High Temperature Coatings


  • Sudhangshu Bose, Fellow, Pratt & Whitney Adjunct Professor, Rensselaer Polytechnic Institute, Hartford Hartford, CT
  • Sudhangshu Bose, Fellow, Pratt & Whitney Adjunct Professor, Rensselaer Polytechnic Institute, Hartford Hartford, CT

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.
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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 chemistrySecondary: 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


Book information

  • Published: January 2007
  • ISBN: 978-0-7506-8252-7

Table of Contents

PREFACECHAPTER 1.0 INTRODUCTIONREFERENCESCHAPTER 2.0 FUNDAMENTAL CONCEPTS2.1 Thermodynamic Concepts Enthalpy Entropy Free Energy Equilibrium Constant Activity Coefficient2.2 Concept of Kinetics Activation Energy Diffusion2.3 Crystal StructureDefects in Crystals2.4 Equilibrium Phases Binary Phase Diagram Ternary Phase DiagramREFERENCESCHAPTER 3.0 SUBSTRATE ALLOYS3.1 Temperature Capability of metal and alloys3.2 Strengthening Mechanisms3.3 Titanium Alloys3.4 Steels3.5 Nickel-Iron Alloys3.6 Nickel and Cobalt base Superalloys3.7 Need for CoatingsREFERENCESCHAPTER 4.0 OXIDATION4.1 Oxidation Process Temperature Effects Partial Pressure Effects Composition Effects Kinetics of Oxidation Oxide Scale Protectiveness4.2 Oxidation Testing and Evaluation Oxidation Rates Parabolic Growth, Linear Growth, Logarithmic Growth Breakaway Oxidation Influence of Thermocycling on Oxidation4.3 Oxidation of Alloys Binary Alloy Systems Ternary and Multicomponent Alloy Systems4.4 Role of Specific Alloying Constituents Aluminum, Chromium, Cobalt, Silicon, Boron, Titanium, Manganese,Tantalum, Molybdenum, Tungsten, Oxygen Reactive Elements, Rhenium / Ruthenium Reduction of Sulfur Level4.5 Oxidation in the Presence of Water vapor4.6 Oxidation of Polycrystalline Alloys versus Single CrystalsREFERENCESCHAPTER 5.0 HIGH TEMPERATURE CORROSION5.1 Hot Corrosion Process The Corroding Salts Acid and Base Characteristics of Salts5.2 Corrosion of Metals and Alloys Solubility of Oxides in Molten Salts Mechanism of Sustained Hot Corrosion Role of Vanadium5.3 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, Platinum5.4 Influence of Other ContaminantsPresence of CarbonPresence of Chlorides5.5 Hot Corrosion of TBC5.6 Hot Corrosion – like DegradationREFERENCESCHAPTER 6.0 OXIDATION & CORROSION RESISTANT COATINGS6.1 Requirements for Metallic Coatings6.2 Coatings Processes6.3 Diffusion Coatings6.3.1 Pack Coatings Aluminiding of Ni base alloysPack Process Above the Pack ProcessPulse AluminidingSlurry AluminidingRole of ActivatorMicrostructure and Mechanism of Coatings Formation6.3.1.2 Aluminiding of Co base alloys6.3.1.3 Chromium Modified Aluminide Coating for Ni base alloys6.3.1.4 Siliconized Coating for Ni base alloys6.3.1.5 Platinum Modified Aluminide for Ni base alloys6.3.2 Chemical Vapor Deposition (CVD) Platinum Aluminide by Chemical Vapor Deposition6.3.3 Role of Reactive Elements in Diffusion Coatings6.3.4 Microstructure of Platinum Aluminides6.3.5 Manufacturing Aspects of the Coatings Process6.3.6 Commercial Diffusion Coatings6.3.7 Coating - Substrate Interdiffision Effects6.3.8 Coatings Phase Stability6.3.8.1 Platinum modified Gamma + Gamma Prime Coating 6.3.9 Oxidation Resistance of Diffusion Coatings6.3.10 Corrosion Resistance of Diffusion Coatings6.3.11 Mechanical Properties of Platinum Aluminides6.4 Overlay Coatings6.5 Overlay Coatings by Spray and Arc Processes6.5.1 Beta – Gamma System Phase Stability6.5.2 Spray Coatings6.5.2.1 Cold Spray6.5.2.2 Thermal SprayDetonation Gun ProcessFlame Spray ProcessHigh Velocity Oxygen Fuel (HVOF)Plasma Spray ProcessLow Pressure Plasma Spray (LPPS)6.5.3 LPPS Coatings Deposition Profile and Microstructure 6.5.4 Arc ProcessElectric Arc SprayElectro – spark Deposition (ESD)6.5.5 Coating - Substrate Diffusion Effects6.5.6 Commercial Overlay Coatings6.6 Overlay Coatings by Physical Vapor Deposition (PVD)6.6.1 SputteringPlaner Diode SputteringTriode SputteringMagnetron SputteringRadio Frequency (R F) Sputtering6.6.2 Ion Plating6.6.3 Ion Implantation6.6.4 Electron Beam Physical Vapor Deposition (EB-PVD)6.6.5 Microstructure of Coatings6.6.6 Mechanical Properties of Coatings and Coated MaterialsDuctile to Brittle Transition Temperature (DBTT)Tensile PropertiesTensile Strength and DuctilityCreep and Rupture PropertiesLow Cycle and Thermal FatigueHigh Cycle Fatigue6.7 Relative Oxidation and Corrosion Resistance of CoatingsOxidation ResistanceCorrosion ResistanceDiffusion CoatingsOverlay CoatingsCoatings for Marine Application6.8 Modeling of Oxidation and Corrosion Life6.8.1 Oxidation Life of Superalloys and Metallic Coatings6.8.1.1 Life Prediction Methodologies6.8.1.2 Life Equation FormulationWeight Change after the First Thermal CycleWeight Change after the Second Thermal CycleCumulative Specific Weight Change of the Sample and Metal LossLife Prediction6.8.2 Hot Corrosion Life of Superalloys and Coatings6.8.2.1 Contributing Processes to the Corrosion RateTotal Contaminant ConcentrationTest Data Generation6.8.2.2 Life Equation FormulationOxidationType I Hot CorrosionType II Hot CorrosionVanadic Hot CorrosionOverall Corrosion RateInfluence of Other Variables6.9 Interaction of Erosion – Oxidation and Erosion – CorrosionREFERENCES CHAPTER 7.0 THERMAL BARRIER COATINGS (TBC)7.1 Temperature Reduction by TBC7.1.1 Magnitude of Temperature Reduction7.1.2 The Benefits of TBC7.2 Materials Requirements for TBC7.3 Partially Stabilized Zirconia7.4 Plasma Sprayed TBC The Plasma7.4.1 The Plasma Spray Process7.4.2 Microstructure of Plasma Sprayed TBC7.4.3 Microstructure Development and Structure Property Relationship7.4.3.1 Microstructure Formation Segmented TBC Phase Identification in Ceramic Coating7.4.3.2 Role of Substrate Surface Roughness7.4.3.3 Thick TBC7.4.3.4 Thermal Properties and Consequence Thermal conductivity7.4.4 Residual Stresses7.4.5 Role of Thermally Grown Oxide (TGO)7.4.6 Structural Properties7.4.7 Plasma TBC Durability7.4.7.1 Effects of Thermal cycling in Oxidizing Environment7.4.7.2 TBC Degradation Modes and Locations7.4.7.3 Failure Mechanism of Plasma Sprayed TBC7.4.7.4 Design Capable Phenomenological Life Model Life Equations Impact of Oxidation7.5 Electron Beam Physical Vapor deposited (EB-PVD) TBC7.5.1 Why Electron Beam7.5.1.1 General Principle7.5.2 Processing7.5.3 Microstructure Formation7.5.3.1 Directed Vapor EB-PVD7.5.4 TGO7.5.4.1 Role of Interface and Surface Roughness7.5.5 EB-PVD TBC Degradation Modes and Locations7.5.5.1 Infiltration by Environmental Deposits7.5.5.2 Hot Corrosion7.5.5.3 Erosion DamageDependence on Microstructure and Test Parameters7.5.5.4 Foreign Object Damage (FOD) Damage Due to Changes in the TGO7.5.6 Role of Residual Stress Stress within the TGO Stress within the Ceramic Coating7.5.7 Role of Oxygen Active Elements7.5.8 Bond Strength7.5.9 Structural Properties7.5.10 Oxidation and Thermocyclic Behavior7.5.11 Failure Mechanisms and Life Modeling7.5.11.1 Spall Mechanism and Fracture Mechanics Model7.5.12 Thermal Properties of TBC7.5.12.1 Thermal Behavior of 7YSZ Thermal Expansion Thermal Conductivity and Specific Heat The Effect of Microstructure7.5.12.2 Reduction of Thermal Conductivity Microstructural Modification Alternate Alloying Additions Novel Oxide CeramicsThermal Consequence of Increased Insulation7.6 Environmental Barrier Coatings (EBC)REFERENCESCHAPTER 8.0 NONDESTRUCTIVE INSPECTION OF COATINGS8.1 NDI TechniquesFluorescent Penetrant Inspection (FPI)Ultrasonic InspectionEddy CurrentInfrared ImagingAcoustic EmissionPhotoacoustic TechniqueMid-Infrared ReflectanceElectrochemical Impedance SpectroscopyPhotoluminescence PiezospectroscopyInterferometric TechniquesREFERENCESCHAPTER 9.0 COATINGS REPAIR 9.1 Limits to Coatings Repair9.2 The Repair Process Component Cleaning Consequence of Remnants of Old Coating9.2.1 Removal of Ceramic Coatings Grit blasting Alkali Solution Molten Alkali Water – jet9.2.2 Removal of Metallic Coatings Acid Stripping9.3 Recoating and Material RestorationREFERENCESCHAPTER 10.0 FIELD AND SIMULATED FIELD EXPERIENCE 10.1 Gas Turbine Engine Application10.1.1 Metallic CoatingsCoating Oxidation in Aircraft EnginesCoating Cracking in Aircraft EnginesOxidation and Hot Corrosion in Aircraft and Marine Engine Simulation TestOxidation and Hot Corrosion in Industrial Gas TurbinesCoating Cracking in Industrial Gas Turbine EnginesMarine Application10.1.2 TBC10.1.2.1 Plasma Sprayed TBCTBC on combustorTBC on vane platformTBC on vane airfoil10.1.2.2 EB-PVD TBCTBC on blades and vanes10.1.2.3 TBC in Industrial Gas Turbine Engines10.2 Other ApplicationsCoal Gasification Combined Cycle Power PlantFast Breeder ReactorsWaste to Energy PlantsDiesel EngineREFERENCESAPPENDIXINDEXSubjectAuthor