P. Eh. Hovsepian, A. P. Ehiassarian, Y. P. Purandare, R. Braun, IM Ross, Plasma. Processes ... NP gas turbine buckets and OSVAT engine valves coated with.
Nanoscale Multilayer PVD Coatings to Serve in Demanding Environments. P. Eh. Hovsepian and A. P. Ehiasarian. National HIPIMS Technology Centre - UK, Materials and Engineering Research Institute, Howard Street, Sheffield Hallam University, Sheffield, S1 1WB, UK.
National HIPIMS Technology Centre - UK
• Definition of "Superlattice" : A superlattice is a periodic structure of layers of two (or more) materials. Typically, the thickness of one layer is several nanometers.
• Discovery: Superlattices were discovered early in 1925 by Johansson and Linde, [1] after the studies on gold-copper and palladium-copper systems through their special X-ray diffraction patterns. • First industrial application: AlN/TiN on cutting tools by Sumitomo of Japan, [2]. 1. Johansson; Linde (1925). Annalen der Physik. 78: 439. doi:10. 1002/andp.19253832104.
2. M. Setoyama, A. Nakayama, M. Tanaka, N. Kitagawa, T. Nomura, Surf. and Coat. Technol. 86-87, (1996). 225-230.
National HIPIMS Technology Centre, UK
Mechanical properties J.S. Koehler University of Illinois in 1970 theoretically predicted that by using alternate (nano-)layers of materials with high and low elastic constants, shearing resistance is improved by up to 100 times as the FrankRead source of dislocations cannot operate in the nanolayers, [1]. The concept of "superhardening" introduced by James Koehler : Q=GA-GB / GA+GB Q- critical stress to move a dislocation across the interface GA, GB, shear modulus of material A and B For Superhard material: Hv > 40 GPa 1. J. S. Koehler, Phys. Rev. B 2, 547 (1970).
National HIPIMS Technology Centre, UK
Theories explaining the Superhardening effect - The Hall-Petch strengthening, (originally developed for bulk materials). N. J. Petch, J. Iron Steel Inst. 174, 25 (1953).
- The "Super modulus effect": Substantial, (150%-500%) Elastic moduli enhancement, (Cu-Ni). R. C. Cammarata, T.E. Schlesinger, C. Kim, S.B. Quadri, A.S. Edelstein, Appl Phys Let 1990, 56, 1862.
- "Coherency stress effect": Coherency stress develops due to the difference in the lattice constants that hinders dislocation motion, (Fe-Pt). B. M. Clemens, H. Kung, and S. A. Barnett, Mater. Res. Soc. Bull. 24, 20 ,1999.
- Dislocation blocking by layer interfaces, Xi Chu and Scott Barnett's model describing hardness- superlattice period relation. Xi Chu and Scott Barnett, J.of Appl. Physics 77, 4403, 1995.
National HIPIMS Technology Centre, UK
Hardness enhancement of various superlattice structured coatings deposited by different PVD techniques TiN/VN by MS Linkoping University
U. Helmersson, S. Todorova, S.A. Barnett, J.-E. Sundgren, L.C. Markert. J. E.Greene, J. Appl. Phys. 62 (1987) 481.
TiN/AlN by Arc Sumitomo Electric Industries Ltd.
M. Setoyama, A. Nakayama, M. Tanaka, N. Kitagawa, T. Nomura. Surf. Coat. Technol. 86-87 (1996),
TiAlN/CrN by ABS Sheffield Hallam University
P. Eh. Hovsepian, W.-D. Münz, Nanostructured Coatings, Edited by A. Cavaleiro and J. Th. M. De Hosson, Springer/Kluwer, 2005, 555-644.
National HIPIMS Technology Centre, UK
Monolithic vs Superlattice structures Monolithic Columnar Structure, BF TEM image
Nanoscale Multilayer Structure, BF TEM image
National HIPIMS Technology Centre, UK
Industrial Scale Hauzer HTC 1000/4 PVD Coater at SHU
a) XSEM of CrN/NbN Coated knife blade b) BF XTEM showing the nanoscale multilayer structure on the tip of the blade, P.Eh. Hovsepian et al, Surf. and Coat. Technol. 133, (2000).
National HIPIMS Technology Centre, UK
Wear mechanism of single and nanoscale multilayer coatings
wear track morphology, single layer coating
wear track morphology, nanoscale multilayer coating
P. Eh. Hovsepian, W.-D. Münz, Nanostructured Coatings, Edited by A. Cavaleiro and J. Th. M. De Hosson, Springer/Kluwer, 2005, 555-644.
National HIPIMS Technology Centre, UK
Lifetime in Dry High-Speed Machining Versus Critical Load Values in Scratch Adhesion Test
National HIPIMS Technology Centre, UK
Introduction to HIPIMS Technology
6 MW (3000 Wcm-2)
Industrial Scale HIPIMS using Huettinger power supplies
Conventional DC Sputtering
power
Target area = 1200 cm2
time A.P. Ehiasarian, book chapter: Fundamentals and Applications of High Power Impulse Magnetron Sputtering, in ed. R. Wei, Plasma Surface Engineering Research and its Practical Applications, Research Signpost, Trivandrum, India ISBN 978-81-308-0257-2
National HIPIMS Technology Centre, UK
Energy Dispersion Functions of Metal Ions Produced in the HIPIMS Plasma as well as Plasma Composition During Pretreatment Stage. 6
6
10
Ar 5
Cr (1+) 60%
Ar (2+) 2% 5
1+
Cr
Cr (2+) 14%
-1
Ion Flux /(counts s )
10
10
1+
Ar (1+) 23%
4
10
2+
Cr
Ar
3
10
Cr (3+) 0.4%
10
4
10
2+ 3
10
3+
Cr 2
2
10
10
1
10
0
a)
20
40
Energy /(eV)
60
A.P. Ehiasarian, P. Eh. Hovsepian, W.-D. Münz, EP 02 011 1 204.1 (2001). 10 0
b)
20
40
60
Energy /(eV)
National HIPIMS Technology Centre, UK
Interface Chemistry - STEM-EDS and Coating Adhesion HIPIMS
100 nm Scratch Test Critical Load on HSS = 85 N National HIPIMS Technology Centre, UK
HRTEM of Interfaces Produced by DC-Argon and HIPIMS Etching
Ar-Etching Courtesy of Jeff Th.M. De Hosson, Dept. Appl. Phys. Mater. Sci. Centre, University of Groningen, The Netherlands.
HIPIMS-Etching National HIPIMS Technology Centre, UK
Local epitaxial growth on large areas due to HIPIMS pre treatment of the substrate
Homogeneous contrast along interface signifies local epitaxial growth on substrate (steel) grain P.Eh. Hovsepian, C. Reinhard, A.P. Ehiasarian, CrAlYN/CrN superlattice coatings deposited by the combined high power impulse magnetron sputtering technique.
Surf. and Coat. Technol. 201(2006)4105-4110.A.
Critical Load L c [N]
Growth defects originating from droplets during arc etching, ABS technology
80 70 60 50 40 30 20 10 0
65 56
CrAlYN/CrN arc etch
CrAlYN/CrN HIPIMS etch
XTEM images of CrN/NbN deposited by various techniques
CrAlYN/CrN nanoscale multilayer
CrAlN base layer
substrate
UBM coating
Arc coating
HIPIMS coating
P. Eh. Hovsepian, A. P. Ehiassarian, Y. P. Purandare, R. Braun, IM Ross, Plasma Processes and Polymers, Vol. 6, issue S1, 2009, pp. S118 – S123. P.Eh. Hovsepian , Q.Luo , D. B. Lewis, A. Farinotti, Thin Solid Films. 488 (2005)1-8.
National HIPIMS Technology Centre, UK
Coating densification by High Power Impulse Magnetron Sputtering, HIPIMS
XTEM of TiAlN deposited by "standard" magnetron sputtering
High purity intercolumnar boundaries in TiN films deposited by HIPIMS. a) AR-cross sectional view, b) AR-plan view National HIPIMS Technology Centre, UK
SHU Nanoscale Multilayer Coating Family CrAlYN/CrN
TiAlCN/VCN
CrN / NbN
Me / C
CrAlN
TiAlN
CrN
MeN
D
interface
interface
interface
interface
SUBSTRATE
SUBSTRATE
SUBSTRATE
SUBSTRATE
D = 3.2 nm D = 4.0 nm High temperature oxidation High hardness low friction resistant Dry machining, automotive and Al and Ti cutting
D = 3.4 nm Corrosion and Wear resistant
aero engines.
National HIPIMS Technology Centre, UK
D = 2 nm Low friction tribological
STRATEGY 1: Combining elements producing dense oxide scales with rare earth element(s), (Y). Application: protection against environmental attack at high temperatures P. Hovsepian, A. P. Ehiasarian, R. Tietema, C. Strondel, UK Patent GB 2450950, 19.05. 2010, priority date 02. 01. 2008.
National HIPIMS Technology Centre, UK
Nanoscale Multilayer CrAlYN/CrN Deposited by HIPIMS/UBM •Ti- free formula, •Y- stabilised interface by Y+ and Cr+ ion etching using HIPIMS
CrAlN
interface
•CrAlYN/CrN nanoscale multilayer, (Δ = 4.7 nm) deposited by HIPIMS or UBM or combined HIPIMS/UBM technique.
SUBSTRATE P. Hovsepian, A. P. Ehiasarian, R. Tietema, C. Strondel, UK Patent GB 2450950, 19.05. 2010, priority date 02. 01. 2008.
National HIPIMS Technology Centre, UK
CrAlYN/CrN Coating-Substrate Interface Microstructure STEM Bright Field
STEM Z-Contrast
CrAlYN/CrN CrAlN g-TiAl High density Y and Cr implanted zone 5nm P.Eh. Hovsepian, C. Reinhard, A.P. Ehiasarian, Surf. and Coat. Technol 201(2006)4105-4110.
National HIPIMS Technology Centre, UK
High Temperature Phase and Hardness Stability of CrAlYN/CrN
P. Eh. Hovsepian, A.P. Ehiasarian, R. Braun, J. Walker, H. Du, Surf and Coat. Technol. 204 (2010) 2702-2708.
National HIPIMS Technology Centre, UK
High Temperature Tribological Behaviour of CrAlYN/CrN
P. Eh. Hovsepian, A.P. Ehiasarian, Y. Purandare, R. Braun, I.M. Ross, Plasma Process. Polym. 2009, 6, 51185123. J.C. Walker, I.M. Ross, C. Reinhard, W.M. Rainforth, P.Eh. Hovsepian, Wear 257 965-975
National HIPIMS Technology Centre, UK
Mass change vs. number of cycles of γ-TiAl specimens bare and coated with CrAlYN/CrN + CrAlYON, thermally cycled at 850°C in air.
R. Braun, W. Braue, M. Fröhlich, C.Leyens, P. Eh. Hovsepian, Materials at High Temperatures, (2009), 26(3) 305-316
National HIPIMS Technology Centre, UK
Maximum stress vs. number of cycles to failure of γ-TiAl specimens bare and coated with CrAlYN/CrN using different magnetron sputtering technologies.
R. Braun, U.Schulz, C. Leyens, P. E. Hovsepian, and A. P.Ehiasarian, Int. J. Mat. Res. 101 (2010) 5, 648-656.
National HIPIMS Technology Centre, UK
NP gas turbine buckets and OSVAT engine valves coated with CrAlYN/CrN nanoscale multilayer coating at SHU.
European Integrated Project "INNOVATIAL" FP6-2003-NMP-NI-3.
National HIPIMS Technology Centre, UK
Wear and fretting resistance of TiAl turbine blades with best available coatings in simulated aero engine environment Low Pressure Turbine Blade required in Gamma TiAl
New Aero Engine Concept: Geared Turbo Fan
Oxidation and Corrosion Resistant Coatings max. 800 °C 35.000 hours
Up to 30% less CO2 Perceived aircraft noise is halved
Wear Resistant Coatings • max . 800 °C 25.000 Cycles
50 % weight reduction per blade compared to current nickel alloy
Fretting wear tests with contact pressures relevant to blade shroud contact area
European Integrated Project "INNOVATIAL" FP6-2003-NMP-NI-3.
CrAlYN/ CrN + Al2O3
STRATEGY 2: Utilisation of Magnéli phases formed in-situ at the asperity contacts during sliding High hardness, low friction V-based nanoscale multilayers, TiAlN/VN. In- situ formation of V2O5, a highly lubricious, low melting point, (Tm= 681Co) tribo-film.
Schematic crystal structure of V2O5
National HIPIMS Technology Centre, UK
High magnification XTEM image showing the nanoscale multilayer structure of TiAlN/VN coating and V2O5 tribo-film.
P. Eh. Hovsepian, D. B. Lewis, W.-D. Münz, Surface and Coatings Technology, 133-134 (2000), p. 166-175. Q. Luo, Z.Zhuo, W.M. Rainforth and P. Eh. Hovsepian. Tribology letters, Vol. 24, No.2 November 2006, 171-178.
National HIPIMS Technology Centre, UK
SEM image of the wear track of TiAlN/VN in dry sliding pin-on-disc test at 7000C.
P. H. Mayrhofer, P.Eh. Hovsepian, W.-D. Münz, C. Mitterer , Surf, Coat and Technol.177, (2004), p. 341-347.
National HIPIMS Technology Centre, UK
Mechanical and tribological properties of various PVD coatings Structure
Hardness Hk, 25gr
Adhesion on HSS Lc, N
Residual Stress, GPa
Coef. of Friction, Al2O3
Sliding Wear Coefficient m3 N-1m
TiAlCrYN
Monolithic
2800
50
- 3. 8
0.8
2.5 10-16
TiAlN/CrN
Superlattice D= 3.2 nm
3500
50
- 5.1
0.7
2.38 10-16
DLC Cr/WC/a-CH
Multilayer
2800
30
- 0.74
0.31
3.0 10-16
70
- 3. 3
0.4
1.26 10-17
Coating
TiAlN/VN
Superlattice D= 3 nm
3500
P. Eh. Hovsepian, D. B. Lewis, W.-D. Münz, Surf. and Coat. Technol. 133-134 (2000) 166-175.
National HIPIMS Technology Centre, UK
STRATEGY 3: Utilisation of Low Shear Strength Interfaces produced by dynamic segregation of small atomic radius elements such as Carbon High hardness, low friction V-Carbon based nanoscale multilayers, TiAlCN/VCN.
Application: Machining of "sticky alloys" and MMC materials. P. Eh. Hovsepian, A. P. Ehiasarian, "PVD Coated Substrate" - GB0508485.0 filed 27 April 2005, EP 1874981, 14.01.2009.
National HIPIMS Technology Centre, UK
BF XTEM Image of TiAlCN/VCN and TiAlN/VN Superlattice Structured Coatings D= 2.2 nm
Base Layer
TiAlCN/VCN
TiAlN/VN
P. Eh. Hovsepian, A.P. Ehiasarian, I.Petrov, C. Schimpf. Surface Engineering. DOI 10.1179/026708408X336337.
National HIPIMS Technology Centre, UK
Flank Wear / No. of Passes in Al 7010-T 7651 Alloy 25 mm dia, HSS, 2- Flute End Mill, Vc:1884 m/min, Ap: 4 mm, Ae: 2 mm, Vf: 0.33 mm/rev. 0.3
Flank Wear (mm)
0.25 Uncoated 0.2
TiAlCrYN DLC
0.15
TiAlN/VN 0.1
TiAlCN/VCN
0.05
80 32 0 56 0 80 0 10 40 12 80 15 20 17 60 20 00 22 40 24 80 27 20 29 60 32 00 34 40 36 80 39 20 41 60 44 00 46 40 48 80 60 20 80 60
0
No. of Passes
Papken Eh. Hovsepian , Arutiun P. Ehiasarian , Anthony Deeming , Christian Schimpf, Plasma Process. Polym. 2007, 4, S897-S901.
National HIPIMS Technology Centre, UK
10-20 nm
Wear Mechanisms of TiAlN/VN and TiAlCN/VCN Superlattice Coatings Low Shear Strength Interface
High Shear Strength Interface
BUILD UP LAYER TRIBOFILM DELAMINATION INTERFACE
BASE LAYER
SUBSTRATE
TiAlN/VN
D= 3- 4 nm
D= 3nm
DELAMINATION INTERFACE
BASE LAYER SUBSTRATE
CARBON ACCUMULATION AT THE INTERFACE
TiAlCN/VCN
P. Eh. Hovsepian, A.P. Ehiasarian, I.Petrov, C. Schimpf. Surface Engineering. DOI 10.1179/026708408X336337.
National HIPIMS Technology Centre, UK
Demonstrator selection Alticut EC Project Automotive component Engine head – Fiat 1.9 JTD
Material: AlSi9Cu1 Machining operations to be considered for the component are: • Face milling • Drilling • Tapping • Thread milling and/or roll tapping CENTRO RICERCHE FIAT
Hauzer || Techno Coating PVD/ PACVD TECHNOLOGY
Demonstrator selection Alticut EC Project Aeronautic component 1 A wingbox rib of a typical Airbus wing •49 •48 •47 •46 •45 •44 •43 •42 •41 •40 •39 •38 •37 •36 •35 •34 •33 •32 •31 •30 •29 •28 •27 •26 •25 •24 •23 •22 •21 •20 •19 •18 •17 •16 •15 •14 •13 •12 •11 •10 •8•9 •7 •6 •5 •2•3•4
Material: Aluminum 7010-T7651 CENTRO RICERCHE FIAT
Hauzer || Techno Coating PVD/ PACVD TECHNOLOGY
Life time of TiAlVCN/VCN coated turning inserts in machining of forged Ti acetabular cups (orthopaedic implants) at SYMMETRY Medical inc., UK
Number of Components turned per turning tip. Constant surface speed of 60 m/min, Feed of 0.15 mm/rev, water based coolant. Coated tip
70
106
71
90
120
91
Uncoated tip
19
56
24
36
34
34
National HIPIMS Technology Centre, UK
STRATEGY 4: Utilisation of high ion irradiation to achieve phase separation and formation of self-organised nanostructures in Me- doped Carbon films. Application: Low friction high wear resistant tribological coatings.
National HIPIMS Technology Centre, UK
XTEM images of the microstructure and friction curves of Cr/C films
Y.N. Kok, P.Eh. Hovsepian, Q. Luo, D.B. Lewis, I. Petrov, Thin Solid Films Volume 475(2005) 219-226.
National HIPIMS Technology Centre, UK
Raman Spectra of C/Cr Coatings Deposited at Various Bias Voltages Downshifted Raman peak intensity, suggesting the replacement of C-C bonds with metal carbides as a consequence of the intensive ion irradiation Intensity G-band
D-band
Raman shift, cm-1
Y.N.Kok, P.Eh. Hovsepian, R.Haasch, I. Petrov. Surf, Coat and Technol.200, (2005) p. 1117-1122.
National HIPIMS Technology Centre, UK
HRXTEM of Self-Organised Multilayer Structure of C/Cr Developed at Ub= - 350V.
~ 20 nm
pronounced self-organised multilayer structure (bi-layer thickness ~20 nm) white contrast: onion-like carbon in the matrix of metal carbides. P.Eh. Hovsepian, Y.N. Kok, A.P. Ehiasarian, R. Haasch, J.-G. Wen, I. Petrov. Surf, Coat and Technol, 200 (2005)1572-1579.
National HIPIMS Technology Centre, UK
BF XTEM Images of C/Cr Films Deposited at Various Bias Voltages g
20 nm Ub = - 350V
25 nm
Ub = - 450V
Ub = -550V
P.Eh. Hovsepian, Y.N. Kok, A.P. Ehiasarian, R. Haasch, J.-G. Wen, I. Petrov, Surf, Coat and Technol, 200 (2005)1572-1579.
National HIPIMS Technology Centre, UK
Microstructure of C/Cr with sequentially deposited low bias/ high bias voltage layers Ub = - 350 V Ub = - 75 V
Ub = - 350 V Ub = - 75 V Ub = - 350 V Ub = - 75V Ub = - 350 V
Ub = - 75V CrN Base Layer
Substrate
Me- doped carbon coating deposited on fine blades in conditions of high ion irradiation
The deposition of high aspect ratio, low friction coating creating sharp but robust cutting edge resulted in reduction of the cutting forces by factor of five and increased life-time by factor of three. National HIPIMS Technology Centre, UK
STRATEGY 5: Utilisation of tribo- chemical reactions to achieve insitu formation of lubricious phases in conditions of boundary lubrication in Me- doped Carbon films. Application: Low friction high wear resistant tribological coatings to operate in boundary lubricated conditions at elevated temperatures. P. Eh. Hovsepian, D. Doerwald, R. Tietema, A.P. Ehiasarian. European Patent 2 963 145. Priority claimed: EP/30.06.2014/EPA 14175063.
National HIPIMS Technology Centre, UK
LAXRD, XSEM and TEM analyses of Mo-W doped Carbon films
P. Eh. Hovsepian, P. Mandal, A. P. Ehiasarian, G. Safran, R. Tietema, D. Doerwald. Applied Surface Science 366(2016) 260-274.
National HIPIMS Technology Centre, UK
Coefficient of friction of various DLC coatings compared to the Mo-W-C, (CMW1R) coating Tests carried out with highly viscous Mobil1 Extended lifeTM 10W-60 multigrade synthetic engine oil free of friction modifiers
P. Eh. Hovsepian, P. Mandal, A. P. Ehiasarian, G. Safran, R. Tietema, D. Doerwald. Applied Surface Science 366(2016) 260-274. P. Mandal, A. P. Ehiasarian, P.Eh. Hovsepian Tribology International, 90(2015)135-147.
National HIPIMS Technology Centre, UK
Raman analyses of the wear track after lubricated sliding at 200oC
MoS2 powder used as a standard
Different positions in the wear track of Mo-W doped Carbon film
WS2 powder used as a standard
P. Eh. Hovsepian, P. Mandal, A. P. Ehiasarian, G. Safran, R. Tietema, D. Doerwald. Applied Surface Science 366(2016) 260-274.
National HIPIMS Technology Centre, UK
Coefficient of friction of Mo-W-Carbon and DLC films as a function of sliding distance in lubricated sliding at 200oC against a 100Cr6 counterpart
P. Eh. Hovsepian, P. Mandal, A. P. Ehiasarian, G. Safran, R. Tietema, D. Doerwald. Applied Surface Science 366(2016) 260-274.
National HIPIMS Technology Centre, UK
Static oxidation behaviour of Me-C and DLC coatings Me-C, 400oC
Me-C, 500oC
DLC, 400oC
DLC, 500oC
Substrate exposed
Coating
National HIPIMS Technology Centre, UK
Typical application of the Mo-W-Carbon films
STRATEGY 6: Combining highly wear resistant with electrochemically stable elements to achieve corrosion and wear resistant coatings, CrN/NbN. Applications: • Corrosion and wear resistant coatings on steel to replace hard chrome. • Corrosion, wear and water droplet erosion resistant coatings on steel to protect components in steam turbines. • Protective coatings on medical implants. National HIPIMS Technology Centre, UK
Corrosion resistance of PVD coatings
National HIPIMS Technology Centre, UK
National HIPIMS Technology Centre, UK
Mass gain of various coatings exposed to pure steam at 650oC after 2000 h. Coated samples vs P92 24 22
P92 Substrate
m/So (mg/cm2)
20 18 16 14
MASS GAIN after 2000 hours
12 10
P92 >>> P92 + Al2O3 >P92 + Fe44Cr5Al > P92 + CrN/NbN
8 6
SHU Coatings: P92 + CrN/NbN
4
GTU Coatings: P92 + Fe44Cr5Al
BAM Coatings: P92 + Al2O3
2 0 0
200
400
600
800
1000
1200
1400
1600
Time (h)
National HIPIMS Technology Centre, UK
1800
2000
Cross-sectional back scattered SEM analysis of CrN/NbN exposed to steam at 650oC after 2000 h: (a) Coating cross-section showing the coating and oxide layers on top (b) Elemental mapping conducted on the cross-section.
P. Eh. Hovsepian , A.P. Ehiasarian , Y.P. Purandare, B. Biswas, F.J. Perez, M.I. Lasanta, M.T. de Miguel, A. Illana, M. Juez-Lorenzo, R. Muelas, A. Agüero, Materials Chemistry and Physics 179 (2016) 110-119.
National HIPIMS Technology Centre, UK
Hot Tensile Test Conditions, T= 650 °C, έ = 1 mm/ min
Strained up to elastic limit YS
Strained up to 20 % of absolute UTS
1: Passing Ultimate Tensile Strength, (UTS) with subsequent testing down to 20% UTS absolute value: pure plastic deformation 2: Up to Yield Strength (YS) value: pure elastic deformation
National HIPIMS Technology Centre, UK
Strain controlled, (0.4% strain) Low Cycle Fatigue tests at 650oC
•
Both uncoated and coated specimens failed after similar number of cycles, Nf = 1700 and Nf= 1712 respectively
High temperature creep tests at 650oC, tensile stress of 120 MPa
•
HIPIMS coating improved the creep lifetime by almost factor of two from 564 hours to 908 hours.
National HIPIMS Technology Centre, UK
Schematic of water droplet / solid surface interaction The pressure during the impact is given by the water hammer equation:
P 0c0V0 VDT
K c 1.41 c d
2 ic R 2 2 w w w
13
Damage Threshold Velocity, VDT - the lowest velocity, which theoretically could cause surface damage.
VDT denotes the Damage Threshold Velocity ,DVT Kic2 the fracture toughness of the target material
National HIPIMS Technology Centre, UK
Fracture Toughness, Indentation Hardness and Young's Modulus of CrN/TiN superlattice film as a function of the bilayer period.
R. Hann, M. Bartosik, R. Soler, C. Kirchlechner, G. Dehm, P. H. Mayerhofer. Scripta Materialia 124 (2016) 67-70
National HIPIMS Technology Centre, UK
CrN/NbN on P92 steel. Water droplet erosion test results. Test conditions: water pressure: 9 bar; impact frequency: 480 m min-1 ;
total number of impacts: 2.4 million
Surface morphology, SEM as deposited CrN/NbN
Surface morphology, SEM after water droplet erosion
2D and 3D profilometry after the impact, showing 20 µm depression but no coating spallation. P. Eh. Hovsepian*, A. P. Ehiasarian, Y. Purandare, P. Mayr, K. G. Abstoss, M. Mosquera, W.Schulz, A. Kranzmann, M. I. Lasanta, J. Trulillo. Journal of Alloys and Compounds, 746 (2018) 583-593.
National HIPIMS Technology Centre, UK
CrN/NbN – In vitro and In vivo Performance details
In vitro : Cobalt ion release 22 ppb uncoated