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PD ISO/TR 16689:2012

Current

Current

The latest, up-to-date edition.

Anodizing of aluminium and its alloys. Experimental research on possible alternative sealing quality test methods to replace the phosphoric acid/chromic acid immersion test. Evaluation of correlations

Available format(s)

Hardcopy , PDF

Language(s)

English

Published date

31-07-2012

€271.12
Excluding VAT

Foreword
Introduction
1 Scope
2 Literature research
3 Materials and experimental
4 Results
5 Discussion
6 Conclusion
Annex A (Informative) - Qualanod working group
        report
Bibliography

Includes data from an evaluation of candidates to replace the chromic/phosphoric acid solution (CPA) test for the quality of sealing of anodic oxidation coatings on aluminium.

Committee
STI/33
DocumentType
Standard
Pages
40
PublisherName
British Standards Institution
Status
Current

This Technical Report contains data from an evaluation of candidates to replace the chromic/phosphoric acid solution (CPA) test for the quality of sealing of anodic oxidation coatings on aluminium.

Following a review by Qualanod (see Working Group report in AnnexA), it was agreed with Sapa Technology that the candidate tests for evaluation would be as follows:

  • acetic acid/sodium acetate solution (AASA) test as described in ISO2932[10], a method used in the 1970s;

  • sulfuric acid solution (SA) test as described by Manhart and Cochran[9].

The evaluation consists of a comparison of the candidates with the CPA (EN12373-6[3]), dye absorption (EN12373-4[12]) and admittance tests (EN12373-5[13]) using four different sealing methods:

  • hot-water sealing;

  • cold sealing;

  • medium-temperature (midtemp) sealing using a nickel-containing solution;

  • midtemp sealing using a nickel-free solution.

An immersion test based on the CPA test, but without the inclusion of chromic acid, was excluded due to the similarity with the SA test. The scope of the work to develop a new phosphoric acid method was considered too comprehensive for this project.

In general, the sealed coating (pores filled by hydration) loses mass and thickness linearly with dissolution time. Different sealing methods (or sealing conditions of time, temperature, pH, composition of sealing solution) result in different pore-filling material with differences in resistance to acid dissolution. When considering replacing the CPA test with an alternative acid dissolution test, there are some criteria for a new test. If possible, the response to the test should be similar for different sealing methods, i.e. it should be possible to use the same standard even if the sealing method is different. There should be a significant difference in the mass loss for a good and a bad sealing.

Standards Relationship
ISO/TR 16689:2012 Identical

ISO 7599:2010 Anodizing of aluminium and its alloys General specifications for anodic oxidation coatings on aluminium
ISO 3210:2017 Anodizing of aluminium and its alloys — Assessment of quality of sealed anodic oxidation coatings by measurement of the loss of mass after immersion in acid solution(s)
EN 12373-6 : 1998 ALUMINIUM AND ALUMINIUM ALLOYS - ANODIZING - PART 6: ASSESSMENT OF QUALITY OF SEALED ANODIC OXIDATION COATINGS BY MEASUREMENT OF THE LOSS OF MASS AFTER IMMERSION IN PHOSPHORIC ACID/CHROMIC ACID SOLUTION WITHOUT PRIOR ACID TREATMENT
EN 12373-2:1998 Aluminium and aluminium alloys - Anodizing - Part 2: Determination of mass per unit area (surface density) of anodic oxidation coatings - Gravimetric method
ISO 2932:1981 Anodizing of aluminium and its alloys — Assessment of sealing quality by measurement of the loss of mass after immersion in acid solution
EN 12373-1 : 2001 ALUMINIUM AND ALUMINIUM ALLOYS - ANODIZING - PART 1: METHOD FOR SPECIFYING DECORATIVE AND PROTECTIVE ANODIC OXIDATION COATINGS ON ALUMINIUM
EN 12373-4 : 1998 ALUMINIUM AND ALUMINIUM ALLOYS - ANODIZING - PART 4: ESTIMATION OF LOSS OF ABSORPTIVE POWER OF ANODIC OXIDATION COATINGS AFTER SEALING BY DYE SPOT TEST WITH PRIOR ACID TREATMENT
EN 12373-7 : 2002 ALUMINIUM AND ALUMINIUM ALLOYS - ANODIZING - PART 7: ASSESSMENT OF QUALITY OF SEALED ANODIC OXIDATION COATINGS BY MEASUREMENT OF THE LOSS OF MASS AFTER IMMERSION IN PHOSPHORIC ACID/CHROMIC ACID SOLUTION WITH PRIOR ACID TREATMENT
EN 12373-5 : 1998 ALUMINIUM AND ALUMINIUM ALLOYS - ANODIZING - PART 5: ASSESSMENT OF QUALITY OF SEALED ANODIC OXIDATION COATINGS BY MEASUREMENT OF ADMITTANCE

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