New Nanotechnology Developments

for Corrosion Protection

„NanoEngeneering - Hannover Messe, 21.04.2010

Dr. Thomas John-Schillings

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Content

• Tasks of metal pretreatment

• Traditional metal pretreatment: Iron- and Zincphosphating

• Question about Phosphating

• Presentation of „Nanoceramics“ – Bonderite® NT-1 & TecTalis®

• Process

• Benefits

• Corrosion protection in comparison with traditional processes

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Why metal pretreatment?

• Prior to painting substrates are often:

• Dusty

• Oily (forming oils, temporary corrosion protection)

• Corroded (rust, welding scale)

• Pretreatment provides:

• Cleaning

• Paint Adhesion

• Better Corrosion Protection

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Traditional Metal Pretreatments

• Zincphosphating

• best corrosion protection

• excellent paint adhesion

• process difficult to monitor

• very cost intensive

• Ironphosphating

• simple, flexible process

• moderate process costs

• Low corrosion protection

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Why should Phosphatings being

replaced?

• very high sludge formation

• very narrow process operation window – lot of parameter

• difficult multi metal pretreatment

• many process steps – lot of active bathes

• high amount of heavy metals (Zn, Mn, Ni)

• environmental unfriendly process (energy, phosphate, COD,

heavy metals…)

Question: “Which aspects of Zinc-/Fe-Phosphating are mostly

unsatisfying?

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Iron-

phosphating

Bonderite® NT-1

Zinc-

phosphating

TecTalis®

Eisen-

phosphatierung

„Nanoceramics“ replace phosphating

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Which benefits provide „Nanoceramics“ with respect to

„Nanoceramics“ replace phosphating

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What are “Nanoceramics”

• phosphate free metal pretreatment process

• provides excellent paint adhesion and corrosion protection

• replacement of iron- or zincphosphating

• multimetal pretreatment process (steel, zinc, aluminium)

• forming a thin “ceramic” conversionlayer (Nanoceramics)

• application in existing lines (dip or spray)

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pH = 3.8 – 5.0

T = 10 - 50 ºC

time= 30 - 180 s

ZnO

Zn

Steel

ZrOXFy

H2ZrF6 Zn+2

H2ZrF6 + M + 2H2O ZrO2 + M2+ + 4H+ + 6F- + H2

M = treated substrate; Fe, Zn, Al, Mg

Nanocearmic coatings

Chemical Reaction

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5

250

1000

5000

10000

Zincphosphate

Ironphosphate

Chromates

““NanoceramicsNanoceramics

bigger Molecules

[nm]

100

50

AFM (Atomic Force Microscopy) AFM (Atomic Force Microscopy)

TecTalis TecTalis CoatingCoating

SEM (Scanning Electron Microscopy)SEM (Scanning Electron Microscopy)

Phosphate Phosphate CoatingCoating

Nanoceramic Coating

Dimensions

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Typical Bonderite® NT-1 process

• Alkaline cleaning – the only heated step

• DI-Rinse prior to Bonderite® NT-1

• Conversion coating with Bonderite® NT-1

(20 sec. or more)

• DI-Rinse after Bonderite® NT-1

• Optional: Dryer after Bonderite® NT-1

• Powder coat, wet paint, CED/AEDC

Cleaning RinseDI-

RinsePaintNT-1

DI-

Rinse

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TecTalis – process layout

typical typical ZincphosphateZincphosphate lineline

Cleaning Rinse Activation Phosphate. PassivationRinse DÍ-Rinse

typicaltypical TecTalis TecTalis processprocess

5555°°CC

Cleaning Rinse TecTalisTecTalis Rinse

230 m

180 m

DI-Rinse

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Corrosion protection and

paint adhesion

Corrosions tests

judgement of the area and the creep at the cut

• Constant climate test DIN EN ISO 6270-2• Neutral Salt spary DIN EN ISO 9227 AASS• Cycling climate test VDA 621 415 • Outdoor exposure VDA 621 414

Adhesion-tests

judgement before and after corrosion test

• cross hatch• stone chip -test• Erichsen-Tiefung

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Perfomance:

Bonderite® NT-1 vs FePhos

Bonderite® NT-1 Fe-Phosphate

• Customer sampes

• Creep after 500h NSS

• Bonderite® NT-1 (left)

• 2.2 mm creep

• Ironphosphate (right)

• 6,5 mm creep

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0,0

0,5

1,0

1,5

2,0

2,5

3,0

3,5

4,0

E-coat 1 E-coat 2 E-coat 3 E-coat 4 E-coat 5 E-coat 6

Creep at cut [U/2 in mm] Granodine 958

TecTalis

spec

Performance: Comparison

Tectalis® vs ZnPhos

70 cycles VDA – Steel + CDP

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Comparison of process costs

example:

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Performance – comparison

ZnPhos vs TecTalis

performance, e.g.

corrosion protection

Proces-

parameter

area i.O. results ZnPhos

areaarea i.Oi.O. . resultsresults TecTalisTecTalis

TecTalisTecTalisZnPhos

Specification

ProcessProcess windowwindow TecTalisTecTalis

Process window ZnPhos

automatical processcontrole (Lineguard Supervisor) for critical parameter possible!!

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Benefits of „Nanoceramics“ vs

Phosphating

• A lot of savings, e.g.

• Maintenance and Cleaning

• Water consumption

• Heating ( ambient temperature)

• Sludge disposal

• Result in: Process costs decrease

Efficiency Process

Environment Quality

• conversion at ambient temperature

• short contact time

• simple bath monitoring (pH)

• real multimetal process

• low energy consumption

• no toxic heavy metals

• phosphate free conversion

• no contribution to COD

• less disposal (sludge)

• no hazardous substances

• enhancement of corrosion

protection vs FePhos

• replacement of Zincphosphating in

often possible

• Compatible with Al, Zn, steel and

most available paint systems

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„Nanoceramics“ - References

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Thanks for your attention!