HPPMS/DC-MSIP (Cr,Al,V)N and (Cr,Al,W)N Thin Films for High Temperature Application

Transcription

1 HPPMS/DC-MSIP (Cr,Al,V)N and (Cr,Al,W)N Thin Films for High Temperature Application Sebastian Theiß K. Bobzin, N. Bagcivan, M. Ewering, R. H. Brugnara April 23, 21 HPPMS/HiPIMS/MPP Workshop, Golden Outline Motivation Thin film development Annealing tests and X-ray diffraction (XRD) phase analysis Electron probe micro analysis (EPMA) HT-Pin-on-Disk tribological measurements Conclusions & outlook SEI, RWTH Aachen University, Slide 2 1

2 Motivation - 1 DFG priority program 1299 Haut (skin effects) SPP 1299 Adaptive surfaces for high temperature application Dead matter (metal/ceramic) can achieve likewise skin properties at higher temperatures (65 C 11 C): Regeneration (self-healing effect) Membrane character Research of IOT Self-cleaning Breathing & transpiration (lubricant storage) General aim: Using these properties for high temperature applications (German Research Foundation) SEI, RWTH Aachen University, Slide 3 Motivation - 2 Aim of IOT: Development of (Cr,Al)N by hybrid DC-MSIP/HPPMS PVD as matrix Adding vanadium or tungsten as tribologically active elements Friction reduction due to formation of oxides (e. g. Magnéli phases) Generation of oxides / formation of Magnéli phases Generation of dry or liquid lubricants at the surface of the coating Thin film as coated PVD coating (Cr,Al,V)N or (Cr,Al,W)N) High temperature activation ( ) Oxygen (O 2 ) V, W Heat + Pressure Friction reduction + hard, wear resistant coating Substrate Substrate SEI, RWTH Aachen University, Slide 4 2

3 Magnéli phases Magnéli phases offer a high amount of shear planes due to the formation of oxygen discontinuity Various shear planes Temperature Pressure [Source: Holleman 95] [Source: S. Anderson 66] Oxygen discontinuity Shear plane Shear planes lead to friction reduction Oxide reduction leads to the formation of different oxide phases at different temperatures V 2 O 5 V 3 O 7 V 4 O 9 V 6 O 13 VO 2 Friction reducing Magnéli phases due to low bulk modulus SEI, RWTH Aachen University, Slide 5 Magnéli phases Magnéli phases offer a high amount of shear planes due to the formation of oxygen discontinuity Various V 2 O 5 has lowest Temperature decohesion energy and lowest melting point ( C) shear planes Thesis: This oxide can provide low friction as dry lubricant at and Pressure as liquid lubricant at [Source: Holleman 95] [Source: S. Anderson 66] Oxygen discontinuity Shear plane Shear planes lead to friction reduction Oxide reduction leads to the formation of different oxide phases at different temperatures V 2 O 5 V 3 O 7 V 4 O 9 V 6 O 13 VO 2 Friction reducing Magnéli phases due to low bulk modulus SEI, RWTH Aachen University, Slide 6 3

4 Deposition setup Thin film deposition using an industrial coating unit CC8/9 HPPMS 2 HPPMS cathodes and 2 DC-MSIP cathodes Deposition on THYROTHERM 2999 EFS SUPRA (1.2999) hot working steel substrates Cathode 3 DC-MSIP Target: AlCr2 Cathode 1 HPPMS Target: CrAl2 Bias Cathode 4 DC-MSIP Target: V/W Cathode 2 HPPMS Target: Cr Cathode setup within the coating unit 1. mm [Source: CemeCon AG] Deposition parameters Deposition time: 72 s Voltage C1+C2: 2 8 V Power C3+C4: 2 4 W Argon flow: 2 sccm N 2 flow: 15 sccm Pressure: 52 mpa Pulse parameters Pulse duration: 2 μs Frequency: 5 Hz SEI, RWTH Aachen University, Slide 7 Methods (Coating, compound and system properties) Coating properties Micrograph of cross section fracture of coatings to obtain morphology and coating thickness via SEM Determination of universal hardness and Young's modulus by means of nano indentation according to Oliver und Pharr Phase detection by means of X-Ray diffraction (XRD) measurements Compound properties Determination of adhesion (Rockwell indentation (VDI 3198)) Annealing tests and electron probe micro analysis (EPMA) to obtain diffusion processes System properties Determination of friction coefficient at different temperatures by means of HT Pin on Disk (PoD) measurements SEI, RWTH Aachen University, Slide 8 4

5 Determination of coating and compound properties (Cr.59 Al.21 V.2 )N (Cr.53 Al.14 W.33 )N Film thickness: 3.1 μm Deposition rate:.3 μm/min Hardness: 25 ±.9 GPa Young s modulus: 485 ± 14 GPa 3.1 μm Film thickness: 4.5 μm 4.5 μm Deposition rate:.4 μm/min Hardness: 28 ± 3. GPa Young s modulus: 47 ± 32 GPa 1 μm Adhesion class 2 1 μm Adhesion class 2 SEI, RWTH Aachen University, Slide 9 Determination of coating and compound properties (Cr.59 Al.21 V.2 )N (Cr.53 Al.14 W.33 )N Film thickness: Film thickness: 3.1 μm 3.1 μm 4.5 μm 4.5 μm Deposition rate: Deposition rate:.3 μm/min.4 μm/min Hardness: Hardness: 25 ±.9 GPa 28 ± 3. GPa Young s Hybrid modulus: process leads to high hardness and, Young s simultaneously, modulus: high deposition rates 485 ± 14 GPa 47 ± 32 GPa 1 μm Adhesion class 2 1 μm Adhesion class 2 SEI, RWTH Aachen University, Slide 1 5

6 Phase analysis by means of XRD of (Cr,Al,V)N c-crn (JCPDS 11-65) CrVO 4 (JCPDS ) c-aln (JCPDS 46-12) VO 2 (JCPDS 25-13) c-vn (JCPDS ) V 2 O 3 (JCPDS ) Intensity [a.u.] V 3 O 7 (JCPDS ) (friction reducing Magnéli phase) CrO (JCPDS 6-532) 1 C Parameters CuK(α), 4 kv, 4 ma GiD: 5 Step width:.5, 5 sec 1. Slit:.3 mm 2. Slit:.2 mm Annealing Annealing time: 4 h Temperature: to 1 C Atmosphere: Ambient air Substrate: Diffraction angle 2Θ [ ] 9 Formation of Magnéli phase V 3 O 7 at and SEI, RWTH Aachen University, Slide 11 Phase analysis by means of XRD of (Cr,Al,W)N CrN (JCPDS 11-65) Fe 3 W 3 C (JCPDS ) AlN (JCPDS ) Cr 2 O 3 (JCPDS ) W 2 N (JCPDS ) WO 3 (JCPDS & ) Intensity [a.u.] W (JCPDS 4-86) Diffraction angle 2Θ [ ] 1 C Parameters CuK(α), 4 kv, 4 ma GiD: 5 Step width:.5, 5 sec 1. Slit:.3 mm 2. Slit:.2 mm Annealing Annealing time: 4 h Temperature: to 1 C Atmosphere: Ambient air Substrate: Formation of WO 3 at 1 C Diffusion from the substrate leads to Fe and C rich phase SEI, RWTH Aachen University, Slide 12 6

7 Morphology of coatings exposed for 4 h in ambient air (Cr,59 Al,21 V,2 )N (Cr,53 Al,14 W,33 )N SEI, RWTH Aachen University, Slide 13 Morphology of coatings exposed for 4 h in ambient air Specimens were annealed for 4 h at different temperatures in ambient air. (Cr,59 Al,21 V,2 )N At diffusion processes are significant Thesis: Diffusion of V to the surface and oxidation Specimens were annealed for 4 h at different temperatures in ambient air. (Cr,53 Al,14 W,33 )N At few oxidation products at the surface of the coating SEI, RWTH Aachen University, Slide 14 7

8 EPMA analysis of (Cr,Al,V)N SEI, RWTH Aachen University, Slide 15 EPMA analysis of (Cr,Al,V)N SEI, RWTH Aachen University, Slide 16 8

9 EPMA analysis of (Cr,Al,V)N 6 8 C SEI, RWTH Aachen University, Slide 17 EPMA analysis of (Cr,Al,V)N 6 8 C At diffusion processes are significant V diffuses to the surface of the coating and leads to an liquid oxide layer due to oxygen affinity and boundary diffusion Cr and Al rich oxide layer is generated Diffusion of Cr into the substrate Thesis: The liquid oxide layer leads to a friction reduction at SEI, RWTH Aachen University, Slide 18 9

10 EPMA analysis of (Cr,Al,W)N SEI, RWTH Aachen University, Slide 19 EPMA analysis of (Cr,Al,W)N At a small amount of oxygen is on the surface of the coating Diffusion of Cr into the surface is preferred compared to the diffusion of W Thesis: No reduction of the friction coefficient will be achieved SEI, RWTH Aachen University, Slide 2 1

11 Friction Reibwert coefficient μ μ Parameters Counterpart: 1Cr6 (AISI 521) Distance: 5 m Radius: 2.5 mm Velocity: 1 cm/s Load: 5 N Atmosphere: Ambient air Distance Distanz [m] SEI, RWTH Aachen University, Slide 21 Friction coefficient μ Friction coefficient μ Results of HT-PoD measurements (Cr.59 Al.21 V.2 )N on (Cr.53 Al.14 W.33 )N on Distance [m] Friction Reibwert coefficient μ μ Distance Distanz [m] SEI, RWTH Aachen University, Slide 22 Results of HT-PoD measurements 1 Parameters (Cr.59 Al.21 V.2 )N on Counterpart: 1Cr6 (AISI 521).8 Distance: 5 m Radius: 2.5 mm.6 Velocity: 1 cm/s.4 Load: 5 N Atmosphere: Ambient air : Friction reduction due to formation of (Cr Cr and.53 Al V.14 Woxides.33 )N on (Cr,Al,W)N: Increase at due to predominance of 6 adhesion C.6 compared to oxide formation Softening of counterpart material leads to lower friction at.2.2 For (Cr,Al,V)N the oxides lead to a much lower friction coefficient Friction coefficient μ Friction coefficient μ Distance [m] 11

12 Conclusions & Outlook Conclusions Deposition of (Cr.59 Al.21 V.2 )N and (Cr.53 Al.14 W.33 )N by means of hybrid DC-MSIP and HPPMS PVD technology Hybrid process leads to high hardness and, simultaneously, to high deposition rates Diffusion of vanadium to the coating s surface was demonstrated (regeneration) HT Pin on Disk measurements show a significant influence of the vanadium oxide phases on the friction coefficient (.6.5) (transpiration) Tungsten does not influence the friction behavior Outlook Development of a diffusion model Analysis of the time behavior of the diffusion process PoD measurements of annealed specimens to determine the influence of the oxide phases SEI, RWTH Aachen University, Slide 23 12