THE ANNALS OF UNIVERSITY ldquoDUNĂREA DE JOS ldquo OF GALAŢI FASCICLE VIII 2004 ISSN 1221-4590

TRIBOLOGY

52

CONTRIBUTIONS IN PVD PROCESSING OF THE CARBON AND MoS2 DOPED TiAlNC NANOCOMPOSITE AS SELF-LUBRICATED HARD COATING FOR

WEAR PROTECTION OF THE MECHANICAL COMPONENTS

Dominic BIROacute

Engineering Department of bdquoPetru Maiorldquo University Targu-Mures Romania biroengineeringuttgmro

ABSTRACT Additives of amorphous carbon and MoS2 have been proved to be operative in

controlling the microstructure and tribological properties of self-lubricated TiAlCN thin films Tailored nanocomposite thin films of multicomponent and multiphase materials have been performed by DC reactive UM magnetron co-sputtering of TiAl TiC and MoS2 target materials in ArndashN2 respectively C2H2 and CH4 as carbon precursor gases Different PVD sputtering process parameters with influence on grain size and grain separation by amount of the amorphous phases were tested at substrate bias of ndash90 V and substrate temperature of 350 degC Microstructure investigations of as deposited coatings performed by XTEM analysis and their tribological behavior indicate that formation of nanostructures can be controlled by selecting appropriate materials combination concentration and deposition parameters

KEYWORDS self-lubricated TiAlCN nanocomposite hard coatings C + MoS2

INTRODUCTION

It is commonly known that transition metal-based nitride and carbo-nitride thin film coatings provide favorable surface attributes of engineered metal components Architectures of tribological and multifunctional coatings are patented by the techno-logy developers [1-3] The successful of nanoscalled multilayer hard coatings applied as protection against the high temperature oxidation and wear of components and tools it is hardly dependent on the adhesion by interface layer crack propagation and fatigue properties of base material and of the multi-phased nanocomposite coating material The current coatings provide only a short term resistance to the hot corrosion while in the automotive and especially aerospace industry there is a great demand for coatings which can provide protection for long term at a temperature up to 900 degC Moreover there is a strong demand from the processing industry for the performance increasing of metal cutting and forming tools exposed to a combined wear and hot corrosion

Recently promising results have been obtained by applying of sputter-deposited structures of Ti-Al based nitride and carbo-nitride coatings which

demonstrated reasonable mechanical properties [4] By selecting of TiAl-based selflubricated nitride and carbide compounds for nanostructuring of the coatings we can get an unsurpassed durability to harsh operation conditions for long term protection of components However these technical objectives can be realized only with the development of the scientific understanding and by optimization of thin film properties

The fundamental problems that are inseparable are related to the three main regions of the coatingsubstrate system namely the interface the bulk and the surface of the coating The optimized process parameters are pathway to the scientific understanding of the new processes in structure evolution of multicomponent nitride films the role of minority additives and trace elements the intrinsic stress origin of superhardness toughness oxidation mechanisms etc

Our firstly introduced fuzzy control to the unbalanced magnetron sputtering technique demonstrated opportunity for reproducible preparation of designed structures of Ti-Al-N compound thin film by applying this control system [5] The aim of this research work was

a) fuzzy-logic controlled preparation of TiAlNC multilayer coatings doped with amorphous carbon and MoS2 as solid lubricants performed in a modulated structures

THE ANNALS OF UNIVERSITY ldquoDUNĂREA DE JOS ldquo OF GALAŢI FASCICLE VIII 2004 ISSN 1221-4590

TRIBOLOGY

53

b) study of carrier gas influence on coating growth In frame of this paper will be presented some of our

new results concerning to the applicability of this control system based on a proper computer software program developed and adapted for UM sputtering control technique

2 EXPERIMENTAL CONDITIONS AND CONCLUSIONS

The experimental research activities are running in

frame of Thin Film Research Laboratory of ldquoPetru Maiorrdquo University for development of nanocomposite hard coatings The scientific co-operation with Sapientia University from Targu-Mures and the technical support from the industrial SME-partner ldquoDuumlrkopp-Adlerrdquo Ltd are related to the better understanding of the interdependency of process parameters - coating structure microstructure- properties

The innovative design of three new magnetron sputtering sources and independently softwar control of the DC powered sputtering targets materials (planar rectangular sheets with dimensions of 12 x 80 x 160 mm3 with composition TiAl =5050 at TiC =5050 at and MoS2 originated from Plansee GmbH Austria) were used in co-deposition process of multiphase and multielemental compound phase formation

An UHV vacuum chamber of about 75 liter made from austenitic stainless steel has been built for implementation of three newly designed highly unbalanced magnetron sources with opportunity of controlling the strongly coupled closedunclosed magnetic field geometry A planetary rotatable substrate carrier and UV radiativ heater were used for uniform coating of substrate and for thermal degassing of the residual adsorbed gases from the vacuum vesselrsquos walls

The WC-Co hard metal and Si(100) substrates were ultrasonically degreased and cleaned in trichloroethylene and in acethone by using of an US washer End-vacuum conditions were established by a turbomolecular pump (AIRCO- Temescal 540 ls TMP) for plim =5middot10-6 mbar Vacuum conditions were evaluated by an ULVAC ion-gauge vacuum sensor and an UHV GI-N3 gauge controller for the selected dynamic pressure of pd = (2hellip3)10-3 mbar a throttle-valve was actuated via a close-loop feedback control unit for conductance controlling of TMP admission Substrates were resistively heated (ts= 400 ordmC) and electrically biased (Us=- 90 V) on a ground independent Mo-boat used as sample holder for a target-substrate distance of about dt-s= 130 mm disposed in front of the DC drived UM-sputter guns Argon gas admission was manually adjusted by use of a needle-valve Reactive gases of N2 respectively C2H2 and CH4 were

admitted by mass flow meters (GFM-17 Aalborg USA) and controlled by an APC 216 Granville-Phillips Automatic PressureFlow Controller unit

Reactive sputtering experiments for deposition of compositionally graded TiAlN respectively C and MoS2 doped TiAlNC multilayer structure were performed in fuzzy-logic process control mode of sputtering power During of deposition process a flow chart of selected process parameters were saved for mapping of in situ deposition conditions

The surface-oxidized monocrystalline n-type Si(100) substrates and mirror polished WC-Co of 15 x 5 x 12 mm hard metal substrates were selected for XTEM microstructure investigation respectively for tribological evaluation of the coatings The main process parameters were defined for preparation of the Ti-Al-N and carbon doped Ti-Al-N samples which are listed in Table 1 The flow rate of N2 reactive gas was controlled for qin_N2 = 04 Nlh by the automatic APC controller Argon gas flow rate of qin_Ar = 16 Nlh was adjusted by needle-valve for a dynamic pressure of pd= 2middot10-3 mbar The time intervals of power pulse width dtaD_min respectively dtaD_max were selected in accordance with the software controlled Pmin and Pmax cycles of discharge power levels

TABLE 1 The main experimental parameters Sample symbol

Coating structure

Compo-nents

Pmax

[watt] Pmin

[watt] NC_23 Modulated TiAl-N 570 388 NC_24 Modulated TiAl-N 505 366 NC_25 Modulated TiAl-N 550 360 NC_26 Modulated TiAl-N 573 372 NC_27 Modulated TiAl-N 794 521 NC_28 Modulated TiAl-N 616 404 NC_33 Isotrope

bilayer TiAl-N 545

600 545 600

NC_29 Modulated TiAlN-C 834 547 NC_30 Modulated TiAlN-C 700 460 NC_31 Modulated TiAlN-C 463 304 NC_32 Modulated TiAlN-C 535 351 NC_34 Modulated TiAlN-C 800 525 NC_35 Isotrope TiAlN-C 505 505 NC_36 Isotrope TiAlN-C 627 627 NC_37 Modulated TiAlN-C 630 410 NC_38 Isotrope TiAlN-C 465 465 NC_39 Modulated TiAlN-C 673 438 NC_40 Modulated TiAlN-C 706 460 NC_41 Isotrope TiAlN-C 721 721 NC_42 Isotrope TiAlN-C 490 490 NC_43 Modulated TiAlN-C 635 413 NC_44 Modulated TiAlN-C 623 405 NC_45 Modulated TiAlN-C 645 420 NC_46 Modulated TiAlN-C 680 443

THE ANNALS OF UNIVERSITY ldquoDUNĂREA DE JOS ldquo OF GALAŢI FASCICLE VIII 2004 ISSN 1221-4590

TRIBOLOGY

54

3 EXPERIMENTAL RESULTS AND CONCLUSIONS

Tribological testing of the TiAlCN coated WC-

Co samples has been performed by dr H Haefke (CSEM ndashTribology Laborator Neuchacirctel Switzerland) in frame of the EU NANOCOMP Project using the following standard test conditions for the friction and wear characterisation of the samples (fig 1) Test type SRV (oscillating movement of the counterpart) Counterpart oslash6 mm 100Cr6 steel ball Normal load 30 N Initial Hertzian pressure 26 GPa Oscillating speed 3 cms Oscillating frequency 75 Hz Stroke 2 mm Test stop criterion 19800 cycles (approx 500 m of sliding)

Tribological curve of Sample 28

0

02

04

06

08

1

12

0 5000 10000 15000 20000

Number of passes

Coe

ffici

ent o

f fric

tion

Tribological curve of Sample 43

0

02

04

06

08

1

12

0 5000 10000 15000 20000

Number of passes

Coe

ffici

ent o

f fric

tion

Fig1 Exemple of evaluated friction coefficient in

SRV tribological test for TiAlN coated NC-28 sample and TiAlCN coated NC-43 sample prepared in similar

controlled condition of power modulation ranging between 600400 W

Microstructure evaluation of as deposited

coatings by transmission electron microscope investigation has been performed on cross section of the ion beam thinned samples The XTEM image of sample NC-28 indicate a competitive growth mode of the columnar like grains perpendicular oriented to the

surface of the substrate (fig 2) The inset of this figure shows the selected area electron diffraction pattern (SAED) from the near substrate surface region The spotty-distributed electron reflections in the Deby-Scherrer rings show a well crystallised structure evolution with a (111) preferred orientation

Fig 2 Bright field XTEM image of the thick TiAlN

coating (samples NC-28) with a well defined competitive columnar microstructure evolution

Figure 3 indicate the dark field XTEM image of

same sample taked by (111) SAED reflection It can be concluded that the TiAlN coatings are not sensitive against the power modulation at least for 600400 W

However a multilayer structure of the TiAlCN coating was identified for the similar power modulation while amorphous carbon phase forming is started by the doping of the condensed phase with C additive (fig 4) The XTEM investigation performed for microstructure evaluation of TiAlN-C (NC-45 sample for 645420 W) indicate a modulated multilayer structure ranging between a vawy modulated interface of microcrystalline and a nanocrystalline amorphous sublayer system of the deposited coating (fig 4)

The thickness of the compound layers increases with increasing of pulse width and amplitude of the power modulation The bright zone of nanocrystalline amorphous interlayers are produced by a reduced Pmin sputtering power while the microcrystalline darker interlayers are produced during of sputtering with Pmax a higher discharge power level

THE ANNALS OF UNIVERSITY ldquoDUNĂREA DE JOS ldquo OF GALAŢI FASCICLE VIII 2004 ISSN 1221-4590

TRIBOLOGY

55

Fig 3 Dark field XTEM image of the TiAlN coating (samples NC-28) revealed that power modulation no changed the columnar like growth of the coatingrsquos

microstructure

Fig 4 BF XTEM image of the multilayered TiAlCN

(sample NC-45) coating prepared by fuzzy controlled power modulation of the sputtering source between

Pmax =645 watt and Pmin= 420 watt

At a higher power modulation (sample NC-34 prepared with 800500 W) the TiAlNC coating system is composed of two crystal phases with a layered-columnar microstructure (fig 5)

The SAED pattern of TiAlNC coating and the Process Diffraction analysis indicate an strengthened (200) preferred orientation and the existence of two phases (marked on figure 5 by red and blue arrows) presumable due to a distorted rhomboid-phase of the cubic NaCl-type TiAlN structure phase

TiAlNC

(111)(200)

Fig 5 BF-XTEM image of TiAlCN (sample NC-34) performed by a higher power modulation

of 800500 W The SAED pattern and the Process Diffraction analysis indicate

the existence of two phases

THE ANNALS OF UNIVERSITY ldquoDUNĂREA DE JOS ldquo OF GALAŢI FASCICLE VIII 2004 ISSN 1221-4590

TRIBOLOGY

56

(111)

(200)

NC28 modulated 45 sec

without C

NC45 modulated 45 sec

NC44 modulated 25 sec

Fig 6 Characteristic X-ray diffraction (XRD) pattern of the TiAlN and TiAlCN coatings indicate a texture modification from (111) to (200) and a grain size lowering by carbon element doping of TiAlN

Fig 7 The plasma distribution of the DC excited sputtering process of MoS2 and TiAl targets in mixture of Ar N2 and C2H2 gases as was viewed through the window of the new DC 3UM

sputtering system equipped with TiAl TiC and MoS2 targets The performed X-ray diffraction investigation

(XRD) for crystalographic structure analysis also indicate the changes of the preferred crystal orientation from (111) to (200) and the decreasing of the grain size with increasing concentration of the C doping element (fig 6)

Our developed fuzzy-logic controlled reactive sputtering system was tested for deposition of multiphase and multi-elemental Ti-Al-C-N-Mo-S

self-lubricated compound thin film coatings (fig 8) and the very recently results indicate that industrial application of multi-layer coatings tailored for high adhesion wear resistance with a friction coefficient lower than 02 and super-hardness up to tens of GPa nowadays becomes a reality for protection of metal components Detailed information about these results will be published in a distinct paper

THE ANNALS OF UNIVERSITY ldquoDUNĂREA DE JOS ldquo OF GALAŢI FASCICLE VIII 2004 ISSN 1221-4590

TRIBOLOGY

57

Fig 8 Bright field-XTEM micrograph of multi-layer structured MoS2 and carbon doped TiAlCN coating deposited on Si(100)SiOx substrate (B-4 Sample investigation performed with a Philips CM 20 TEM microscope by Prof P B Barna from Research Institute for Technical Physics and Material Sciences Hungarian Academy of Sciences Budapest) The 5 microm thick coating was deposited by started from the substrate of SiSiOx in the following structure Ti-Al alloyed adhesion layer gradient composition TiAlN transition layer columnar TiAlCN hard layer superhard nc-TiAlCNa-CH nanocomposite layer C-fiber enforced MoS2 doped TiAlCN transition layer C and MoS2 doped nc-TiAlCNa-C layer system

ACKNOWLEDGEMENTS

This work was partly supported by the EU

NANOCOMP project Contract No G5RD-CT2001-00578 The author is greatly indebted to the KFKI-Condensed Matter Research Center and to the NATO Science Fellowship Programme-Hungary-2002 for awarding visiting fellowship grants The grants awarded to DB by KPI-EMTE respectively by MEC-CNCSIS also are gratefully acknowledged The author would like to thank sincerely to BBPfor the XTEM and HH for tribological investigations performed in frame of EU NANOCOMP project

REFERENCES 1 Renevier NM Lobiondo N Fox VC Teer DG Hampshire J 2000 Performance of MoS2metal composite coatings used for dry machining and their industrial applications Surface and Coatings Technology 123 p 84-91 2 Fox V Teer DG Hampshire J Wear resistant MoS2 coatings (private communication) 3 Camino D Jones AH S Mercs D Teer DG High performance sputtered carbon coatings for wear resistant application Magnetron Ion Platinrdquo UK Patent No GB 2 258 343 B 4 Zehnder T Schwaller P Munnik F Mikhailov S Patscheider J 2004 Journal of Applied Physics Vol 95(8) p 4327-4334 5 Manaila A Devenyi Biro D David L Barna PB Kovacs A 2002 Multilayer TiAlN coatings with composition gradient Surface and Coatings Technology 151-152 p 21-25

THE ANNALS OF UNIVERSITY ldquoDUNĂREA DE JOS ldquo OF GALAŢI FASCICLE VIII 2004 ISSN 1221-4590

TRIBOLOGY

53

b) study of carrier gas influence on coating growth In frame of this paper will be presented some of our

new results concerning to the applicability of this control system based on a proper computer software program developed and adapted for UM sputtering control technique

2 EXPERIMENTAL CONDITIONS AND CONCLUSIONS

The experimental research activities are running in

frame of Thin Film Research Laboratory of ldquoPetru Maiorrdquo University for development of nanocomposite hard coatings The scientific co-operation with Sapientia University from Targu-Mures and the technical support from the industrial SME-partner ldquoDuumlrkopp-Adlerrdquo Ltd are related to the better understanding of the interdependency of process parameters - coating structure microstructure- properties

The innovative design of three new magnetron sputtering sources and independently softwar control of the DC powered sputtering targets materials (planar rectangular sheets with dimensions of 12 x 80 x 160 mm3 with composition TiAl =5050 at TiC =5050 at and MoS2 originated from Plansee GmbH Austria) were used in co-deposition process of multiphase and multielemental compound phase formation

An UHV vacuum chamber of about 75 liter made from austenitic stainless steel has been built for implementation of three newly designed highly unbalanced magnetron sources with opportunity of controlling the strongly coupled closedunclosed magnetic field geometry A planetary rotatable substrate carrier and UV radiativ heater were used for uniform coating of substrate and for thermal degassing of the residual adsorbed gases from the vacuum vesselrsquos walls

The WC-Co hard metal and Si(100) substrates were ultrasonically degreased and cleaned in trichloroethylene and in acethone by using of an US washer End-vacuum conditions were established by a turbomolecular pump (AIRCO- Temescal 540 ls TMP) for plim =5middot10-6 mbar Vacuum conditions were evaluated by an ULVAC ion-gauge vacuum sensor and an UHV GI-N3 gauge controller for the selected dynamic pressure of pd = (2hellip3)10-3 mbar a throttle-valve was actuated via a close-loop feedback control unit for conductance controlling of TMP admission Substrates were resistively heated (ts= 400 ordmC) and electrically biased (Us=- 90 V) on a ground independent Mo-boat used as sample holder for a target-substrate distance of about dt-s= 130 mm disposed in front of the DC drived UM-sputter guns Argon gas admission was manually adjusted by use of a needle-valve Reactive gases of N2 respectively C2H2 and CH4 were

admitted by mass flow meters (GFM-17 Aalborg USA) and controlled by an APC 216 Granville-Phillips Automatic PressureFlow Controller unit

Reactive sputtering experiments for deposition of compositionally graded TiAlN respectively C and MoS2 doped TiAlNC multilayer structure were performed in fuzzy-logic process control mode of sputtering power During of deposition process a flow chart of selected process parameters were saved for mapping of in situ deposition conditions

The surface-oxidized monocrystalline n-type Si(100) substrates and mirror polished WC-Co of 15 x 5 x 12 mm hard metal substrates were selected for XTEM microstructure investigation respectively for tribological evaluation of the coatings The main process parameters were defined for preparation of the Ti-Al-N and carbon doped Ti-Al-N samples which are listed in Table 1 The flow rate of N2 reactive gas was controlled for qin_N2 = 04 Nlh by the automatic APC controller Argon gas flow rate of qin_Ar = 16 Nlh was adjusted by needle-valve for a dynamic pressure of pd= 2middot10-3 mbar The time intervals of power pulse width dtaD_min respectively dtaD_max were selected in accordance with the software controlled Pmin and Pmax cycles of discharge power levels

TABLE 1 The main experimental parameters Sample symbol

Coating structure

Compo-nents

Pmax

[watt] Pmin

[watt] NC_23 Modulated TiAl-N 570 388 NC_24 Modulated TiAl-N 505 366 NC_25 Modulated TiAl-N 550 360 NC_26 Modulated TiAl-N 573 372 NC_27 Modulated TiAl-N 794 521 NC_28 Modulated TiAl-N 616 404 NC_33 Isotrope

bilayer TiAl-N 545

600 545 600

NC_29 Modulated TiAlN-C 834 547 NC_30 Modulated TiAlN-C 700 460 NC_31 Modulated TiAlN-C 463 304 NC_32 Modulated TiAlN-C 535 351 NC_34 Modulated TiAlN-C 800 525 NC_35 Isotrope TiAlN-C 505 505 NC_36 Isotrope TiAlN-C 627 627 NC_37 Modulated TiAlN-C 630 410 NC_38 Isotrope TiAlN-C 465 465 NC_39 Modulated TiAlN-C 673 438 NC_40 Modulated TiAlN-C 706 460 NC_41 Isotrope TiAlN-C 721 721 NC_42 Isotrope TiAlN-C 490 490 NC_43 Modulated TiAlN-C 635 413 NC_44 Modulated TiAlN-C 623 405 NC_45 Modulated TiAlN-C 645 420 NC_46 Modulated TiAlN-C 680 443

THE ANNALS OF UNIVERSITY ldquoDUNĂREA DE JOS ldquo OF GALAŢI FASCICLE VIII 2004 ISSN 1221-4590

TRIBOLOGY

54

3 EXPERIMENTAL RESULTS AND CONCLUSIONS

Tribological testing of the TiAlCN coated WC-

Co samples has been performed by dr H Haefke (CSEM ndashTribology Laborator Neuchacirctel Switzerland) in frame of the EU NANOCOMP Project using the following standard test conditions for the friction and wear characterisation of the samples (fig 1) Test type SRV (oscillating movement of the counterpart) Counterpart oslash6 mm 100Cr6 steel ball Normal load 30 N Initial Hertzian pressure 26 GPa Oscillating speed 3 cms Oscillating frequency 75 Hz Stroke 2 mm Test stop criterion 19800 cycles (approx 500 m of sliding)

Tribological curve of Sample 28

0

02

04

06

08

1

12

0 5000 10000 15000 20000

Number of passes

Coe

ffici

ent o

f fric

tion

Tribological curve of Sample 43

0

02

04

06

08

1

12

0 5000 10000 15000 20000

Number of passes

Coe

ffici

ent o

f fric

tion

Fig1 Exemple of evaluated friction coefficient in

SRV tribological test for TiAlN coated NC-28 sample and TiAlCN coated NC-43 sample prepared in similar

controlled condition of power modulation ranging between 600400 W

Microstructure evaluation of as deposited

coatings by transmission electron microscope investigation has been performed on cross section of the ion beam thinned samples The XTEM image of sample NC-28 indicate a competitive growth mode of the columnar like grains perpendicular oriented to the

surface of the substrate (fig 2) The inset of this figure shows the selected area electron diffraction pattern (SAED) from the near substrate surface region The spotty-distributed electron reflections in the Deby-Scherrer rings show a well crystallised structure evolution with a (111) preferred orientation

Fig 2 Bright field XTEM image of the thick TiAlN

coating (samples NC-28) with a well defined competitive columnar microstructure evolution

Figure 3 indicate the dark field XTEM image of

same sample taked by (111) SAED reflection It can be concluded that the TiAlN coatings are not sensitive against the power modulation at least for 600400 W

However a multilayer structure of the TiAlCN coating was identified for the similar power modulation while amorphous carbon phase forming is started by the doping of the condensed phase with C additive (fig 4) The XTEM investigation performed for microstructure evaluation of TiAlN-C (NC-45 sample for 645420 W) indicate a modulated multilayer structure ranging between a vawy modulated interface of microcrystalline and a nanocrystalline amorphous sublayer system of the deposited coating (fig 4)

The thickness of the compound layers increases with increasing of pulse width and amplitude of the power modulation The bright zone of nanocrystalline amorphous interlayers are produced by a reduced Pmin sputtering power while the microcrystalline darker interlayers are produced during of sputtering with Pmax a higher discharge power level

THE ANNALS OF UNIVERSITY ldquoDUNĂREA DE JOS ldquo OF GALAŢI FASCICLE VIII 2004 ISSN 1221-4590

TRIBOLOGY

55

Fig 3 Dark field XTEM image of the TiAlN coating (samples NC-28) revealed that power modulation no changed the columnar like growth of the coatingrsquos

microstructure

Fig 4 BF XTEM image of the multilayered TiAlCN

(sample NC-45) coating prepared by fuzzy controlled power modulation of the sputtering source between

Pmax =645 watt and Pmin= 420 watt

At a higher power modulation (sample NC-34 prepared with 800500 W) the TiAlNC coating system is composed of two crystal phases with a layered-columnar microstructure (fig 5)

The SAED pattern of TiAlNC coating and the Process Diffraction analysis indicate an strengthened (200) preferred orientation and the existence of two phases (marked on figure 5 by red and blue arrows) presumable due to a distorted rhomboid-phase of the cubic NaCl-type TiAlN structure phase

TiAlNC

(111)(200)

Fig 5 BF-XTEM image of TiAlCN (sample NC-34) performed by a higher power modulation

of 800500 W The SAED pattern and the Process Diffraction analysis indicate

the existence of two phases

THE ANNALS OF UNIVERSITY ldquoDUNĂREA DE JOS ldquo OF GALAŢI FASCICLE VIII 2004 ISSN 1221-4590

TRIBOLOGY

56

(111)

(200)

NC28 modulated 45 sec

without C

NC45 modulated 45 sec

NC44 modulated 25 sec

Fig 6 Characteristic X-ray diffraction (XRD) pattern of the TiAlN and TiAlCN coatings indicate a texture modification from (111) to (200) and a grain size lowering by carbon element doping of TiAlN

Fig 7 The plasma distribution of the DC excited sputtering process of MoS2 and TiAl targets in mixture of Ar N2 and C2H2 gases as was viewed through the window of the new DC 3UM

sputtering system equipped with TiAl TiC and MoS2 targets The performed X-ray diffraction investigation

(XRD) for crystalographic structure analysis also indicate the changes of the preferred crystal orientation from (111) to (200) and the decreasing of the grain size with increasing concentration of the C doping element (fig 6)

Our developed fuzzy-logic controlled reactive sputtering system was tested for deposition of multiphase and multi-elemental Ti-Al-C-N-Mo-S

self-lubricated compound thin film coatings (fig 8) and the very recently results indicate that industrial application of multi-layer coatings tailored for high adhesion wear resistance with a friction coefficient lower than 02 and super-hardness up to tens of GPa nowadays becomes a reality for protection of metal components Detailed information about these results will be published in a distinct paper

THE ANNALS OF UNIVERSITY ldquoDUNĂREA DE JOS ldquo OF GALAŢI FASCICLE VIII 2004 ISSN 1221-4590

TRIBOLOGY

57

Fig 8 Bright field-XTEM micrograph of multi-layer structured MoS2 and carbon doped TiAlCN coating deposited on Si(100)SiOx substrate (B-4 Sample investigation performed with a Philips CM 20 TEM microscope by Prof P B Barna from Research Institute for Technical Physics and Material Sciences Hungarian Academy of Sciences Budapest) The 5 microm thick coating was deposited by started from the substrate of SiSiOx in the following structure Ti-Al alloyed adhesion layer gradient composition TiAlN transition layer columnar TiAlCN hard layer superhard nc-TiAlCNa-CH nanocomposite layer C-fiber enforced MoS2 doped TiAlCN transition layer C and MoS2 doped nc-TiAlCNa-C layer system

ACKNOWLEDGEMENTS

This work was partly supported by the EU

NANOCOMP project Contract No G5RD-CT2001-00578 The author is greatly indebted to the KFKI-Condensed Matter Research Center and to the NATO Science Fellowship Programme-Hungary-2002 for awarding visiting fellowship grants The grants awarded to DB by KPI-EMTE respectively by MEC-CNCSIS also are gratefully acknowledged The author would like to thank sincerely to BBPfor the XTEM and HH for tribological investigations performed in frame of EU NANOCOMP project

REFERENCES 1 Renevier NM Lobiondo N Fox VC Teer DG Hampshire J 2000 Performance of MoS2metal composite coatings used for dry machining and their industrial applications Surface and Coatings Technology 123 p 84-91 2 Fox V Teer DG Hampshire J Wear resistant MoS2 coatings (private communication) 3 Camino D Jones AH S Mercs D Teer DG High performance sputtered carbon coatings for wear resistant application Magnetron Ion Platinrdquo UK Patent No GB 2 258 343 B 4 Zehnder T Schwaller P Munnik F Mikhailov S Patscheider J 2004 Journal of Applied Physics Vol 95(8) p 4327-4334 5 Manaila A Devenyi Biro D David L Barna PB Kovacs A 2002 Multilayer TiAlN coatings with composition gradient Surface and Coatings Technology 151-152 p 21-25

THE ANNALS OF UNIVERSITY ldquoDUNĂREA DE JOS ldquo OF GALAŢI FASCICLE VIII 2004 ISSN 1221-4590

TRIBOLOGY

54

3 EXPERIMENTAL RESULTS AND CONCLUSIONS

Tribological testing of the TiAlCN coated WC-

Co samples has been performed by dr H Haefke (CSEM ndashTribology Laborator Neuchacirctel Switzerland) in frame of the EU NANOCOMP Project using the following standard test conditions for the friction and wear characterisation of the samples (fig 1) Test type SRV (oscillating movement of the counterpart) Counterpart oslash6 mm 100Cr6 steel ball Normal load 30 N Initial Hertzian pressure 26 GPa Oscillating speed 3 cms Oscillating frequency 75 Hz Stroke 2 mm Test stop criterion 19800 cycles (approx 500 m of sliding)

Tribological curve of Sample 28

0

02

04

06

08

1

12

0 5000 10000 15000 20000

Number of passes

Coe

ffici

ent o

f fric

tion

Tribological curve of Sample 43

0

02

04

06

08

1

12

0 5000 10000 15000 20000

Number of passes

Coe

ffici

ent o

f fric

tion

Fig1 Exemple of evaluated friction coefficient in

SRV tribological test for TiAlN coated NC-28 sample and TiAlCN coated NC-43 sample prepared in similar

controlled condition of power modulation ranging between 600400 W

Microstructure evaluation of as deposited

coatings by transmission electron microscope investigation has been performed on cross section of the ion beam thinned samples The XTEM image of sample NC-28 indicate a competitive growth mode of the columnar like grains perpendicular oriented to the

surface of the substrate (fig 2) The inset of this figure shows the selected area electron diffraction pattern (SAED) from the near substrate surface region The spotty-distributed electron reflections in the Deby-Scherrer rings show a well crystallised structure evolution with a (111) preferred orientation

Fig 2 Bright field XTEM image of the thick TiAlN

coating (samples NC-28) with a well defined competitive columnar microstructure evolution

Figure 3 indicate the dark field XTEM image of

same sample taked by (111) SAED reflection It can be concluded that the TiAlN coatings are not sensitive against the power modulation at least for 600400 W

However a multilayer structure of the TiAlCN coating was identified for the similar power modulation while amorphous carbon phase forming is started by the doping of the condensed phase with C additive (fig 4) The XTEM investigation performed for microstructure evaluation of TiAlN-C (NC-45 sample for 645420 W) indicate a modulated multilayer structure ranging between a vawy modulated interface of microcrystalline and a nanocrystalline amorphous sublayer system of the deposited coating (fig 4)

The thickness of the compound layers increases with increasing of pulse width and amplitude of the power modulation The bright zone of nanocrystalline amorphous interlayers are produced by a reduced Pmin sputtering power while the microcrystalline darker interlayers are produced during of sputtering with Pmax a higher discharge power level

THE ANNALS OF UNIVERSITY ldquoDUNĂREA DE JOS ldquo OF GALAŢI FASCICLE VIII 2004 ISSN 1221-4590

TRIBOLOGY

55

Fig 3 Dark field XTEM image of the TiAlN coating (samples NC-28) revealed that power modulation no changed the columnar like growth of the coatingrsquos

microstructure

Fig 4 BF XTEM image of the multilayered TiAlCN

(sample NC-45) coating prepared by fuzzy controlled power modulation of the sputtering source between

Pmax =645 watt and Pmin= 420 watt

At a higher power modulation (sample NC-34 prepared with 800500 W) the TiAlNC coating system is composed of two crystal phases with a layered-columnar microstructure (fig 5)

The SAED pattern of TiAlNC coating and the Process Diffraction analysis indicate an strengthened (200) preferred orientation and the existence of two phases (marked on figure 5 by red and blue arrows) presumable due to a distorted rhomboid-phase of the cubic NaCl-type TiAlN structure phase

TiAlNC

(111)(200)

Fig 5 BF-XTEM image of TiAlCN (sample NC-34) performed by a higher power modulation

of 800500 W The SAED pattern and the Process Diffraction analysis indicate

the existence of two phases

THE ANNALS OF UNIVERSITY ldquoDUNĂREA DE JOS ldquo OF GALAŢI FASCICLE VIII 2004 ISSN 1221-4590

TRIBOLOGY

56

(111)

(200)

NC28 modulated 45 sec

without C

NC45 modulated 45 sec

NC44 modulated 25 sec

Fig 6 Characteristic X-ray diffraction (XRD) pattern of the TiAlN and TiAlCN coatings indicate a texture modification from (111) to (200) and a grain size lowering by carbon element doping of TiAlN

Fig 7 The plasma distribution of the DC excited sputtering process of MoS2 and TiAl targets in mixture of Ar N2 and C2H2 gases as was viewed through the window of the new DC 3UM

sputtering system equipped with TiAl TiC and MoS2 targets The performed X-ray diffraction investigation

(XRD) for crystalographic structure analysis also indicate the changes of the preferred crystal orientation from (111) to (200) and the decreasing of the grain size with increasing concentration of the C doping element (fig 6)

Our developed fuzzy-logic controlled reactive sputtering system was tested for deposition of multiphase and multi-elemental Ti-Al-C-N-Mo-S

self-lubricated compound thin film coatings (fig 8) and the very recently results indicate that industrial application of multi-layer coatings tailored for high adhesion wear resistance with a friction coefficient lower than 02 and super-hardness up to tens of GPa nowadays becomes a reality for protection of metal components Detailed information about these results will be published in a distinct paper

THE ANNALS OF UNIVERSITY ldquoDUNĂREA DE JOS ldquo OF GALAŢI FASCICLE VIII 2004 ISSN 1221-4590

TRIBOLOGY

57

Fig 8 Bright field-XTEM micrograph of multi-layer structured MoS2 and carbon doped TiAlCN coating deposited on Si(100)SiOx substrate (B-4 Sample investigation performed with a Philips CM 20 TEM microscope by Prof P B Barna from Research Institute for Technical Physics and Material Sciences Hungarian Academy of Sciences Budapest) The 5 microm thick coating was deposited by started from the substrate of SiSiOx in the following structure Ti-Al alloyed adhesion layer gradient composition TiAlN transition layer columnar TiAlCN hard layer superhard nc-TiAlCNa-CH nanocomposite layer C-fiber enforced MoS2 doped TiAlCN transition layer C and MoS2 doped nc-TiAlCNa-C layer system

ACKNOWLEDGEMENTS

This work was partly supported by the EU

NANOCOMP project Contract No G5RD-CT2001-00578 The author is greatly indebted to the KFKI-Condensed Matter Research Center and to the NATO Science Fellowship Programme-Hungary-2002 for awarding visiting fellowship grants The grants awarded to DB by KPI-EMTE respectively by MEC-CNCSIS also are gratefully acknowledged The author would like to thank sincerely to BBPfor the XTEM and HH for tribological investigations performed in frame of EU NANOCOMP project

REFERENCES 1 Renevier NM Lobiondo N Fox VC Teer DG Hampshire J 2000 Performance of MoS2metal composite coatings used for dry machining and their industrial applications Surface and Coatings Technology 123 p 84-91 2 Fox V Teer DG Hampshire J Wear resistant MoS2 coatings (private communication) 3 Camino D Jones AH S Mercs D Teer DG High performance sputtered carbon coatings for wear resistant application Magnetron Ion Platinrdquo UK Patent No GB 2 258 343 B 4 Zehnder T Schwaller P Munnik F Mikhailov S Patscheider J 2004 Journal of Applied Physics Vol 95(8) p 4327-4334 5 Manaila A Devenyi Biro D David L Barna PB Kovacs A 2002 Multilayer TiAlN coatings with composition gradient Surface and Coatings Technology 151-152 p 21-25

THE ANNALS OF UNIVERSITY ldquoDUNĂREA DE JOS ldquo OF GALAŢI FASCICLE VIII 2004 ISSN 1221-4590

TRIBOLOGY

55

Fig 3 Dark field XTEM image of the TiAlN coating (samples NC-28) revealed that power modulation no changed the columnar like growth of the coatingrsquos

microstructure

Fig 4 BF XTEM image of the multilayered TiAlCN

(sample NC-45) coating prepared by fuzzy controlled power modulation of the sputtering source between

Pmax =645 watt and Pmin= 420 watt

At a higher power modulation (sample NC-34 prepared with 800500 W) the TiAlNC coating system is composed of two crystal phases with a layered-columnar microstructure (fig 5)

The SAED pattern of TiAlNC coating and the Process Diffraction analysis indicate an strengthened (200) preferred orientation and the existence of two phases (marked on figure 5 by red and blue arrows) presumable due to a distorted rhomboid-phase of the cubic NaCl-type TiAlN structure phase

TiAlNC

(111)(200)

Fig 5 BF-XTEM image of TiAlCN (sample NC-34) performed by a higher power modulation

of 800500 W The SAED pattern and the Process Diffraction analysis indicate

the existence of two phases

THE ANNALS OF UNIVERSITY ldquoDUNĂREA DE JOS ldquo OF GALAŢI FASCICLE VIII 2004 ISSN 1221-4590

TRIBOLOGY

56

(111)

(200)

NC28 modulated 45 sec

without C

NC45 modulated 45 sec

NC44 modulated 25 sec

Fig 6 Characteristic X-ray diffraction (XRD) pattern of the TiAlN and TiAlCN coatings indicate a texture modification from (111) to (200) and a grain size lowering by carbon element doping of TiAlN

Fig 7 The plasma distribution of the DC excited sputtering process of MoS2 and TiAl targets in mixture of Ar N2 and C2H2 gases as was viewed through the window of the new DC 3UM

sputtering system equipped with TiAl TiC and MoS2 targets The performed X-ray diffraction investigation

(XRD) for crystalographic structure analysis also indicate the changes of the preferred crystal orientation from (111) to (200) and the decreasing of the grain size with increasing concentration of the C doping element (fig 6)

Our developed fuzzy-logic controlled reactive sputtering system was tested for deposition of multiphase and multi-elemental Ti-Al-C-N-Mo-S

self-lubricated compound thin film coatings (fig 8) and the very recently results indicate that industrial application of multi-layer coatings tailored for high adhesion wear resistance with a friction coefficient lower than 02 and super-hardness up to tens of GPa nowadays becomes a reality for protection of metal components Detailed information about these results will be published in a distinct paper

THE ANNALS OF UNIVERSITY ldquoDUNĂREA DE JOS ldquo OF GALAŢI FASCICLE VIII 2004 ISSN 1221-4590

TRIBOLOGY

57

Fig 8 Bright field-XTEM micrograph of multi-layer structured MoS2 and carbon doped TiAlCN coating deposited on Si(100)SiOx substrate (B-4 Sample investigation performed with a Philips CM 20 TEM microscope by Prof P B Barna from Research Institute for Technical Physics and Material Sciences Hungarian Academy of Sciences Budapest) The 5 microm thick coating was deposited by started from the substrate of SiSiOx in the following structure Ti-Al alloyed adhesion layer gradient composition TiAlN transition layer columnar TiAlCN hard layer superhard nc-TiAlCNa-CH nanocomposite layer C-fiber enforced MoS2 doped TiAlCN transition layer C and MoS2 doped nc-TiAlCNa-C layer system

ACKNOWLEDGEMENTS

This work was partly supported by the EU

NANOCOMP project Contract No G5RD-CT2001-00578 The author is greatly indebted to the KFKI-Condensed Matter Research Center and to the NATO Science Fellowship Programme-Hungary-2002 for awarding visiting fellowship grants The grants awarded to DB by KPI-EMTE respectively by MEC-CNCSIS also are gratefully acknowledged The author would like to thank sincerely to BBPfor the XTEM and HH for tribological investigations performed in frame of EU NANOCOMP project

REFERENCES 1 Renevier NM Lobiondo N Fox VC Teer DG Hampshire J 2000 Performance of MoS2metal composite coatings used for dry machining and their industrial applications Surface and Coatings Technology 123 p 84-91 2 Fox V Teer DG Hampshire J Wear resistant MoS2 coatings (private communication) 3 Camino D Jones AH S Mercs D Teer DG High performance sputtered carbon coatings for wear resistant application Magnetron Ion Platinrdquo UK Patent No GB 2 258 343 B 4 Zehnder T Schwaller P Munnik F Mikhailov S Patscheider J 2004 Journal of Applied Physics Vol 95(8) p 4327-4334 5 Manaila A Devenyi Biro D David L Barna PB Kovacs A 2002 Multilayer TiAlN coatings with composition gradient Surface and Coatings Technology 151-152 p 21-25

THE ANNALS OF UNIVERSITY ldquoDUNĂREA DE JOS ldquo OF GALAŢI FASCICLE VIII 2004 ISSN 1221-4590

TRIBOLOGY

56

(111)

(200)

NC28 modulated 45 sec

without C

NC45 modulated 45 sec

NC44 modulated 25 sec

Fig 6 Characteristic X-ray diffraction (XRD) pattern of the TiAlN and TiAlCN coatings indicate a texture modification from (111) to (200) and a grain size lowering by carbon element doping of TiAlN

Fig 7 The plasma distribution of the DC excited sputtering process of MoS2 and TiAl targets in mixture of Ar N2 and C2H2 gases as was viewed through the window of the new DC 3UM

sputtering system equipped with TiAl TiC and MoS2 targets The performed X-ray diffraction investigation

(XRD) for crystalographic structure analysis also indicate the changes of the preferred crystal orientation from (111) to (200) and the decreasing of the grain size with increasing concentration of the C doping element (fig 6)

Our developed fuzzy-logic controlled reactive sputtering system was tested for deposition of multiphase and multi-elemental Ti-Al-C-N-Mo-S

self-lubricated compound thin film coatings (fig 8) and the very recently results indicate that industrial application of multi-layer coatings tailored for high adhesion wear resistance with a friction coefficient lower than 02 and super-hardness up to tens of GPa nowadays becomes a reality for protection of metal components Detailed information about these results will be published in a distinct paper

THE ANNALS OF UNIVERSITY ldquoDUNĂREA DE JOS ldquo OF GALAŢI FASCICLE VIII 2004 ISSN 1221-4590

TRIBOLOGY

57

Fig 8 Bright field-XTEM micrograph of multi-layer structured MoS2 and carbon doped TiAlCN coating deposited on Si(100)SiOx substrate (B-4 Sample investigation performed with a Philips CM 20 TEM microscope by Prof P B Barna from Research Institute for Technical Physics and Material Sciences Hungarian Academy of Sciences Budapest) The 5 microm thick coating was deposited by started from the substrate of SiSiOx in the following structure Ti-Al alloyed adhesion layer gradient composition TiAlN transition layer columnar TiAlCN hard layer superhard nc-TiAlCNa-CH nanocomposite layer C-fiber enforced MoS2 doped TiAlCN transition layer C and MoS2 doped nc-TiAlCNa-C layer system

ACKNOWLEDGEMENTS

This work was partly supported by the EU

NANOCOMP project Contract No G5RD-CT2001-00578 The author is greatly indebted to the KFKI-Condensed Matter Research Center and to the NATO Science Fellowship Programme-Hungary-2002 for awarding visiting fellowship grants The grants awarded to DB by KPI-EMTE respectively by MEC-CNCSIS also are gratefully acknowledged The author would like to thank sincerely to BBPfor the XTEM and HH for tribological investigations performed in frame of EU NANOCOMP project

REFERENCES 1 Renevier NM Lobiondo N Fox VC Teer DG Hampshire J 2000 Performance of MoS2metal composite coatings used for dry machining and their industrial applications Surface and Coatings Technology 123 p 84-91 2 Fox V Teer DG Hampshire J Wear resistant MoS2 coatings (private communication) 3 Camino D Jones AH S Mercs D Teer DG High performance sputtered carbon coatings for wear resistant application Magnetron Ion Platinrdquo UK Patent No GB 2 258 343 B 4 Zehnder T Schwaller P Munnik F Mikhailov S Patscheider J 2004 Journal of Applied Physics Vol 95(8) p 4327-4334 5 Manaila A Devenyi Biro D David L Barna PB Kovacs A 2002 Multilayer TiAlN coatings with composition gradient Surface and Coatings Technology 151-152 p 21-25

THE ANNALS OF UNIVERSITY ldquoDUNĂREA DE JOS ldquo OF GALAŢI FASCICLE VIII 2004 ISSN 1221-4590

TRIBOLOGY

57

Fig 8 Bright field-XTEM micrograph of multi-layer structured MoS2 and carbon doped TiAlCN coating deposited on Si(100)SiOx substrate (B-4 Sample investigation performed with a Philips CM 20 TEM microscope by Prof P B Barna from Research Institute for Technical Physics and Material Sciences Hungarian Academy of Sciences Budapest) The 5 microm thick coating was deposited by started from the substrate of SiSiOx in the following structure Ti-Al alloyed adhesion layer gradient composition TiAlN transition layer columnar TiAlCN hard layer superhard nc-TiAlCNa-CH nanocomposite layer C-fiber enforced MoS2 doped TiAlCN transition layer C and MoS2 doped nc-TiAlCNa-C layer system

ACKNOWLEDGEMENTS

This work was partly supported by the EU

NANOCOMP project Contract No G5RD-CT2001-00578 The author is greatly indebted to the KFKI-Condensed Matter Research Center and to the NATO Science Fellowship Programme-Hungary-2002 for awarding visiting fellowship grants The grants awarded to DB by KPI-EMTE respectively by MEC-CNCSIS also are gratefully acknowledged The author would like to thank sincerely to BBPfor the XTEM and HH for tribological investigations performed in frame of EU NANOCOMP project

REFERENCES 1 Renevier NM Lobiondo N Fox VC Teer DG Hampshire J 2000 Performance of MoS2metal composite coatings used for dry machining and their industrial applications Surface and Coatings Technology 123 p 84-91 2 Fox V Teer DG Hampshire J Wear resistant MoS2 coatings (private communication) 3 Camino D Jones AH S Mercs D Teer DG High performance sputtered carbon coatings for wear resistant application Magnetron Ion Platinrdquo UK Patent No GB 2 258 343 B 4 Zehnder T Schwaller P Munnik F Mikhailov S Patscheider J 2004 Journal of Applied Physics Vol 95(8) p 4327-4334 5 Manaila A Devenyi Biro D David L Barna PB Kovacs A 2002 Multilayer TiAlN coatings with composition gradient Surface and Coatings Technology 151-152 p 21-25