Design of Thermal Barrier Coatings A Modelling Approach

This book details the relationships between microstructure, interface roughness, and properties of thermal barrier coatings. The author proposes a method for the reduction of the thermal conductivity of the ceramic layer in order to increase the lifetime of thermal barrier coatings. He includes models for the optimization of ceramic layer microstructure and interface roughness.

1 Introduction 1.1 Scope and Limitations 2 Background 2.1 Thermal Spraying 2.1.1 Atmospheric Plasma Spraying 2.1.2 High Velocity Oxy-Fuel (HVOF) Spraying 2.1.3 Liquid Feedstock Plasma Spraying 2.2 Thermal Barrier Coatings 2.3 Coating Formation 2.4 Process Parameters 2.5 Coating Materials for TBCs 2.5.1 Topcoat 2.5.2 Bondcoat 2.5.3 Thermally Grown Oxides References 3 Characteristics of TBCs 3.1 Microstructure 3.2 Heat Transfer Mechanism 3.2.1 General Theory 3.2.2 Application to TBCs 3.3 Mechanical Behaviour 3.3.1 Stress Formation 3.3.2 Young’s Modulus 3.3.3 Nonlinear Properties 3.4 Interface Roughness 3.4.1 Roughness Relationship with Lifetime 3.4.2 Stress Inversion Theory 3.5 Oxide Formation 3.6 Failure Mechanisms References 4 Experimental Methods 4.1 Microstructure Characterisation 4.2 Thermal Conductivity Measurements 4.3 Young’s Modulus Measurements 4.4 Roughness Measurements 4.5 Lifetime Testing References 5 Modelling of Properties of TBCs 5.1 Thermal Conductivity 5.1.1 Analytical Models 5.1.2 Numerical Models 5.2 Young’s Modulus 5.2.1 Analytical Models 5.2.2 Numerical Models 5.3 Finite Element Modelling 5.3.1 Basics of FEM and FDM 5.3.2 Image Based Finite Element Model 5.4 Artificial Coating Morphology Generator 5.5 Recent Work References 6 Modelling of Interface Roughness in TBCs 6.1 Simplified Interface Roughness Modelling 6.2 Real Interface Roughness Modelling 6.2.1 Two-Dimensional Approach 6.2.2 Three-Dimensional Approach 6.2.3 Results References 7 Modelling of Oxide Growth in TBCs 7.1 Diffusion-based Modelling 7.1.1 Previous Work 7.1.2 Real Interface Roughness Modelling 7.1.3 Recent Work 7.2 Mixed Oxide Growth References 8 Conclusions – How to Design TBCs? 8.1 Future Work