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EP0249650A1 - Electrolyte for electrochemically polishing metal surfaces - Google Patents

Electrolyte for electrochemically polishing metal surfaces Download PDF

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Publication number
EP0249650A1
EP0249650A1 EP86108474A EP86108474A EP0249650A1 EP 0249650 A1 EP0249650 A1 EP 0249650A1 EP 86108474 A EP86108474 A EP 86108474A EP 86108474 A EP86108474 A EP 86108474A EP 0249650 A1 EP0249650 A1 EP 0249650A1
Authority
EP
European Patent Office
Prior art keywords
electrolyte
acid
aluminum
polishing
electrolyte according
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP86108474A
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German (de)
French (fr)
Other versions
EP0249650B1 (en
Inventor
Friedrich Ruhstorfer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Poligrat-Holding Te Muenchen Bon GmbH
Original Assignee
Poligrat GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Poligrat GmbH filed Critical Poligrat GmbH
Priority to AT86108474T priority Critical patent/ATE48661T1/en
Priority to EP86108474A priority patent/EP0249650B1/en
Priority to DE8686108474T priority patent/DE3667505D1/en
Priority to US07/064,095 priority patent/US4740280A/en
Priority to JP62151525A priority patent/JPS634100A/en
Publication of EP0249650A1 publication Critical patent/EP0249650A1/en
Application granted granted Critical
Publication of EP0249650B1 publication Critical patent/EP0249650B1/en
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Classifications

    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25F—PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
    • C25F3/00—Electrolytic etching or polishing
    • C25F3/16—Polishing
    • C25F3/18—Polishing of light metals
    • C25F3/20—Polishing of light metals of aluminium
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25F—PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
    • C25F3/00—Electrolytic etching or polishing
    • C25F3/16—Polishing
    • C25F3/22—Polishing of heavy metals
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25F—PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
    • C25F3/00—Electrolytic etching or polishing
    • C25F3/16—Polishing
    • C25F3/22—Polishing of heavy metals
    • C25F3/24—Polishing of heavy metals of iron or steel

Definitions

  • the electrochemical polishing or glossing of metal surfaces is widely used in technology to treat smaller or larger objects made of steel, stainless steel, nickel alloys as well as aluminum and aluminum alloys on the surface.
  • the electrolytes used here usually contain phosphoric and sulfuric acid and optionally chromic acid, the workpieces being switched anodically.
  • the objects to be polished which hang on corresponding support elements or are arranged in baskets or the like, are inserted into the electrolyte, i.e. the polishing bath, sunk and lifted out of it after a certain polishing time. After the bath liquid has drained off the polished surfaces, the objects are then immersed in rinsing baths in order to remove the electrolyte.
  • Electrolytes containing sulfuric acid / phosphoric acid and optionally chromic acid are used for the electrochemical polishing of steel, in particular stainless steel, and nickel alloys.
  • the gloss that can be achieved by electrochemical polishing largely depends on the degree of leveling, which is improved with increasing polishing time.
  • satisfactory results are generally achieved at a current density of approximately 25 A / dm2 in 7 minutes or of approximately 10 A / dm2 in approximately 20 minutes.
  • the object of the invention is to provide a chromic acid-free electrolyte for electrochemical deburring and polishing, that is to say To provide electrolytic or electrochemical removal of metal unevenness from the surface of moldings made of aluminum and aluminum alloys on the one hand and steel, stainless steel and nickel alloys on the other hand, which in aluminum and aluminum alloys provides protection against the subsequent etching and matting of the treated surfaces before the electrolyte is rinsed off brings freshly polished surface and gives high shine to steel, stainless steel and nickel alloys.
  • chelating agents based on phosphonic acids - preferably in an amount of 1 to 100 g / l - are added to the electrolyte containing sulfuric and phosphoric acid.
  • 20 to 30 g / l is preferred for the aluminum electrolyte and 10 to 20 g / l of phosphonic acid, based on the acid electrolyte, is preferred for the electrolyte for workpieces made of steel or nickel alloys.
  • the phosphonic acid additive according to the invention achieves the desired gloss in a much shorter time than was possible with the known electrolytes when electrochemically polishing objects made of steel, stainless steel or nickel alloy.
  • This reduced polishing time - reductions of around 30% are easy to achieve - leads to a lower metal removal overall and thus to a longer working capacity of the electrolyte.
  • Morpholinomethane diphosphonic acid of the general formula proved to be a particularly advantageous phosphonic acid for the purpose according to the invention: But 1-hydroxyethane-1,1-diphosphonic acid, aminotrismethylenephosphonic acid, diethylenetriamine-pentamethylenephosphonic acid and hydroxymethyldiphosphonic acid are also very suitable.
  • the polishing of aluminum and aluminum alloys is carried out with a current density of 5 to 15 A / dm2, preferably 8 to 10 A / dm2, a polishing time of 15 to 20 minutes and an electrolyte temperature of about 80 ° C.
  • the current density should be 10 to 15 A / dm2, preferably about 15 A / dm2, at about 50 ° C and for nickel alloys 5 to 30 A / dm2 at temperatures of the same order of magnitude with a polishing time of approx. 15 min .
  • phosphonic acid to acidic electrolytes can be improved in difficult working conditions, such as very high working temperatures and thus increased aggressiveness of the electrolyte, by adding satbilizers.
  • Such stabilizers are nitrilotriacetic acid, in particular its sodium salt, in a concentration of 0.5 to 2% by weight, in particular approximately 1% by weight, and sodium glucoheptonate in a concentration of 0.5 to 2% by weight, in particular approximately 1% by weight, particularly proven.
  • An electrolyte was used to polish objects made of aluminum or an aluminum alloy 900 cm3 / l phosphoric acid (85% by weight) and 100 cm3 / l sulfuric acid (96% by weight) used with an addition of 25 g / l morpholinomethane diphosphonic acid and polished for 10 min at a current density of 9 A / dm2 and 80 ° C.
  • the objects were then lifted out of the polishing bath; the electrolyte could run off at rest without the surface being etched after 60 s.
  • the objects were then rinsed acid-free. This time can be extended by increasing the amount of phosphonic acid.
  • the etching begins after 3 s.
  • Electrolyte for nickel alloys 600 cm3 / l phosphoric acid (85% by weight) 400 cm3 / l sulfuric acid (96% by weight) 30 g / l diethylenetriamine-pentamethylenephosphonic acid Current density 15 A / dm2 Polishing time 7 min

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • ing And Chemical Polishing (AREA)
  • Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)

Abstract

The electrolyte according to the invention for electrochemically polishing articles made of steel, stainless steel, nickel alloys, aluminum, and aluminum alloys, and containing phosphoric acid and sulfuric acid comprises an addition of a chelating agent on the basis of phosphonic acids and, if desired, a stabilizer for the latter.

Description

Das elektrochemische Polieren oder Glänzen von Metallober­flächen wird in der Technik vielfach angewendet, um kleinere oder größere Gegenstände aus Stahl, Edelstahl, Nickellegierun­gen sowie Aluminium und Aluminiumlegierungen oberflächlich zu behandeln. Die hierbei verwendeten Elektrolyte enthalten in der Regel Phosphor- und Schwefelsäure und gegebenenfalls Chromsäu­re, wobei die Werkstücke anodisch geschaltet werden. Bei diesem Elektropolieren werden die zu polierenden Gegenstände, die an entsprechenden Tragelementen hängen oder in Körben oder der­gleichen angeordnet sind, in den Elektrolyt, d.h. das Polier­bad, eingesenkt und nach einer gewissen Polierzeit aus diesem herausgehoben. Nach dem Abfließen der Bad-Flüssigkeit von den polierten Oberflächen werden anschließend die Gegenstände in Spülbäder getaucht, um den Elektrolyt zu entfernen.The electrochemical polishing or glossing of metal surfaces is widely used in technology to treat smaller or larger objects made of steel, stainless steel, nickel alloys as well as aluminum and aluminum alloys on the surface. The electrolytes used here usually contain phosphoric and sulfuric acid and optionally chromic acid, the workpieces being switched anodically. In this electropolishing, the objects to be polished, which hang on corresponding support elements or are arranged in baskets or the like, are inserted into the electrolyte, i.e. the polishing bath, sunk and lifted out of it after a certain polishing time. After the bath liquid has drained off the polished surfaces, the objects are then immersed in rinsing baths in order to remove the electrolyte.

Für das elektrochemische Polieren von Aluminium und Aluminium­legierungen werden nach dem Stand der Technik Elektrolyte auf der Basis Schwefelsäure/Phosphorsäure/Chromsäure eingesetzt. Die Chromsäure soll durch ihre inhibitorische Wirkung ein Anätzen des Aluminiums im stromlosen Zustand verhindern, hat aber zwei Nachteile.

  • a) Während des elektrochemischen Polierens wird ein gewisser Anteil an Chromsäure zu Chrom-(III)-ionen reduziert, die sich mit der Zeit im Elektrolyten anreichern. Ab etwa 2 Gew.-% Chrom-(III)-ionen wird der Poliervorgang beinträch­tigt.
  • b) Chrom-(III)-ionen gelangen mit dem Spülwasser in das Abwas­wasser und erfordern wegen ihrer hohen Giftigkeit eine be­besondere Stufe in der Abwasseraufbereitung zur Reduzierung zu Chrom-(III)-ionen, die weniger giftig sind.
According to the prior art, electrolytes based on sulfuric acid / phosphoric acid / chromic acid are used for the electrochemical polishing of aluminum and aluminum alloys. The inhibitory effect of chromic acid is to prevent the aluminum from being etched in the currentless state, but has two disadvantages.
  • a) During electrochemical polishing, a certain proportion of chromic acid is reduced to chromium (III) ions, which accumulate in the electrolyte over time. From about 2% by weight of chromium (III) ions, the polishing process is impaired.
  • b) Chromium (III) ions get into the wastewater with the rinsing water and, because of their high toxicity, require a special step in the wastewater treatment to reduce to chromium (III) ions, which are less toxic.

Daher war man bestrebt, chromsäurefreie Elektrolyte anzuwenden, bei denen jedoch das Problem der raschen Anätzung der polierten Oberflächen im stromlosen Zustand auftritt. Ein solches nach­trägliches Anätzen ist aber sehr unerwünscht, weil es zum Mattieren der bereits polierten Oberfläche führt und dadurch sowohl das dekorative Aussehen der glänzenden Oberfläche gestört als auch durch die damit verbundene Aufrauhung der Oberfläche deren Widerstandsfähigkeit bei der späteren Anwendung der Gegenstände beeinträchtigt wird. Um dies zu vermeiden, ist schnelles Überheben aus dem Elektrolyten in das Spülbad not­wendig. Dies führt wiederum zu einer hohen Elektrolytverschlep­pung und damit hohem Chemikalienverbrauch mit entsprechender Belastung und Verteuerung der Abwasseraufbereitung.Therefore, efforts have been made to use chromic acid-free electrolytes, which, however, have the problem of rapid etching of the polished surfaces in the currentless state. Such a subsequent etching is very undesirable because it leads to the matting of the already polished surface and thereby both disturbs the decorative appearance of the glossy surface and is impaired by the roughening of the surface associated with this, its resistance to later use of the objects. To avoid this, quick lifting from the electrolyte into the rinsing bath is necessary. This in turn leads to a high carryover of electrolytes and thus a high consumption of chemicals with a corresponding burden and increase in the cost of wastewater treatment.

Zum elektrochemischen Polieren von Stahl, insbesondere Edel- stahl, sowie Nickellegierungen werden Elektrolyte enthaltend Schwefelsäure/Phosphorsäure und gegebenenfalls Chromsäure eingesetzt. Der durch das elektrochemische Polieren erzielbare Glanz ist weitgehend abhängig vom Grad der Einebnung, die mit zunehmender Polierdauer verbessert wird. Zufriedenstellende Ergebnisse werden je nach Zusammensetzung des Elektrolyten in der Regel bei einer Stromdichte von etwa 25 A/dm² in 7 min bzw. von etwa 10 A/dm² in ca. 20 min erreicht.Electrolytes containing sulfuric acid / phosphoric acid and optionally chromic acid are used for the electrochemical polishing of steel, in particular stainless steel, and nickel alloys. The gloss that can be achieved by electrochemical polishing largely depends on the degree of leveling, which is improved with increasing polishing time. Depending on the composition of the electrolyte, satisfactory results are generally achieved at a current density of approximately 25 A / dm² in 7 minutes or of approximately 10 A / dm² in approximately 20 minutes.

Aufgabe der Erfindung ist es, einen chromsäurefreien Elektroly­ten zum elektrochemischen Entgraten und Polieren, also zum elektrolytischen oder elektrochemischen Abtrag von Metall-­Unebenheiten von der Oberfläche von Formkörpern aus Aluminium und Aluminiumlegierungen einerseits und Stahl, Edelstahl und Nickellegierungen andererseits bereitzustellen, welcher bei Aluminium und Aluminiumlegierungen einen Schutz gegen das nachträgliche Ätzen und Mattieren der behandelten Oberflächen vor dem Abspülen des Elektrolyten von der frisch polierten Oberfläche bringt und bei Stahl, Edelstahl und Nickellegie­rungen hohen Glanz ergibt.The object of the invention is to provide a chromic acid-free electrolyte for electrochemical deburring and polishing, that is to say To provide electrolytic or electrochemical removal of metal unevenness from the surface of moldings made of aluminum and aluminum alloys on the one hand and steel, stainless steel and nickel alloys on the other hand, which in aluminum and aluminum alloys provides protection against the subsequent etching and matting of the treated surfaces before the electrolyte is rinsed off brings freshly polished surface and gives high shine to steel, stainless steel and nickel alloys.

Diese Aufgaben werden erfindungsgemäß nun dadurch gelöst, daß dem Elektrolyten enthaltend Schwefel- und Phosphorsäure Chelat­bildner auf der Basis von Phosphonsäuren - vorzugsweise in einer Menge von 1 bis 100 g/l - zugesetzt sind.These objects are now achieved according to the invention in that chelating agents based on phosphonic acids - preferably in an amount of 1 to 100 g / l - are added to the electrolyte containing sulfuric and phosphoric acid.

Für den Aluminium-Elektrolyten bevorzugt man 20 bis 30 g/l und für den Elektrolyten für Werkstücke aus Stahl oder Nickellegie­rungen 10 bis 20 g/l Phosphonsäure, bezogen auf den Säure-Elek­trolyten.20 to 30 g / l is preferred for the aluminum electrolyte and 10 to 20 g / l of phosphonic acid, based on the acid electrolyte, is preferred for the electrolyte for workpieces made of steel or nickel alloys.

Es ist sehr überraschend, daß derartige Phosphonsäurezusätze zu dem Elektrolyten auf die frisch polierte Metallfläche eine Inhibitor-Wirkung haben, durch die das Anätzen von Aluminium-­Werkstücken im stromlosen Zustand bei der Überführung aus dem Elektrolyten in die Spülbader weitestgehend herabgesetzt ist. Man hat daher mit dem erfindungsgemäßen Elektrolyt die Möglich­keit, die frisch polierten Gegenstände aus dem Elektrolyt herauszuheben, ablaufen zu lassen und dann erst in das erste Spülbad zu tauchen, ohne die Gefahr des Anätzens und des Einschleppens von großen Säuremengen in das Spülbad.It is very surprising that such phosphonic acid additions to the electrolyte on the freshly polished metal surface have an inhibiting effect, by means of which the etching of aluminum workpieces in the currentless state is largely reduced when they are transferred from the electrolyte to the rinsing bath. It is therefore possible with the electrolyte according to the invention to lift the freshly polished objects out of the electrolyte, to allow them to run off and only then to immerse them in the first rinsing bath without the risk of large amounts of acid being etched into the rinsing bath.

Ebenso überraschend ist es, daß durch den erfindungsgemäßen Phosphonsäurezusatz beim elektrochemischen Polieren von Gegenständen aus Stahl, Edelstahl oder Nickellegierung der angestrebte Glanz in viel kürzerer Zeit erreicht wird, als dies mit den bekannten Elektrolyten möglich war. Diese verkürzte Polierzeit - Verkürzungen um etwa 30 % sind leicht zu erreichen - führt zu einem geringeren Metallabtrag insgesamt und dadurch zu längerer Arbeitsfähigkeit des Elektrolyten.It is also surprising that the phosphonic acid additive according to the invention achieves the desired gloss in a much shorter time than was possible with the known electrolytes when electrochemically polishing objects made of steel, stainless steel or nickel alloy. This reduced polishing time - reductions of around 30% are easy to achieve - leads to a lower metal removal overall and thus to a longer working capacity of the electrolyte.

Als besonders vorteilhafte Phosphonsäure für den erfindungsge­mäßen Zweck erwies sich Morpholinomethandiphosphonsäure der allgemeinen Formel:

Figure imgb0001
Aber auch 1-Hydroxyethan-1,1-diphosphonsäure, Aminotris­methylenphosphonsäure, Diethylentriamin-pentamethylenphosphon­säure und Hydroxymethyldiphosphonsäure sind sehr geeignet.Morpholinomethane diphosphonic acid of the general formula proved to be a particularly advantageous phosphonic acid for the purpose according to the invention:
Figure imgb0001
 But 1-hydroxyethane-1,1-diphosphonic acid, aminotrismethylenephosphonic acid, diethylenetriamine-pentamethylenephosphonic acid and hydroxymethyldiphosphonic acid are also very suitable.

Beim elektrolytischen Polieren kommt es durch Wasser-Elektroly­se zur Wasserstoff- und Sauerstoffentwicklung. Es it bekannt, daß diese Gase, besonders in statu nascendi, außerordentlich aggresiv sind. Es ist daher erforderlich, daß alle Zusätze zu dem Elektrolyten eine außerordentlich hohe Stabilität, insbeson­dere Reduktions- und Oxidations-Stabilität, besitzen. Falls es dennoch zu einer geringfügigen Zersetzung kommen sollte, so sind die Zusätze im Hinblick darauf auszuwählen, daß diese Zersetzungsprodukte nicht toxisch und insbesondere cancerogen sein dürfen. Im Hinblick auf diese Anforderungen, insbesondere der Stabilität gegenüber nascierendem Sauerstoff und Wasser­stoff, ist nun gerade die Morpholinomethandiphosphonsäure für den erfindungsgemäßen Elektrolyt besonders geeignet.In electrolytic polishing, hydrogen and oxygen are evolved through water electrolysis. It is known that these gases, particularly in statu nascendi, are extremely aggressive. It is therefore necessary that all additives to the electrolyte have an extremely high stability, in particular reduction and oxidation stability. If there is nevertheless slight decomposition, the additives should be selected with a view to the fact that these decomposition products must not be toxic and in particular carcinogenic. In view of these requirements, in particular the stability to nascent oxygen and hydrogen, morpholinomethane diphosphonic acid is now particularly suitable for the electrolyte according to the invention.

Die Wirkung dieser chelatbildenden Phosphonsäuren beim elektro­lytischen Polieren oder Entgraten von Metalloberflächen ist deshalb so überraschend, weil Chelatbildner in elektrolytischen Bädern für die Elektroplattierung, d.h. also bei der elektro­lytischen Abscheidung von Metallüberzügen, insbesondere von Gold und anderen Edelmetallen sowie deren Legierungen, auf kathodisch geschalteten Gegenständen verwendet wurden, um besonders fest haftende Überzüge und Metallabscheidungen zu erhalten.The effect of these chelating phosphonic acids in the electrolytic polishing or deburring of metal surfaces is so surprising because chelating agents in electrolytic baths for electroplating, i.e. thus in the electrolytic deposition of metal coatings, in particular of gold and other precious metals and their alloys, on cathodically connected objects, in order to obtain particularly firmly adhering coatings and metal deposits.

Im allgemeinen arbeitet man für das Polieren von Aluminium und Aluminiumlegierungen mit einer Stromdichte von 5 bis 15 A/dm², vorzugsweise 8 bis 10 A/dm², einer Polierzeit von 15 bis 20 min und einer Elektrolyt-Temperatur von etwa 80°C. Für Stahl und Edelstahl soll die Stromdichte 10 bis 15 A/dm², vorzugsweise etwa 15 A/dm² , bei etwa 50°C und für Nickellegierungen 5 bis 30 A/dm² bei Temperaturen in der gleichen Größenordnung sein bei einer Polierzeit von ca. 15 min.In general, the polishing of aluminum and aluminum alloys is carried out with a current density of 5 to 15 A / dm², preferably 8 to 10 A / dm², a polishing time of 15 to 20 minutes and an electrolyte temperature of about 80 ° C. For steel and stainless steel, the current density should be 10 to 15 A / dm², preferably about 15 A / dm², at about 50 ° C and for nickel alloys 5 to 30 A / dm² at temperatures of the same order of magnitude with a polishing time of approx. 15 min .

Die an sich gute Beständigkeit von Phosphonsäure gegenüber sauren Elektrolyten kann bei erschwerten Arbeitsbedingungen, wie sehr hoher Arbeitstemperatur und dadurch erhöhte Aggres­sivität des Elektrolyten, durch den Zusatz von Satbilisatoren noch verbessert werden. Als derartige Stabilisatoren haben sich Nitrilotriessigsäure, insbesondere deren Natriumsalz, in einer Konzentration von 0,5 bis 2 Gew-%, insbesondere etwa 1 Gew.-%, und Natriumglukoheptonat in einer Konzentration von 0,5 bis 2 Gew.-%, insbesondere etwa 1 Gew-%, besonders bewährt.The inherently good resistance of phosphonic acid to acidic electrolytes can be improved in difficult working conditions, such as very high working temperatures and thus increased aggressiveness of the electrolyte, by adding satbilizers. Such stabilizers are nitrilotriacetic acid, in particular its sodium salt, in a concentration of 0.5 to 2% by weight, in particular approximately 1% by weight, and sodium glucoheptonate in a concentration of 0.5 to 2% by weight, in particular approximately 1% by weight, particularly proven.

Die Erfindung wird an folgenden Beispielen weiter erläutert.The invention is further illustrated by the following examples.

Beispiel 1example 1

Zum Polieren von Gegenständen aus Aluminium bzw. einer Aluminiumlegierung wurde ein Elektrolyt enthaltend
900 cm³/l Phosphorsäure (85 gew.-%-ig) und
100 cm³/l Schwefelsäure (96 gew.-%-ig)
mit einem Zusatz von 25 g/l Morpholinomethandiphosphonsäure verwendet und bei einer Stromdichte von 9 A/dm² und 80°C 10 min poliert. Die Gegenstände wurden dann aus dem Polierbad heraus­gehoben; der Elektrolyt konnte in Ruhe ablaufen, ohne daß nach 60 s eine Anätzung der Oberfläche festgestellt werden konnte. Anschließend wurden die Gegenstände säurefrei gespült. Durch Erhöhung der Phosphonsäuremenge kann diese Zeit noch verlängert werden.An electrolyte was used to polish objects made of aluminum or an aluminum alloy
900 cm³ / l phosphoric acid (85% by weight) and
100 cm³ / l sulfuric acid (96% by weight)
used with an addition of 25 g / l morpholinomethane diphosphonic acid and polished for 10 min at a current density of 9 A / dm² and 80 ° C. The objects were then lifted out of the polishing bath; the electrolyte could run off at rest without the surface being etched after 60 s. The objects were then rinsed acid-free. This time can be extended by increasing the amount of phosphonic acid.

Wird jedoch ein Elektrolyt ohne dem erfindungsgemäßen Zusatz verwendet, so beginnt das Anätzen bereits nach 3 s.However, if an electrolyte is used without the additive according to the invention, the etching begins after 3 s.

Beispiel 2Example 2

Einem Elektrolyt enthaltend 660 cm³/l Phosphorsäure (85 gew.-%-ig) und 340 cm³/l Schwefelsäure (96 gew.-%-ig) wurden 10 g/l Morpholinomethandiphosphonsäure sowie 1 Gew.-% Nitrilotri­essigsäure zugesetzt und darin Gegenstände aus Edelstahl poliert. Man erhielt bei einer Stromdichte von 15 A/dm² und 50°C in einer Polierzeit von 6 bis 7 min einwandfreien Glanz.10 g / l of morpholinomethane diphosphonic acid and 1% by weight of nitrilotriacetic acid were added to an electrolyte containing 660 cm 3 / l of phosphoric acid (85% by weight) and 340 cm 3 / l of sulfuric acid (96% by weight), and 1% by weight of nitrilotriacetic acid and objects therein Polished stainless steel. A perfect gloss was obtained at a current density of 15 A / dm 2 and 50 ° C. in a polishing time of 6 to 7 minutes.

In einem Elektrolyten ohne dem Phosphonsäurezusatz benötigte man für den gleichen Glanz 10 min.In an electrolyte without the addition of phosphonic acid, it took 10 minutes for the same gloss.

Beispiel 3Example 3

Elektrolyt für Nickellegierungen:
600 cm³/l Phosphorsäure (85 gew.-%-ig)
400 cm³/l Schwefelsäure (96 gew.-%-ig)
30 g/l Diethylentriamin-pentamethylen­phosphonsäure
Stromdichte 15 A/dm²
Polierzeit 7 minElectrolyte for nickel alloys:
600 cm³ / l phosphoric acid (85% by weight)
400 cm³ / l sulfuric acid (96% by weight)
30 g / l diethylenetriamine-pentamethylenephosphonic acid
Current density 15 A / dm²
Polishing time 7 min

Wird jedoch ein Elektrolyt ohne dem erfindungsgemäßen Zusatz verwendet, so benötigt man für den gleichen Glanz etwa 10,5 min.However, if an electrolyte is used without the additive according to the invention, about 10.5 minutes are required for the same gloss.

Claims (6)

1. Elektrolyt zum elektrochemischen Polieren von Gegenständen aus Stahl, Edelstahl, Nickellegierungen, Aluminium und Aluminiumlegierungen enthaltend Phosphorsäure und Schwefelsäure,
gekennzeichnet durch
einen Zusatz an einem Chelatbildner auf der Basis von Phosphonsäuren.1. electrolyte for the electrochemical polishing of objects made of steel, stainless steel, nickel alloys, aluminum and aluminum alloys containing phosphoric acid and sulfuric acid,
characterized by
an addition to a chelating agent based on phosphonic acids. 2. Elektrolyt nach Anspruch 1,
dadurch gekennzeichnet,
daß das Bad 1 bis 100 g/l Chelatbildner enthält.2. Electrolyte according to claim 1,
characterized by
that the bath contains 1 to 100 g / l chelating agent. 3. Elektrolyt nach Anspruch 1 oder 2,
dadurch gekennzeichnet,
daß der Chelatbildner Morpholinomethandiphosphonsäure ist.3. electrolyte according to claim 1 or 2,
characterized by
that the chelating agent is morpholinomethane diphosphonic acid. 4. Elektrolyt nach Anspruch 1 bis 3,
dadurch gekennzeichnet,
daß er zusätzlich einen Stabilisator für die Phosphonsäure enthält.4. electrolyte according to claim 1 to 3,
characterized by
that it also contains a stabilizer for the phosphonic acid. 5. Elektrolyt nach Anspruch 4,
dadurch gekennzeichnet,
daß er 0,5 bis 2 Gew.-% Stabilisator enthält.5. electrolyte according to claim 4,
characterized by
that it contains 0.5 to 2 wt .-% stabilizer. 6. Elektrolyt nach Anspruch 4 oder 5,
dadurch gekennzeichnet,
daß der Stabilisator Nitrilotriessigsäure oder deren Salz oder Natriumglukoheptonat ist.6. electrolyte according to claim 4 or 5,
characterized by
that the stabilizer is nitrilotriacetic acid or its salt or sodium glucoheptonate.
EP86108474A 1986-06-20 1986-06-20 Electrolyte for electrochemically polishing metal surfaces Expired EP0249650B1 (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
AT86108474T ATE48661T1 (en) 1986-06-20 1986-06-20 ELECTROLYTE FOR ELECTROCHEMICAL POLISHING OF METAL SURFACES.
EP86108474A EP0249650B1 (en) 1986-06-20 1986-06-20 Electrolyte for electrochemically polishing metal surfaces
DE8686108474T DE3667505D1 (en) 1986-06-20 1986-06-20 ELECTROLYT FOR ELECTROCHEMICAL POLISHING OF METAL SURFACES.
US07/064,095 US4740280A (en) 1986-06-20 1987-06-18 Electrolyte for electrochemically polishing metal surfaces
JP62151525A JPS634100A (en) 1986-06-20 1987-06-19 Electrolyte for electrochemical polishing of metal surface

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP86108474A EP0249650B1 (en) 1986-06-20 1986-06-20 Electrolyte for electrochemically polishing metal surfaces

Publications (2)

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EP0249650A1 true EP0249650A1 (en) 1987-12-23
EP0249650B1 EP0249650B1 (en) 1989-12-13

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EP86108474A Expired EP0249650B1 (en) 1986-06-20 1986-06-20 Electrolyte for electrochemically polishing metal surfaces

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US (1) US4740280A (en)
EP (1) EP0249650B1 (en)
JP (1) JPS634100A (en)
AT (1) ATE48661T1 (en)
DE (1) DE3667505D1 (en)

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WO1992020841A1 (en) * 1991-05-15 1992-11-26 Sandvik Ab Etching process
WO2005004941A1 (en) * 2003-07-08 2005-01-20 Poligrat Gmbh Cementable endoprostheses
WO2007017156A1 (en) * 2005-08-09 2007-02-15 Poligrat Gmbh Electropolishing method

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DE19514272C2 (en) * 1995-04-21 1997-02-20 Amtra Aquaristik Gmbh Means and methods for regulating the hardness and pH of the water in freshwater aquariums
SE511777C2 (en) * 1998-02-02 1999-11-22 Avesta Sheffield Ab Method of processing a metal product
KR20030003838A (en) * 2001-07-04 2003-01-14 이은상 Method and apparatus of the electrochemical fusion machining of micro grooves and mirror-like surface for air lubricated hydrodynamic bearings
DE10151180B4 (en) * 2001-10-17 2010-05-12 Nowack, Norbert, Prof. Dr.-Ing. Process and solution for delamination of metallic objects with nickel corrosion protection coating
CN1908248B (en) * 2006-07-26 2012-09-05 沈阳工业大学 Precision polishing technique for stainless steel printed circuit board
DE102007011632B3 (en) * 2007-03-09 2008-06-26 Poligrat Gmbh Method for electropolishing and/or electrochemical deburring of surfaces made from titanium or titanium-containing alloys comprises using an electrolyte made from methane sulfonic acid or one or more alkane diphosphonic acids
SI2225175T1 (en) * 2007-12-12 2013-04-30 Akzo Nobel N.V. Stabilized hydrogen peroxide solutions
US20100215926A1 (en) 2009-02-25 2010-08-26 Askin Albert L Aluminum alloy substrates having a multi-color effect and methods for producing the same
JP5917909B2 (en) * 2011-12-27 2016-05-18 株式会社中野科学 Method for electrolytic polishing of aluminum members
CN103436947B (en) * 2013-09-13 2016-01-20 上海化工研究院 The electrochemical polishing method of coating conductor Ni-5at.%W alloy base band
EP2878713A1 (en) * 2013-11-28 2015-06-03 Abbott Laboratories Vascular Enterprises Limited Electrolyte composition and method for the electropolishing treatment of Nickel-Titanium alloys and/or other metal substrates including tungsten, niob and tantal alloys
PL3186417T3 (en) 2014-08-29 2018-11-30 Poligrat Gmbh Electrolyte for polishing of high-grade steels, comprising a pyridine carboxylic acid
CN104532338A (en) * 2014-12-11 2015-04-22 沈阳富创精密设备有限公司 Hastelloy electrolytic polishing process
EP3109348B1 (en) * 2015-06-24 2020-06-03 Airbus Defence and Space GmbH Electrolyte and process for the electrolytic polishing of a metallic substrate
WO2018191695A1 (en) 2017-04-13 2018-10-18 Arconic Inc. Aluminum alloys having iron and rare earth elements
JP7177425B2 (en) * 2017-12-28 2022-11-24 株式会社日本科学エンジニアリング Electropolishing liquid for stainless steel

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Cited By (3)

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WO1992020841A1 (en) * 1991-05-15 1992-11-26 Sandvik Ab Etching process
WO2005004941A1 (en) * 2003-07-08 2005-01-20 Poligrat Gmbh Cementable endoprostheses
WO2007017156A1 (en) * 2005-08-09 2007-02-15 Poligrat Gmbh Electropolishing method

Also Published As

Publication number Publication date
ATE48661T1 (en) 1989-12-15
DE3667505D1 (en) 1990-01-18
EP0249650B1 (en) 1989-12-13
JPS634100A (en) 1988-01-09
US4740280A (en) 1988-04-26

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