EP0001778A2 - Electrodes for electrolytic purposes - Google Patents
Electrodes for electrolytic purposes Download PDFInfo
- Publication number
- EP0001778A2 EP0001778A2 EP78101152A EP78101152A EP0001778A2 EP 0001778 A2 EP0001778 A2 EP 0001778A2 EP 78101152 A EP78101152 A EP 78101152A EP 78101152 A EP78101152 A EP 78101152A EP 0001778 A2 EP0001778 A2 EP 0001778A2
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- Prior art keywords
- tantalum
- metals
- electrodes
- iron
- alloy
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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
- C25B11/073—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
- C25B11/075—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of a single catalytic element or catalytic compound
- C25B11/081—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of a single catalytic element or catalytic compound the element being a noble metal
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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
- C25B11/073—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
- C25B11/091—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of at least one catalytic element and at least one catalytic compound; consisting of two or more catalytic elements or catalytic compounds
Definitions
- the invention relates to electrodes for electrolysis purposes, which contain a metal alloy tantalum, tantalum boride, tantalum carbide or alloys of metals of the iron group individually or in a mixture and are doped on the surface with metals of the platinum group, in particular with rhodium.
- German Offenlegungsschrift 23 46 055 describes electrodes for electrolysis purposes which, in addition to an alloy of tungsten with metals of the iron group tantalum, tantalum boride, tantalum carbide or alloys of tantalum with metals of the iron group, contain individually or in a mixture and on the surface with metals of. Platinum group, especially with rhodium, are doped. If these anodes are used in amalgam cells, small amounts of tungsten can reach the cathode in the event of short circuits with the amalgam cathode, which reduce the hydrogen overvoltage.
- the invention seeks to remedy this.
- the invention as characterized in the claim, solves the problem of creating electrodes when used as anodes in amalgam cells when short circuits occur a reduction in the hydrogen overvoltage at the cathode is definitely avoided.
- the electrodes according to the invention have the further advantage over the known, tungsten-containing electrodes that when used as anodes in chlor-alkali electrolysis at pH ranges from 2 to 4.5, as are usually observed, they give about 50% less chlorate and that the oxygen content in the anodically developed chlorine is about 60% lower.
- the proportion of tantalum, tantalum boride, tantalum carbide or a tantalum alloy in the electrode should be at least 10 percent by weight, preferably 30 to 60 percent by weight, in each case calculated as tantalum, in order to obtain well-adhering, dense, corrosion-resistant layers which provide adequate protection for the electrically conductive carrier guarantee. With tantalum contents of more than 60 percent by weight one obtains extremely stable and stable anodes, such electrodes have somewhat higher overvoltages, so that generally higher tantalum contents should be avoided.
- the metals of the iron group are particularly advantageous as alloy components for the metals niobium or tantalum, since lower overvoltages can be achieved with these elements.
- iron which enables particularly good adhesion when doped with the platinum metals.
- the content of metals of the iron group in the niobium and optionally the tantalum alloy should total less than 10 percent by weight, preferably 0.5 to 5 percent by weight. Higher iron contents deteriorate the corrosion resistance, while too low iron contents do not Ensure sufficient adhesion of the platinum metals and conductivity.
- the electrode contains tantalum in the form of alloys with metals of the iron group, the proportion of iron in the niobium alloy to that in the tantalum alloy is 1: 0.1 to 1: 5.
- Platinum metals can be used for doping the electrodes. Rhodium has proven to be the cheapest metal because, at high anodic current densities, it is superior to all other platinum metals with regard to the adhesive strength on the electrode surface.
- the content of platinum metals should be less than 1.5 g / m electrode surface, preferably 0.25 to 0.75 g / m 2 .
- the electrodes can be used as such or also applied to an electrically conductive carrier.
- Titanium, graphite and in particular titanium-tantalum and titanium-niobium alloys are preferred, since these alloys are particularly corrosion-resistant.
- the tantl or niobium content in the alloys should be at least 10 percent by weight in order to achieve a significant improvement over unalloyed titanium.
- the electrodes can be produced by applying a mixture consisting of a fine-grained alloy of niobium with metals from the iron group and fine-grained tantalum, tantalum carbide, tantalum boride or an alloy from tantalum with metals from the iron group with the aid of a plasma torch on an electrically conductive base and the layer thus applied is then doped on the surface with platinum metals, in particular rhodium.
- the grain size of the metal powder used should be 40 to 100 / um.
- the electrodes can also be produced, for example, by rolling layers of the mixtures described above onto an electrically conductive base or by plating them.
- the layers applied to the electrically conductive carrier should be thicker than 0.1 mm in this process. Layer thicknesses between 0.1 and 0.8 mm are preferably selected.
- the electrodes are impregnated with a 0.1 to 10, in particular 0.5 to 3, percent by weight solution of an inorganic platinum metal compound and then at +600 to + 1200 ° C, preferably +800 to + 900 ° C, under Protective gas atmosphere annealed for about 1 to 10 seconds.
- An aqueous hydrochloric acid rhodium (III) chloride solution with a pH of 0 to 0.5 has proven to be particularly advantageous for the doping.
- this solution and the iron-containing niobium or tantalum alloys a particularly stable doping and clean electrode surfaces are obtained, since the iron chlorides formed sublimate immediately when doping.
- such electrode surfaces that are not contaminated with oxides have particularly low overvoltages on.
- the doping itself must be carried out under a protective gas atmosphere or in a high vacuum in order to avoid oxidation. Argon is preferably used as the protective gas.
- the electrodes can be manufactured using electrically conductive metallic carrier bodies, for example, by first degreasing the carrier body and freeing it from oxides by chemical etching with hydrofluoric or oxalic acid b or ion etching with noble gases at low pressures.
- the layer of an alloy of niobium with metals of the iron group, optionally simultaneously with tantalum or the tantalum compound, is then applied to the oxide-free, electrically conductive supports with the aid of vapor deposition or ion plating processes in a high vacuum.
- the platinum metals are doped into the surface of this layer by ion plating or implantation in a high vacuum.
- the layer of the niobium alloy with metals of the iron group and with tantalum or tantalum compounds, by vapor deposition ion plating or the plasma process can be applied simultaneously with platinum metals. It has proven to be advantageous here if the proportion of metals of subgroup VIII in the layer is 1/10 to 1/100 of the content of the surface.
- a titanium sheet with the dimensions of 30 x 20 x 2 mm is blasted with corundum and one side of the plasma torch with a fine-grain mixture consisting of 50 parts by weight of a lesiaration with 95% by weight of niobium and 5% by weight of 88 s and 50 parts by weight of tantalum, about 0.25 mm thick sighted.
- the finished anode is preferably suitable for the electrolysis of dye waste water, alkali chloride solutions and sulfuric acid.
- the overvoltage in aqueous alkali chloride solution is approximately 30 mV at a load of 2.3 kA / m 2 (anode surface).
- a titanium expanded metal mesh with the dimensions of 240 x 240 mm is degreased and oxides are removed by etching with argon in vacuo. Then a 2,000 ⁇ thick niobium iron layer (with 3 weight percent iron) is applied to the oxide-free surface.
- the surface is then doped with rhodium by ion plating.
- the rhodium content on the electrode is ⁇ 0.34 g / m 2 .
- the electrode can be used as an anode for the electrolysis of alkali chloride solutions and hydrochloric acid. After an operating period of 50 days at a current density of 15 kA / m 2 , there is no increase in the overvoltage. In the event of short circuits with the mercury cathode, there is no reduction in the hydrogen overvoltage.
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Abstract
Elektroden für Elektrolysezwecke, die insbesondere als Anoden für die Chloralkali-Elektrolyse geeignet sind, enthalten neben einer Legierung von Niob mit den Metallen der Eisengruppe Tantal, Tantalcarbid oder Legierungen von Tantal mit Metallen der Eisengruppe einzeln oder im Gemisch. Die Oberfläche dieser Elektroden ist mit Metallen der Platingruppe, insbesondere mit Rhodium, dotiert.Electrodes for electrolysis purposes, which are particularly suitable as anodes for chlor-alkali electrolysis, contain, in addition to an alloy of niobium with the metals of the iron group tantalum, tantalum carbide or alloys of tantalum with metals of the iron group individually or in a mixture. The surface of these electrodes is doped with platinum group metals, in particular with rhodium.
Description
Die Erfindung betrifft Elektroden für Elektrolysezwecke, die neben einer Metallegierung Tantal, Tantalborid, Tantalcarbid oder Legierungen von Metallen der Eisengruppe einzeln oder im Gemisch enthalten und auf der Oberfläche mit Metallen der Platingruppe, insbesondere mit Rhodium, dotiert sind.The invention relates to electrodes for electrolysis purposes, which contain a metal alloy tantalum, tantalum boride, tantalum carbide or alloys of metals of the iron group individually or in a mixture and are doped on the surface with metals of the platinum group, in particular with rhodium.
In der deutschen Offenlegungsschrift 23 46 055 sind Elektroden für Elektrolysezwecke beschrieben, die neben einer Legierung von Wolfram mit Metallen der Eisengruppe Tantal, Tantalborid, Tantalcarbid oder Legierungen von Tantal mit Metallen der Eisengruppe einzeln oder im Gemisch enthalten und auf der Oberfläche mit Metallen der. Platingruppe, insbesondere mit Rhodium, dotiert sind. Bei Verwendung dieser Anoden in Amalgamzellen können bei Kurzschlüssen mit der Amalgamkathode geringe Mengen Wolfram auf die Kathodegelangen, die die Wasserstoffüberspannung herabsetzen.German Offenlegungsschrift 23 46 055 describes electrodes for electrolysis purposes which, in addition to an alloy of tungsten with metals of the iron group tantalum, tantalum boride, tantalum carbide or alloys of tantalum with metals of the iron group, contain individually or in a mixture and on the surface with metals of. Platinum group, especially with rhodium, are doped. If these anodes are used in amalgam cells, small amounts of tungsten can reach the cathode in the event of short circuits with the amalgam cathode, which reduce the hydrogen overvoltage.
Hier will die Erfindung Abhilfe schaffen. Die Erfindung, wie sie in dem Anspruch gekennzeichnet ist, löst die Aufgabe Elektroden zu schaffen, bei deren Verwendung als Anoden in Amalgamzellen beim Auftreten von Kurzschlüssen eine Herabsetzung der Wasserstoffüberspannung an der Kathode mit Sicherheit vermieden wird.The invention seeks to remedy this. The invention, as characterized in the claim, solves the problem of creating electrodes when used as anodes in amalgam cells when short circuits occur a reduction in the hydrogen overvoltage at the cathode is definitely avoided.
Die erfindungsgemäßen Elektroden haben den weiteren Vorteil gegenüber den bekannten,Wolfram enthaltenden Elektroden, daß sie bei Verwendung als Anoden in der Chloralkali-Elektrolyse bei pH-Bereichen von 2 bis 4,5, wie sie üblicherweise eingehalten werden, etwa 50 % weniger Chlorat ergeben und daß die Sauerstoffgehalte im anodisch entwickelten Chlor um etwa 60 % niedriger liegen.The electrodes according to the invention have the further advantage over the known, tungsten-containing electrodes that when used as anodes in chlor-alkali electrolysis at pH ranges from 2 to 4.5, as are usually observed, they give about 50% less chlorate and that the oxygen content in the anodically developed chlorine is about 60% lower.
Der Anteil an Tantal, Tantalborid, Tantalcarbid oder einer Tantallegierung in der Elektrode sollte mindestens 10 Gewichtsprozent, vorzugsweise 30 bis 60 Gewichtsprozent, jeweils berechnet als Tantal, betragen, um gut haftende, dichte korrosionsfeste Schichten zu erhalten, die einen ausreichenden Schutz des elektrisch leitenden Trägers gewährleisten. Bei Tantalgehalten über 60 Gewichtsprozent erhält man zwar außerordentlich stabile und beständige Anoden, doch weisen solche Elektroden etwas höhere Überspannungen auf, so daß in der Regel höhere Tantalgehalte vermieden werden sollten.The proportion of tantalum, tantalum boride, tantalum carbide or a tantalum alloy in the electrode should be at least 10 percent by weight, preferably 30 to 60 percent by weight, in each case calculated as tantalum, in order to obtain well-adhering, dense, corrosion-resistant layers which provide adequate protection for the electrically conductive carrier guarantee. With tantalum contents of more than 60 percent by weight one obtains extremely stable and stable anodes, such electrodes have somewhat higher overvoltages, so that generally higher tantalum contents should be avoided.
Als Legierungskomponenten für die Metalle Niob oder Tantal sind die Metall der Eisengruppe (Eisen, Kobalt und Nickel) besonders vorteilhaft, da sich mit diesen Elementen niedrigere Überspannungen erreichen lassen. Bevorzugt eignet. sich Eisen, welches bei der Dotierung mit den Platinmetallen eine besonders gute Haftung ermöglicht. Der Gehalt an Metallen der Eisengruppe in der Niob- und gegebenenfalls der Tantallegierung sollte insgesamt weniger als 10 Gewichtsprozent, vorzugsweise 0,5 bis 5 Gewichtsprozent, betragen. Höhere Eisengehalte verschlechtern die Korrosionsbeständigkeit, während zu geringe Eisengehalte keine aus- reichende Haftung der Platinmetalle und Leitfähigkeit gewährleisten. Für den Fall, daß die Elektrode Tantal in Form von Legierungen mit Metallen der Eisengruppe enthält, verhält sich der Anteil.des Eisens in der Nioblegierung zu demjenigen in der Tantallegierung wie 1 : 0,1 bis 1 : 5.The metals of the iron group (iron, cobalt and nickel) are particularly advantageous as alloy components for the metals niobium or tantalum, since lower overvoltages can be achieved with these elements. Preferably suitable. iron, which enables particularly good adhesion when doped with the platinum metals. The content of metals of the iron group in the niobium and optionally the tantalum alloy should total less than 10 percent by weight, preferably 0.5 to 5 percent by weight. Higher iron contents deteriorate the corrosion resistance, while too low iron contents do not Ensure sufficient adhesion of the platinum metals and conductivity. In the event that the electrode contains tantalum in the form of alloys with metals of the iron group, the proportion of iron in the niobium alloy to that in the tantalum alloy is 1: 0.1 to 1: 5.
Zur Dotierung der Elektroden kommen Platinmetalle in Betracht. Als günstigstes Metall hat sich Rhodium erwiesen, da es bei hohen anodischen Stromdichten allen anderen Platinmetallen bezüglich der Haftfestigkeit auf der Elektrodenoberfläche überlegen ist. Der Gehalt an Platinmetallen sollte weniger als 1,5 g/m Elektrodenoberfläche vorzugsweise 0,25 bis 0,75 g/m2, betragen. Die Elektroden können als solche oder auch aufgebracht auf einen elektrisch leitenden Träger, eingesetzt werden.Platinum metals can be used for doping the electrodes. Rhodium has proven to be the cheapest metal because, at high anodic current densities, it is superior to all other platinum metals with regard to the adhesive strength on the electrode surface. The content of platinum metals should be less than 1.5 g / m electrode surface, preferably 0.25 to 0.75 g / m 2 . The electrodes can be used as such or also applied to an electrically conductive carrier.
Als elektrisch leitende Träger können Materialien, die in dem jeweils verwendeten Elektrolyten weitgehend beständig sind, eingesetzt werden. Bevorzugt sind Titan, Graphit und insbesondere Titan-Tantal- und Titan-Niob-Legierungen, da diese Legierungen besonders korrosionsbeständig sind. Der Tantl- bzw. Niobgehalt in den Legierungen sollte mindestens 10 Gewichtsprozent betragen, um eine wesentliche Verbesserung gegenüber unlegiertem Titan zu erreichen.Materials which are largely stable in the electrolyte used in each case can be used as the electrically conductive carrier. Titanium, graphite and in particular titanium-tantalum and titanium-niobium alloys are preferred, since these alloys are particularly corrosion-resistant. The tantl or niobium content in the alloys should be at least 10 percent by weight in order to achieve a significant improvement over unalloyed titanium.
Die Elektroden können dadurch hergestellt werden, daß man ein Gemezge, bestehend aus einer feinkörnigen Legierung von Niob mit Metallen der Eisengruppe und feinkörnigem Tantal, Tantalcarbid, Tantalborid oder einer Legierung aus Tantal mit Metallen der Eisengruppe mit Hilfe eines Plasmabrenner auf eine elektrisch leitende Unterlage aufträgt und die so aufgetragene Schicht anschließend oberflächlich mit Platinmetallen, insbesondere Rhodium, dotiert. Die Korngröße der verwendeten Metallpulver sollte 40 bis 100/um betragen. Beim Auftragen ist unter Schutzgasatmosphäre vorzugsweise Argon, zu arbeiten, um eine Oxidation der aufgetragenen Schicht zu vermeiden. Die Herstellung der Elektroden kann aber z.B. auch dadurch erfolgen, daß man Schichten aus den vorangehend beschriebenen Mischungen auf eine elektrisch leitende Unterlage aufwalzt oder diese damit plattiert.The electrodes can be produced by applying a mixture consisting of a fine-grained alloy of niobium with metals from the iron group and fine-grained tantalum, tantalum carbide, tantalum boride or an alloy from tantalum with metals from the iron group with the aid of a plasma torch on an electrically conductive base and the layer thus applied is then doped on the surface with platinum metals, in particular rhodium. The grain size of the metal powder used should be 40 to 100 / um. When applying is in a protective gas atmosphere preferably argon, to avoid oxidation of the applied layer. However, the electrodes can also be produced, for example, by rolling layers of the mixtures described above onto an electrically conductive base or by plating them.
Die auf dem elektrisch leitenden Träger aufgebrachten Schichten sollten bei diesem Verfahren stärker als 0,1 mm sein. Bevorzugt wählt man Schichtdicken zwischen 0,1 und 0,8 mm.The layers applied to the electrically conductive carrier should be thicker than 0.1 mm in this process. Layer thicknesses between 0.1 and 0.8 mm are preferably selected.
Bei der Herstellung von Elektroden ohne Träger geht man z.B. so vor, daß man ein Gemisch aus den feinkörnigen Komponenten mit Hilfe eines Plasmabrenners auf einen Träger aus einem unedlen Metall aufbringt, diesen danach, z.B. durch Behandlung mit Säuren oder Laugen, wieder ablöst und die so erhaltene Schicht dann mit einem Platinmetall dotiert.In the production of electrodes without a carrier, e.g. so that a mixture of the fine-grained components is applied with the aid of a plasma torch to a base made of a base metal, this, e.g. by treatment with acids or bases, detaches again and the layer thus obtained is then doped with a platinum metal.
Zur Dotierung werden die Elektroden mit einer 0,1- bis 10-, insbesondere 0,5- bis 3-gwichtsprozentigen Lösung einer anorganischen Platinmetallverbindung imprägniert und anschließend bei +600 bis +1200°C, vorzugsweise +800 bis +900°C, unter Schutzgasatmosphäre etwa 1 bis 10 Sekunden lang getempert. Als besonders vorteilhaft für die Dotierung hat sich eine wäßrige salzsaure Rhodium(III)-chlorid-Lösung mit einem pH-Wert von 0 bis 0,5 erwiesen. Bei Verwendung dieser Lösung und den eisenhaltigen Niob- bzw. Tantallegierungen erhält man eine besonders stabile Dotierung und saubere Elektrodenoberflächen, da die entstehenden Eisenchloride beim Dotieren sofort absublimieren. Außerdem weisen solche nicht mit Oxiden verunreinigten Elektrodenoberflächen besonders niedrige Überspannungen auf. Die Dotierung selbst muß unter Schutzgasatmosphäre oder im Hochvakuum vorgenommen werden, um eine Oxidation zu vermeiden. Als Schutzgas kommt vorzugsweise Argon in Betracht.For doping, the electrodes are impregnated with a 0.1 to 10, in particular 0.5 to 3, percent by weight solution of an inorganic platinum metal compound and then at +600 to + 1200 ° C, preferably +800 to + 900 ° C, under Protective gas atmosphere annealed for about 1 to 10 seconds. An aqueous hydrochloric acid rhodium (III) chloride solution with a pH of 0 to 0.5 has proven to be particularly advantageous for the doping. When using this solution and the iron-containing niobium or tantalum alloys, a particularly stable doping and clean electrode surfaces are obtained, since the iron chlorides formed sublimate immediately when doping. In addition, such electrode surfaces that are not contaminated with oxides have particularly low overvoltages on. The doping itself must be carried out under a protective gas atmosphere or in a high vacuum in order to avoid oxidation. Argon is preferably used as the protective gas.
Die Fertigung der Elektroden bei Verwendung elektrisch leitender metallischer Trägerkörper kann z.B. auch in der Weise erfolgen, daß zunächst der Trägerkörper entfettet und durch eine chemische Ätzung mit Fluß- oder Oxalsäure bzw. eine Ioneuätzung mit Edelgasen bei niedrigen Drucken von Oxiden befreit wird. Auf den oxidfreien elektrisch leitenden Trägern wird anschließend mit Hilfe von Aufdampf- oder Ionenplattierungsverfahren im Hochvakuum die Schicht aus einer Legierung von Niob mit Metallen der Eisengruppe, gegebenenfalls gleichzeitig mit Tantal oder der Tantalverbindung, aufgetragen. In die Oberfläche dieser Schicht werden durch lonenplattierung oder Implantation im Hochvakuum die Platin-Metalle dotiert.The electrodes can be manufactured using electrically conductive metallic carrier bodies, for example, by first degreasing the carrier body and freeing it from oxides by chemical etching with hydrofluoric or oxalic acid b or ion etching with noble gases at low pressures. The layer of an alloy of niobium with metals of the iron group, optionally simultaneously with tantalum or the tantalum compound, is then applied to the oxide-free, electrically conductive supports with the aid of vapor deposition or ion plating processes in a high vacuum. The platinum metals are doped into the surface of this layer by ion plating or implantation in a high vacuum.
Schließlich kann die Schicht der Nioblegierung mit Metallen der Eisengruppe sowie mit Tantal bzw. Tantalverbindungen, durch Aufdampf-Ionenplattierungs- oder dem Plasmaverfahren gleichzeitig mit Platinmetallen aufgetragen werden. Hierbei hat es sich als günstig erwiesen, wenn der Anteil an Metallen der VIII. Nebengruppe in der Schicht 1/10 bis 1/100 des Gehaltes der Oberfläche beträgt.Finally, the layer of the niobium alloy with metals of the iron group and with tantalum or tantalum compounds, by vapor deposition ion plating or the plasma process can be applied simultaneously with platinum metals. It has proven to be advantageous here if the proportion of metals of subgroup VIII in the layer is 1/10 to 1/100 of the content of the surface.
Ein Titanblech mit den Abmessungen von 30 x 20 x 2 mm wird korundgestrahlt und mite duife des Plasmabrenners einseitig mit einem feinkörnigen Gemenge, bestehend aus 50 Gewichtsteilen einer Lesiarung mit 95 Gewichtsprozent Niob und 5 Gewichtsprozent 88 en und 50 Gewichtsteilen Tantal, etwa 0,25 mm dick besahichtet.A titanium sheet with the dimensions of 30 x 20 x 2 mm is blasted with corundum and one side of the plasma torch with a fine-grain mixture consisting of 50 parts by weight of a lesiaration with 95% by weight of niobium and 5% by weight of 88 s and 50 parts by weight of tantalum, about 0.25 mm thick sighted.
Die beschichtete Seite wird anschließend mit einer 1,5 gewichtsprozentigen Rhodium(III)-chlorid-Lösung (berechnet als RhCl3), pH-Wert = 0,2, imprägniert. Nach dem Trocknen erhitzt man diese Schicht etwa 2 Sekunden lang mit einem Argon-Stickstoff-Plasma auf etwa +900°C und kühlt mit Argon wieder auf Raumtemperatur ab.The coated side is then impregnated with a 1.5 percent by weight rhodium (III) chloride solution (calculated as RhCl 3 ), pH = 0.2. After drying, this layer is heated to about + 900 ° C. for about 2 seconds with an argon-nitrogen plasma and cooled again to room temperature with argon.
Die fertige Anode eignet sich vorzugsweise zur Elektrolyse von Farbstoffabwässern, Alkalichloridlösungen und Schwefelsäure. Die Überspannung in wäßriger Alkaliehloridlösung beträgt etwa 30 mV bei einer Belastung von 2,3 kA/m2 (Anodenoberfläche).The finished anode is preferably suitable for the electrolysis of dye waste water, alkali chloride solutions and sulfuric acid. The overvoltage in aqueous alkali chloride solution is approximately 30 mV at a load of 2.3 kA / m 2 (anode surface).
Ein Titanstreckmetallnetz mit den Abmessungen von 240 x 240 mm wird entfetter und durch eine Icnenätzung mit Argon im Vakuum von Oxiden befreit. Auf die oxidfreie Oberfläche wird anschließend eine 2 000 Å dicke Niob-Eisenschicht (mit 3 Gewichtsprozent Eisen) aufgetragen.A titanium expanded metal mesh with the dimensions of 240 x 240 mm is degreased and oxides are removed by etching with argon in vacuo. Then a 2,000 Å thick niobium iron layer (with 3 weight percent iron) is applied to the oxide-free surface.
Anschließend wird die Oberfläche durch Ionenplattierung mit Rhodium dotiert. Der Rhodiumgehalt auf der Elektrode beträgt ~0,34 g/m2. Die Elektrode kann als Anode zur Elektrolyse von Alkalichloridlosungen und Salzsäure verwendet werden. Nach einer Betriebsdauer von 50 Tagen bei einer Stromdichte von 15 kA/m2 ist kein Anstieg der Überspannung festzustellen. Bei Kurzschlüssen mit der Quecksilberkathode tritt keine Absenkung der Wasserstoffüberspannung auf.The surface is then doped with rhodium by ion plating. The rhodium content on the electrode is ~ 0.34 g / m 2 . The electrode can be used as an anode for the electrolysis of alkali chloride solutions and hydrochloric acid. After an operating period of 50 days at a current density of 15 kA / m 2 , there is no increase in the overvoltage. In the event of short circuits with the mercury cathode, there is no reduction in the hydrogen overvoltage.
Claims (1)
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE2750029 | 1977-11-09 | ||
| DE19772750029 DE2750029A1 (en) | 1977-11-09 | 1977-11-09 | ELECTRODES FOR ELECTROLYSIS PURPOSES |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0001778A2 true EP0001778A2 (en) | 1979-05-16 |
| EP0001778A3 EP0001778A3 (en) | 1979-05-30 |
Family
ID=6023309
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP78101152A Withdrawn EP0001778A3 (en) | 1977-11-09 | 1978-10-14 | Electrodes for electrolytic purposes |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US4212725A (en) |
| EP (1) | EP0001778A3 (en) |
| BE (1) | BE33T1 (en) |
| DE (1) | DE2750029A1 (en) |
| FR (1) | FR2436195A1 (en) |
| GB (1) | GB2058838B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4316787A (en) * | 1979-08-06 | 1982-02-23 | Themy Constantinos D | High voltage electrolytic cell |
| JPS6022074B2 (en) * | 1982-08-26 | 1985-05-30 | ペルメレツク電極株式会社 | Durable electrolytic electrode and its manufacturing method |
| JPS6022075B2 (en) * | 1983-01-31 | 1985-05-30 | ペルメレック電極株式会社 | Durable electrolytic electrode and its manufacturing method |
| EP0300452B1 (en) * | 1987-07-23 | 1991-11-06 | Asahi Glass Company Ltd. | Field formation apparatus |
| WO2006133709A2 (en) * | 2005-06-15 | 2006-12-21 | Danfoss A/S | A corrosion resistant object having an outer layer of a precious metal |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1290488A (en) * | 1960-04-30 | 1962-04-13 | Hoechst Ag | Metal anode for the electrolytic separation of chlorine |
| DE1927059A1 (en) * | 1968-05-28 | 1970-05-27 | Gwynn Ross Merton | Electrode and process for its manufacture |
| DE1812522A1 (en) * | 1968-12-04 | 1970-06-18 | Basf Ag | Anode for alkali chloride electrolysis |
| DE2346055B2 (en) * | 1973-09-13 | 1975-07-24 | Basf Ag, 6700 Ludwigshafen | Anodes for electrolysis purposes |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3915838A (en) * | 1968-04-02 | 1975-10-28 | Ici Ltd | Electrodes for electrochemical processes |
-
1977
- 1977-11-09 DE DE19772750029 patent/DE2750029A1/en not_active Ceased
-
1978
- 1978-10-14 EP EP78101152A patent/EP0001778A3/en not_active Withdrawn
- 1978-10-14 GB GB7935270A patent/GB2058838B/en not_active Expired
- 1978-10-14 BE BEBTR33A patent/BE33T1/en not_active IP Right Cessation
- 1978-10-30 US US05/955,580 patent/US4212725A/en not_active Expired - Lifetime
-
1979
- 1979-09-17 FR FR7923304A patent/FR2436195A1/en active Granted
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1290488A (en) * | 1960-04-30 | 1962-04-13 | Hoechst Ag | Metal anode for the electrolytic separation of chlorine |
| DE1927059A1 (en) * | 1968-05-28 | 1970-05-27 | Gwynn Ross Merton | Electrode and process for its manufacture |
| DE1812522A1 (en) * | 1968-12-04 | 1970-06-18 | Basf Ag | Anode for alkali chloride electrolysis |
| DE2346055B2 (en) * | 1973-09-13 | 1975-07-24 | Basf Ag, 6700 Ludwigshafen | Anodes for electrolysis purposes |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0001778A3 (en) | 1979-05-30 |
| GB2058838B (en) | 1983-04-20 |
| GB2058838A (en) | 1981-04-15 |
| US4212725A (en) | 1980-07-15 |
| BE33T1 (en) | 1979-12-07 |
| DE2750029A1 (en) | 1979-05-10 |
| FR2436195B1 (en) | 1984-01-27 |
| FR2436195A1 (en) | 1980-04-11 |
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Inventor name: HABERMANN, WOLFGANG Inventor name: THOMA, PETER, DR. Inventor name: WINTERMANTEL, KLAUS, DR. |