US20050121115A1 - Hexavalent chromium-free sealing method applicable after sulfuric anodization of aluminum alloys, a sealing solution used in said method, and an article treated using said method - Google Patents

Hexavalent chromium-free sealing method applicable after sulfuric anodization of aluminum alloys, a sealing solution used in said method, and an article treated using said method Download PDF

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Publication number
US20050121115A1
US20050121115A1 US11/000,058 US5804A US2005121115A1 US 20050121115 A1 US20050121115 A1 US 20050121115A1 US 5804 A US5804 A US 5804A US 2005121115 A1 US2005121115 A1 US 2005121115A1
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Prior art keywords
liter
range
mole
cobalt
lithium
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Abandoned
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US11/000,058
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English (en)
Inventor
Michel Ruimi
Guillaume Oberlaender
Valerie Gonzalez
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Safran Aircraft Engines SAS
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SNECMA Moteurs SA
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Assigned to SNECMA MOTEURS reassignment SNECMA MOTEURS ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: GONZALEZ, VALERIE, OBERLAENDER, GUILLAUME, RUIMI, MICHEL
Publication of US20050121115A1 publication Critical patent/US20050121115A1/en
Assigned to SNECMA reassignment SNECMA CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). Assignors: SNECMA MOTEURS
Abandoned legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
    • C25D11/02—Anodisation
    • C25D11/04—Anodisation of aluminium or alloys based thereon
    • C25D11/18—After-treatment, e.g. pore-sealing
    • C25D11/24—Chemical after-treatment
    • C25D11/246—Chemical after-treatment for sealing layers

Definitions

  • the invention relates to a sealing method for producing a layer or film of oxide which is resistant to saline corrosion on a metal substrate, to the sealing solution used in said method, and to an article treated by said method.
  • the present invention relates to the application of said sealing method-or said sealing solution to a metal substrate formed from an aluminum or aluminum alloy substrate, said method being carried out after a prior sulfuric anodization step.
  • Aluminum enjoys natural protection against atmospheric corrosion by oxidation of its surface, resulting in the formation of amorphous Al 2 O 3 type alumina. That alumina forms naturally in air and can also result from sulfuric acid anodization, which is preferable when a layer is to be produced rapidly and, moreover, when it has to be thicker. This is the case in conventional anodization of the sulfuric anodization (SA) type (sulfuric anodic oxydation), which produces a thickness of 10 micrometers ( ⁇ m) to 20 ⁇ m and up to 100 ⁇ m in the case of “hard” anodization.
  • SA sulfuric anodization
  • a thin layer of alumina on the surface of aluminum alloys is not sufficiently resistant to the corrosion to which the part is subjected.
  • the alumina which is formed has a columnar structure with a geometry which is close to a hexagonal symmetry, with pores rendering it relatively sensitive to its environment, in particular permeable to chemical attack.
  • the sealing which is to be carried out is aimed at fixing (metallic) elements in said pores to reduce their permeability in order to enhance the anti-corrosive properties of the alumina layer without, however, degrading the mechanical properties of the alumina.
  • the alumina layer is sealed in known manner by placing the part in a chemical bath.
  • that bath is a solution based on chromic acid, which allows the pores to be plugged with hexavalent chromium or chromium VI.
  • Sealing methods of that type used to plug the pores of the alumina layer present on the surface of an aluminum or aluminum alloy part to form a film which is resistant to saline corrosion, have conventionally used acidic solutions comprising chromium VI, as described in U.S. Pat. Nos. 2,796,370 and 2,796,371.
  • the present invention aims to overcome the problems with prior art sealing solutions, in particular problems with chromium toxicity, by proposing a novel sealing method using a sealing solution that contains no chromium, that produces good results and that is easy to carry out, in particular in an industrial context.
  • the sealing method of the present invention comprises steps consisting in:
  • said “mixed cobalt/lithium chemical sealing” can protect a previously anodized substrate, forming an extremely adhesive sealing layer which has anti-corrosion properties and good paint keying properties.
  • a combination of at least one simple cobalt II salt and at least one simple lithium III salt provides very good results which are relatively superior to those obtained by using only at least one simple cobalt II salt or by using only at least one simple lithium III salt.
  • said simple cobalt II salt is from the group constituted by cobalt sulfate, cobalt nitrate, cobalt carbonate and cobalt acetate.
  • said simple cobalt II salt is cobalt acetate Co(CH 3 COO) 2 ,4H 2 O in a concentration in the range 3 grams/liter (g/liter) to 6 g/liter, i.e. in the range 1.2 ⁇ 10 ⁇ 2 mole/liter to 2.41 ⁇ 10 ⁇ 2 mole/liter, preferably in the range 4 g/liter to 5 g/liter, i.e. in the range 1.61 ⁇ 10 ⁇ 2 mole/liter to 2.01 ⁇ 10 ⁇ 2 mole/liter.
  • said simple lithium III salt is from the group constituted by lithium sulfate, lithium nitrate, lithium carbonate and lithium acetate.
  • said simple lithium III salt is lithium carbonate LiCO 3 in a concentration in the range 0.5 g/liter to 1.5 g/liter, i.e. in the range 6.77 ⁇ 10 ⁇ 3 mole/liter to 2.03 ⁇ 10 ⁇ 2 mole/liter, preferably in the range 0.75 g/liter to 1 g/liter, i.e. in the range 1.02 ⁇ 10 ⁇ 2 mole/liter to 1.35 ⁇ 10 ⁇ 2 mole/liter.
  • said sealing solution also comprises at least one weak acid from the group constituted by boric acid, acetic acid, citric acid and tartaric acid.
  • said weak acid is boric acid H 3 BO 3 in a concentration in the range 3 g/liter to 6 g/liter, i.e. in the range 4.85 ⁇ 10 ⁇ 2 mole/liter to 9.7 ⁇ 10 ⁇ 2 mole/liter, preferably in the range 4 g/liter to 5 g/liter, i.e. in the range 6.47 ⁇ 10 ⁇ 2 mole/liter to 8.09 ⁇ 10 ⁇ 2 mole/liter.
  • Said solution has the additional advantage of being easy to reproduce, of giving a homogeneous result, and of allowing the sealing solution to be re-used because of the buffer effect of the weak acid which stabilizes the pH of the sealing solution.
  • Said weak acid can buffer the sealing solution which then has a pH in the range 5 to 6, advantageously in the range 5.1 to 5.9, preferably 5.5 ⁇ 0.1.
  • the sealing solution in question also comprises a surfactant such as sodium lauryl sulfate and/or sodium dodecyl sulfate C 12 H 25 NaO 4 S.
  • a surfactant such as sodium lauryl sulfate and/or sodium dodecyl sulfate C 12 H 25 NaO 4 S.
  • said surfactant is sodium lauryl sulfate present in a concentration in the range 1.5 mg/liter to 3.5 mg/liter, i.e. in the range 5.20 ⁇ 10 ⁇ 6 mole/liter to 1.21 ⁇ 10 ⁇ 5 mole/liter, preferably in the range 2 mg/liter to 3 mg/liter, i.e. in the range 6.94 ⁇ 10 ⁇ 6 mole/liter to 1.04 ⁇ 10 ⁇ 5 mole/liter.
  • Adding such a compound can enhance the results (a more even layer and better distribution of simple cobalt and lithium salts in the pores of the alumina). In fact, it contributes to reducing the surface tension between the metal substrate and the sealing solution, and it also improves the pH stability of the solution by capturing hydrogen ions H + liberated by the weak acid.
  • the temperature of the sealing solution is over 87° C., preferably over 90° C., advantageously over 95° C., and more preferably in the range 95° C. to 98° C.
  • the duration of the step for bringing the substrate into contact with the sealing solution is more than 15 minutes (min.), advantageously more than 20 min., and preferably in the range 20 min. to 25 min.
  • the present invention also pertains to a sealing solution comprising at least one simple cobalt II salt, at least one simple lithium III salt and being buffered, by means of which a mixed cobalt/lithium film is obtained.
  • the present invention also pertains to a treated article resulting from carrying out the method of the type defined above, using the sealing solution of the type defined above.
  • said article comprises a sealed anodization film having a thickness in the range 15 ⁇ m to 20 ⁇ m.
  • the proposal of the present invention renders it possible to produce, in a simple and certain manner and without recourse to chromium, mixed cobalt/lithium sealing resulting in a film having corrosion resistance properties on a metal substrate.
  • FIG. 1 shows a section through a specimen (AUZGN blade) treated using the method of the present invention, after 790 hours exposure to a saline mist;
  • FIG. 2 shows a top view of the surface appearance of a specimen treated using the method of the present invention.
  • a sealing solution was obtained the pH of which was kept at 5.5 ⁇ 0.1 as the solution was buffered by the boric acid.
  • FIG. 1 is a photograph showing a section of the specimen after exposure to a saline mist for 790 hours:
  • said article comprises:
  • the article treated using the method of the invention has a film formed by a layer of sealed alumina, which is non porous and has a conventional cracked structure at its surface. This can be seen in the accompanying photograph shown in FIG. 2 .

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  • Chemical & Material Sciences (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Chemical Treatment Of Metals (AREA)
  • Other Surface Treatments For Metallic Materials (AREA)
  • Sealing Battery Cases Or Jackets (AREA)
US11/000,058 2003-12-09 2004-12-01 Hexavalent chromium-free sealing method applicable after sulfuric anodization of aluminum alloys, a sealing solution used in said method, and an article treated using said method Abandoned US20050121115A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR0314382A FR2863276B1 (fr) 2003-12-09 2003-12-09 Procede de colmatage exempt de chrome hexavalent applicable apres anodisation sulfurique d'alliages d'aluminium, solution de colmatage utilisee dans ce procede et article traite issu d'un tel procede
FR0314382 2003-12-09

Publications (1)

Publication Number Publication Date
US20050121115A1 true US20050121115A1 (en) 2005-06-09

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US11/000,058 Abandoned US20050121115A1 (en) 2003-12-09 2004-12-01 Hexavalent chromium-free sealing method applicable after sulfuric anodization of aluminum alloys, a sealing solution used in said method, and an article treated using said method

Country Status (5)

Country Link
US (1) US20050121115A1 (enrdf_load_stackoverflow)
EP (1) EP1541718A3 (enrdf_load_stackoverflow)
JP (1) JP4334466B2 (enrdf_load_stackoverflow)
CA (1) CA2487990A1 (enrdf_load_stackoverflow)
FR (1) FR2863276B1 (enrdf_load_stackoverflow)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102392284A (zh) * 2011-11-03 2012-03-28 湖南大学 铝阳极氧化膜着色封闭一步处理的方法
CN103290453A (zh) * 2013-05-10 2013-09-11 黄山金瑞泰科技有限公司 Ctp版材封孔处理用封孔剂
CN103469276A (zh) * 2013-09-16 2013-12-25 杭州和韵科技有限公司 一种提高铝阳极氧化膜耐酸碱腐蚀性能的方法
CN103710736A (zh) * 2013-12-23 2014-04-09 广西博士海意信息科技有限公司 铝合金封孔剂
EP2957658A4 (en) * 2014-02-18 2016-07-27 Suzuki Motor Corp METAL ELEMENT WITH EXCELLENT CORROSION RESISTANCE, MANUFACTURING METHOD AND REPAIR MATERIAL AND METAL ELEMENT REPAIR PROCESS
CN112135931A (zh) * 2018-05-24 2020-12-25 斯瑞昂高级电池公司 使用低纯度起始前体来电镀锂化过渡金属氧化物
US20220380904A1 (en) * 2013-05-14 2022-12-01 Prc-Desoto International, Inc. Permanganate based conversion coating compositions

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101270671B1 (ko) * 2011-03-25 2013-06-03 주식회사 영광와이케이엠씨 알루미늄 아노다이징의 봉공처리 조성물
RU2722953C1 (ru) 2016-08-12 2020-06-05 Прк-Десото Интернэшнл, Инк. Герметизирующая композиция

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5411607A (en) * 1993-11-10 1995-05-02 Novamax Technologies Holdings, Inc. Process and composition for sealing anodized aluminum surfaces
US6447665B1 (en) * 1997-08-22 2002-09-10 Henkel Corporation Faster two-step sealing of anodized aluminum surfaces

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5411607A (en) * 1993-11-10 1995-05-02 Novamax Technologies Holdings, Inc. Process and composition for sealing anodized aluminum surfaces
US6447665B1 (en) * 1997-08-22 2002-09-10 Henkel Corporation Faster two-step sealing of anodized aluminum surfaces

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102392284A (zh) * 2011-11-03 2012-03-28 湖南大学 铝阳极氧化膜着色封闭一步处理的方法
CN103290453A (zh) * 2013-05-10 2013-09-11 黄山金瑞泰科技有限公司 Ctp版材封孔处理用封孔剂
US20220380904A1 (en) * 2013-05-14 2022-12-01 Prc-Desoto International, Inc. Permanganate based conversion coating compositions
CN103469276A (zh) * 2013-09-16 2013-12-25 杭州和韵科技有限公司 一种提高铝阳极氧化膜耐酸碱腐蚀性能的方法
CN103710736A (zh) * 2013-12-23 2014-04-09 广西博士海意信息科技有限公司 铝合金封孔剂
EP2957658A4 (en) * 2014-02-18 2016-07-27 Suzuki Motor Corp METAL ELEMENT WITH EXCELLENT CORROSION RESISTANCE, MANUFACTURING METHOD AND REPAIR MATERIAL AND METAL ELEMENT REPAIR PROCESS
US9944801B2 (en) 2014-02-18 2018-04-17 Suzuki Motor Corporation Metal member having excellent corrosion resistance, method for producing the same, and material and method for repairing metal member
CN112135931A (zh) * 2018-05-24 2020-12-25 斯瑞昂高级电池公司 使用低纯度起始前体来电镀锂化过渡金属氧化物

Also Published As

Publication number Publication date
FR2863276B1 (fr) 2006-01-20
EP1541718A2 (fr) 2005-06-15
EP1541718A3 (fr) 2008-10-15
JP2005171385A (ja) 2005-06-30
JP4334466B2 (ja) 2009-09-30
CA2487990A1 (fr) 2005-06-09
FR2863276A1 (fr) 2005-06-10

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Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:RUIMI, MICHEL;OBERLAENDER, GUILLAUME;GONZALEZ, VALERIE;REEL/FRAME:016044/0115

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