DE423758C - Process for producing a protective and at the same time electrically insulating coating on aluminum - Google Patents

Process for producing a protective and at the same time electrically insulating coating on aluminum

Info

Publication number
DE423758C
DE423758C DEB112171D DEB0112171D DE423758C DE 423758 C DE423758 C DE 423758C DE B112171 D DEB112171 D DE B112171D DE B0112171 D DEB0112171 D DE B0112171D DE 423758 C DE423758 C DE 423758C
Authority
DE
Germany
Prior art keywords
aluminum
protective
same time
electrically insulating
insulating coating
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.)
Expired
Application number
DEB112171D
Other languages
German (de)
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.)
E H OSWALD BAUER DR ING
OTTO VOGEL DR
Original Assignee
E H OSWALD BAUER DR ING
OTTO VOGEL DR
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 E H OSWALD BAUER DR ING, OTTO VOGEL DR filed Critical E H OSWALD BAUER DR ING
Priority to DEB112171D priority Critical patent/DE423758C/en
Application granted granted Critical
Publication of DE423758C publication Critical patent/DE423758C/en
Expired legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
    • C23C22/60—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using alkaline aqueous solutions with pH greater than 8
    • C23C22/66—Treatment of aluminium or alloys based thereon
    • C23C22/67—Treatment of aluminium or alloys based thereon with solutions containing hexavalent chromium

Landscapes

  • Chemical & Material Sciences (AREA)
  • General Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Chemical Treatment Of Metals (AREA)

Description

Verfahren zur Erzeugung eines schützenden und zugleich elektrisch isolierenden Überzuges auf Aluminium. Es ist bekannt, daß Aluminium und Aluminiumlegierungen durch Behandeln mit einer alkalischen Chromsalzlösung sich mit einem (lichten schützenden Überzug bedecken lassen. Die bisherige Ausführungsweise erfordert jedoch viel Zeit und, da auch die Behandlung iri der Wärine erfolgen muß, nicht unerhebliche Erwärmungskosten, namentlich bei Ausübung im großen. Es hat sich nun gezeigt, claß der Cberzug in gleicher Güte aber viel leichter und schneller hervorgebracht werden kann, wenn man der Lösung Alaun oder andere Aluminiumverbindungen in solcher Menge von vornherein. zusetzt oder in ihr erzeugt, daß die Bildung der Schutzschicht erheblich in der Weise einer Katalyse beschleunigt wird. So abgeändert wird das Verfahren in folgender Weise ausgeübt: Es wird eine Lösung verwendet, die z. B. o,5 Prozent Kaliumbichromat und etwa o,5 Prozent Ätznatron oder i Prozent Soda enthält. Andere alkalisch wirkende Verbindu-ige@i sind ebenfalls verwendbar. Zu dieser Lösung wird Alaun oder eine andere Aluminiumverbindung zugesetzt, oder es wird dafür gesorgt, elaß während der Behandlung der Aluminiumgegenstände eine Aluminiumverbindung durch teilweise Auflösung sich bildet. Während der Behandlung wird die Lösung auf 9o bis 95' erhitzt. Je nach der Dauer der Erhitzung kann die Dicke des Überzuges beliebig stark erzeugt werden. Die Schutzwirkung des Überzuges erstreckt sich auf neutrale Salzlösungen, insbesondere Seewasser, ferner auf Isolation gegen den elektrischen Strom. Der Überzug ist festhaftend. Er bröckelt selbst bei mehrfachem Biegen der Gegenstände nicht ab. Beispiel. In 3 1 Wasser werden i o g Kalibichromat und 40 g kalzinierte Soda aufgelöst. Ferner wird zu Beginn als Katalysator 3 g Alaun hinzugefügt und bei Zubereitung des Bades bereits ein Stückchen Aluminium hineingelegt. I?in einen gleichmäßigen Überzug zu erhalten, ist es zweckmäßig, den Gegenstand im Bade zu bewegen. Die Zeitdauer der Verchromung beträgt - durchschnittlich 30 Minuten bis r Stunde. Nach dem Herausnehmen aus dem Bade werden die Gegenstände in Leitungswasser gut gespült und darauf gut getrocknet.Process for producing a protective and at the same time electrically insulating coating on aluminum. It is known that aluminum and aluminum alloys can be covered with a light protective coating by treating them with an alkaline chromium salt solution It has now been shown that the coating of the same quality can be produced much more easily and more quickly if alum or other aluminum compounds are added to the solution in advance or produced in it in such an amount that the formation of the protective layer is considerable Modified in this way, the process is carried out in the following way: A solution is used which contains, for example, 0.5 percent potassium dichromate and about 0.5 percent caustic soda or 1 percent soda Compounds @ i can also be used.Alum or another aluminum is added to this solution An aluminum compound is added or it is ensured that an aluminum compound is formed by partial dissolution during the treatment of the aluminum articles. During the treatment, the solution is heated to 90-95 '. Depending on the duration of the heating, the thickness of the coating can be made as desired. The protective effect of the coating extends to neutral salt solutions, in particular sea water, and also to insulation against electrical current. The coating is firmly adherent. It does not crumble even if the objects are bent several times. Example. Iog potassium chromate and 40 g calcined soda are dissolved in 3 liters of water. In addition, 3 g of alum are added as a catalyst at the beginning and a piece of aluminum is already placed in the bath when the bath is being prepared. In order to obtain a uniform coating, it is advisable to move the object in the bath. The duration of the chrome plating is - on average 30 minutes to r hour. After taking them out of the bath, the items are rinsed well in tap water and then dried well.

Claims (1)

PATEINT-ANsrauci;: VerfahrenzurErzeugungeines schützenden und zugleich elektrisch isolierenden Überzuges auf AluminiumundAluminiumlegierungen durch Erhitzen in einer alkalischen Chromatlösung, dadurch gekennzeichnet, daß der Lösung Alaun oder andere Aluminiumverbindungen in solcher Menge von vornherein zugesetzt oder in ihr erzeugt werden, daß die Bildung der Schutzschicht erheblich beschleunigt wird.PATEINT-ANsrauci ;: Process to create a protective and at the same time electrically insulating coating on aluminum and aluminum alloys by heating in an alkaline chromate solution, characterized in that the solution has alum or other aluminum compounds are added in advance in such an amount or are generated in it that the formation of the protective layer accelerated considerably will.
DEB112171D 1923-12-29 1923-12-30 Process for producing a protective and at the same time electrically insulating coating on aluminum Expired DE423758C (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DEB112171D DE423758C (en) 1923-12-29 1923-12-30 Process for producing a protective and at the same time electrically insulating coating on aluminum

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE226776X 1923-12-29
DEB112171D DE423758C (en) 1923-12-29 1923-12-30 Process for producing a protective and at the same time electrically insulating coating on aluminum

Publications (1)

Publication Number Publication Date
DE423758C true DE423758C (en) 1926-01-09

Family

ID=25764351

Family Applications (1)

Application Number Title Priority Date Filing Date
DEB112171D Expired DE423758C (en) 1923-12-29 1923-12-30 Process for producing a protective and at the same time electrically insulating coating on aluminum

Country Status (1)

Country Link
DE (1) DE423758C (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2504434A (en) * 1947-01-28 1950-04-18 Aluminum Co Of America Forming oxide coatings on aluminum
US5492766A (en) * 1989-09-19 1996-02-20 Michigan Chrome And Chemical Company Corrosion resistant coated articles and process for making same

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2504434A (en) * 1947-01-28 1950-04-18 Aluminum Co Of America Forming oxide coatings on aluminum
US5492766A (en) * 1989-09-19 1996-02-20 Michigan Chrome And Chemical Company Corrosion resistant coated articles and process for making same

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