reading

Cover
Dedication
Preface
Acknowledgments
Chapter 1: Introduction
1. 1.1 Definition of High Temperature Corrosion
2. 1.2 Historical Development
3. 1.3 High Temperature Corrosion Phenomena
4. 1.4 High Temperature Materials
5. 1.5 Corrosive Environments
6. 1.6 Films and Scales
7. 1.7 Academic Impact of High Temperature Corrosion
8. 1.8 Industrial Impact of High Temperature Corrosion
9. 1.9 Questions
10. References
11. Further Reading
Chapter 2: Metallurgical Structure and Metals
1. 2.1 Imperfections in an Essentially Perfect Structure
2. 2.2 Solidification
3. 2.3 Alloys
4. 2.4 Iron and Steel
5. 2.5 Deformation and Recrystallization
6. 2.6 Fracture and Fatigue
7. 2.7 Questions and Problems
8. References
9. Further Reading
3 High Temperature Equilibria
1. 3.1 Introduction
2. 3.2 Thermochemical Analysis
3. 3.3 Electrochemical Analysis
4. References
5. Further Reading
Chapter 4: Lattice Defects in Metal Compounds
1. 4.1 Introduction
2. 4.2 Defect Reactions
3. 4.3 Defect Equilibria
4. 4.4 Equilibrium Constants
5. 4.5 Questions
6. References
7. Further Reading
Chapter 5: Diffusion in Solid‐State Systems
1. 5.1 Introduction
2. 5.2 General Theory of Diffusion
3. 5.3 Diffusion Coefficients
4. 5.4 Matano–Boltzmann Analysis
5. 5.5 Kirkendall Effect
6. 5.6 Darken Analysis
7. 5.7 Factors Influencing Diffusion
8. 5.8 Impurity Diffusion in Metals
9. 5.9 Grain Boundary Diffusion in Metals
10. 5.10 Diffusion in Solid Oxides
11. 5.11 Morphology of Reaction Products
12. 5.12 Measurement of Diffusion Parameters
13. 5.13 Questions and Problems
14. References
15. Further Reading
Chapter 6: High Temperature Electrochemistry
1. 6.1 Introduction
2. 6.2 Electrochemical Nature of Molten Salt Corrosion
3. 6.3 The Single Potential of an Electrode
4. 6.4 Equilibrium Diagrams
5. 6.5 The Tafel Relationship
6. 6.6 Corrosion Potential–pO Relationship
7. 6.7 Electrochemical Polarization and Monitoring
8. 6.8 Electrochemical Nature of Metal Oxidation
9. 6.9 Usefulness of Electrochemical Cells
10. 6.10 Current–Potential Measurements on Solid Electrodes
11. 6.11 Simple Concepts of Oxide Semiconductors
12. 6.12 Conduction Processes in Ionic Oxides
13. 6.13 Common Solid‐State Electrochemical Situations
14. References
15. Further Reading
Chapter 7: Oxidation
1. 7.1 Introduction
2. 7.2 Thermodynamic Considerations
3. 7.3 Kinetic Considerations
4. 7.4 Defect Structures
5. 7.5 Compact Scale Growth
6. 7.6 Multilayered Scale Growth
7. 7.7 Oxidation Resistance
8. 7.8 Oxidation of Engineering Materials
9. 7.9 Conclusions
10. 7.10 Questions
11. References
12. Further Reading
Chapter 8: Sulfidation
1. 8.1 Introduction
2. 8.2 The Process of Sulfidation
3. 8.3 Sulfidation Kinetics
4. 8.4 Sulfidation of Selected Materials
5. 8.5 Defect Structures of Metal Sulfides
6. 8.6 Questions
7. References
8. Further Reading
Chapter 9: Carburization and Metal Dusting
1. 9.1 Introduction
2. 9.2 Carburization
3. 9.3 Alloy Resistance to Carburization
4. 9.4 Metal Dusting Problem
5. 9.5 Metal Dusting Mechanisms
6. 9.6 Alloy Resistance to Metal Dusting
7. References
8. Further Reading
Chapter 10: Nitridation
1. 10.1 Introduction
2. 10.2 Nitridation Mechanisms
3. 10.3 Nitridation in Industrial Media
4. 10.4 Questions and Problems
5. References
6. Further Reading
Chapter 11: Halogenation
1. 11.1 Introduction
2. 11.2 Metal–Halogen Reactions
3. 11.3 Alloy–Halogen Reactions
4. 11.4 Laboratory Studies
5. 11.5 Conclusions
6. 11.6 Questions
7. References
8. Further Reading
Chapter 12: Corrosion by Hydrogen and Water Vapor
1. 12.1 Introduction
2. 12.2 Corrosion by Hydrogen
3. 12.3 Corrosion by Water Vapor
4. 12.4 Conclusions
5. References
6. Further Reading
Chapter 13: Corrosion in Molten Salts
1. 13.1 Introduction
2. 13.2 Corrosion Process
3. 13.3 Thermodynamic Diagrams
4. 13.4 Corrosion Rate Measurements
5. 13.5 Test Methods
6. 13.6 Fluorides
7. 13.7 Chlorides
8. 13.8 Nitrates/nitrites
9. 13.9 Hydroxides
10. 13.10 Carbonates
11. 13.11 Vanadates
12. 13.12 Sulfates
13. 13.13 Prevention of Molten Salt Corrosion
14. 13.14 Summary
15. References
16. Further Reading
Chapter 14: Corrosion in Molten Metals
1. 14.1 Introduction
2. 14.2 Corrosive Processes
3. 14.3 Industrial Liquid Metals
4. 14.4 Conclusions
5. References
6. Further Reading
Chapter 15: Hot Corrosion
1. 15.1 Introduction
2. 15.2 Engine Description and Materials
3. 15.3 Early Studies
4. 15.4 Mechanisms of Hot Corrosion
5. 15.5 Hot Corrosion of Gas Turbine Alloys
6. 15.6 Methods of Evaluating Hot Corrosion
7. 15.7 Prevention of Corrosion
8. 15.8 Conclusions
9. 15.9 Questions
10. References
11. Further Reading
Chapter 16: Fireside Corrosion
1. 16.1 Introduction
2. 16.2 Coal‐Fired Boilers
3. 16.3 Coal‐ash Corrosion
4. 16.4 Oil‐Fired Boilers
5. 16.5 Corrosion in Waste Incinerators
6. 16.6 Plant Experience with Fireside Corrosion
7. 16.7 Conclusions
8. References
9. Further Reading
Chapter 17: Testing and Evaluation
1. 17.1 Introduction
2. 17.2 Testing Equipment and Monitoring
3. 17.3 Optical Microscopy
4. 17.4 Thermogravimetry
5. 17.5 Spectroscopy
6. 17.6 Diffraction Techniques
7. 17.7 Electron Microscopy
8. 17.8 Electron Spectroscopy and Ion Scattering
9. 17.9 Surface Microscopy
10. 17.10 Optical Spectroscopy
11. 17.11 Nondestructive Inspection Techniques
12. 17.12 Traditional Electrochemical Methods
13. 17.13 Nontraditional Electrochemical Methods
14. 17.14 Combined Electrochemical Methods
15. References
16. Further Reading
Chapter 18: Protective Coatings
1. 18.1 Introduction
2. 18.2 Coating Systems
3. 18.3 Coating Processes
4. 18.4 Coating Degradation
5. 18.5 Summary and Future Trends
6. 18.6 Questions
7. References
8. Further Reading
Chapter 19: Examples of Engineering Importance
1. 19.1 Introduction
2. 19.2 Molten Carbonate Fuel Cells
3. 19.3 Solid Oxide Fuel Cells
4. 19.4 Direct Carbon Fuel Cells
5. 19.5 Nuclear Power Plants
6. References
7. Further Reading
Chapter 20: Case Studies
1. 20.1 Making Stainless Steels
2. 20.2 Corrosion Protection of Turbine Blades
3. 20.3 Oxidation of Silicides for VLSI Applications
4. 20.4 Naphthenic Acid Corrosion in Petrochemical Plants
5. 20.5 Oxidation of Ceramic Matrix Composites
6. 20.6 Shell Corrosion of Rotary Cement Kilns
7. 20.7 Corrosion of Steels in a Linear α Olefin Plant
8. References
9. Further Reading
Appendix A
1. References
List of Acronyms
Glossary of Selected Terms Used in High Temperature Corrosion
Author Index
Subject Index
End User License Agreement

List of Tables

Chapter 1
1. Table 1.1 Classification of steel grades DIN EN 10027 (1992)
2. Table 1.2 Some properties of typical manufactured nonmetallic high temperature m...
3. Table 1.3 Heat‐resisting irons
4. Table 1.4 Development of industrial use of stainless steel
5. Table 1.5 Composition of stainless steels according to EN 10088‐I and correspond...
6. Table 1.6 Mechanical and physical properties of stainless steel
7. Table 1.7 Cold‐worked austenitic stainless steels in the Euro standard EN 10088–...
8. Table 1.8 Minimum bending radius of austenitic and ferritic stainless steels, th...
9. Table 1.9 Typical values of formability parameters for austenitic (EN 1.4301) an...
10. Table 1.10 Alloying elements and their major effects in high temperature alloys
11. Table 1.11 Nominal composition of high temperature cobalt alloys
12. Table 1.12 Melting points of oxides
13. Table 1.13 Possible crucible materials
14. Table 1.14 Refractory metals
15. Table 1.15 Some commercially available titanium alloys
16. Table 1.16 Spinel phases encountered in alloy oxidation
17. Table 1.17 High temperature corrosion problems found in different industries
18. Table 1.18 Current uses of advanced ceramics
19. Table 1.19 Factors affecting materials selection
Chapter 2
1. Table 2.1 Common crystal structures of metals
2. Table 2.2 Imperfections
3. Table 2.3 Young's moduli
4. Table 2.4 Discrepancy between theoretical and experimental yield stress (σ _L
5. Table 2.5 Strengthening mechanisms for metals
Chapter 3
1. Table 3.1 Thermodynamic data for reactions involving oxygen
2. Table 3.2 Thermochemical data for the Cr–O system
3. Table 3.3 Thermochemical data for the Cr–O system at 1473 K
4. Table 3.4 Standard energy of reactions for the Cr–O system at 1473 K
5. Table 3.5 Data for the construction of thermodynamic phase stability diagram M–S...
6. Table 3.6 Thermochemical data for the species under consideration
7. Table 3.7 Data for the heats and entropies of the formation of Fe, Na₂O, Na₂S, N...
8. Table 3.8 Nernst equations at 1173 K
Chapter 6
1. Table 6.1 BasicitiespO²⁻ of various molten salts where p _gas is the partial...
2. Table 6.2 An overview of electrochemical devices and measurement techniques base...
3. Table 6.3 Combination of reversible (O²⁻, e⁻|, typically porous Pt) ...
Chapter 7
1. Table 7.1 Kinetic laws characteristic of the oxidation of several metals as a fu...
2. Table 7.2 Pilling–Bedworth ratios for some metal–oxygen systems
3. Table 7.3 Linear coefficients of thermal expansion of metals and oxides, 1/°C (S...
4. Table 7.4 Calculation factor∫_z for the conversion of mass gain data into s...
5. Table 7.5 A comparison of the deviation from stoichiometry, self‐diffusion coeff...
Chapter 8
1. Table 8.1 Experimental methods for assessing sulfide defect structures
Chapter 9
1. Table 9.1 Possible phases formed in AISI 304L at 650 °C during carburization and...
Chapter 10
1. Table 10.1 Nitrogen absorbed (mg cm⁻²) and the average depth of internal n...
2. Table 10.2 Corrosion behavior of various alloys in an ammonia converter and ammo...
3. Table 10.3 Corrosion performance of various alloys/components in an ammonia conv...
4. Table 10.4 Depth of nitridation for various alloys after one and three years in ...
5. Table 10.5 Nitridation attack of various alloys in an ammonia‐bearing environmen...
6. Table 10.6 Reaction mechanisms of the catalytic reduction of nitrogen oxides
7. Table 10.7 Chemical composition of AISI 304L and 904L austenitic stainless steel...
8. Table 10.8 Oxide thicknesses for as‐received and nitrided austenitic 304L and 90...
Chapter 12
1. Table 12.1 Inspection methods to detect and quantify hydrogen attack
Chapter 13
1. Table 13.1 General applications of molten salt technology in several industries ...
2. Table 13.2 Weight change and visual evidence of attack in Na₂SO₄‐immersed cerami...
3. Table 13.3 Weight versus time of mullite in molten Na₂SO₄ at 900 °C, in air (a m...
4. Table 13.4 Results of corrosion test in LiF–19.5CaF₂ at 797 °C for 500 h (Misra ...
5. Table 13.5 Results of corrosion tests in molten eutectic NaCl–KCl–MgCl₂ salt at ...
6. Table 13.6 Alloys considered for molten chloride salts
7. Table 13.7 Alloys considered for molten carbonate salts
8. Table 13.8 Standard potentials on the molal scale in sulfate melts
Chapter 14
1. Table 14.1 Solubility of elements in pure liquid aluminum
2. Table 14.2 Results of static immersion tests in molten aluminum at 760 °C for fo...
3. Table 14.3 Results of static immersion tests in molten zinc at 455 °C for 50 hou...
4. Table 14.4 Corrosion of several iron–nickel–chromium and nickel‐based alloys in ...
Chapter 15
1. Table 15.1 Relevance and importance of hot corrosion in energy systems
2. Table 15.2 Comparison of hot corrosion evaluation techniques
3. Table 15.3 Typical superalloys characterized for their hot corrosion resistance
4. Table 15.4 Lifetimes of some coatings for aero, industrial, and marine gas turbi...
Chapter 16
1. Table 16.1 Typical salt deposits found on superheater tubes
2. Table 16.2 Properties of several types of US coal (Stultz and Kitto 1992)
3. Table 16.3 Typical mineral species found in coal
4. Table 16.4 Melting points of coal‐ash constituents
5. Table 16.5 Comparison of the properties of the ferritic–martensitic steel P91 (H...
6. Table 16.6 Summary of the analysis of the scale and deposit formed on the Cu/Mo ...
7. Table 16.7 Comparison of various rate processes (700–950 °C)
8. Table 16.8 Volume ratio and free energy of formation of the metal oxides in rela...
9. Table 16.9 Action constants characteristic of the outward diffusion of the produ...
10. Table 16.10 Range of ash analyses in CEGB coals (%)
11. Table 16.11 Materials used in Danish power plants
12. Table 16.12 Boiler tube materials in use in many boilers of Dutch electricity su...
13. Table 16.13 Slagging tendency of coals fired in the Netherlands
14. Table 16.14 Coextruded materials tested in the oil‐fired KEMA boiler
15. Table 16.15 Specification of the boiler
16. Table 16.16 Coal and ash characteristics
17. Table 16.17 Deposit characteristics
Chapter 17
1. Table 17.1 Description of optical anisotropy and OTI
2. Table 17.2 Gas flow regimes where perturbation of thermogravimetric measurements...
3. Table 17.3 Methods of material characterization by excitation and emission
4. Table 17.6 Types of samples and techniques nearly appropriate for their analysis
5. Table 17.7 Selected values of coherent scattering length,b (King 1997)
6. Table 17.8 Coherent scattering length density of selected molecules,ρ, at 2...
7. Table 17.9 Acronyms for various forms of EXAFS
8. Table 17.10 Summary of STM and AFM functions
9. Table 17.11 Examples of spectroscopic techniques involving an exchange of energy...
10. Table 17.12 Electronic transitions involving n, σ, and π molecular orbitals
11. Table 17.13 A comparison of the sensitivity, energy, time, and spatial resolutio...
Chapter 18
1. Table 18.1 Different pack mixes and processing parameters for various pack cemen...
2. Table 18.2 Principal sections of a laser
Chapter 19
1. Table 19.1 Typical useful life of various industrial devices
2. Table 19.2 Electrode reactions for fuel cells
3. Table 19.3 Contact list for MCFC deployment
4. Table 19.4 Thermodynamic characteristics and voltages of fuel cell reactions at ...
5. Table 19.5 Candidate alloys evaluated for the MCFC bipolar plate (Yuh et al. 199...
6. Table 19.6 Items to study to attain a 40 000 h stack life (Tatsumi et al. 1996)
7. Table 19.7 Comparison of Li/Na and Li/K electrolytes for MCFC (Yuh and Pigeaud 1...
8. Table 19.8 Composition (in wt%) of some ferritic stainless steels developed for ...
9. Table 19.9 Specific conductivitiesσ (given in S cm⁻¹) and thermal exp...
10. Table 19.10 Different types of direct carbon fuel cells
11. Table 19.11 Technology status of various types of DCFCs
12. Table 19.12 The record for the cladding material Zircaloy 2 (reactor grade)
Chapter 20
1. Table 20.1 Energy of oxides formation at 273 K
2. Table 20.2 Time, in hours, for material to be oxidized to a depth of 0.1 mm at 0...
3. Table 20.3 Alloy requirements
4. Table 20.4 Composition of typical creep‐resistance blade
5. Table 20.5 High temperature composites
6. Table 20.6 Ceramics for high temperature structures
7. Table 20.7 Overall properties of preferred silicides for VLSI applications
8. Table 20.8 Kinetics of SiO₂growth by thermal annealing of silicide films on vari...
9. Table 20.9 Dominant diffusion species during silicide formation and oxidation
10. Table 20.10 The different possible movements for mass transport during silicide ...
11. Table 20.11 Current uses of ceramics

List of Illustrations

Chapter 1
1. Figure 1.1 Key components of the HTC system.
2. Figure 1.2 Development of high‐strength weldable structural steels.
3. Figure 1.3 Fe–Cr phase diagram (Kubaschewski 1982).
4. Figure 1.4 Thermal convection loop.
5. Figure 1.5 Stages in thermal gradient mass transfer.
6. Figure 1.6 The effect of cold rolling reduction on the volume percentage of mar...
7. Figure 1.7 Swift cup test samples with different ear heights.
8. Figure 1.8 Forming limit diagram (to fracture) for austenitic and ferritic stai...
9. Figure 1.9 Bystram diagram for stainless steels in arc welding (Bystram 1956).
10. Figure 1.10 Schematic of (a) a coherent precipitate with large strain fields in...
11. Figure 1.11 Aluminosilicate refractories. Silica refractories are readily obtai...
12. Figure 1.12 Schematic of (a) α and (b) β alloy stabilization.
13. Figure 1.13 Understanding the high temperature oxidation of a metal/oxygen reac...
14. Figure 1.14 Causes of corrosion‐related failure.
15. Figure 1.15 Functions of personnel in different stages of a corrosion performan...
Chapter 2
1. Figure 2.1 Ideal close‐packed structures.
2. Figure 2.2 Unit cells.
3. Figure 2.3 Miller indices and the cubic system.
4. Figure 2.4 Face‐centered cubic structure.
5. Figure 2.5 Body‐centered cubic structure.
6. Figure 2.6 Force–distance curve.
7. Figure 2.7 Dislocations (see also screw dislocation in Section 2.2). (a) Edge d...
8. Figure 2.8 Field ion micrograph of a normal metal tip–ideal structure (×10⁷).
9. Figure 2.9 Field ion micrograph of a vacancy (×10⁷).
10. Figure 2.10 Field ion micrograph of grain boundary (×10⁷). (a) Stage 1 and (b) ...
11. Figure 2.11 Grain structure of pure zinc cast from different temperatures (etch...
12. Figure 2.12 Cooling curve and the radii of successful nuclei.
13. Figure 2.13 Grain structure of a weld metal (×5).
14. Figure 2.14 Holes in a solidified ingot (×1/3) (Hume‐Rothery et al. 1969).
15. Figure 2.15 A spiral dislocation emerging from a magnesium crystal (×325) (Hume...
16. Figure 2.16 Grain growth of bismuth (×11 430).
17. Figure 2.17 Dendrites.
18. Figure 2.18 Dendrites in antimony (×1).
19. Figure 2.19 Dendrites in a 9% tin bronze. (a) Normal etch (×100) and (b) prolon...
20. Figure 2.20 Needle crystals of CuAl₂ (×4/7).
21. Figure 2.21 Grain structure of some iron alloys (×1).
22. Figure 2.22 Grain structure of a wrought high‐strength precipitation‐hardening ...
23. Figure 2.23 Gray cast iron (×750).
24. Figure 2.24 Wrought iron (×150).
25. Figure 2.25 Fractured metal specimen containing carbon fibers (×100).
26. Figure 2.26 The solute and solvent are indistinguishable in a solid solution. A...
27. Figure 2.27 Decrease of mean interatomic distance as nickel is added to copper ...
28. Figure 2.28 The two types of solid solution.
29. Figure 2.29 Idealized cooling curves for metals and alloys.
30. Figure 2.30 Equilibrium diagram for two metals that are completely miscible in ...
31. Figure 2.31 Equilibrium diagram for two metals completely soluble in the liquid...
32. Figure 2.32 Equilibrium diagram for two metals that are completely miscible in ...
33. Figure 2.33 (a) Coring in a sand cast 70/30 copper–zinc brass (×100). (b) The s...
34. Figure 2.34 Copper–zinc equilibrium diagram (simplified).
35. Figure 2.35 A section of the aluminum–copper equilibrium diagram.
36. Figure 2.36 Simplified portion of iron–carbon equilibrium diagram.
37. Figure 2.37 Pearlite forms as carbon diffuses from the ferrite into adjacent la...
38. Figure 2.38 Pearlite (×225).
39. Figure 2.39 Microstructure of some annealed carbon steels. (a) 0.5–0.6% C steel...
40. Figure 2.40 Cooling curve for a steel with 0.25–0.3% of carbon.
41. Figure 2.41 Pearlite in annealed carbon steels (at room temperature).
42. Figure 2.42 Mechanical properties of annealed carbon steels (see Figures 2.47 a...
43. Figure 2.43 Quenching and tempering carbon steels.
44. Figure 2.44 Heat treatment of carbon steels (0.07–0.15% C). (a) Annealed (×250)...
45. Figure 2.45 Needlelike crystals of martensite (×1500).
46. Figure 2.46 The iron–iron carbide metastable phase diagram.
47. Figure 2.47 Tensile stress–strain curves.
48. Figure 2.48 Forces between atoms and the elastic deformation of a very strong s...
49. Figure 2.49 Stress–strain curves for typical alloys.
50. Figure 2.50 Slip (×20) (Hume‐Rothery et al. 1969).
51. Figure 2.51 Plastic flow – the shear stress needed to move one layer over anoth...
52. Figure 2.52 Slip planes in a polycrystalline material (×1000).
53. Figure 2.53 Effect of compression on soft pure copper (×1/4).
54. Figure 2.54 Slip and the movement of dislocations.
55. Figure 2.55 Influence of vacancies on the deformation of aluminum.
56. Figure 2.56 Deformation of a single crystal of copper initially free of disloca...
57. Figure 2.57 Deformation of single and polycrystalline samples of HCP and FCC me...
58. Figure 2.58 Influence of grain size on yield stress.
59. Figure 2.59 Substitutional solid solutions. The influence of solute concentrati...
60. Figure 2.60 Interactions between dislocations and precipitates (e.g. of CuAl₂ o...
61. Figure 2.61 Schematic of solid solution. (a) Substitutional (Al dissolved in Ni...
62. Figure 2.62 Deformation under constant load (creep).
63. Figure 2.63 Hot working. Grain structure of cast and hot‐rolled alloys (×9/10)....
64. Figure 2.64 Schematic representation of stress concentrations. (a) In a perfect...
65. Figure 2.65 Strength as a function of radius for small glass fibers.
66. Figure 2.66 Crack nucleation.
67. Figure 2.67 Intergranular fracture.
68. Figure 2.68 Brittle‐to‐ductile transition in BCC metals. (a) Yield stress of BC...
69. Figure 2.69 Fatigue. The metal fail by fatigue at the values of S and N indicat...
70. Figure 2.70 Formation of surface cracks during fatigue. Extrusions and intrusio...
71. Figure 2.71 Preventing crack propagation. A crack which is a wedge shape hole, ...
72. Figure 2.72 Temperature dependence of the Charpy V‐notch impact energy (curve A
73. Figure 2.73 Schematic curves for the three general types of impact energy‐versu...
Chapter 3
1. Figure 3.1 Standard free energy of the formation of selected oxides as a funct...
2. Figure 3.2 Free energy of the formation of sulfides (Richardson and Jeffes 1952...
3. Figure 3.3 Free energy of the formation of carbides (Richardson and Jeffes 1953...
4. Figure 3.4Figure 3.4 Free energy of the formation of nitrides (Pearson and Ende ...
5. Figure 3.5Figure 3.5 Free energy of the formation of chlorides (Villa 1950).
6. Figure 3.7 Free energy versus composition and activity diagrams for a hypotheti...
7. Figure 3.6 The graphical method for obtaining equilibrium compositions for free...
8. Figure 3.8 Free energy diagram for a binary system consisting of metal M and ga...
9. Figure 3.9 Activity versus composition diagram for Fe₂O₃–Mn₂O₃ system at 1300 °...
10. Figure 3.10 Volatile species in the Cr–O system at 1473 K (Birks et al. 2006).
11. Figure 3.11 Cr–O system volatile species versus temperature. The line for Cr(g)...
12. Figure 3.12 Equilibrium diagram for for the Fe–O system (between 830 and 2200...
13. Figure 3.13 Phase stability diagram for a metal–sulfur–oxygen (M–S–O) system at...
14. Figure 3.14 Thermochemical stability diagram for the system Fe–S–O at 1000 K sh...
15. Figure 3.15 Condensed phase equilibria for the Ni–O–S system at 1250 K (Giggins...
16. Figure 3.16Figure 3.16 Thermochemical stability diagram for the 310 stainless‐st...
17. Figure 3.17Figure 3.17 Stability diagram for the Cr–C–O system at 1250 K (Hemmin...
18. Figure 3.18Figure 3.18 Composition ranges in the U–O–Cl system at 450 °C (Knacke...
19. Figure 3.19 Stability diagram for the Ni–O–S system where regions of solution w...
20. Figure 3.20 Stability data for the Ni–O–S system at 1250 K expressed as versu...
21. Figure 3.21 Stability diagram for the Fe–Cr–O system at 1300 °C (Sticher and Sc...
22. Figure 3.22 Superimposed predominance area diagrams at 950 K for the Co–S–O sys...
23. Figure 3.24 Thermodynamic stability diagram for the Fe–Ni–Cr system at 1143 K, ...
24. Figure 3.25 Thermodynamic stability diagram for some oxides and sulfides at 100...
25. Figure 3.23 Superimposed simplified thermodynamic stability diagrams for three ...
26. Figure 3.26 Predominance volume diagram for the Fe–S–O system for the temperatu...
27. Figure 3.27 Electrochemical equilibria for Na₂SO₄ at 1173 K. The numbers corres...
28. Figure 3.28 Electrochemical equilibria for Fe/Na₂SO₄ at 1173 K assuming the oxi...
29. Figure 3.29 Electrochemical equilibria for Fe/Na₂SO₄ at 1173 K assuming the sul...
30. Figure 3.30 E– pO²⁻ diagram for the system Fe/Na₂SO₄ at 1173 K based on th...
31. Figure 3.31 E– pO²⁻ diagram for the system Fe/Na₂SO₄ at 1173 K based on th...
32. Figure 3.32 E– pO²⁻ diagram for the system Fe/Na₂SO₄ at 1173 K based on th...
Chapter 4
1. Figure 4.1 Schematic illustration of Schöttky disorder with equivalent concent...
2. Figure 4.2 Schematic illustration of Frenkel disorder involving doubly charged ...
3. Figure 4.3 Schematic illustration of an oxygen‐deficient oxide, MO_2−x, in...
4. Figure 4.4 Schematic illustration of an oxygen‐deficient oxide (excess metal), ...
5. Figure 4.5 Schematic illustration of a metal‐deficient oxide (excess oxygen), M
6. Figure 4.6 (a) Schematic illustration of a metal‐deficient oxide, M_1−yO, ...
7. Figure 4.7 Schematic presentation of the concentration of and e^′ as a f...
8. Figure 4.8 Schematic presentation of the concentrations of , ,and e^′ as ...
9. Figure 4.9 Schematic presentation of the concentration of oxygen point defects ...
10. Figure 4.10 Effect of higher valent cation impurities on defect structure in ...
11. Figure 4.11 Schematic illustration of the splitting of energy levels when atoms...
12. Figure 4.12 Schematic illustration of the energy band diagram for a pure semico...
13. Figure 4.13 Schematic illustration of additional localized energy levels due to...
14. Figure 4.14 Correlation between the forbidden energy gap, E _g , and bond energy f...
Chapter 5
1. Figure 5.1 Octahedral (a) and tetrahedral (b) interstitial sites in the FCC (l...
2. Figure 5.2 Direct interstitial mechanism of diffusion.
3. Figure 5.3 Vacancy mechanism of diffusion.
4. Figure 5.4 Divacancy mechanism of diffusion.
5. Figure 5.5 Interstitialcy mechanism of diffusion.
6. Figure 5.6 Interstitial–substitutional exchange mechanisms of foreign atom diff...
7. Figure 5.7 Initial configurations for diffusion experiments: (a) Thin layer of ...
8. Figure 5.8 Comparison of self‐diffusion coefficients in several metal sulfides ...
9. Figure 5.9 Chemical diffusion coefficient in niobium sulfide on the background ...
10. Figure 5.10 Comparison of chemical diffusion coefficients in several metal sulf...
11. Figure 5.11 (a) Diffusion couple with end‐member compositions and before an...
12. Figure 5.12 Schematic representation of a cross section of the diffusion couple...
13. Figure 5.13 Atomic diffusion mechanisms: (a) direct exchange mechanism, (b) rin...
14. Figure 5.14 Schematic representations of a diffusion couple with the end‐member...
15. Figure 5.15 Schematic geometry of the Fisher model of grain boundary diffusion.
16. Figure 5.16 Schematic experimental setup for the measurement of the effective c...
17. Figure 5.17 Schematic illustration of a displacement reaction with a layered mo...
18. Figure 5.18 A “four‐point probe” arrangement on a diffused layer.
19. Figure 5.19 A “cloverleaf” Hall specimen. Coding 1, 2, 3, 4 describes the diffe...
Chapter 6
1. Figure 6.1 Polarization curves of a fast electrochemical reaction. (a) Arithmet...
2. Figure 6.2 Polarization curves of a slow electrochemical reaction. (a) Arithmet...
3. Figure 6.3 Corrosion of a metal M in a molten sulfate with SO₂ evolution. Anodi...
4. Figure 6.4 Schematic representation of the different reactions occurring at the...
5. Figure 6.5 Rate constants for the growth of selected oxides.
6. Figure 6.6 Experimental setup for the investigation of the oxygen reduction rea...
7. Figure 6.7 Energy bands of solids. A represents the atom of an element.
8. Figure 6.8 Mechanisms of charge carrier generation. (a) Thermal generation. (b)...
9. Figure 6.9 The Fermi level and the effects of doping.
10. Figure 6.10 Defect concentration versus for an oxide solid electrolyte (logar...
11. Figure 6.11 Ionic conductor with ohmic contacts.
12. Figure 6.12 Ionic conductor with ohmic contacts but no current supply.
13. Figure 6.13 Blocking or polarizing electrode.
Chapter 7
1. Figure 7.1 Schematic diagram of combined scale growth and oxide volatilization...
2. Figure 7.2 The Mo–O system volatile species diagram for 1250 K (Birks et al. 20...
3. Figure 7.3 The W–O system volatile species diagram for 1250 K (Birks et al. 200...
4. Figure 7.4 Chromium oxidation, between 1000 and 1200 °C, under 1 bar of oxygen ...
5. Figure 7.5 Successive kinetic laws observed for the oxidation of a given metal ...
6. Figure 7.6 Interfacial reactions and transport processes for high temperature o...
7. Figure 7.7 Interstitial cations and excess electrons in ZnO – an n‐type metal e...
8. Figure 7.8 Schematic illustration of transport mechanisms in crystalline solids...
9. Figure 7.9 Cracking and spallation by compressive oxide stresses (Evans 1995).
10. Figure 7.10 Diagram of scale forming according to Wagner's model (Birks et al. ...
11. Figure 7.11 Schematic diagram of hypothetical two‐layered scale.
12. Figure 7.12 Schematic representation of total weight gain Δm illustrating paral...
13. Figure 7.13 Schematic rate laws associated with formation of stratified scales.
14. Figure 7.14 Diagram of condensed phases in the case of the oxidation of a binar...
15. Figure 7.15 Schematic representation of modes of oxidation of alloy AB of varia...
16. Figure 7.16 Crystal structure of Cr₂O₃ – the bigger atoms are Cr³⁺ and the ...
17. Figure 7.17 Lattice structures of the matrix y and the intermetallic phase y′ (...
Chapter 8
1. Figure 8.1 Summary of the various mechanisms leading to the formation of sulfi...
2. Figure 8.2 The reaction between silver and liquid sulfur to form silver sulfide...
3. Figure 8.3 Modified McConomy curves providing predicted corrosion rates as a fu...
4. Figure 8.4 Modified Couper–Gorman curves showing corrosion rates as a function ...
5. Figure 8.5 Modified Couper–Gorman curves showing corrosion rates as a function ...
6. Figure 8.6 Formation of external sulfides on top of the chromium oxide scale an...
Chapter 9
1. Figure 9.1 Stability domains of M₂O_b and M₂O_b′ in a H₂/H₂O gas mixture.
2. Figure 9.2 Stability domains of iron and iron oxides as functions of temperatur...
3. Figure 9.3 Stability data domains of iron and iron oxides as functions of tempe...
4. Figure 9.4 Chart illustrating the variation with temperature of the equilibrium...
5. Figure 9.5 Equilibrium constants for the reaction Fe3C + CO2 = 3Fe + 2CO...
6. Figure 9.6 Equilibrium constants for the reaction 3Fe + CH4 = Fe3C + 2H2...
7. Figure 9.7 Three possible carbon concentration profiles of carburized alloys (K...
8. Figure 9.8 Oxygen potentials of the test environments used in carburization stu...
9. Figure 9.9 Schematic illustration of the metal dusting mechanism on iron and lo...
10. Figure 9.10 Fe–C–O metastable phase stability diagram showing that metastable c...
11. Figure 9.11 Schematic representation of the MD mechanism on high‐alloyed steels...
12. Figure 9.12 Schematic representation of the processes and reaction layers invol...
13. Figure 9.13 The mechanisms of metal dusting as they appear on stainless steels....
Chapter 10
1. Figure 10.1 Schematic showing a model for internal nitridation attack in high ...
2. Figure 10.2 Model of the SCR system.
Chapter 11
1. Figure 11.1 Parabolic scale growth with linear evaporation of halide scales.
2. Figure 11.2 Schematic drawing of chlorine cycle as described by Reese and Grabk...
Chapter 12
1. Figure 12.1 Illustration of API 941 Nelson curve – material selection for equi...
2. Figure 12.2 Illustration of API 941 Nelson curve – damaged refractory can resul...
3. Figure 12.3 Schematic of Ni–Al–O stability diagram at 1000 °C with the activiti...
Chapter 13
1. Figure 13.1 Typical E versus pO²⁻ diagram for cobalt in molten sodium sul...
2. Figure 13.2 Typical high temperature cell assembly (Sequeira and Hocking 1978a)...
3. Figure 13.3 Proposed specimen holder for corrosion studies in sulfate melts.
4. Figure 13.4 Reference electrode for molten sulfates (Sequeira and Hocking 1978a...
5. Figure 13.5 Experimental potential versus time of AMS 5384 nickel‐based superal...
6. Figure 13.6 Corrosion data for nickel‐based gas turbine alloys in molten sulfat...
7. Figure 13.7 Electrochemical behavior of Ni–Cr alloys in (Li,Na)₂SO₄ melts at 97...
Chapter 14
1. Figure 14.1 Sketch of a hot‐dip bath.
2. Figure 14.3 Fe–Li phase diagram.
3. Figure 14.2 Energies involved in the growth of a crack.
4. Figure 14.5 Stages in thermal‐gradient mass transfer.
5. Figure 14.4 Thermal‐convection loop.
6. Figure 14.6 Ag–Pb phase diagram.
7. Figure 14.7 Plug from a Type 446 stainless steel thermal‐convection loop that o...
8. Figure 14.8 Cu–Pb phase diagram.
9. Figure 14.9 Schematic diagram showing the mechanisms of molten aluminum alloy a...
10. Figure 14.10 Corrosion rates of Types 304 and 316, primary candidate alloy (PCA...
11. Figure 14.11 Solubilities of some metals in liquid mercury (Weeks 1967). Note: ...
Chapter 15
1. Figure 15.1 Model for the Na₂SO₄‐induced catastrophic oxidation of a Ni–31Al–Mo...
2. Figure 15.2 Potentiodynamic polarization curves for nickel in Na₂SO₄, Na₂SO₄–0....
3. Figure 15.3 Diagram of a typical Ni section.
4. Figure 15.4 Ni, 900 °C, Na₂SO₄–15% NaCl in air after potentiodynamic sweep AEI ...
5. Figure 15.5 Conditions as in Figure 15.4, X‐ray image (×1200): distribution of ...
6. Figure 15.6Figure 15.6 Conditions as in Figure 15.4, AEI (×300): complete view o...
7. Figure 15.8 Electron microprobe analysis of the scale formed on Nimonic 105 imm...
8. Figure 15.7 Nimonic 105 after immersion in Na₂SO₄ for 100 hours at 900 °C under...
9. Figure 15.9 Schematic view of Nimonic 105 after corrosion in Na₂SO₄ at 900 °C f...
10. Figure 15.10 Na₂SO₄–NiSO₄ phase diagram showing the eutectic temperature of 671...
11. Figure 15.11 Loop test for studying the corrosion produced by molten salts.
Chapter 16
1. Figure 16.1 Principle of a coal‐fired power plant.
2. Figure 16.2 Trends in global electricity production from 1971 to 2020 (Parker 2...
3. Figure 16.3 Schematic of a typical fuel‐fired boiler showing areas of corrosion...
4. Figure 16.4 Acceleration of the oxidation mechanism by the formation of metal o...
5. Figure 16.5 Section showing deposit layers on a leading superheater or reheater...
6. Figure 16.6 Schematic of a typical thermal gradient through a deposit from flue...
7. Figure 16.7 Development progress of ferritic steels (Masuyama 2002). Some comme...
8. Figure 16.8 Profile of a scale and deposit formed on the test probe after 6000 ...
9. Figure 16.9 Schematic illustration of coal‐ash corrosion sequence.
10. Figure 16.10 Isocorrosion diagram of 17Cu–14Mo steel in coal combustion atmosph...
11. Figure 16.11 Comparison of corrosion resistance of commercial alloys in coal co...
12. Figure 16.12 General nature of the vanadic corrosion of cobalt in the presence ...
13. Figure 16.13 Corrosion of vanadium in oxygen with 0.4 cm depth of molten vanadi...
14. Figure 16.14 Effect of oxygen pressure on the corrosion of metals at 850 °C wit...
15. Figure 16.15 Shape of corroded metal disks.
16. Figure 16.16 Corrosion of iron electrodes immersed in vanadium pentoxide.
17. Figure 16.17 Schematic of the main reactions in the system gas/fly ash deposit/...
18. Figure 16.18 The use of faceted mild steel tube to fit in a tangent waterwall c...
19. Figure 16.19 SO₃ flux (dashed line) calculated in superheater deposits from the...
Chapter 17
1. Figure 17.1 Polarized light optical microscopy and interference colors.
2. Figure 17.2 Optical micrograph of coke surface – fine‐grained mosaic, OTI = 1.
3. Figure 17.3 Optical micrograph of coke surface – medium and coarse mosaic, OTI ...
4. Figure 17.4Figure 17.4 Optical micrograph of coke surface – coarse flow, OTI = 3...
5. Figure 17.5 Typical experimental arrangement for measuring oxidation kinetics w...
6. Figure 17.6 Convection currents in reaction vessels. (a) Vertical open vessel. ...
7. Figure 17.7 Normal and tangential forces acting on a vertical cylindrical sampl...
8. Figure 17.8 Schematic illustrating relative sizes of areas scanned by spectrome...
9. Figure 17.9 X‐ray diffraction.
10. Figure 17.10 X‐ray diffraction line broadening.
11. Figure 17.11 Compilation for elements of the inelastic mean free path λ _m (...
12. Figure 17.12 Scheme of the LEED setup. An incoming beam of electrons e⁻ i...
13. Figure 17.13 The model used in this chapter to calculate RHEED patterns. The el...
14. Figure 17.14 Calculated RHEED patterns for three finite atomic lattices: (a) 10...
15. Figure 17.15 Calculated RHEED pattern for the same model as in Figure 17.13a bu...
16. Figure 17.16 (a) Typical wavelength distributions for neutrons from a reactor, ...
17. Figure 17.17 Main components of a typical SEM.
18. Figure 17.18 Excited volume and electron interaction within specimen.
19. Figure 17.19 Optical micrograph of calcinated shot coke – before etching.
20. Figure 17.20 SEM micrograph of calcinated shot coke – after chromic acid etchin...
21. Figure 17.21 SEM micrograph of blast furnace coke – original surface.
22. Figure 17.22 SEM micrograph of blast furnace coke – after 75% burn‐off in CO₂.
23. Figure 17.23 Schematic of a TEM.
24. Figure 17.24 Schematic summary of the TEM cross‐sectional preparation technique...
25. Figure 17.25 HRTEM micrograph of highly graphitic carbon – highly ordered.
26. Figure 17.26 HRTEM micrograph of PVDC carbon (HTT 1473 K) – disordered.
27. Figure 17.27 Microscope image of slow electrons in the phase transition from 7 ...
28. Figure 17.28 Typical LEEM experimental setup used for surface science studies.
29. Figure 17.29 Basic principles of EXAFS. On excitation of atom A by an X‐ray pho...
30. Figure 17.30 EXAFS spectra (a) and resulting atomic distributions (b) around Si...
31. Figure 17.31 Schematic representation of the Auger process.
32. Figure 17.32 Changes in the oxygen O 1s peak during oxidation of nickel (Allen ...
33. Figure 17.33 Auger spectra from stainless steel exposed to a low oxygen pressur...
34. Figure 17.34 Surface composition of stainless steel during exposure to 10⁻⁵...
35. Figure 17.35 RBS spectra, α‐particles, 2 MeV, showing Y, Fe(Cr, Ti), impurity i...
36. Figure 17.36 MCs⁺ analysis of alumina scale on Fe–20Cr–5Al ODS alloy, compo...
37. Figure 17.37 SIMS spectrum as a function of depth of the oxide scale formed by ...
38. Figure 17.38 Total energy distribution of secondary electron emission from a su...
39. Figure 17.39 Example low EELS spectra obtained for the Co–Cr–Mo alloy surface a...
40. Figure 17.40 Schematic representation of the surface force apparatus. The dista...
41. Figure 17.41 Lateral deflection of the cantilever from changes in surface frict...
42. Figure 17.42 The PSPD for AFM (a) and LFM (b).
43. Figure 17.43 BLS setup with six‐pass tandem Fabry–Perot interferometer. Electro...
44. Figure 17.44 Surface with film(s) or island films showing interference effects ...
45. Figure 17.45 Polar nomogram showing one‐to‐one mapping between ψ, Δ, and n
46. Figure 17.46 Basic optical arrangements for (a) nulling ellipsometer and (b) a ...
47. Figure 17.47 Simplified energy diagram showing the absorption and emission of a...
48. Figure 17.48 Diagram showing two electronic energy levels (E ₀ and E ₁), each wit...
49. Figure 17.49 (a) Resonant second‐harmonic and (b) resonant sum‐frequency genera...
50. Figure 17.50 Eddy current field depth of penetration and density.
51. Figure 17.51 Illustration of different reflection types.
52. Figure 17.52 Representation of diffuse reflectance.
53. Figure 17.53 Integrating Ulbrich sphere.
54. Figure 17.54 Spectral emission of α‐alumina.
55. Figure 17.55 Piezospectroscopic effect.
56. Figure 17.56 Layered structure used in the work of Rosencwaig and Gersho.
57. Figure 17.57 (a) EBSD scheme. (b) One example of orientation map of the grains,...
58. Figure 17.58 Potential excitation function and current response for double‐step...
59. Figure 17.59 Cathodic chronopotentiometry of K₂S₆ in LiCl–KCl eutectic; 423 °C;...
60. Figure 17.60 Charge components in a chronocoulometric (Q versus t ^1/2) plot.
61. Figure 17.61 A typical linear sweep voltammogram. E _1/2 = −0.500 V.
62. Figure 17.62 Potential excitation function for NPV experiments. The dots indica...
63. Figure 17.63 A typical excitation function for DPV. See text for symbol definit...
64. Figure 17.64 A typical excitation function for square wave voltammetry.
65. Figure 17.65 Cyclic voltammogram (υ = 100 mV s⁻¹) for the determinat...
66. Figure 17.66 Electrical scheme and equivalent circuit of the measurement method...
67. Figure 17.67 Schematic cross‐sectional image of the experimental setup (Öijerho...
68. Figure 17.68 (a–c) Voltammograms recorded at 500, 600, and 800 °C for the ferri...
69. Figure 17.69 Typical SECM setup.
70. Figure 17.70 Illustration of feedback modes in SECM.
71. Figure 17.71 Schematic of the electrochemical three‐electrode setup used in the...
72. Figure 17.72 Electrochemical ESR cell (Koopman and Gerischer 1966).
73. Figure 17.73 Electrochemical cell with porous working electrode acting as the w...
74. Figure 17.74 Proof of CO₂ as the main product of oxidation of adsorbed CO durin...
75. Figure 17.75 Schematic configuration of the electrochemical STM. RE and CE are ...
76. Figure 17.76 Potential barrier for electron tunneling.
77. Figure 17.77 Enhancement through electron exchange between metal and adsorbate.
78. Figure 17.78 Diagram showing the experimental setup for EC‐SERS, which includes...
79. Figure 17.79 Principle of electrochemical strain microscopy. (a) During ESM, a ...
80. Figure 17.80 Operational regimes for electrochemical strain microscopy. (a) A b...
Chapter 18
1. Figure 18.1 Scheme of a high temperature coating protecting the base metal by ...
2. Figure 18.2 Diffusion aluminide formation on pure Ni.
3. Figure 18.3 Growth rate curve of a CVD process – schematic.
4. Figure 18.4 The main chemical reactions involved in the pack cementation proces...
5. Figure 18.5 FeAl phase diagram.
6. Figure 18.6 Simplified scheme of the two archetypes of pack cementation alumini...
7. Figure 18.7 A nickel aluminide diffusion coating produced using LAHT pack cemen...
8. Figure 18.8 A nickel aluminide diffusion coating produced using LTHA pack cemen...
9. Figure 18.10 (a) SIFCO vapor‐phase coating process facility. (b) Vapor‐phase co...
10. Figure 18.9 Schematic of the out‐of‐pack vapor‐phase aluminizing process. Sourc...
11. Figure 18.11 Schematic of an electron beam physical vapor deposition (EBPVD) pr...
12. Figure 18.12 Schematic of a plasma gun. Source: Gill and Tucker (1986).
13. Figure 18.13 Schematic of air plasma spray and LPPS process. Source: Nicoll (19...
14. Figure 18.14 Ion‐plating apparatus: schematic diagram. Source: Hocking et al. (...
15. Figure 18.15 One‐ and two‐stage processes of laser surface alloying. Source: Kh...
16. Figure 18.17 Schematic diagram of a PPW process device. Source: Khanna (2002).
17. Figure 18.16 Stress generation in Cr films in Xe atmosphere.
18. Figure 18.18 The morphology of the reaction 2Co + SiO₂ = Co₂SiO₄ in air. SiX is...
Chapter 19
1. Figure 19.1 Schematic view of an individual MCFC.
2. Figure 19.2 The principle of a molten carbonate fuel cell stack.
3. Figure 19.3 Side view and top view sections of a molten carbonate single cell s...
4. Figure 19.4 Triple‐phase boundary (TPB) model.
5. Figure 19.5 Illustration of solid oxide fuel cell components and basic operatin...
6. Figure 19.6 Illustration of the general four‐point setup for measuring area‐spe...
7. Figure 19.7 The maximum or theoretical efficiency for different fuels as a func...
8. Figure 19.8 Operating schematic of a direct carbon MCFC.
9. Figure 19.9 Operating schematic of a gasification‐driven direct carbon SOFC.
10. Figure 19.10 Operating schematic of a direct carbon SOFC with a molten carbonat...
11. Figure 19.11 Operating schematic of CellTech Power's molten Sn anode SOFC.
12. Figure 19.12 Swelling as a function of temperature for two EBR‐II 316 stainless...
13. Figure 19.14 Irradiation causes a decrease in toughness of welded joint, making...
14. Figure 19.13 Effect of irradiation on yield strength of iron and steel (dpa is ...
15. Figure 19.15 Damage mechanisms for metals as a function of temperature (Allen e...
16. Figure 19.16 Pourbaix diagram for nickel‐based alloy 600 in an aqueous solution...
17. Figure 19.17 General corrosion rate for Alloy 22 waste package outer barrier (A...
18. Figure 19.18 A new process for producing reactor‐grade zirconium.
Chapter 20
1. Figure 20.1 Superalloy developments by a sort of creepy Darwinism.
2. Figure 20.2 Temperature evolution and future materials trends in turbine blades...
3. Figure 20.3 Directionally solidified eutectics for turbine blades.
4. Figure 20.4 K _p variation with temperature.
5. Figure 20.5 Protection of turbine blades by sprayed‐on aluminum.

High Temperature Corrosion

Fundamentals and Engineering

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