High Temperature Coatings

High Temperature Coatings

1st Edition - January 23, 2007
  • Author: Sudhangshu Bose
  • eBook ISBN: 9780080469553
  • Hardcover ISBN: 9780750682527

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Description

High Temperature Coatings demonstrates how to counteract the thermal effects of the rapid corrosion and degradation of exposed materials and equipment that can occur under high operating temperatures. This is the first true practical guide on the use of thermally-protective coatings for high-temperature applications, including the latest developments in materials used for protective coatings. It covers the make-up and behavior of such materials under thermal stress and the methods used for applying them to specific types of substrates, as well as invaluable advice on inspection and repair of existing thermal coatings.With his long experience in the aerospace gas turbine industry, the author has compiled the very latest in coating materials and coating technologies, as well as hard-to-find guidance on maintaining and repairing thermal coatings, including appropriate inspection protocols. The book will be supplemented with the latest reference information and additional support for finding more application-type and industry-type coatings specifications and uses, with help for the reader in finding more detailed information on a specific type of coating or a specific type of use.

Key Features

· Offers overview of the underlying fundamental concepts of thermally-protective coatings, including thermodynamics, energy kinetics, crystallography, and equilibrium phases
· Covers essential chemistry and physics of underlying substrates, including steels, nickel-iron alloys, nickel-cobalt alloys, and titanium alloys
· Provides detailed guidance on wide variety of coating types, including those used against high temperature corrosion and oxidative degradation, as well as thermal barrier coatings

Readership

Primary: Professional engineers in materials engineering, metallurgy, mechanical engineering, aerospace engineering, and chemical engineering, Chemists and Physicists with any interest in high temperature physics and physical chemistry
Secondary: Graduate students in materials engineering, metallurgy, mechanical engineering, aerospace engineering, and chemical engineering,Graduate students in chemistry and physics taking courses in solid physics and related subjects in physical chemistry

Table of Contents

  • PREFACE

    CHAPTER 1.0 INTRODUCTION
    REFERENCES

    CHAPTER 2.0 FUNDAMENTAL CONCEPTS
    2.1 Thermodynamic Concepts
    Enthalpy
    Entropy
    Free Energy
    Equilibrium Constant
    Activity Coefficient
    2.2 Concept of Kinetics
    Activation Energy
    Diffusion
    2.3 Crystal Structure
    Defects in Crystals
    2.4 Equilibrium Phases
    Binary Phase Diagram
    Ternary Phase Diagram
    REFERENCES

    CHAPTER 3.0 SUBSTRATE ALLOYS
    3.1 Temperature Capability of metal and alloys
    3.2 Strengthening Mechanisms
    3.3 Titanium Alloys
    3.4 Steels
    3.5 Nickel-Iron Alloys
    3.6 Nickel and Cobalt base Superalloys
    3.7 Need for Coatings
    REFERENCES

    CHAPTER 4.0 OXIDATION
    4.1 Oxidation Process
    Temperature Effects
    Partial Pressure Effects
    Composition Effects
    Kinetics of Oxidation
    Oxide Scale Protectiveness
    4.2 Oxidation Testing and Evaluation
    Oxidation Rates
    Parabolic Growth, Linear Growth, Logarithmic Growth
    Breakaway Oxidation
    Influence of Thermocycling on Oxidation
    4.3 Oxidation of Alloys
    Binary Alloy Systems
    Ternary and Multicomponent Alloy Systems
    4.4 Role of Specific Alloying Constituents
    Aluminum, Chromium, Cobalt, Silicon, Boron, Titanium, Manganese,
    Tantalum, Molybdenum, Tungsten, Oxygen Reactive Elements, Rhenium / Ruthenium
    Reduction of Sulfur Level
    4.5 Oxidation in the Presence of Water vapor
    4.6 Oxidation of Polycrystalline Alloys versus Single Crystals
    REFERENCES

    CHAPTER 5.0 HIGH TEMPERATURE CORROSION
    5.1 Hot Corrosion Process
    The Corroding Salts
    Acid and Base Characteristics of Salts
    5.2 Corrosion of Metals and Alloys
    Solubility of Oxides in Molten Salts
    Mechanism of Sustained Hot Corrosion
    Role of Vanadium
    5.3 Role of Specific Alloying Elements in Hot Corrosion of Ni and Co Based Alloys and Coatings
    Chromium, Nickel, Cobalt, Tungsten, Molybdenum, Vanadium, Titanium,
    Rare Earth Elements, Platinum
    5.4 Influence of Other Contaminants
    Presence of Carbon
    Presence of Chlorides
    5.5 Hot Corrosion of TBC
    5.6 Hot Corrosion – like Degradation
    REFERENCES

    CHAPTER 6.0 OXIDATION & CORROSION RESISTANT COATINGS
    6.1 Requirements for Metallic Coatings
    6.2 Coatings Processes
    6.3 Diffusion Coatings
    6.3.1 Pack Coatings
    6.3.1.1 Aluminiding of Ni base alloys
    Pack Process
    Above the Pack Process
    Pulse Aluminiding
    Slurry Aluminiding
    Role of Activator
    Microstructure and Mechanism of Coatings Formation
    6.3.1.2 Aluminiding of Co base alloys
    6.3.1.3 Chromium Modified Aluminide Coating for Ni base alloys
    6.3.1.4 Siliconized Coating for Ni base alloys
    6.3.1.5 Platinum Modified Aluminide for Ni base alloys
    6.3.2 Chemical Vapor Deposition (CVD)
    6.3.2.1 Platinum Aluminide by Chemical Vapor Deposition
    6.3.3 Role of Reactive Elements in Diffusion Coatings
    6.3.4 Microstructure of Platinum Aluminides
    6.3.5 Manufacturing Aspects of the Coatings Process
    6.3.6 Commercial Diffusion Coatings
    6.3.7 Coating - Substrate Interdiffision Effects
    6.3.8 Coatings Phase Stability
    6.3.8.1 Platinum modified Gamma + Gamma Prime Coating
    6.3.9 Oxidation Resistance of Diffusion Coatings
    6.3.10 Corrosion Resistance of Diffusion Coatings
    6.3.11 Mechanical Properties of Platinum Aluminides
    6.4 Overlay Coatings
    6.5 Overlay Coatings by Spray and Arc Processes
    6.5.1 Beta – Gamma System Phase Stability
    6.5.2 Spray Coatings
    6.5.2.1 Cold Spray
    6.5.2.2 Thermal Spray
    Detonation Gun Process
    Flame Spray Process
    High Velocity Oxygen Fuel (HVOF)
    Plasma Spray Process
    Low Pressure Plasma Spray (LPPS)
    6.5.3 LPPS Coatings Deposition Profile and Microstructure
    6.5.4 Arc Process
    Electric Arc Spray
    Electro – spark Deposition (ESD)
    6.5.5 Coating - Substrate Diffusion Effects
    6.5.6 Commercial Overlay Coatings
    6.6 Overlay Coatings by Physical Vapor Deposition (PVD)
    6.6.1 Sputtering
    Planer Diode Sputtering
    Triode Sputtering
    Magnetron Sputtering
    Radio Frequency (R F) Sputtering
    6.6.2 Ion Plating
    6.6.3 Ion Implantation
    6.6.4 Electron Beam Physical Vapor Deposition (EB-PVD)
    6.6.5 Microstructure of Coatings
    6.6.6 Mechanical Properties of Coatings and Coated Materials
    Ductile to Brittle Transition Temperature (DBTT)
    Tensile Properties
    Tensile Strength and Ductility
    Creep and Rupture Properties
    Low Cycle and Thermal Fatigue
    High Cycle Fatigue
    6.7 Relative Oxidation and Corrosion Resistance of Coatings
    Oxidation Resistance
    Corrosion Resistance
    Diffusion Coatings
    Overlay Coatings
    Coatings for Marine Application
    6.8 Modeling of Oxidation and Corrosion Life
    6.8.1 Oxidation Life of Superalloys and Metallic Coatings
    6.8.1.1 Life Prediction Methodologies
    6.8.1.2 Life Equation Formulation
    Weight Change after the First Thermal Cycle
    Weight Change after the Second Thermal Cycle
    Cumulative Specific Weight Change of the Sample and Metal Loss
    Life Prediction
    6.8.2 Hot Corrosion Life of Superalloys and Coatings
    6.8.2.1 Contributing Processes to the Corrosion Rate
    Total Contaminant Concentration
    Test Data Generation
    6.8.2.2 Life Equation Formulation
    Oxidation
    Type I Hot Corrosion
    Type II Hot Corrosion
    Vanadic Hot Corrosion
    Overall Corrosion Rate
    Influence of Other Variables
    6.9 Interaction of Erosion – Oxidation and Erosion – Corrosion
    REFERENCES

    CHAPTER 7.0 THERMAL BARRIER COATINGS (TBC)
    7.1 Temperature Reduction by TBC
    7.1.1 Magnitude of Temperature Reduction
    7.1.2 The Benefits of TBC
    7.2 Materials Requirements for TBC
    7.3 Partially Stabilized Zirconia

    7.4 Plasma Sprayed TBC
    The Plasma
    7.4.1 The Plasma Spray Process
    7.4.2 Microstructure of Plasma Sprayed TBC
    7.4.3 Microstructure Development and Structure Property Relationship
    7.4.3.1 Microstructure Formation
    Segmented TBC
    Phase Identification in Ceramic Coating
    7.4.3.2 Role of Substrate Surface Roughness
    7.4.3.3 Thick TBC
    7.4.3.4 Thermal Properties and Consequence
    Thermal conductivity
    7.4.4 Residual Stresses
    7.4.5 Role of Thermally Grown Oxide (TGO)
    7.4.6 Structural Properties
    7.4.7 Plasma TBC Durability
    7.4.7.1 Effects of Thermal cycling in Oxidizing Environment
    7.4.7.2 TBC Degradation Modes and Locations
    7.4.7.3 Failure Mechanism of Plasma Sprayed TBC
    7.4.7.4 Design Capable Phenomenological Life Model
    Life Equations
    Impact of Oxidation

    7.5 Electron Beam Physical Vapor deposited (EB-PVD) TBC
    7.5.1 Why Electron Beam
    7.5.1.1 General Principle
    7.5.2 Processing
    7.5.3 Microstructure Formation
    7.5.3.1 Directed Vapor EB-PVD
    7.5.4 TGO
    7.5.4.1 Role of Interface and Surface Roughness
    7.5.5 EB-PVD TBC Degradation Modes and Locations
    7.5.5.1 Infiltration by Environmental Deposits
    7.5.5.2 Hot Corrosion
    7.5.5.3 Erosion Damage
    Dependence on Microstructure and Test Parameters
    7.5.5.4 Foreign Object Damage (FOD)
    7.5.5.5 Damage Due to Changes in the TGO
    7.5.6 Role of Residual Stress
    Stress within the TGO
    Stress within the Ceramic Coating
    7.5.7 Role of Oxygen Active Elements
    7.5.8 Bond Strength
    7.5.9 Structural Properties
    7.5.10 Oxidation and Thermocyclic Behavior
    7.5.11 Failure Mechanisms and Life Modeling
    7.5.11.1 Spall Mechanism and Fracture Mechanics Model
    7.5.12 Thermal Properties of TBC
    7.5.12.1 Thermal Behavior of 7YSZ
    Thermal Expansion
    Thermal Conductivity and Specific Heat
    The Effect of Microstructure
    7.5.12.2 Reduction of Thermal Conductivity
    Microstructural Modification
    Alternate Alloying Additions
    Novel Oxide Ceramics
    Thermal Consequence of Increased Insulation
    7.6 Environmental Barrier Coatings (EBC)
    REFERENCES

    CHAPTER 8.0 NONDESTRUCTIVE INSPECTION OF COATINGS
    8.1 NDI Techniques
    Fluorescent Penetrant Inspection (FPI)
    Ultrasonic Inspection
    Eddy Current
    Infrared Imaging
    Acoustic Emission
    Photoacoustic Technique
    Mid-Infrared Reflectance
    Electrochemical Impedance Spectroscopy
    Photoluminescence Piezospectroscopy
    Interferometric Techniques
    REFERENCES

    CHAPTER 9.0 COATINGS REPAIR
    9.1 Limits to Coatings Repair
    9.2 The Repair Process
    Component Cleaning
    Consequence of Remnants of Old Coating
    9.2.1 Removal of Ceramic Coatings
    Grit blasting
    Alkali Solution
    Molten Alkali
    Water – jet
    9.2.2 Removal of Metallic Coatings
    Acid Stripping
    9.3 Recoating and Material Restoration
    REFERENCES

    CHAPTER 10.0 FIELD AND SIMULATED FIELD EXPERIENCE
    10.1 Gas Turbine Engine Application
    10.1.1 Metallic Coatings
    Coating Oxidation in Aircraft Engines
    Coating Cracking in Aircraft Engines
    Oxidation and Hot Corrosion in Aircraft and Marine Engine Simulation Test
    Oxidation and Hot Corrosion in Industrial Gas Turbines
    Coating Cracking in Industrial Gas Turbine Engines
    Marine Application
    10.1.2 TBC
    10.1.2.1 Plasma Sprayed TBC
    TBC on combustor
    TBC on vane platform
    TBC on vane airfoil
    10.1.2.2 EB-PVD TBC
    TBC on blades and vanes
    10.1.2.3 TBC in Industrial Gas Turbine Engines
    10.2 Other Applications
    Coal Gasification Combined Cycle Power Plant
    Fast Breeder Reactors
    Waste to Energy Plants
    Diesel Engine
    REFERENCES

    APPENDIX

    INDEX
    Subject
    Author

Product details

  • No. of pages: 312
  • Language: English
  • Copyright: © Butterworth-Heinemann 2007
  • Published: January 23, 2007
  • Imprint: Butterworth-Heinemann
  • eBook ISBN: 9780080469553
  • Hardcover ISBN: 9780750682527

About the Author

Sudhangshu Bose

Dr. Sudhangshu Bose is a retired Fellow and Manager, and currently consultant at Pratt & Whitney, the manufacturer of Gas Turbine and Rocket Engines. He has also been Professor of Practice in Mechanical Engineering at Rensselaer Polytechnic Institute, Troy, New York and Hartford, Connecticut, USA. He holds a Ph.D in Materials Science and Engineering from University of California, Berkeley, having previously obtained B.Sc (Honors) and M.Sc in Physics from Ranchi University, Ranchi, India. While at Pratt & Whitney and its sister divisions, Dr. Bose has conducted and managed research, development, and testing of advanced materials and processes including oxidation and corrosion in fuel cells and gas turbine engine, catalysis, high temperature coatings, superalloys, intermetallics, and ceramic matrix composites. He holds over 24 patents. As a Professor of Practice at Rensselaer, he taught courses and supervised research in the areas of Superalloys, High Temperature Coatings, and Conventional and Renewable Energy Technologies. He is currently associated with the Department of Mechanical Engineering and Materials Science at Yale University, New Haven, Connecticut.

Affiliations and Expertise

Retired Fellow, Pratt and Whitney. Retired Professor Emeritus, Rensselaer Polytechnic Institute, Hartford, CT, USA