REACH compliant surface treatments: Current trends and overview in the frame of Clean Sky

© CIDETEC 2018

12,7 m.€ Turnover

in 2017

47% Private

funding

25% European

funding

12 European

Projects led

175 People in the

workforce

70 % of researchers

are doctors

CIDETEC Surface Engineering is part of

CIDETEC, specialized in three technological

areas, among which Surface Engineering is

to be highlighted.

• Surface preparation

technologies.

• Chemical and

electrochemical deposition

of metals, alloys and

composites.

• Selective deposition

techniques.

• Ceramic coatings (dip, spray,

electrophoresis).

• Anodization, metallization

and functionalization of

lightweight alloys (Al, Ti, Mg).

• Chemical polishing,

electropolishing and

electrocoloring.

• Sol-gel based and nano-

enabled coatings (dip,

spin and spray coating).

• Printing technologies

(ink-jet, screen printing).

• Laser coloring, marking

and structuring.

• Smart resin formulations.

• Compounding of

thermoplastic polymers.

• Polymers and

composites processing

technologies (extrusion,

injection, RTM, infusion

and prepreg).

Technical offer available technologies for R&D

Aeronautic European projects

AIRPOXY

“ThermoformAble,

repaIrable and

bondable smaRt

ePOXY based

composites for aero

structures”

Period: 2018-2022

Coordinator

H2020-CLEAN SKY2 -----

Advanced epoxy based

composites

HARVEST

“Hierarchical

multifunctional

composites with

thermoelectrically

powered autonomous

structural health

monitoring for the

aviation industry”

Period: 2018-2022

H2020- Societal

Challenges -----

Advanced composites and

SHM

IN-LIGHT

“INnovative bifunctional

aircraft window for

LIGHTing control to

enhance passenger

comfort”

Period: 2012-2015

Coordinator

FP7-TRANSPORT -----

Electrochromism

Aeronautic European projects

CHOPIN

“Coatings with

Hydrophobic and/or

Omniphobic

Properties against

INsect contamination”

Period: 2018-2021 H2020-CLEAN SKY2

TM: AIRBUS

-----

Multifunctional and

Omniphobic coatings

ECOLAND

“Development of ECO-

friendly protection

procedures for

LANDing gear

aluminium alloys”

Period: 2018-2019

Coordinator

H2020-CLEAN SKY2

TM: LIEBHERR -----

Surface modification and

protection of aluminium

alloys

REMART

“Recycling of Metallic

Materials from

Rotorcraft

Transmissions”

Period: 2013-2015

FP7-CLEAN SKY -----

Anodic layer removal

SEALANT

“Optimization and

scale-up of final sealing

of Sulfuric Acid

Anodizing employing

Design of Experiments”

Period: 2016-2018

H2020-CLEAN SKY2

TM: LIEBHERR -----

Surface modification of

light alloys

Aeronautic

• Recyclable, repairable and reprocessable thermoset composites.

• Anticontamination coatings (ice, insects etc).

• Post treatments on Additive manufacturing parts.

• Light alloys surface treatments.

• REACH candidate list alternatives.

• Penetrant Testing.

• Magnetic Particle.

• Nital Etching.

• Barkhausen Inspection.

• Stress Relieve.

Market

REACH Regulation

REACH is a regulation of the European

Union, adopted to improve the protection of

human health and the environment from

the risks that can be posed by chemicals,

while enhancing the competitiveness of the

EU chemicals industry. It also promotes

alternative methods for the hazard

assessment of substances in order to

reduce the number of tests on animals.

The European Chemicals

Agency (ECHA) is the driving

force among regulatory

authorities in implementing the

EU's groundbreaking chemicals

legislation.

CANDIDATE LIST

Substance Date of inclusion Comments

Chromium (VI) compounds 2008-2011 Authorisation before it is used

Borate compounds 2010-2018 Some uses are restricted

Cadmium compounds 2013-2018 Some uses are restricted

Substance Sunset Main use

Chromium trioxide 2017 Hard chromium

Anodising/Anodic layer removal

Conversion coating

Sodium and potassium chromate/dichromate 2017 Anodised sealant

Dichromium (III) tris(chromate) 2019 Conversion coating (Reparation)

Strontium chromate 2019 Primers Source ECHA

APPLICATIONS FOR AUTHORISATION OF CHROMIUM COMPOUNDS

Date of expiry of

review period

2024-2031

Source ECHA

SAFRAN-Sept 2027

MTU-Sept 2029

CHROMIUM (VI) COMPOUNDS

00

Source ECHA

Surface treatments based on chromium (VI) have unique technical

functions that confer:

- Outstanding corrosion protection and prevention for the used

metals under a wide range of conditions.

- Active corrosion inhibition (self-healing, e.g. Repaiting a local

scratch on the surface).

- Excellent adhesion properties to support application of subsequent

coatings or paints.

- Excellent chemical and electrical resistivity

- Extensive experience on dealing with corrosion problemas related

to these treatments

- Excellent wear and abrasion properties combined wiht hardness

- Low coefficient of friction

- Adequate layer thickness

- Ability to maintain lubrication due to micro-cracking

IMPLEMENTATION OF A NEW SURFACE TREATMENT

Source ECHA

MATERIALS AND SURFACE TREATMENTS

• Conversion coatings (1-2 mm)

• Anodising + Sealant /Anodic layer removal (3-10 mm)

• Primers (20-40 mm)

Main surface treatments for aluminium

• Hard Chromium (30-300 mm)

• Cadmium/Zn-Ni (7-10 mm)

• Primers (20-40 mm)

Main surface treatments for steel

A320

Aluminium / 65.5 %

Composite / 12.5 %

Steel / 9.3 %

Titanium / 7.2 %

Others / 5.5 %

Conversion coatings

Aviall Services Inc.

Wesco Aircraft EMEA Limited

MTU Aero Engines AG

HENKEL

…

01 Cr(III)-Zr

Organometallics

(Zr & Ti) Mn Mo

Sol-Gel or other

thin coating

Corrosion resistance

Depending on

solution and

substrate

Active corrosion

inhibition

Repair applications For single

applications

Paint Adhesion

Depending on

solution and

substrate

Fatigue

Conductivity Depending on post-

treatment

Layer thickness

Reproducibility

With impact on

corrosion and paint

adhesion

Complex geometry

Assessment overview for Cr(VI)-free CC alternatives to Cr(VI) CC

Source ECHA

Chromium Trioxide

Dichromium (III) tris(chromate)

CONVERSION COATINGS

Degreasing Rinsing Alkaline

etching Rinsing 1 Rinsing 2

Acidic

picking Rinsing 1 Rinsing 2

Cr(III)-Zr

CCC Rinsing 1 Rinsing 2

Improvements/challenge for REACH-compliant alternatives:

- Detectability of the layer after treatment (sometimes colorless)

- Repeatability, upscaling effect, compatibility with customer in-house pretreatment

- Optimal CCC parameters may vary with alloy type

- Total Cr-free process. Production of Cr(III) containing substances involves potential

exposure to Cr(VI). Cr (III) may contain Cr(VI) traces.

Source AIRBUS

CONVERSION COATINGS

Project acronym Title Programme Start Date /

End Date Description

MAGNOLYA

Advanced environmentally

friendly chemical

surface treatments for cast

Mg helicopter transmission

alloys preservation

FP7-JTI-CS 2012-2013

Development of new eco-friendly chemical

conversion technologies for the protection of

magnesium.

COMAG

Development and

Implementation of

Conductive coating for Mg

sheets in A/C

FP7-JTI-CS 2012-2014

The objective was to develop and implement

high corrosion resistance conductive coating

for Mg.

ALMAGIC

Aluminium and Magnesium

Alloys Green Innovative

Coatings

TM: MTU Aero Engines AG

H2020-Clean

Sky 2,

ENGINES

2017-2018 Validation of different Cr (VI)-free

alternatives for Al and Mg protection.

ANODISING

MTU Aero Engines AG

ZF Luftfahrttechnik GmbH

CROMITAL S.P.A.

Atotech Deutschland GmbH

MacDermid Enthone GmbH

Elementis Chromium LLP

…

02

Assessment overview for

Cr(VI)-free acids as

replacement for chromic

acid anodising

Corrosion

resistance

For some

applications

Repair

applications

Adhesion

Layer thickness

Compatibility

with substrates

Chromium Trioxide

Na & K Chromate/Dichromate

Source ECHA

ANODISING

Degreasing Rinsing Alkaline

etching Rinsing 1 Rinsing 2

Acidic

picking Rinsing 1 Rinsing 2 Anodising Rinsing 1 Rinsing 2

Impregnation

Cr(III)/Zr Rinsing 1 Rinsing 2 Sealer Rinsing 1 Rinsing 2

Improvements/challenge for REACH-compliant alternatives:

- Repeatability, upscaling effect, compatibility with customer in-house pretreatment

- Optimal parameters may vary with alloy type

- Total Cr-free process. Production of Cr(III) containing substances involves potential

exposure to Cr(VI). Cr (III) may contain Cr(VI) traces. Source AIRBUS

ANODISING

Project acronym Title Programme Start Date /

End Date Description

TARTASEAL Cr(VI)- free and energy efficient sealing of

TSA anodic films for corrosion protection

FP7-Clean Sky,

ECO 2011-2012 Development of green sealing for aircraft industry.

CO-PROCLAM Corrosion protective coating on light alloys

by micro-arc oxidation

FP7-Clean Sky,

ECO 2011-2013

MAO as an alternative to anodising-sealing process

in aeronautic applications.

SAA-SEAL

Corrosion protection of Al unpainted parts:

development of an appropriated Cr free

sealing process on thin SAA layer (≤5 µm)

FP7-Clean Sky,

ECO 2012-2014

Development of a silane-based sealing for coatings

obtained from SAA.

ValidateTSAA

Validate of TSAA coating technology.

Development of procedures and standards

manual. Technical and economic study.

FP7-Clean Sky,

ECO 2013-2014

Validation of a whole process (TSA, pre- and post-

treatments) and its implementation in industrial scale.

ChromFree Cr free surface pre-treatments and sealing of

Tartaric Sulphuric Anodising

FP7-Clean Sky,

ECO 2013-2015

Development of green pre-treatment and sealing for

coatings obtained from TSA.

SEALANT

Optimization and scale-up of final sealing of

SAA employing Design of Experiments

TM: LIEBHERR-Toulouse

H2020-Clean Sky

2, SYS 2016-2018

Assessment of two new eco-friendly sealing

formulations.-TITANIA

Cr-free Removal

Development and testing of innovative Cr

free anodic layers removal solution

TM: LIEBHERR-Toulouse

H2020-Clean Sky

2 2019-2020

Developing of a Cr free solution to remove anodic

layers obtained with new alternative treatments,

without deteriorating the aluminium alloy substrate.

MECAPROTEC

PRIMERS

AKZO Nobel Car Refinishes B.V.

Habich GmbH

Henkel Global Supply Chain B.V.

Indestructible Paint Ltd.

Finalin GmbH

Mapaero

PPG Industries (UK) Ltd

PPG Coatings SA

Aviall Services Inc.

Wesco Aircraft EMEA

Cytec Engineered Materials Ltd.

03

Source ECHA

Strontium Chromate

PRIMERS

Source ECHA

Application Matrix/Process Cr(VI)-free corrosion inhibitors Technical failure

Primer

specialty coatings

Epoxy

Polyurethane-based

primers

Confidential Cr(VI)-free corrosion inhibitors Corrosion resistance not sufficient

Adhesion not sufficient

Organic corrosion inhibitors like 5-methyl-

1H-benzotriazol

Corrosion resistance not sufficient

Chemical resistance not sufficient

Phosphate-based corrosion Inhibitors Corrosion resistance not sufficient

Magnesium-based corrosion inhibitors Corrosion resistance not sufficient

Compatibility with various substrate not sufficient

Electrocoat primer Various Corrosion resistance (long-term) not sufficient

MRO applications

Silane-based coatings Sol-Gel coatings Corrosion resistance not sufficient

Complex geometries

PRIMERS

Project

acronym Title Programme

Start Date

End Date Description

CR FREE

EPAINT

Development of non chromated,

REACH’s compliant anodic

electropaint, with very low volatile

organic compounds, for high

protection against electrochemical

corrosion of pickle aluminium alloys

used

FP7-JTI 2010-2014

Development of anaphoretic e-

coating technology for aerospace

aluminium components (focused on

Al 2024 alloy) at industrial pilot

scale.

ECOLAND

Development of ECO-friendly

protection procedures for LANDing

gear aluminium alloys

TM: LIEBHERR-Lindenberg

H2020-Clean Sky 2 2018-2019

Validation of eco-friendly surface

treatments for landing gear

aluminium alloys (focused on Al

7075 alloy). CIDETEC

ecoTECH

Development of innovative and

ECO-friendly airframe

TECHnologies from design to

manufacturing to improve aircraft

life cycle environmental footprint

H2020-Clean Sky 2 2016-2022 Proposal for Core Partners

PRIMERS

- +

e-

e-

Al a

lloy

Cath

od

e

An

od

e (w

ork

pie

ce)

+

-

-

-

-

-

+

+ -

-

-

-

-

-

-

+

+

+

+

+

+

+

+

+

Sta

inless S

teel

- e-coating + water

HARD CHROMIUM

Safran Aircraft Engines

[SNECMA]

MTU Aero Engines AG

…

04

Source ECHA/AIRBUS

There is no 1-to-1 replacement solution. The ideal solution for the future:

Hard Cr(III) electrolytic, where the challenge is to stabilize/control the crack

formation due to organic species.

Several alternatives have been qualified over the years, depending on

specific part requirements, i.e. Cr2O3 plasma or WCCo HVOF. The latest

one is hardened NiP.

Chromium Trioxide

Improvements/challenge for REACH-compliant

alternatives:

Fatigue behaviour

Cracking /porosity control

Total Cr-free process. Production of Cr(III) containing

substances involves potential exposure to Cr(VI). Cr

(III) may contain Cr(VI) traces and it is generate at

anodes during the electrolytic processes.

CADMIUM

Zn-Ni

05

Source SAFRAN/LIEBHERR

Cadmium Zn-Ni

Process type Electrolytic Electrolytic

Thickness (mm) 7-10 7-10

H-embrittlement Degassing required Degassing required

Difficulties REACH-impacted Alloy uniformity ( ±3 %)

Improvements/challenge for REACH-compliant alternatives:

Efficiency H-embrittlement

Alloy uniformity ( ±3 %)

What is needed?

Need to develop of PROCESS MONITORING TECHNIQUES

Need to develop of CORROSION MONITORING TECHNIQUES

Need to develop NEW REPRESENTATIVE ADVANCE TESTS

Need to develop of PREDICTIVE CORROSION TOOLS

© CIDETEC 2018