Plasma Spray Coating. Principles and Applications WILEY- WILEY-VCH Verlag GmbH & Co. KGaA. Robert B. Heimann VCH

Transcription

1 Robert B. Heimann Plasma Spray Coating Principles and Applications Second, Completely Revised and Enlarged Edition WILEY- VCH WILEY-VCH Verlag GmbH & Co. KGaA

2 Contents Preface XIII Preface to the First Edition XV Synopsis XVII 1 Introduction Coatings in the Industrial Environment Market Position Survey of Surface Coating Techniques Brief History of Thermal Spraying Synergistic Nature of Coatings Applications of Thermally Sprayed Coatings 13 References 15 2 Principles of Thermal Spraying Characterization of Flame vs. Plasma Spraying Concept of Energy Transfer Processes Unique Features of the Plasma Spray Process 22 References 24 3 The First Energy Transfer Process: Electron Gas Interactions The Plasma State Characteristic Plasma Parameters Langmuir Plasma Frequency Debye Screening Length Landau Length Collision Path Length Collision Frequency Classification of Plasmas Low Density Plasmas 30 Plasma Spray Coating: Principles and Applications. Robert B. Heimann Copyright 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim ISBN:

3 V I Contents Medium Density Plasmas High Density Plasmas Equilibrium and Nonequilibrium Plasmas Maxwellian Distribution of Plasma Energies Equilibrium Composition of Plasma Gases (Phase Diagrams) Plasma Generation Plasma Generation by Application of Heat Plasma Generation by Compression z-pinch Pinch Plasma Focus Plasma Generation by Radiation Plasma Generation by Electric Currents (Gas Discharges) Glow Discharges Arc Discharges Structure of the Arc Column Positive Column The Cathode Fall Region The Anode Region Design of Plasmatrons Arc Discharge Generators and their Applications Electrode-supported Plasmas Electrode-less Plasmas Hybrid Devices Stabilization of Plasma Arcs Wall-stabilized Arcs Convection-stabilized Arcs Electrode-stabilized Arcs Other Stabilization Methods Temperature and Velocity Distributions in a Plasma Jet Turbulent Jets Quasi-laminar Jets Plasma Diagnostics: Temperature, Enthalpy and Velocity Measurements Temperature Measurements Spectroscopic Methods Two-wavelengths Pyrometry Chromatic Monitoring Velocity Measurements Enthalpy Probe and Pitot Tube Techniques Laser Doppler Anemometry (LDA) Other Methods 75 References 76

4 Contents I vh 4 The Second Energy Transfer Process: Plasma Particle Interactions Injection of Powders Characteristics of Feed Materials Solid Wires, Rods and Filled Wires Powders Atomization Fusion and Crushing Compositing Agglomeration Momentum Transfer Connected Energy Transmission Transfer of Plasma Velocity to Particles Surface Ablation of Particles Heat Transfer Heat Transfer under Low Loading Conditions Exact Solution of Heat Transfer Equations Particle Heating without Evaporation Particle Heating with Evaporation Evaporation Time of a Particle Heat Transfer under Dense Loading Conditions Heat Transfer Catastrophy Energy Economy Particle Diagnostics: Velocity, Temperature and Number Densities Particle Velocity Determination Particle Temperature Determination Particle Number Density Determination 107 References The Third Energy Transfer Process: Particle Substrate Interactions Basic Considerations Estimation of Particle Number Density Momentum Transfer from Particles to Substrate Heat Transfer from Particles to Substrate Generalized Heat Transfer Equation Heat Transfer from Coating to Substrate Crystallinity of Coatings Fractal Properties of Surfaces Box Counting Method Density Correlation Function Mass Correlation Function Slit Island Analysis (SIA) Fracture Profile Analysis (FPA) Scale-sensitive Fractal Analysis 140

5 VllIl Contents Residual Stresses 143 Blind Hole Test 145 X-ray Diffraction Measurements (sin2w-technique) 145 Curvature Monitoring Technique (Almen-type test) 151 Photoluminescence Piezospectroscopy 155 Neutron Diffraction 157 References Modeling and Numerical Simulation Principal Aspects of Modeling Modeling of Plasma Properties Modeling of the Plasma Partide Interaction Modeling of Heat Transfer Conservation Equations Experimental Validation of Modeling under Dense Loading Conditions Modeling of Heat Transfer in Two-fluid Interfacial Flow Modeling of Momentum Transfer Modeling of the Drag Coefficient Modeling of Particle Dispersion Modeling of Particle Substrate Interaction D Simulation of Coating Microstructure Modeling of Splat Shapes Modeling of Residual Coating Stresses Modeling of Thermal Conductivity 185 References Solutions to Industrial Problems 1: Structural Coatings Carbide Coatings Pure Carbides Cemented Carbides Tungsten Carbide-based Coatings Titanium Carbide-based Coatings Chromium Carbide-based Coatings Other Hard Carbide Coatings Nitride Coatings Titanium Nitride-based Coatings Silicon Nitride-based Coatings Oxide Coatings Alumina-based Coatings Chromium Oxide-based Coatings Other Oxide Coatings Metallic Coatings Refractory Metal Coatings Superalloy Coatings 223

6 Contents 1 IX 7.5 Diamond Coatings 224 References Solutions to Industrial Problems II: Functional Coatings Thermal (TBC) and Chemical (CBC) Barrier Coatings Partially Yttria-stabilized Zirconia Coatings (Y-PSZ) Stress Development and Control Sealing of As-sprayed Surfaces Laser Surface Remelting of Y-PSZ Coatings Other Thermal and Chemical Barrier Coatings Superconducting and Electrocatalytic Coatings HT-Superconducting Coatings Electrocatalytic Coatings for Solid Oxide Fuel Cells (SOFC) Photocatalytic Coatings Coatings with High Friction Coefficient 267 References Solutions to Industrial Problems III: Bioceramic Coatings Classification of Biomaterials and Mechanism of Bone Bonding Properties of Bioceramic Coatings Plasma Spraying of Osseoconductive Hydroxyapatite Phase Composition Parametric Study of HAp Coating Properties Bioinert Bond Coats Composition of Bioinert Bond Coats Calcium Silicate Bond Coats Zirconia Bond Coats Zirconia/Titania Bond Coats Titania Bond Coats and Ti0 2/HAp Composite Coatings Other Thermal Coating Techniques Outlook 297 References Quality Control and Coating Diagnostic Procedures Quality Implementation Total Quality Management (TQM) Quality Tools Quality Philosophy Management Style Qualification Procedures Characterization and Test Procedures Powder Characterization Microstructure of Coatings Splat Configuration 310

7 Contents Mechanical Properties Adhesion of Coatings and Determination of Bond Strength Macro- and Microhardness Tests Fracture Toughness Porosity of Coatings Tribological Properties Simulation of Basic Wear Mechanisms Surface Roughness of Coatings Chemical Properties Thermally Induced Chemical Changes Tests of Chemical Corrosion Resistance Burner Rig Test 354 References Design of Novel Coatings Property-based Approaches Coating Design Based on Chemical Bonding Design of Novel Advanced Layered Coatings Gradient Layers Multilayers Coating Design Based on Materials Informatics Process Mapping Stochastic Approaches Statistical Design of Experiments (SDE) The Experimental Environment and its Evolution Screening Designs Response Surface (RSM) Designs Theoretical Models Anatomy of Screening Designs Anatomy of Factorial Designs Box Behnken Designs Designs of Higher Dimensionality Neyer D-optimal Designs Optimization of Coating Properties: Case Studies Plackett Burman (Taguchi) Screening Designs Full Factorial Designs Fractional Factorial Designs Artificial Neuronal Network Analysis Fuzzy Logic Control Future Developments 398 References 403 Appendix A: Dimensionless Groups 407 A.1 Momentum Transfer 407 A.2 Heat Transfer 407

8 Contents I XI A.3 Mass Transfer 408 A.4 Materials Constants 408 Appendix B: Calculation of Temperature Profiles of Coatings 409 B.1 Heat Conduction Equations 409 B.2 Solutions of the Equations 410 B.2.1 Substrate Temperature Profile 410 B.2.2 Deposit Temperature Profile 410 B.3 Real Temperature Profiles 412 References 412 Appendix C: Calculation of Factor Effects for a Fractional Factorial Design References 416 Index 417