Roger W. Staehle

Bio: Roger W. Staehle is an academic researcher. The author has contributed to research in topics: Embrittlement & Pourbaix diagram. The author has an hindex of 2, co-authored 2 publications receiving 585 citations.

Advances in Corrosion Science and Technology

Abstract: 1 Techniques for the Measurement of Electrode Processes at Temperatures Above 100 C.- Experimental Techniques.- Pressure Vessels and Liners.- Insulation and Sealing of Electrode Leads.- Metallized Ceramic Seals.- Compression Seals.- Line Seals.- Reference Electrodes.- High-Temperature Reference Electrodes.- External Reference Electrodes.- Application of High-Temperature Electrochemical Techniques.- Corrosion Studies.- Nonferrous Alloys.- Ferrous Materials.- Measurement of emf.- Measurement of pH.- Conductance Measurements.- Electrodeposition and Electrolysis.- Polarography.- Fuel Cells.- Acknowledgments.- References.- 2 Surface- and Environment-Sensitive Mechanical Behavior.- The Nature of Crystal Surfaces.- Clean Surfaces.- Surface Structure.- Chemical Segregation at Free Surfaces.- Space-Charge Effects.- Summary.- Environmental Effects on Crystalline Solids with Clean Surfaces.- Metals.- Clean Metals in Electrolytes.- Adsorption of Surface-Active Species.- Gaseous Environments and Vacuum Effects.- Nonmetals.- Solvent Environments (Joffe Effect).- Effects of Surface-Active Species.- Effects of Solid Surface Films.- Nonmetals.- Metals.- Mechanism of Surface Barrier Effects.- Elastic Theory.- Atomistic Nature of the Film-Substrate Interface.- Concluding Remarks.- Acknowledgments.- References.- 3 Mechanism and Phenomenology of Organic Inhibitors.- Mechanisms of the Action of Organic Inhibitors.- Adsorption.- Influence of Structural Parameters on Adsorption and Inhibition.- Action of Reduction, Polymerization, or Reaction Products.- Steric Effects.- Action of the Organic Cations.- The Role of the Metal in Inhibition.- Surface Charge of the Metal.- Cold Working.- Surface State.- Surface Treatments.- Purity of the Metal.- Hydrogen Penetration.- Methods of Studying Inhibitors.- Corrosion Rate Measurements.- Electrochemical Methods.- Radiochemical Methods.- IR and UV Spectroscopic Methods.- Mass Spectrometry and NMR Methods.- Other Methods.- Determination of Inhibitor Behavior vs Hydrogen Penetration.- Organic Inhibitors in Various Aggressive Environments.- Atmospheric Corrosion Inhibitors.- Inhibitors in the Steam Zone of Industrial Installations.- Inhibitors in Aqueous Solutions.- Inhibitors in Acid Solutions.- Inhibitors in Alkaline Solutions.- Inhibitors in a Nonaqueous Environment.- Summary.- References.- 4 Anodic Oxidation of Aluminum.- Short History.- Anodizing Processes of Current Importance and Interest.- Outline of Anodic Oxidation of Aluminum.- Scope of Anodizing Electrolytes and Their Characteristics.- Sulfuric Acid.- Oxalic Acid.- Chromic Acid.- Sulfamic Acid.- Phosphoric Acid.- Bright Anodizing.- Hard Anodizing.- Integral Color Anodizing.- Coloring by Dyestuffs and Pigments.- Special Anodizing Processes.- Anodizing in Molten Salts.- Anodizing in a Nonaqueous Solvent System.- Continuous and High-Current Anodizing.- Sealing.- Mechanism of Anodic Oxidation.- Stability and Corrosion of Aluminum (Pourbaix Diagram).- Classification of Anodic Films on Metal.- Chemical Composition of Anodic Oxide Films.- Barrier Film.- Duplex Film.- Theory of Dyeing Anodic Films.- Sealing Mechanism.- Properties of Anodic Oxide Films on Aluminum.- Corrosion Problems in Anodized Aluminum.- Acknowledgment.- References.

Stress-Corrosion Cracking of Metallic Materials. Part III. Hydrogen Entry and Embrittlement in Steel

Abstract: : The chemical environment and metallurgical structure play important roles in the entry of hydrogen into iron and steel. In particular, the effect of compounds of sulfur, arsenic, phosphorus, selenium, and other elements, generally called 'cathodic poisoners,' is considered. The role of pH, electrochemical potential, stress, and temperature on the hydrogen entry kinetics is also considered. Metallurgical factors that influence the hydrogen entry and permeation rates include the alloy composition (substitutional and interstitial atoms), annealing and tempering (temperature, time), grain size, and the microstructure (form and distribution of carbides, etc.). The literature regarding the stress corrosion cracking of high-strength steel is reviewed. Studies of slow crack growth in gaseous environments are reviewed, with a comparison of crack growth behavior in both gaseous and aqueous media.

Introduction to the high-temperature oxidation of metals

Abstract: Acknowledgments Preface Introduction 1. Methods of investigation 2. Thermodynamic fundamentals 3. Mechanisms of oxidation 4. Oxidation of pure metals 5. Oxidation of alloys 6. Oxidation by oxidants other than oxygen 7. Reactions of metals in mixed environments 8. Hot corrosion 9. Erosion-corrosion of metals in oxidizing atmospheres 10. Protective coatings 11. Atmosphere control for the protection of metals during production processes Appendix A. Solution to Fick's second law for a semi-infinite solid Appendix B. Rigorous derivation of the kinetics of internal oxidation Appendix C. Effects of impurities on oxide defect structure Index.

Hexagonal pore arrays with a 50-420 nm interpore distance formed by self-organization in anodic alumina

Abstract: Self-organized hexagonal pore arrays with a 50–420 nm interpore distance in anodic alumina have been obtained by anodizing aluminum in oxalic, sulfuric, and phosphoric acid solutions. Hexagonally ordered pore arrays with distances as large as 420 nm were obtained under a constant anodic potential in phosphoric acid. By comparison of the ordered pore formation in the three types of electrolyte, it was found that the ordered pore arrays show a polycrystalline structure of a few micrometers in size. The interpore distance increases linearly with anodic potential, and the relationship obtained from disordered porous anodic alumina also fits for periodic pore arrangements. The best ordered periodic arrangements are observed when the volume expansion of the aluminum during oxidation is about 1.4 which is independent of the electrolyte. The formation mechanism of ordered arrays is consistent with a previously proposed mechanical stress model, i.e., the repulsive forces between neighboring pores at the metal/oxide interface promote the formation of hexagonally ordered pores during the oxidation process.

Corrosion in high-temperature and supercritical water and aqueous solutions: a review

Abstract: The aim of the present article is to review some of the common corrosion phenomena and describe the predominant corrosion mechanisms in high-temperature and supercritical water. Corrosion in aqueous systems up to supercritical temperatures is determined by several solution-dependent and material-dependent factors. Solution-depending factors are the density, the temperature, the pH value, and the electrochemical potential of the solution, and the aggressiveness of the attacking anions. Material-dependent parameters include alloy composition, surface condition, material purity, and heat treatment. Corrosion phenomena that are observed include intergranular corrosion, pitting, general corrosion, and stress corrosion cracking. The solubility and dissociation of both attacking species and corrosion products play the most important role for corrosion in high-temperature water. Both solubility and dissociation processes are strongly influenced by the density, or the ionic product, respectively, of the solvent. High values of both parameters favor ionic reactions, and thus, accelerate electrochemical forms of corrosion. At low densities, water behaves like a non-polar solvent, and thus, ions associate. In these cases, the concentation of e.g. aggressive H + drops down and thus, solutions containing species such as HCl become neutral and thus less aggressive. Further, corrosion products plug the surface and material loss stops. Materials parameters have influence especially on the initiation of corrosion. In the present article, these factors are linked with the physical and chemical properties of high-temperature and supercritical water. An outlook is also given for future research needs.