Table of Contents
COLD SPRAY TECHNOLOGY
Preface
Chapter I Discovery of the cold spray phenomenon and its basic features
1.1 Supersonic two-phase flow around bodies and discovery of the cold spray phenomenon
1.1.1 Experimental setup and research techniques
1.1.2 Structure of disturbances induced by reflected particles
1.1.3 Interaction of a supersonic two-phase flow with the surface. Effect of coating formation
1.2 Spraying with a jet incoming onto a target
1.2.1 Acceleration of particles in gas-dynamic spraying
1.2.1.1 Diagnostic methods
1.2.1.2 Experimental measurement of particle velocity
1.2.2 Description of the setup
1.2.3 Interaction of single particles with the surface
1.2.4 Coating formation process. Transition from substrate erosion to coating formation.
Critical velocity
1.2.5 Effect of temperature on the deposition efficiency
References
Symbol List
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Chapter II High-velocity interaction of particles with the target. Experiment and modeling
2.1 Deformation of micro particles under high-velocity impact
2.1.1 Experimental setup and materials
2.1.2 Measurement technique
2.1.3 Statistical processing
2.1.4 Results of microscopic studies
2.1.5 Dependence of strain on impact velocity
2.2 Influence of the Substrate Surface Activation by Sprayed Particles on the Process of Coating Formation
2.2.1 Activation of the substrate surface by the particles. Induction time.
2.2.3 Determination of the mass of the first coating layer
2.2.4 Steady stage of coating formation
2.2.5 Kinetics of coating-mass growth
2.2.6 Deposition efficiency
2.3 Modeling of interaction of single particles with the target within the framework of mechanics of continuous media
2.3.1Impact of a spherical particle on a rigid target
2.3.1.1 Impact of elastic particles
2.3.1.2 Elastic-plastic impact
2.3.2Impact of micro particles on deformable target
2.4 Formation of a layer of a high-velocity flow in the vicinity of the micro particle-solid target contact plane
2.4.1 Background
2.4.2 Modeling of the high-velocity flow layer
2.5 Adhesive particle-surface interaction under the impact
2.5.1 Estimates of the contact time and particle strain under a high-velocity impact
2.5.2 Temperature of the particle-substrate contact area at a high-velocity impact
2.5.2.1 Analytical modeling
2.5.2.2 Results
2.5.2.3 Numerical estimates
2.5.3 Specific features of adhesive interaction of a non-melted particle with the substrate
2.5.3.1 Governing equation for the number of bonds formed
2.5.3.2 Heated volume
2.5.3.3 Critical velocities
2.5.3.4 Diagram of thermal states
2.5.3.5 Volume of the material at the melting point
2.5.3.6 Contact temperature
2.5.3.7 Activation energy
2.5.3.8 Adhesion energy
2.5.3.9 Elastic energy
2.5.3.10 Comparison of energies
2.5.3.11 Adhesion probability
2.5.3.12 Optimization problem
2.5.3.13 Polydispersity
2.5.4 Effect of surface activation on the gas-dynamic spraying process
2.5.4.1 Activation energy
2.5.4.2 Numerical experiment
2.5.4.3 Modeling results
2.5.4.4 Dependence of the coated area on the particle velocity
2.5.4.5 Dependence of the coated area on the particle temperature
2.6 Numerical simulation of self-organization processes during the particle-surface impact by the molecular dynamics method
2.6.1Impact of a spherical copper cluster on a rigid target
2.6.2Melting at the contact plane under impact of a nickel cluster on a rigid wall
2.6.2.1 Melting of spherical clusters
2.6.2.2 Analysis in the near-contact region of the cluster-rigid wall impact
References
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Chapter III Gas-dynamic aspects of the Cold Spray
3.1 Flow in a supersonic nozzle with a large aspect ratio and a rectangular cross section
3.1.1 Experimental determination of gas-flow parameters at the exit of a plane supersonic nozzle
3.1.1.1 Experimental setup
3.1.1.2 Analysis of experimental results
3.1.2 Calculation of gas parameters inside the nozzle
3.1.2.1 Allowance for the displacing action of the boundary layer
3.1.2.2 Calculation of flow parameters averaged over the cross section
3.2 Investigation of supersonic air jets exhausting from a rectangular nozzle
3.2.1 Experimental setup and research techniques
3.2.2 Profiles of gas parameters in the jet
3.2.2.1 Mach number profiles
3.2.2.2 Profiles of excess temperature
3.2.3 Stream wise distribution of axial parameters
3.2.4 Jet thickness
3.2.5 Effect of the jet-pressure ratio
3.3 Impact of rectangular supersonic jet on a target
3.3.1 Pressure distribution on the target surface and velocity gradient at the stagnation point
3.3.1.1 Velocity gradient at the stagnation point
3.3.1.2 Comparison of pressure distributions in the jet and on the target surface
3.3.2 Effect of the distance from the nozzle exit to the target on jet parameters. Oscillations of the jet
3.3.3 Near-wall jet
3.3.4 Thickness of the compressed layer
3.4 Heat transfer between a supersonic plane jet and a target
3.4.1 Method for measuring the heat-transfer coefficient
3.4.2 Heat-transfer coefficient
3.4.3 Temperature of the target surface
3.5 Optimization of geometric parameters of the nozzle for obtaining the maximum impact velocity
3.5.1 Pattern of gas and particle motion
3.5.2 Model for calculating gas and particle parameters
3.5.3 Computer application
3.5.4 Determination of impact temperature of particles
3.5.5 Optimization of nozzle parameters in terms of the impact velocity of particles
References
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Chapter IV Cold Spray equipment and technologies
4.1 Institute of Theoretical and Applied Mechanics of RussianAcademy of Science (Russia)
4.1.1 Development of main parts of the equipment
4.1.1.1 Nozzle assembly
4.1.1.2 Powder Feeder
4.1.1.3 Gas Heater
4.1.2 Installations for applying corrosion resistant coatings on tubes
4.1.2.1 Installation for applying coatings on outside surface of long tubes
4.1.2.2 Installation for applying coatings on inside surface of long tubes
4.1.3 Portable unit
4.1.4 Some technologies and applications
4.1.4.1 Spraying electro conductive coatings
4.1.4.2 Spraying metal-polymer coatings
Experimental unit
Results of studies
Modeling of friction of metal-polymer composits
4.2 Ktech Corporation (USA)
4.2. Ktech’ equipment and technologies
4.2.1 Ktech’ equipment
4.2.1.1 System layout
4.2.1.2 Prechamber and nozzle design
4.2.1.3 Gas heater
4.2.1.4 Gas control module
4.2.1.5 Laboratory powder feeder
4.2.1.6 Passivation system
4.2.1.7 Process control and data acquisition system
4.2.2 Technology of spray forming Titanium alloys
4.2.2.1 Powder selection (particle morphology, chemical composition, particle size analysis)
4.2.2.2 Spray tests, analysis and results
4.2.2.3 Spray forming tests
Heat treating
HIPing
Material properties results
Spray forming shapes
4.3 Cold Gas Technology (Germany)
4.3.1 Control unit
4.3.2 LINSPRAY gas heater
4.3.3 Spray gun
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Chapter V. Overview of CurrentState of Studies in the Field of Cold Spray process over the World.
Introduction
5.1 Gas-Dynamics of Cold Spray
5.2 High Speed Particle Impact and Mechanism of Adhesion
5.3 Technologies and Applications
Conclusion
References
Symbol List
Conclusion