the like, can be a mixture of platinum group metals.

Mixtures of iridium and tantalum have been found to work very well in the practice of the present invention. Preferably, the mixture contains 50-80% iridium and 20-50% tantalum (expressed in elemental weight percent).

The electrochemically active coating layer may be applied directly on the conductive substrate or above the optional lower layer, which facilitates adhesion of the electrochemically active coating layer to the electrode substrate. And / or the passivation of the conductive substrate can be prevented.

It is understood that the underlayer will have a different composition than the composition of the electrochemically active coating.

The underlayer may contain a mixture of valve metal oxides, such as a mixture of tantalum and titanium oxides. The latter has been found to work well for the practice of the present invention. In particular, it has been observed that the composition of 10-40% Ta and 60-90% Ti provides very good adhesion of the electrochemically active coating layer to the electrode substrate and prevents passivation. Was done.

Each electrochemically active coating layer and each optional underlayer can be formed according to methods known in the art.

Preferably, the electrochemically active coating is formed by thermal decomposition of the precursor. Preferably, the precursor is decomposed at a temperature of 400-600 ° C. In some cases, the pyrolyzed coating may be further baked at a temperature of 430-600 ° C. after applying the last layer.

The Nb-based topcoat according to the invention is applied to at least one layer above the electrochemically active coating; each topcoat layer is dried according to standard procedures known in the art and then pyrolyzed. Will be done.

One of ordinary skill in the art will apply as many top coating layers as necessary to achieve the desired load. The inventor has found that good results are usually obtained when the total amount of Nb in the top coating is 2-18 g / m ^2. To reduce the number of cycles, 2-12g / ^{m 2,} preferably be used a load with reduced 7-10 g / ^{m 2.}

Higher loads of, for example, 12-18 g / m ² can result in further improved additive consumption.

Such a load can be achieved in many layers, i.e., preparation cycles, which depend on the pickup of each top coating layer. A 3-20 cycle count and ^{a pickup of 0.5-2 gNb / m 2} per layer were found to work well in the practice of the present invention.

Any of the coating layers utilized in the electrodes according to the invention is an electrode of a liquid composition, such as a brush or roller coater, dip spin and dip drain method, spraying, electric spraying, or application by any combination of the techniques described above. It can be applied by any of the means known in the art suitable for application to the substrate.

Usually, the capacity of the electrode to minimize the consumption of additives depends, among other parameters, on the thickness of the top coating, which is the preparation cycle for a given metal pickup per layer. May be related to the number of. The inventor has observed that the Nb-based top of the electrodes according to the invention can reach the same thickness as a Ta-based topcoat with half the number of top coating layers, using the same pickups layer by layer. The thickness of the top coating is not the only parameter that affects the volume of the coating to prevent additive consumption, but it is the introduction of physical separation between the electrode active layer and the organic components in the electrolyte. Note that this contributes to such an effect.

^{The inventor has found that the barrier effect of the Nb-based topcoat according to the invention per g / m 2} of the total metal load of the topcoat is improved by more than 51% over the barrier effect of the same electrode without a topcoat. I observed that.

The improvement in barrier effect was measured via a cyclic voltamogram and the effect of the top coating on the oxidation of iron ions in the electrolytic cell was determined according to the procedure described in Comparative Test 3.

Usually, the electrochemical and chemical reversible reaction Fe (II)-> Fe (III) + e-characteristic cyclic voltamogram peak depends on the type of top coating applied, depending on its thickness and porosity. Change.

Under fixed experimental conditions (referenced experimental temperature, redox reaction, scan rate, redox probe, etc.), the peak height of the cyclic voltammogram of the electrode can penetrate the "barrier" provided by the top coating. The result is proportional to the number of iron (II) ions that can be oxidized in the active layer of the electrode.

The higher the peak height, the lower the barrier effect of the top coating on the consumption of iron (II) ions, and therefore the lower the barrier effect of the top coating on the consumption of the brightener, but the latter is the particular brightener used. It will also be partially affected by other parameters such as molecules.

The inventor quantitatively improves the barrier effect provided by the top coating by dividing the peak height of the cyclic voltammogram of the electrode without the top coating by the peak height of the cyclic voltammogram of the same electrode with the top coating. Calculated in. The result is then adjusted to the total metal load at ^{g / m 2} present in the top coating.

Under one embodiment, the top coating layer of the electrode according to the invention contains substantially 100% Nb or an oxide thereof.

The expression "substantially 100% Nb or oxide thereof" means a top coating layer of niobium, with the exception of trace elements or trace impurities in precursor solutions that may diffuse from the coating below. do.

The top coating of the electrode according to an embodiment of the present invention is such that it can be obtained through thermal decomposition of a niobium precursor solution according to the present invention, that is, an aqueous solution containing niobium oxalate in acetic acid. Can be diluted with deionized water.

Electrodes according to this embodiment were found to exhibit an improved barrier effect on additive consumption for electrodes with the same number of layers and Ta-based top coatings with the same load.

Furthermore, it has been found that the electrodes according to this embodiment show a significant improvement in barrier effect over electrodes with an Nb-based top coating layer prepared according to the methods described in the art.

In particular, in connection with this embodiment, the inventor has determined that ^{the barrier effect of the Nb top coating per gNb / m 2} is the barrier of the electrochemically active coating alone measured according to the procedure described in Comparative Test 3. It was observed that the effect was improved by more than 85% and further by more than 100%.

Under alternative embodiments, the Nb-based top coating layer is suitable for inclusion as a doping agent precursor in a precursor solution of a first composition such as antimony, indium, molybdenum, tungsten, bismuth or tantalum. Also provided with at least one dope. Such a doping agent may typically be present in an amount of about 0.01% to about 10% by weight, preferably from about 0.01% to about 5% by weight, in the top coating layer. .. The doping agent can be in the form of an oxide thereof, including a metal or a suboxide.

The present invention is different from the conductive substrate, the top coating containing at least one top coating layer of the first composition containing 90-100% niobium or an oxide thereof, and the second composition. The adjusted barrier effect of the top coating is also redox with respect to electrodes suitable for electroplating or electrodeposition of metal from an electrolyte solution in an electrolytic bath containing at least one electrochemically active coating layer of the composition. Probe Fe (II) | 51-200% of the barrier effect of the potentially electrochemically active coating as measured by cyclic voltammetry in the presence of Fe (III). The adjusted barrier effect measurement is as described in Comparative Test 3 by dividing the peak height of the cyclic voltammogram of the electrode without the top coating by the peak height of the electrode with the Nb-based top coating. It shall be made and adjusted for the total metal load (g / m ^{2) of the top coating.}

The Nb-based top coating according to an embodiment of the present invention can be obtained via thermal decomposition of a precursor solution containing an Nb precursor solution containing niobium oxalate in acetic acid. The precursor solution corresponds to the precursor solution described herein alone or in connection with a preferred or alternative embodiment of the invention.

Nb-based top coatings prepared with Nb precursor solutions described in the art show an adjusted barrier effect that does not reach a 51% improvement for uncoated electrodes at best.

According to a preferred embodiment of the above electrode, the first composition of the above electrode contains substantially 100% Nb or an oxide thereof, and the improvement of the barrier effect of the electrode having the top coating is It is 85-200% times the barrier effect of electrodes without a top coating and can reach 100-200% as measured per ^{total gNb / m 2.}

In a further aspect, the invention relates to a method for manufacturing the electrodes described above. The method comprises coating the conductive substrate with an electrochemically active coating comprising at least one layer, followed by forming a top coating on top of the electrochemically active coating. The top coating comprises at least one top coating layer containing 90-100% niobium or an oxide thereof. Each top coating layer is formed by performing the following sequential steps:
(I) A step of applying a precursor solution containing an Nb precursor solution above the activated conductive substrate;
(Ii) A step of drying the precursor solution at a temperature of 50-100 ° C. for 5-20 minutes, preferably at a temperature of 50-70 ° C. for 7-15 minutes;
(Iii) A step of thermally decomposing the dried precursor solution at a temperature of 320-600 ° C. for 5-20 minutes.

Preferably, the above pyrolysis step is carried out at 350-550 ° C. for 5-20 minutes, even more preferably at 470-550 ° C. for 7-15 minutes.

Steps (i)-(iii) may be cyclically repeated as many times as necessary to achieve the desired metal load.

It is understood by those skilled in the art that after each cycle, at the end of the precursor solution pyrolysis step (iii), the electrodes are cooled to room temperature before proceeding to subsequent cycles.

A number of cycles of 3-20 was found to produce a top coating thickness that provided a suitable barrier effect. In some embodiments, the number of cycles of 4-16 has been found to function without compromising the increase in overvoltage, thus maintaining a relatively small number of thermal cycles, resulting in cost savings. ..

The above Nb precursor solution is obtained by mixing an aqueous solution containing niobium oxalate in dilute acetic acid.

The concentration of Nb in the Nb precursor solution can be selected at 20-50 g / l. It was observed that this range ensures a particularly compact top coating layer structure that is beneficial in reducing additive consumption.

_{Dilute acetic acid is CH 3} COOH diluted with water, preferably deionized water, preferably at a concentration of 5-20%, even more preferably at a concentration of 7-13%, to provide particularly good wettability. Means.

According to the claimed method, the formation of at least one top coating layer occurs above the activated substrate, i.e., the substrate with at least one electrochemically active coating layer. The latter may be formed directly above the clean or pretreated substrate, or may be formed on top of at least one optional lower layer coated above the substrate.

The electrochemically active coating layer, optional underlayer, and electrode substrate may be by any of the embodiments described above.

According to one embodiment, the precursor solution comprises an Nb precursor solution. Thus, the resulting electrodes are substantially 100, except for trace elements of the electrochemically active coating that can partially diffuse into the top coating, or traces of other metals in the Nb precursor solution. It will be provided with a top coating containing% Nb or an oxide thereof.

According to an alternative embodiment, the precursor solution contains an Nb precursor solution and a doping agent precursor solution, and the doping agent is selected from the group consisting of antimony, indium, molybdenum, tungsten, bismuth, and tantalum. The weight ratio of Nb to the doping agent in the precursor solution is 90-99,999: 10-0,001; preferably 95-99,999: 5-0,001.

Under different embodiments, the present invention is an inseparable electrolytic cell for electroplating or electrodeposition of metal from an electrolyte solution containing at least one anode and at least one cathode that is partially or completely immersed in the electrolyte solution. Regarding. The electrolyte solution contains the metal deposited / plated in the solution and at least one organic substituent.

The anode used in the tank is the electrode described above.

The tank can be used in printed circuit boards.

For example, the tank according to the present invention can be used for electrodeposition of copper foil from an aqueous electrolyte containing copper sulfate.

The organic substituent can be an organic additive.

Under different embodiments, the present invention is a method for electroplating or electrodeposition of a metal from an electrolyte solution, wherein the method is performed in any electrolytic cell as described above and is present in the electrolyte. At least one anode in the tank is manipulated so that the consumption of organic substituents is reduced without compromising the anode potential of the tank.

The following examples are included to demonstrate a particular method of putting the invention into practice, the feasibility of which has been largely validated within the range of claimed values.

Those skilled in the art should appreciate that the devices, compositions and techniques disclosed below represent devices, compositions and techniques discovered by the inventor to function well in the practice of the present invention. However, one of ordinary skill in the art can make many changes in the particular embodiments disclosed in the light of the present disclosure and still obtain similar or similar results without departing from the scope of the invention. Should be understood.

Experimental Preparation In all the electrode samples used in the following examples, counterexamples and comparative tests, the electrodes were degreased with acetone for 10 minutes in an ultrasonic bath, starting from a titanium grade 1 mesh with a size of 100 mm × 100 mm × 1 mm. Manufactured the substrate. The mesh was then sandblasted with steel grit and then etched at boiling point with 20% by weight HCl.

Example 1
A clean electrode substrate sample was coated with an electrochemically active coating solution containing a mixture based on an oxide of iridium and tantalum in a weight ratio of 65:35.

Ten layers of electrochemically active coating precursor solution were applied to bring the total load of iridium to 15 g / m ² .

Each electrochemically active coating layer was applied with a brush and dried at a temperature of 50 ° C. for 10 minutes. Each electrochemically active coating layer was then pyrolyzed at a temperature of 510 ° C. for 15 minutes and finally cooled to room temperature before proceeding to the next layer.

The activated electrode was then coated with a top coating solution of Nb precursor.

The Nb precursor solution consisted of an aqueous solution containing niobium oxalate at 45 g / l in 13% aqueous CH3COOH.

Nine layers of top coating were applied to bring the total load of Nb to 9 g / m ² .

Each top coating layer was brushed and dried at a temperature of 55 ° C. for 10 minutes. Each top coating layer was then pyrolyzed at a temperature of 500 ° C. for 10 minutes and cooled to room temperature before proceeding to the next layer.

The electrode thus obtained was labeled as S1.

Counterexample 1
Sample electrodes were prepared according to the procedure outlined in Example 1, except that the Nb precursor solution _{consisted of NbCl 5} dissolved in butanol and the concentration of niobium in the Nb precursor solution was 45 g / l. bottom.

The electrode thus obtained was labeled as CS1.

Counterexample 2
A clean electrode substrate sample was coated with the electrochemically active coating described in Example 1 according to the procedure described in Example 1.

The activated electrode was then coated with a top coating solution of Ta precursor.

The Ta precursor solution consisted of an aqueous solution containing _{TaCl 5 in butanol at 45 gTa / l.}

Nine layers of the top coating solution were applied to bring the total load of Ta to 9 g / m ² .

Each top coating layer was brushed and dried at a temperature of 55 ° C. for 10 minutes. Each top coating layer was then pyrolyzed at a temperature of 500 ° C. for 10 minutes and cooled to room temperature before proceeding to the next layer.

The electrode thus obtained was labeled as CS2.

Counterexample 3
As described in Example 1, a clean electrode substrate sample was coated with an electrochemically active coating.

After that, 18 layers of the top coating solution were applied, and the activated electrode was coated with the top coating solution of the Ta precursor as described in Counterexample 2, except that ^{the total load of Ta was 18 g / m 2.} ..

The electrode thus obtained was labeled as CS3.

Samples S1, CS1 and CS3 showed an average top coating thickness of 4 micrometers as measured by SEM cross-section imaging. Sample CS2 showed an average thickness of 2 micrometers.

Comparative test 1
All samples were measured for brightener consumption by performing dummy copper plating in a Haring tank for 190 minutes at 25 ASF (amps per square foot).

For the anode, samples S1, CS1, CS2, CS3 were used as alternatives inside the polypropylene bag.

The cathode was a brass plate.

The electrolyte contained water, sulfuric acid, formaldehyde, organic salts and copper sulphate. The organic salt, or brightener, was disodium 3,3'-dithiobis [propanesulfonate].

Brightener consumption was measured by cyclic voltammetry stripping by determining the charge required to consume 1 liter of brightener. The results are reported in Ah / l in Table 1.

Comparative test 2
All samples were life tested at 1 kA / m ² _{in a beaker at H 2} SO ₄ 150 g / l and monitored every 1000 hours.

Table 1 lists the inactivation times of each sample corresponding to the time (in hours) required to measure the rapid increase in tank voltage above 6 V.

Comparative test 3
The barrier effect of samples S1, CS1, CS2 and CS3 was measured by cyclic voltammetry in the presence of redox probes Fe (II) | Fe (III).

A solution of 50ml of Fe _(II), was prepared in Fe of 20 g / l from H 2 SO ₄ in ferrous 150 g / l sulfuric acid (II).

An experiment was conducted at a scanning speed of 20 mV / s at room temperature (25 ° C.) in a three-electrode tank.

The counter electrode is ^{a dimensionally stable titanium anode in the active portion of 3 cm 2} , prepared as described in Example 1, having no top coating, and electrochemically active with 65% iridium and 35% tantalum. Coated with a nice coating.

The reference electrode was a saturated mercuric chloride electrode.

For each of the test samples S1, CS1, CS2, CS3, a baseline referred to as BL according to the procedure described in Example 1, except that no top coating layer was applied above the electrochemically active coating. Electrodes were prepared.

Samples S1, CS1, CS2, CS3, and baseline BL were cut to a size of 10 mm × 30 mm and covered with Teflon tape to leave an active portion of ^{10 × 10 mm 2.}

The experiment consisted of 5 tests and the working electrode was selected as an alternative from samples S1, CS1, CS2, CS3 and baseline BL.

The peak height of the cyclic voltammogram was measured for all samples and BL.

The improvement in the top coating barrier effect (TC BE) of each sample S1, CS1, CS2, CS3 was calculated as the ratio between the peak height of the corresponding baseline BL electrode and the peak height measured for the sample. That is,
TC BE (sample) = peak height (BL) / peak height (sample).

The improvement in the top coating barrier effect of each sample is then obtained by dividing the TC BE (sample) by the metal content of the top coating ( ^{measured at g / m 2} and the numerical value is expressed as a percentage (g / m). ² )) The total metal load of the top coating was adjusted.

The measurement results are listed in Table 1.

The above description is not intended to limit the invention, the invention may be used in accordance with different embodiments without departing from its scope, the scope of which depends on the appended claims. Only defined.

Throughout the specification and claims of the present application, the term "comprise" and its variations such as "comprising" and "comprises" may be other elements, components, or additions. It is not intended to exclude the existence of the process process of.

Discussions of documents, acts, materials, devices, articles, etc. are included herein for the sole purpose of providing the context of the present invention. That any or all of these matters formed part of the foundation of the prior art, or that it was general knowledge in the field relating to the invention prior to the priority date of each claim of the present application. , Not suggested or expressed.

Claims (10)

An electrolyte solution in an electrolytic bath comprising a conductive substrate, at least one top coating layer of the first composition and at least one electrochemically active coating layer of a second composition different from the first composition. An electrode suitable for electrolysis or electrodeposition of metal from, where an electrochemically active coating layer is placed between the conductive substrate and the top coating layer, and the first composition is 90-. An electrode containing 100% niobium or an oxide thereof, wherein the top coating layer is obtained via thermal decomposition of a precursor solution containing an aqueous solution of niobium oxalate in acetic acid. The electrode according to claim 1, wherein the first composition contains substantially 100% niobium or an oxide thereof. The first composition comprises at least one doping agent selected from the group consisting of antimonide, indium, molybdenum, tungsten, bismuth, tantalum, or oxides thereof in an amount of 0.01-10% by weight. Item 1. The electrode according to Item 1. The electrode according to any one of claims 1 to 3, wherein the total amount of niobium in the top coating layer is 2-18 g / m ^2. The electrode according to any one of claims 1 to 4, wherein the second composition is composed of 50-80% iridium and 20-50% tantalum in terms of weight percentage. A third composition further comprises at least one lower layer containing a third composition different from the second composition, wherein the lower layer is disposed between the conductive substrate and the electrochemically active coating layer. The electrode according to any one of claims 1 to 5, wherein the material preferably contains a mixture of tantalum and an oxide of titanium. One of claims 1 to 6, wherein the conductive substrate is made of a valve metal selected from the group consisting of titanium, tantalum, zirconium, niobium, tungsten, aluminum, silicon, alloys thereof and intermetal mixtures. The electrodes described in. The conductive substrate is coated with an electrochemically active coating containing at least one electrochemically active coating layer, and the top coating contains at least one top coating layer containing 90-100% niobium or an oxide thereof. The method for manufacturing the electrode according to claim 1, which comprises forming a top coating on the conductive substrate, comprising the above.
Forming the at least one top coating layer is a sequential step that follows: (i) Applying the precursor solution over the conductive substrate coated with at least one electrochemically active coating layer;
(Ii) A step of drying the precursor solution at a temperature of 50-100 ° C. for 5-20 minutes, preferably at a temperature of 50-70 ° C. for 7-15 minutes;
(Iii) A step of pyrolyzing the dried precursor solution at a temperature of 350-600 ° C. for 5-20 minutes, preferably at a temperature of 470-550 ° C. for 7-15 minutes;
Including
A method comprising a precursor solution comprising an Nb precursor solution obtained by diluting an aqueous solution of acetic acid containing niobium oxalate. An inseparable electrolytic cell for electroplating or electrodeposition of metal from an electrolyte solution containing at least one anode and at least one cathode immersed in the electrolyte solution, wherein the electrolyte solution is organically substituted into the solution. Contains the group and the metal;
An inseparable electrolytic cell, wherein the at least one anode is the electrode according to any one of claims 1 to 7. An electrolyte solution performed in the electrolytic cell according to claim 11, wherein at least one anode in the tank is engineered so as to reduce the consumption of the organic substituent while maintaining the anode potential in the phase. A method for electroplating or electrodeposition of metal from.