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Surface Treatment of Titanium
Christiane JungKKS Ultraschall AG, Steinen SZ
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
The Tribology of Precision
Swiss Tribology Meeting
SBB Centre Löwenberg in Murten, Switzerland
16. November 2007
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Outline:
1. KKS Ultraschall AG
2. Surface Treatment of Titanium
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
3Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
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KKS-Ultraschall AGUltrasonic & Surface Technologies
Profile
- Development and Production of Cleaning Units based on Ultrasonic Technology.
- Surface Finish and Cleaning of Metal Parts, in particular of Implants made from Titanium and Stainless Steel.
History
1982: Foundation of the Company KKS Keller H.P. 1999: Change to an „Aktiengesellschaft“
→ KKS Ultraschall AG – Ultraschall & Oberflächentechnik2006: New Building – “Medical Surface Center”2007: 25 Anniversary
Coworkers: ~ 55 (2007)
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
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2005
2006
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
Medical Surface Center
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ProductsUnits for Surface Treatment and Cleaning
Ultrasonic Generators
Small Ultrasonic Bath, 40-95 Liter
Ultrasonic Vibrators
One-Chamber Ultrasonic Unit (Cleaning, Rinsing, Drying) Automated Cleaning Unit
(Cleaning, Rinsing, Passivation, Drying)
Unit for ElectropolishingDry-Blasting Units
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
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Services
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
Titanium
Stainless steel
Metals
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Medical Surface CenterSurface Treatment of Implants and Instruments made from Titanium and Titanium Alloys
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
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Titanium
Surface properties are important !
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
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1. Protective effect (P)- chemical resistance; friction; wear; hardness; ….
The PDF-Effect of the Surface
„Surface Treatment“
2. Decorative effect (D)- color; brightness; haptic ….
3. Functional effect (F)- improvement of the interaction with other materials(i.e. metals, polymers, biological tissues, bone …)
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
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Outline:
2. Surface Treatment of Titanium
2.1. Passive Layer
2.2. Color-Anodizing (KKS01, TioCol)
2.3. Importance of Mechanical Pretreatment (KKS00)for the Quality of Color-Anodized Surfaces
2.4. Dark-Anodizing (KKS02, TioDark)
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
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2.1.1. The natural passive layer
Titanium + Oxygen ⇒ Titanium dioxide (natural oxidation)
[ Ti ] + [ O2 ] ⇒ [ TiO2 ]
titanium substrate
Titanium dioxide passive layer(TiO2)
(~ 5 nm thickness)
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
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2.1.2. The artificial passive layer
natural passive layer
titanium substrate
artificial passive layer
titanium substrate
Electrochemical Oxidation(„Anodizing“)Thermal OxidationChemical Oxidation
Oxidizing agents such as:
Nitric acid (HNO3)Hydrogen peroxide (H2O2)Thickness < 40 nm
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
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2.1.3. Electrochemical Oxidation („Anodizing“)
Thicker passive layer (up to ~ 300 nm)Protection against further corrosion.
Protective Effect
Functional EffectDecorative Effect
Color-Anodizing
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007“TioCol”
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2.2. Color-Anodizing (KKS01, TioCol) start
Electrochemical cell
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
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Electrochemical cell
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
2.2. Color-Anodizing (KKS01, TioCol) step 1
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Electrochemical cell
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
2.2. Color-Anodizing (KKS01, TioCol) step 2
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Increase of layer thickness changes the colordue to light ray interference.
Gasoline on water
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
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Colors are used as codes for implants and tools.
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
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Medical Surface Center
Electrochemical Cells
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
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Surface roughnessRa ~0.045 - 0.100 µm
Side-view topography
2.4. Importance of mechanical pretreatment ( KKS00 ) for the quality of color-anodized surfaces
grinding media
High brightness of the surfaces
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
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Microcrystals acting as grinding and polishing particles ? microscopic images; magnification 500
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
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pH ~ 5
Magnification 63
Granulate
impregnated with wax, plant and mineral oils, fatty acids, emulsifier, and oxides as grinding particles
Pretreatment with small-sized granulate combines mechanical with chemical treatment ?
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
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Surface Roughness of Titanium Discs
Ti 6Al 7Nbbefore anodizingsRa = 0.047 µm
color-anodized at 62 V sRa = 0.045 µm
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
(polished with granulate)
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Electrochemical cell
2.4. Dark-Anodizing (KKS02, TioDark)
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
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Main steps for Dark-Anodizing (KKS02, TioDark)
Oxygen evolutionColor formation
Titanium substrate
Conversion layer
Porous outermost layer
Start Sparking
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
Increasing voltage
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Raster Electron Microscopic Picture(cpTi, grade 2)
Titanium substrate
Conversion layer
Porous outermost layer
before anodizing
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
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Examples for dark-anodized titanium surfaces( TioDark )
(Ti 6Al 4V, porous layer removed)
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
afterbefore
before
after
before after
afterbefore
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sRa = 0.241 µm sRa = 0.327 µm
Surface Topography of untreated and dark-anodized Ti 6 Al 4 V - samples
sRa ~ 0.24 – 0.40 µm
Surface roughness for different samples of cpTi (grade 2 & 4), Ti6Al4V, Ti6Al7Nb)
before after
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
afterbefore
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Surface characterization by Raman spectroscopy
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
Rutile TiO2 Anatase TiO2Suggested assignment:Contributions of:
31Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
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Scratch testdark-anodized sample scratches color-anodized sample
(Ti 6Al 4V / Ti 6Al 4V - pair)
Scratch spots:Magnification: 63
Surface of dark-anodized sampleMagnification 63
Ti 6Al 4V
expected color in scratch spot
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
33Diamond cone 90°; velocity: 0.1 mm/s; distance: 5 mm; zero load: 1.0 mN; load: 20 mN; load cycles: 10
Scratch test(diamond / cpTi grade 4 - pair)
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
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Dependence of the friction coefficient on the sliding distance
CSM: standard tribometer, „ball on disc“ method
ball: steel 100Cr6
Friction: Steel/Titanium – Pair
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
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Initial friction coefficientsliding distance = 6.7 mm, scaled to untreated surfaces
CSM standard tribometer
ball: steel 100Cr6, 6mm ∅, dry; linear mode, ½ amplitude: 2mm, max linear speed: 2 cm/s, normal load: 250 mN, cycles: 470, acquisition rate: 10 Hz, temperature: 25°C, atmosphere: air, huminity: 35%CSM: standard tribometer, „ball on disc“ method
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
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Comparison: CSM nano tribometer (20 mN load) and standard tribometer (250 mN load)
Initial friction coefficientscaled to untreated surfaces
Steel/Titanium Pair
CSM nano tribometerDr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
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Nano- and micro-hardness of dark-anodized surfaces.
Indentation profil
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
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Lower initial friction coefficient.
Increased micro- and nano-hardness.
Increased layer thickness.
Very good haptic.
Dense, dark and low-reflective
Biocompatible
compared to untreated surfaces
TioDark
Summary
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
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Surface Treatment
A great challenge
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007
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Acknowledgement
CSM (Micro- and nano-hardness; tribology studies)
INNOWEP (Nano-scratch test, wear rate)
CSEM (Thickness measurements)
SGS Institute Fresenius (XPS depth profile analysis)
Fachhochschule der Nordwestschweiz (REM/EDX)
Technical University Berlin, Institute for Chemistry (Raman spectroscopy)
FRT Suisse AG (Surface topography analysis)
Dr. Christiane Jung, Swiss Tribology Meeting, Murten, 16. November 2007