Cold Spray Materials Deposition Technology

Transcription

1 Cold Spray Materials Deposition Technology Kumar Sridharan University of Wisconsin, Madison, USA International Thermal Spray Conference, Houston, TX May 21 st to 24 th, 2012

2 Presentation Outline Introduction Overview of Cold Spray Materials Deposition Process Examples of Research and Development Activities World-Wide Cold Spray Research Program at the University of Wisconsin, Madison Concluding Remarks

3 Historical Perspective Invented by Prof. Anatolii Payrin at the Institute of Theoretical and Applied Mechanics - Russian Academy of Sciences (mid-1980s) Discovered incidentally while studying twophase flow = particles of Al and Cu entrained in high velocity gas incident on target (left), stuck to the target (below) A. Papyrin, The Cold Spray Materials Deposition Process, Woodhead Publishers, 2007.

4 Examples of Cold Spray Systems World-Wide Germany: Helmut Schmidt University, Linde, Innovaris, EADS, Praxair, FNE Freiberg, OBS, RWTH Aachen, H.C. Starck, Hermle, Siemens, TU Chemnitz France: Critt Lorius, CEA, UTBM, Ecole des Mineurs de Paris USA: ASB Industries, Army Research Laboratory, Penn State University, Inovati, University of Wisconsin, United Technology Research Center, Sandia National Laboratory Netherlands: FST Belgium: Advanced Coating Italy: Nanofab UK: Cambridge University. TWI Technology Czech: Newspray Brazil: Mahle Canada: Centerline, McGill University Korea: Hanyang University Australia: CSIRO, DSTO, KIRK Group India: ACRI China: Bao Steel Japan: Toyohashi University of Technology, Plasma Giken Singapore: Nanyang Technological University A good blend of industries, national laboratories, and universities is indicative of strong potential of the technology

5 Brief Overview of Cold Spray Materials Deposition Process

6 Cold Spray Materials Deposition Process High velocity powder particles propelled by a gas onto the surface of a part or a substrate to form a coating Particle temperature is low particles are not melted and deposition occurs in solid state High deposition efficiency

7 Low Powder Particle Temperatures Low temperature, high velocity process Low particle temperature confers several advantages: Little or no oxide inclusions in the coating/deposited material No porosity due to solidification shrinkages Ideally suited for spraying metallic materials (e.g., Al, Cu, Ni)

8 High Deposition Efficiency High deposition efficiencies allow for: Repair and dimensional restoration Manufacture of near-net shape products Celloto et al, The Cold Spray Materials Deposition Process, Woodhead Publishers, Cold Spray is not just a coating process it is also a process for dimensional restoration and for manufacturing 3-D products

9 Merits and Limitations of Cold Spray Process Additional Merits Compressive stresses in the coating Good adhesion to substrate without inter-layers No thermally-induced differences in powder vs. coating (what is in the powder is in the coating) No liquid effluents Limitations Limited for now to metallic materials, not suited for ceramic material coatings High gas consumption (economics are effected if helium has to be used) Line-of-sight process Work-hardening of coating can lead to loss in ductility

10 Critical Particle Velocity A critical velocity is required to form an adherent coating, which depends on powder material and its temperature

11 High Velocity Particle Impact Kinetic energy of particles converts to plastic deformation and heat leading to a transient temperature increase in particles Deformation occurs at high strain rates From: M. Grujicic in The Cold Spray Materials Deposition Technology, Woodhead Publishing, UK, 2007 Modeling of Al particles on Cu

12 Structural and Interfacial Effects Transient temperature spike and high strain rate can lead to interesting materials effects: Dynamic recrystallization that may lead to novel structures Fragmentation of native oxide monolayers on particles In situ surface cleaning Metallurgical bonding on nanometer length scales (possibly due to temperature spike) Al coating on Al substrate showing a bond layer (~8-10nm) from: Hanyang University, Korea Kang, Won, Bae, Ha, Lee, J. Materials Science, 2012.

13 Examples of Research and Development Activities World-Wide

14 Cold Spray Deposition of Al for Repair of Mg Aircraft Components Mg components used extensively in DoD aircrafts Susceptible to corrosion in marine environments Cold spray technology [with Al, 6061 Al-alloy] being extensively used for repair and maintenance resulting in millions of dollars of savings Corroded Sites on Mg Flange Repaired with Cold Spray of Al Powder U.S. Army Research Laboratory Courtesy V. Champagne and B. Gabriel MIL-STD-3021, 2008 (test standards for corrosion, fatigue, bond strength, microstructure etc.)

15 Copper Cold Spray for Spent Nuclear Fuel Applications 10mm thick Cu encasement on prototype cast iron canisters for storing spent nuclear fuel disposal Use of 10mm thick encasement rather than a use a 50mm thick Cu container, 600 tons of Cu can be saved per canister Cold Sprayed Cu encasement Korea Atomic Energy Institute Choi, Lee, and Lee, Nuclear Engr. Design, 240 (2010) CS Cu had no oxides and showed very good corrosion resistance, but loss in ductility

16 Ni Cold Spray Coatings on Ti-Alloy to Reduce High Temp. Fretting Wear for Aerospace Applications High temperature fretting wear is an issue in Ti-alloy/Ti-Alloy metallic contacts in aerospace applications Ni-cold spray coatings on one of the mating surfaces reduced friction and fretting wear Annealing of cold sprayed Ni coating Ti-alloy against Ni-cold sprayed Ti-alloy United Technology, Air Force, and Penn State C.H. Hager, J. Sanders, S. Sharma, A. Voevodin, and A. Segall, Tribology International, 42 (2009) pp Low friction lubricious Ni glaze oxide film forms on surface at high temperatures and reduces galling and fretting wear

17 Nano-crystalline Ni Coatings by Cold Spray Pore free coating achieved with hardness of 605 H V After cryo-milling (0.51% O and 0.19% N); ball milled in L-N 2 for 15 hrs to form nano-crystalline structure University of California, Davis, and University of Ottawa, Canada Ajdelsztjan, Jodoin, Schoenung Surface and Coatings Technology, 201 (2006) pp Ni 3 N and NiO nanoparticles pin grain boundaries at high temperatures Ring patterns typical of nanocrystalline materials

18 Ni-50Cr Cold Spray Coatings for High Temperature Power Plant Boiler Applications T22 Steel Testing in Na 2 SO 4-60%V 2 O 5 power plant effluents at 900 o C SA 516 Steel Indian Institute of Technology, Roorkee, India and ASB Industries, USA; N. Bala, H. Singh, and S. Prakash, Materials and Design, 31 (2010), pp CS Ni-50Cr significantly reduced corrosion in power plant steels

19 Cold Spray of Refractory and Reactive Metals Cold sprayed Ta Ductile fracture in as-coated Ta Intl. Advanced Research Centre for Powder Metallurgy and New Materials, India Courtesy: Dr. S. Joshi Ductile fracture in as-coated Nb Ductile fracture in as coated Ti High strain rate deformation may be responsible for ductility

20 Cold Spray Amorphous Alloy Coatings Amorphous alloys (metallic glasses) have high hardness and corrosion resistance, but they are also quite brittle Fe 44 Co 6 Cr 15 Mo 14 C 15 B 6 amorphous alloy cold spray coatings successfully deposited by balancing gas pre-heat temperature (~950 o C), particle temperature, and substrate heating Amorphous structure retained in the coating Helmut Schmidt University, Hamburg Germany List, Gartner, Schmidt, and Klassen, J. Thermal Spray Technology, February High hardness: 1100Hv Deposition Efficiencies up to 70%

21 Helmut-Schmidt University, Hamburg, Germany Cold Spray Courtesy Prof. T. Klassen, Helmut Schmidt University, Germany Ti-Mo being Cold Sprayed

22 Nanocrysatlline Structures in Amorphous Cold Spray Coatings Strain induced nanocrystallization of amorphous Cu 54 Ni 6 Ti 18 Zr 22 has been discovered using cold spray X-ray diffraction and TEM of powders Hanyang University, Korea Yoon, Bae, Xiong, Kumar, Kang, Kim, Lee, Acta Materialia, 2009, Nanocrystalline regions in the coating

23 Nanostructured WC-Co Cold Spray Coatings WC-17%Co sprayed with helium cold spray process (mild steel substrate) Two WC particle sizes studied: > 1µm and 40 to 800nm XRD for 40 to 800nm WC powders and coatings showed no oxidation or decarburization WC-Co with > 1µm showed erosion of substrate and little build-up WC-Co with 40 to 800nm WC good build-up Hardness for finer WC-Co: 10 GPa Adhesion > 60MPa Swinburne University Australia, SIM University Singapore, and Russian Academy of Sciences; Ang, Berndt, and Cheang, Surface and Coatings Technology, 205 (2011) pp

24 Cold Spray of Ceramic Coatings Nanoscale particles agglomerated to a porous structure 10 to 20µm Primary particles oriented along a single axis TiO 2 coatings deposited!! Toyohashi University of Technology, Japan Courtesy: Yamada and Fukumoto

25 Cold Spray Research Program at the University of Wisconsin, Madison

26 University of Wisconsin Cold Spray System Robot for pre-programmed movement of spray gun Sample stage and dust collector (below that) Sound-proof spray booth KINETIK System, from ASB Industries/CGT- GmBH Spray booth from Noise Barriers Robot controlled (Nachi system, from Antennen) Nitrogen/helium gas cylinders Robot controls (left) and spray gun control (right)

27 Safety Features Oxygen sensors Cut-off switches MERV-11 filter (filter checked frequently and replaced when visibly contaminated Explosion proof vacuum being purchased to clean up excess powders Downdraft Table collects large fraction of excess sprayed particles (adheres to NFPA 484, i.e. non-sparking motors, etc.) Class D (metal fires) fire extinguisher

28 University of Wisconsin Cold Spray - Live

29 Aluminum and Copper Cold Spray Coatings on Various Material Substrates Pure Al coating on 6061 Alalloy Pure Cu on 6061 Alalloy Pure Al on plasma sprayed alumina

30 Interface Comparison between Electroplating and Cold spray process: Cu on 4140 steel Composition (Wt. %) Composition (Wt. %) Electroplated Copper on 4140 Steel 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Distance from Interface (µm) Cold Sprayed Copper on 4140 Steel 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Distance from Interface (µm) Oxygen Iron Copper Oxygen Iron Copper

31 Addressing Problem with Sensitization of 5xxx series Al-alloys with Cold Spray 5xxx series Al-Mg alloys contain 4% 5 % Mg 5XXX series Al-alloys used in Navy ships Experience sensitization (i.e, segregation of Al 3 Mg 2 β phase at grain boundaries Electrochemical potential of β-phase, Al 3 Mg 2 β phase: -1150mV SCE Electrochemical Potential of Al-5Mg solid solution: -790mV SCE Al 3 Mg 2 β phase corrodes and then leads to stress corrosion cracking (SCC)

32 Cross-sectional SEM image of 5083 Al-alloy Cold Spray Coatings 240 µm Coating Substrate Very good coating produced (seamless transition between the coating and the substrate)

33 Knoop Microhardness of 5083 Al-alloy Cold Spray Coatings and Substrate Higher hardness of cold spray coating is indicative of good densification and work-hardening

34 Dimensional Restoration by Cold Spray Cold spray materials deposition model

35 Concluding Remarks Metrics such as international workshops, conferences, and publications indicate that interest in cold spray technology is growing world-wide Originally investigated for soft or low melting point materials, cold spray is now being used for higher melting point and reactive materials (e.g. Ta, Ti), composites (WC-Co), amorphous materials, and nanocrystalline materials, vastly expanding scope of its applications Modifications in equipment, new designs, and development of portable systems are making the process even more attractive and economical Strong interest and R&D programs at universities, national laboratories, and industry alike are indicators of a bright outlook for the cold spray deposition technology

36 University of Wisconsin Cold Spray Laboratory, Madison, WI, USA Thank you! UW Cold Spray Laboratory