prEN 4868

Aerospace series - Anodic electrodeposition of hexavalent chromium free primer

This document defines the requirements for hexavalent chromium free anodic electrodeposition of organic coatings on aluminium and aluminium alloys for corrosion protection of parts.
The purpose of this document is to give design, quality and manufacturing requirements. It does not give complete in-house process instructions; these are given in the processors detailed process instructions.

Luft- und Raumfahrt - Anodische Elektrotauchlackierung mit einer Grundierung ohne hexavalentes Chrom

Série aérospatiale - Électrodéposition anodique d'un primaire sans chrome hexavalent

Le présent document définit les exigences relatives à l'électrodéposition anodique sans chrome hexavalent de revêtements organiques sur l'aluminium et les alliages d'aluminium pour la protection de pièces contre la corrosion.
L’objet du présent document est d’indiquer les exigences de conception, de qualité et de fabrication. Il ne donne pas de gamme de production complète ; ces informations sont données dans les instructions détaillées de l’applicateur relatives au procédé.

Aeronavtika - Anodno potopno barvanje s temeljno barvo brez šestvalentnega kroma

General Information

• Status: Not Published
• Publication Date: 13-Feb-2024
• ICS: 49.040 - Coatings and related processes used in aerospace industry
• Technical Committee: ASD-STAN - Aerospace
• Drafting Committee: ASD-STAN/D 4/S 6 - Surface treatments for Metallic
• Current Stage: 4599 - Dispatch of FV draft to CMC - Finalization for Vote
• Start Date: 04-Jan-2023
• Completion Date: 04-Jan-2023
• Ref Project: oSIST prEN 4868:2021 - Aerospace series - Anodic electrodeposition of hexavalent chromium free primer

Relations

• Revises: EN 4868:2019 - Aerospace series - Anodic electrodeposition of hexavalent chromium free primer
• Effective Date: 18-Jan-2023

Standards Content (Sample)

SLOVENSKI STANDARD
oSIST prEN 4868:2021
01-september-2021
Aeronavtika - Anodno potopno barvanje s temeljno barvo brez šestvalentnega
kroma
Aerospace series - Anodic electrodeposition of hexavalent chromium free primer

Luft- und Raumfahrt - Anodische Elektrotauchlackierung mit einer Grundierung ohne

hexavalentes Chrom

Série aérospatiale - Électrodéposition anodique d'un primaire sans chrome hexavalent

Ta slovenski standard je istoveten z: prEN 4868
ICS:
49.040 Prevleke in z njimi povezani Coatings and related
postopki, ki se uporabljajo v processes used in aerospace
letalski in vesoljski industriji industry
87.020 Postopki za nanašanje Paint coating processes
barvnih premazov
oSIST prEN 4868:2021 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN 4868:2021
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oSIST prEN 4868:2021
DRAFT
EUROPEAN STANDARD
prEN 4868
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2021
ICS 49.040 Will supersede EN 4868:2019
English Version
Aerospace series - Anodic electrodeposition of hexavalent
chromium free primer

Série aérospatiale - Électrodéposition anodique d'un Luft- und Raumfahrt - Anodische

primaire sans chrome hexavalent Elektrotauchlackierung mit einer Grundierung ohne

hexavalentes Chrom

This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee ASD-

STAN.

If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations

which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other

language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC

Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

United Kingdom.

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are

aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without

notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 4868:2021 E

worldwide for CEN national Members.
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oSIST prEN 4868:2021
prEN 4868:2021 (E)
Contents Page

European foreword ...................................................................................................................................................... 4

1 Scope .................................................................................................................................................................... 5

2 Normative references .................................................................................................................................... 5

3 Terms and definitions ................................................................................................................................... 5

3.1 General terms ................................................................................................................................................... 6

3.2 Technical terms ............................................................................................................................................... 6

4 Purpose of process ......................................................................................................................................... 7

4.1 General................................................................................................................................................................ 7

4.2 Applicability ...................................................................................................................................................... 7

4.3 Limitations ........................................................................................................................................................ 7

5 Protection system classification ................................................................................................................ 8

6 Process requirements ................................................................................................................................... 8

6.1 Information for the processor .................................................................................................................... 8

6.2 Condition of parts prior to the treatment .............................................................................................. 8

6.3 Process conditions .......................................................................................................................................... 8

6.3.1 Tooling ................................................................................................................................................................ 8

6.3.2 Masking .............................................................................................................................................................. 9

6.3.3 Surface pre-treatment ................................................................................................................................... 9

6.3.4 Anodic electrodeposition ............................................................................................................................. 9

6.3.5 Anodic electrodeposition post-treatments ........................................................................................... 9

6.4 Water quality .................................................................................................................................................... 9

6.5 Rework ................................................................................................................................................................ 9

7 Required characteristics ............................................................................................................................ 10

7.1 Visual appearance ........................................................................................................................................ 10

7.2 Film thickness ................................................................................................................................................ 10

7.3 Physical properties of the film ................................................................................................................. 10

7.4 Corrosion performance of coated parts ................................................................................................ 10

7.4.1 Filiform corrosion......................................................................................................................................... 10

7.4.2 Corrosion resistance .................................................................................................................................... 10

7.5 Fatigue requirements and test methods .............................................................................................. 10

7.6 Fluid resistance ............................................................................................................................................. 10

8 Quality requirements .................................................................................................................................. 10

8.1 Process approval ........................................................................................................................................... 10

8.2 General points ................................................................................................................................................ 11

8.3 Periodic tests .................................................................................................................................................. 11

8.4 Periodic chemical analysis ........................................................................................................................ 11

8.5 Parts acceptance inspection ..................................................................................................................... 11

8.5.1 Inspections before treatment ................................................................................................................... 11

8.5.2 Inspections during treatment .................................................................................................................. 11

8.5.3 Inspections after anodic electrodeposition ........................................................................................ 11

Annex A (normative) Engineering requirements ............................................................................................. 12

Annex B (normative) Test methods ...................................................................................................................... 15

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oSIST prEN 4868:2021
prEN 4868:2021 (E)

B.1 Tape adhesion test ....................................................................................................................................... 15

B.1.1 Tape definition .............................................................................................................................................. 15

B.1.2 Method .............................................................................................................................................................. 15

B.2 Curing inspection .......................................................................................................................................... 15

B.2.1 Criteria .............................................................................................................................................................. 15

Annex C (normative) Parts acceptance inspections ........................................................................................ 16

Annex D (normative) Periodic tests requirements ......................................................................................... 17

Annex E (informative) Standard evolution form .............................................................................................. 18

Bibliography ................................................................................................................................................................. 19

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oSIST prEN 4868:2021
prEN 4868:2021 (E)
European foreword

This document (prEN 4868:2021) has been prepared by the Aerospace and Defence Industries

Association of Europe — Standardization (ASD-STAN).

After enquiries and votes carried out in accordance with the rules of this Association, this document has

received the approval of the National Associations and the Official Services of the member countries of

ASD, prior to its presentation to CEN.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 4868:2019.
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oSIST prEN 4868:2021
prEN 4868:2021 (E)
1 Scope

This document defines the requirements for hexavalent chromium free anodic electrodeposition of

organic coatings on aluminium and aluminium alloys for corrosion protection of parts.

The purpose of this document is to give design, quality and manufacturing requirements. It does not

give complete in-house process instructions; these are given in the processors detailed process

instructions.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

EN 3840, Aerospace series - Paints and varnishes - Technical specification

EN ISO 1518-1, Paints and varnishes - Determination of scratch resistance - Part 1: Constant-loading

method (ISO 1518-1)
EN ISO 1519, Paints and varnishes - Bend test (cylindrical mandrel) (ISO 1519)
EN ISO 2409, Paints and varnishes - Cross-cut test (ISO 2409)

EN ISO 2812-1, Paints and varnishes - Determination of resistance to liquids - Part 1: Immersion in liquids

other than water (ISO 2812-1)

EN ISO 2812-2, Paints and varnishes - Determination of resistance to liquids - Part 2: Water immersion

method (ISO 2812-2)

EN ISO 4623-2, Paints and varnishes - Determination of resistance to filiform corrosion - Part 2:

Aluminium substrates (ISO 4623-2)

EN ISO 4628-8, Paints and varnishes - Evaluation of degradation of coatings - Designation of quantity and

size of defects, and of intensity of uniform changes in appearance - Part 8: Assessment of degree of

delamination and corrosion around a scribe or other artificial defect (ISO 4628-8)

EN ISO 4628-10, Paints and varnishes - Evaluation of degradation of coatings - Designation of quantity

and size of defects, and of intensity of uniform changes in appearance - Part 10: Assessment of degree of

filiform corrosion (ISO 4628-10)

EN ISO 9227, Corrosion tests in artificial atmospheres - Salt spray tests (ISO 9227)

EN ISO 17872, Paints and varnishes - Guidelines for the introduction of scribe marks through coatings on

metallic panels for corrosion testing (ISO 17872)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

• ISO Online browsing platform: available at https://www.iso.org/obp
• IEC Electropedia: available at https://www.electropedia.org/
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oSIST prEN 4868:2021
prEN 4868:2021 (E)
3.1 General terms
3.1.1
OEM

producer who has the design authority and manufactures products or components that are purchased

by a company and retailed under that purchasing company’s brand name
Note 1 to entry: The OEM can also apply the process.
3.1.2
manufacturer
company or person who makes, manufactures, assembles components
Note 1 to entry: The manufacturer can also apply the process.
3.1.3
processor
company or person who applies the process
3.1.4
process instruction

document that describes the application scopes, detailed process (key parameters, detailed steps, etc.),

quality management, environmental and safety regulations, etc.
3.1.5
batch

unless otherwise specified, it comprises parts of the same type (i.e. shape, size, material), processed at

the same time in the same bath
3.2 Technical terms
3.2.1
mechanically disturbed layer

layer that is present at the surface resulting from the rolling process of the material

3.2.2
pit
surface corrosion defect at which the anodic coating is penetrated
Note 1 to entry: Typical characteristics of corrosion pits are:
• rounded or irregular or elongated geometry,
• comet tail or line or halo that emerges from the cavity,

• some corrosion by products inside pits (on aluminium the by-product may be granular, powdery or

amorphous and white, grey or black in colour).

To be considered as a corrosion pit, a surface cavity shall exhibit at least two of the above characteristics.

3.2.3
rework

repetition of the anodic electrodeposition process step after complete stripping of the layer

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oSIST prEN 4868:2021
prEN 4868:2021 (E)
3.2.4
anodic electrodeposition

industrial coating method in which negatively charged organic coating particles in aqueous solution

migrate (electrophoresis) toward the anode of a direct-current electrical circuit passing through the

solution, so that electrolysis of water creates a localized pH gradient, precipitating a uniform layer of

coating on the anode
3.2.5
ultra-filtrate

effluent generated from an electrocoat bath passing across an ultrafilter membrane

Note 1 to entry: The effluent is mainly composed of water and water-soluble species.

4 Purpose of process
4.1 General

This specification establishes the requirements for a waterborne, hexavalent chromium free corrosion

inhibiting, chemical and solvent resistant, anodic electrodeposition of organic coating capable of curing

at 110 °C to 120 °C.

The anodic electrodeposition process applies a protective coating with uniform film thickness control,

complete coverage of recessed areas, minimal surface defects and high transfer efficiency. Once the film

is deposited on the substrate, a thermal cure is required to achieve the final properties of the coated

parts.
4.2 Applicability

It can be used as a protection against corrosion, as an organic coating primer before topcoat application,

for electrical insulation, and as a masking before anodizing and/or conversion.
4.3 Limitations
4.3.1 Al
...