Ion Bombardment Treatments for Metallic and Polymeric Bio ... · BIOMEDICAL SURFACES 2006 Churchill...

Centre of AdvancedSurface Engineering

BIOMEDICAL SURFACES 2006 Churchill College, Cambridge, UK, 10/10/2006 /40

Ion Bombardment Treatments for Metallic and Polymeric Bio-medical Materials

Rafael J. Rodríguez


Centro de Ingeniería Avanzada de Superficies, AIN, E-31191 Cordovilla-Pamplona (Spain).

Ion Bombardment Treatments

for Metallic and Polymeric

Bio-medical Materials





1 Ion implantation in the frame of advanced surface treatments

2 Ion implantation treatment of metal alloys

3 Ion implantation treatment of polymers

4 Conclusions on bio-medical applications

PRESENTATION





Coating Substrate

Coatings always change the dimensions of the pieces and have an abrupt transition Ion implantation does not change dimensions and has a smooth transition to the substrate

Implanted region

COATINGS

ION IMPLANTATION

TREATMENT STRATEGIES





EFFECTS OF ION BOMBARDMENT

Ion Implantation is a ballistic treatment.

Depending on the bombardment energy, the dominant effect on the surface can be very different:

• Coatings (E < 100 eV)

• Sputtering (100 eV < E < 1000 eV)

• Implantation (E > 10.000 eV)

Typical energies for Ion Implantation industrial surface treatment are between 10.000 eV and 200.000 eV

Coatings

100 eV

1.000 eV

100.000 eV

Sputtering

Ion Implantation





In all cases, the relevant parameters are:- Ion(s) to be implanted- Energy- Dose

ION BOMBARDMENT STRATEGIES

ION BEAM IMPLANTATION (II) PLASMA IMMERSION IMPLANTATION (PI3)





1 1 eVeV 10 10 eVeV 100 100 eVeV 1 1 keVkeV 10 10 keVkeV 100 100 keVkeV 1 1 MeVMeV 10 10 MeVMeV

dE/dE/dxdx

elastic

inelastic

STOPPING POWER





Subtrate atoms “Oxide” Implanted atoms

Disordered regionImplanted layer

Crystaline region

ION IMPLANTATION RESULT





0 100 200 300 400 500 6000

2

4

6

8

10

1.5 1017 Si 200 KeV

6 1016 Si 110 KeV

3 1016 Si 55 KeV Total

% a

t.

Depth (nm)

Range and distribution of implanted ions can be calculated by using TRIM or PROFILE codes.

Codes help to:

• design the implantation

• design co-implantations

• estimate saturation limits

• estimate other effects:

• sputtering

• ionization...

SIMULATION OF THE ION IMPLANTATION RESULT





Tem

pera

ture

1200ºC

1000ºC

800ºC

600ºC

400ºC

200ºC

0,1 µm 1 µm 10 µm 0,1 mm 1 mm 10 mm

Plasma S.

Plasma Nitriding

Surfacehardening

Nitriding

Weldcoating

CVD

PA-CVD

PVDIon Impl.

TD

Carbonitriding

Carburising

TEMPERATURE vs. THICKNESS

Thickness





HARDNESS vs. THICKNESS10.000

5.000

2.000

1.000

500

200

0,1 µm 1 µm 10 µm 0,1 mm 1 mm 10 mm

Har

dnes

sH

V

Thickness

Ion Implant.

Nitriding

TD

Nitrocarburising

Plasma S.

Surface hardening

Weldcoating

PVD

CVD - Diamond

CVD

Carburising





Gas

Plasma

100 kV

Target

Targetchamber

Holder

Ion source Acceleration Chamber

Ion beam

Secondaryelectrons

For Nitrogen or other gas implantations it is enough to have:

• Gas ion source

• One acceleration step (100 keV)

• A target chamber with mechanical scanning

Again, the equipment operates at high vacuum (10-6 mbar)

NO MASS SEPARATION INDUSTRIAL ION IMPLANTER





TECVAC 223 Implanter

• Gas ion source

• No mass separation

• Beam intensities up to 3 mA

• Energies up to 100 keV

• Turbomolecular vacuum

• 2 axis mechanical scanning

• Automated control

NO MASS SEPARATION INDUSTRIAL ION IMPLANTER





Ion source

Magneticfield

WindowHeavy ionsFoccussing,

scanning, etc.

Ion beam

Treatmentchamber

Light ions

MASS SEPARATION INDUSTRIAL ION IMPLANTER

For all species implantation, a mass separation system is needed.

That lead to more complex and expensive equipment.





WHICKHAM IBS

AIN - ion implanter

• Freeman ion source

• Mass separation

• Beam currents up to 5 mA

• Beam energy up to 200 keV

• Cryogenic vacuum

• 5 axis mechanical scanning

• Automated control

MASS SEPARATION INDUSTRIAL ION IMPLANTER





H1

He2

Li3

Be4

B5

C6

N7

O8

F9

Ne10

Na11

Mg12

Al13

Si14

P15

S16

Cl17

Ar18

K19

Ca20

Sc21

Ti22

V23

Cr24

Mn25

Fe26

Co27

Ni28

Cu29

Zn30

Ga31

Ge32

As33

Se34

Br35

Kr36

Rb37

Sr38

Y39

Zr40

Nb41

Mo42

Tc43

Ru44

Rh45

Pd46

Ag47

Cd48

In49

Sn50

Sb51

Te52

I53

Xe54

Cs55

Ba56

La57

Hf72

Ta73

W74

Re75

Os76

Ir77

Pt78

Au79

Hg80

Tl81

Pb82

Bi83

Po84

At85

Rn86

Fr87

Ra88

Ac89

Ce58

Pr59

Nd60

Pm61

Sm62

Eu63

Gd64

Tb65

Dy66

Ho67

Er68

Tm69

Yb70

Lu71

Th90

Pa91

U92

Np93

Pu94

Am95

Cm96

Bk97

Cf98

Es99

Fm100

Md101

No102

Lr103

TYPICAL ELEMENTS TO BE IMPLANTED





PRACTICAL SURFACE ANALYSIS: GD-OES

Dischargechamber

DC orRF

Rowlandcircle

Gas (Ar)

Detectors (PM)

Secondarywindows

Diffractiongrid

Primarywindow

Spectrometer

Glow Discharge Optical Emission Spectroscopy (GD-OES) allows to obtain precision quantitative composition profiles in few minutes. No UHV is required. Just well polished flat implanted samples.





0,0 0,1 0,2 0,3 0,4 0,5

0

10

20

30

40

50

60

70

80

90

100

110

N por RF

Ti por RF

N por DC

Ti por DC

% a

tóm

ico

Depth (μ m )

GD-OES analysis of a Ti sample implanted with 8*1017 N2+

PRACTICAL SURFACE ANALYSIS: GD-OES





Friction coefficient before and after implantation

0

0,2

0,4

0,6

0,8

1

AISI 316 Al 7075 Tit anio

Coe

ficie

nte

de

Fric

ción

Sin implantarImplantado

Hardness before and after implantation

0

1000

20003000

4000

5000

AISI 316 Al 7075 TitanioDure

za U

nive

rsal

(N

/mm

2 )

Sin implantarImplantado

EFFECTS ON THE IMPLANTED MATERIALS

INCREASE OF HARDNESS• Precipitation of nitrides, carbides, etc.• New alloys formation• Cross-linking of polymersBETTER TRIBOLOGICAL BEHAVIOUR• More homogeneous / coherent oxide layersRESISTANCE TO ROLLING FATIGUE• Compressive tensions at the surfaceCORROSION RESISTANCE• New alloys with better resistance• Better adhered and compact oxide layersOXIDACION RESISTANCE• Surface doping with lanthanide elements

R. Rodríguez, A. Sanz, A. Medrano and J.A. García-Lorente.Tribological properties of ion implanted Aluminium alloys.Vacuum 52 (1999), 187.





ELEMENTS THAT CAN BE IMPROVED BY NITROGEN IMPLANTATION

H1

He2

Li3

Be4

B5

C6

N7

O8

F9

Ne10

Na11

Mg12

Al13

Si14

P15

S16

Cl17

Ar18

K19

Ca20

Sc21

Ti22

V23

Cr24

Mn25

Fe26

Co27

Ni28

Cu29

Zn30

Ga31

Ge32

As33

Se34

Br35

Kr36

Rb37

Sr38

Y39

Zr40

Nb41

Mo42

Tc43

Ru44

Rh45

Pd46

Ag47

Cd48

In49

Sn50

Sb51

Te52

I53

Xe54

Cs55

Ba56

La57

Hf72

Ta73

W74

Re75

Os76

Ir77

Pt78

Au79

Hg80

Tl81

Pb82

Bi83

Po84

At85

Rn86

Fr87

Ra88

Ac89

Ce58

Pr59

Nd60

Pm61

Sm62

Eu63

Gd64

Tb65

Dy66

Ho67

Er68

Tm69

Yb70

Lu71

Th90

Pa91

U92

Np93

Pu94

Am95

Cm96

Bk97

Cf98

Es99

Fm100

Md101

No102

Lr103





SURFACE MECHANICAL PROPERTIES: HU and E

Universal Hardness (HU) can be

measured from 1mN, till 1000 mN of

maximum load by using a

Fischeroscope microindentation

equipment. At 2mN, the indentation

depth in metals is less than 0,2 microns

Elastic and plastic hardness as well as

elastic modulus can be obtained from

the load – unload curves.





0,0 0,5 1,0 1,5 2,0

0,02

0,04

0,06

0,08

0,10

0,12

0,14

sin implantar

4e17 N+/cm2

8e17 N+/cm2

4e17 N2+/cm2

8e17 N2+/cm2

Prof

undi

dad

(μm

)Carga (mN)

UNIVERSAL HARDNESS TESTS ON IMPLANTED SURFACES

J. A. García, A. Guette, A. Medrano, C. Labrugere, M. Rico, M. Lahaye, R. Sánchez, R. Martínez and R. J. Rodríguez: Nitrogen ion implantation on Group IV metals: chemical, structural and tribological study, Vacuum 64, 343 (2002).

N+ Implanted Zirconium at different doses

LOW LOADS:

Low indentation loads are needed because the implanted region is thinner than few tenths of micron.

DEFFECTLESS SURFACES:

Hardness tests can be carried out only on mirror polished surfaces.

BETTER ON SOFT METALS:

Changes in hardness are more visible on soft metals.





02468

10121416

Al-7

075 Ti Zr Hf V N

b Ta Cr

Mo W

ReferenceLow doseHigh dose

HARDNESS (GPa) OF NITROGEN IMPLANTED METALS

J. A. García, A. Guette, A. Medrano, C. Labrugere, M. Rico, M. Lahaye, R. Sánchez, R. Martínez and R. J. RodríguezNitrogen ion implantation on Group IV metals: Chemical, structural and tribological study. Vacuum 64 (2002), 343.J. A. García, R. J. Rodríguez, A. Medrano, R. Sánchez, M. Rico, R. Martínez, B. Lerga, C. Labrugere, M. Lahaye, and A. GuetteStudy of the tribological modifications induced by nitrogen implantation on group V metals. Surface and Coatings Technology 158-159 (2002), 653.R. Martínez, J. A. García, R. J. Rodríguez, B. Lerga, C. Labrugere, M. Lahaye, and A. GuetteStudy of the tribological modifications induced by nitrogen implantation on groupVI: Cr, Mo and W. Surface and Coatings Technology 174-175 (2003), 1253.





APPLICATIONS FOR HIP AND KNEE PROSTHESIS





ION IMPLANTATION ON POLYMERSThe main effect of ion implantation on polymers is the increase in hardness due to the cross linking of polymer chains because the ionisation produced by ion bombardment.

The effect is more intense for light and energetic ions because they loss energy preferentially by ionisation (inelastic stopping power), have minor chain breakage effects (elastic stopping power) and goes deeper.

Nitrogen implantation on Polyethylene

Helium implantation on Polyethylene





INCREASE OF POLYMER HARDNESS

BY HIDROGEN IMPLANTATION

LOW DOSE IMPLANTATION ON POLYCARBONATE:

A low dose implantation is enough to produce a dramatic increase of hardness.

HU vs. HV:

Elastic recovery reach the 100% for a implanted surface. That would lead to an apparently infinite HV.

R. Rodríguez, J. A. García, R. Sánchez, A. Pérez, Blas Garrido and J. Morante:Modification of surface mechanical properties of polycarbonate by ion implantation.Surface and Coatings Technology 158-159 (2002), 636.





Universal Hardness of samples implanted with 1e16 ion/cm2

0

100

200

300

400

500

600

Sinimplantar

N+ H2+ D2+ H+ D+

Implanted ions

N/m

m2

2 mN5 mN10 mN25 mN200 mN

Reference

ION IMPLANTATION OF POLYCARBONATE

R. Rodríguez, J. A. García, R. Sánchez, A. Pérez, Blas Garrido and J. Morante:Modification of surface mechanical properties of polycarbonate by ion implantation.Surface and Coatings Technology 158-159 (2002), 636.





a b c d

Visual inspection of samples after the implantation with different doses and ions shows that:

• After the treatments a change in the surface color was observed, the higher the dose the darker the color.

• Nitrogen implantation produced a darker surface than Helium.

IMPLANTATION OF UHMPWD SAMPLES

a) UHMWPE sample implanted with 1x1016 ions/cm2 of N.

b) UHMWPE sample implanted with 5x1015 ions/cm2 of N.

c) UHMWPE sample implanted with 5x1015 ions/cm2 of He.

d) Untreated UHMWPE sample.

UHMWPE SAMPLES AFTER IMPLANTATION





NITROGEN EFFECTS ON UHMWPE

The TRIM stopping power calculations shows that:

• The range of Nitrogen implantation on UHMWPE, at 90 keV, is about 400 nm.

• A 80,5% of the bombardment energy is lost through inelastic mechanism and lead to ionization of the polymer chains.

• The other 19,5% of the energy is lost through elastic mechanism, leading to chain breakdown.

TRIM CALCULATION OF THE NITROGEN RANGE ON UHMWPE AND ENERGY LOSS MECHANISMS





HELIUM EFFECTS ON UHMWPEThe TRIM stopping power calculations shows that:

• The range of Helium implantation on UHMWPE, at 90 keV, is about 1000 nm.

• A 94,5% of the bombardment energy is lost through inelastic mechanism and lead to ionization of the polymer chains.

• The other 5,5% of the energy is lost through elastic mechanism, leading to chain breakdown.

TRIM CALCULATION OF THE HELIUM RANGE ON UHMWPE AND ENERGY LOSS MECHANISMS





RESULTS OF INDENTENTION TESTS

0.2 0.4 0.6 0.8 1.0 1.2 1.4

30

40

50

60

70

80

90

100

110

SinImplantar

He 5x1015iones/cm2

Muestra circular 1 100 KGy TT 130º

Dur

eza

Uni

vers

al (N

/mm

2 )

Profundidad (μm)

UNIVERSAL HARDNESS IN (N/mm2)

SAMPLE 2 mN

UNTREATED 34 ± 2

IMPLANTATION 1 - N 5x1015 43 ± 4

IMPLANTATION 2 - N 1x1016 42 ± 8

IMPLANTATION 3 - He 5x1015 53 ±6

IMPLANTATION 4 - He 1x1016 59 ± 5

IMPLANTATION 5 - He 2x1016 40 ± 9

PROFILE OF HARDNESS vs. DEPTH FOR IMPLANTATION 4 AND UNTREATED SAMPLE HU at 2mN OF FINAL LOAD





0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.620

40

60

80

100

120

140

160

180 Implantaciones sobre TT 130º

He 1x1016iones/cm2

He 5x1015iones/cm2

N 1xE16 iones/cm2

Sin implantar

Dur

eza

Uni

vers

al (N

/mm

2 )

Profundidad (μm)


COMPARISON OF HARDNESS PROFILES OF THE IMPLANTATIONS CARRIED OUT ON UHMWPE SAMPLES WITH PRETREATMENT AT 130ºC





0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.620

40

60

80

100

120

140

160

180 Implantaciones sobre TT 150º

He 2x1016 iones/cm2

N 1x1016iones/cm2

N 5x1015iones/cm2

Sin Implantar

Dur

eza

Uni

vers

al (N

/mm

2 )

Profundidad (μm)

RESULTS OF INDENTATION TESTS

COMPARISON OF HARDNESS PROFILES OF THE IMPLANTATIONS CARRIED OUT ON UHMWPE SAMPLES WITH PRETREATMENT AT 150ºC





0,2 0,4 0,6 0,8 1,0 1,2 1,4 1,620

40

60

80

100

120

140

160

180

He 1x1016atm/cm2

He 5x1015 atm/cm2

N 1x1016atm/cm2

N 5x1015atm/cm2

sin implantar

Dur

eza

Uni

vers

al (N

/mm

2 )

Profundidad (μm)


COMPARISON OF HARDNESS PROFILES OF THE IMPLANTATIONS WITH ALL THE DIFFERENT DOSES AND IONS





ELASTIC MODULUS AND ELASTIC WORK

UHMWPE + PRETREATMENT 130ºC

0

0,2

0,4

0,6

0,8

1

1,2

ref 1e16 N 5e15 He 1e16 He

E/(1

-v2)

(Gpa

)

UHMWPE+PRETREATMENT 130ºC

01020304050607080

ref 1e16 N 5e15 He 1e16 He

%W

e

(a) ELASTIC MODULUS AND (b) % OF ELASTIC WORK OF THE IMPLANTED SAMPLES, MEASURED AT FINAL LOAD OF 2mN.

a b





PLASMA IMMERSION ION IMPLANTATION

Plasma Immersion Ion Implantation (PI3) has been claimed as the future solution of the ion implantation problems (line-of-light process, sequential process...).

The no directional intense bombardment can increase the temperature. That would lead to a combined ballistic - diffusionalprocess.

PI3 is an excellent alternative to conventional processes for treating large series of small complex shape components like stents





Stents are being extensively employed in many surgical operations.

There are some concerns about the stability of stents that have to remain implanted in the human body. It is worth to mention the effects of metal ion migration (possible toxicity).

To prevent the migration of undesired ions, (e.g. Nickel) a possible technique is the creation of an oxide barrier. Ion implantation of Oxygen could be a good strategy, but the ordinary line-of-sight ion implantation process is not adequate to implant thousands of small components.

APLICATIONS ON STENTS





OXYGEN PLASMA IMMERSION IMPLANTATION ON STEEL

0,00 0,02 0,04 0,06 0,080

10

20

30

40

50

60

70

80 O2

10kV 20kV 30kV

%A

t

Profundidad (μm)0,00 0,02 0,04 0,06 0,08

0

2

4

6

8

10

12

14

16

18

20Ni

10kV 20kV 30kV

%A

t

Profundidad (μm)

PI3 leads to saturated implantation profiles, which goes deeper as a function of the energy.

In the case of Oxygen implanted on stainless steel, it can be shown how the oxide barrier confines the Nickel at increasing depth.





II

PI3

In spite of its functional advantages, PI3 can lead to more relevant surface heating as well as to increases of roughness (e.g., more than 10 times in the case of Al alloys)

PLASMA IMMERSION ION IMPLANTATION





FINAL REMARKS

• Ion Implantation has demonstrated to be an effective technique for the prevention of wear, excessive friction and some oxidation and corrosion problems of metal alloys employed in medical implants and devices (stainless steel, Titanium alloys, CrCo, NiTinol...).

• In addition, other benefical effects of ion implantation have been reported: implantation of CO+ ions seems to facilitate the bone growth and integration. Theimplantation of Ag+ has bacteriocide effects. The implantation of oxigen allows tocreate difusional barriers for toxic ions...

• The ion implantation treatment of polymers is still more promising, and the requireddose is 10 – 20 times smaller.

• Ion implantation is economically affordable when size and geometry collaborate to short times of treatment per unit. Future developments like PI3 could lead to even cheaper treatments.





AIN - Centre of Advanced Surface Engineering

• Private technological center, founded in 1963• Association of 157 companies• Employees (2005): 121 (15 AIN - CIAS)• Clients (2005): 1085 (90 AIN - CIAS)

e-mail: [email protected]

Ion Bombardment Treatments for Metallic and Polymeric Bio ... · BIOMEDICAL SURFACES 2006 Churchill...

Documents

Transcript of Ion Bombardment Treatments for Metallic and Polymeric Bio ... · BIOMEDICAL SURFACES 2006 Churchill...