Anodic Protection: Theory and Practice in the Prevention of Corrosion

ISBN-13: 9781468438741 / Angielski / Miękka / 2012 / 284 str.

Olen Riggs

Opis

The objectives of this book are to give technical information about anodic pro- tection, explain how economic analyses are made to determine whether or not it should be used, and describe some of the applications and equipment. Lim- itations of the technique will be pointed out. Technological changes that have resulted in higher temperatures, pres- sures, and velocities increase corrosion rates and markedly influence materials selection and design decisions. Continuous cycle systems impose increased demands on system reliability. New processes require more sophisticated equipment made of costlier metals which are often in short supply and subject to the vagaries of international commerce. The impact of continuing inflation influences decisions related to capital expenditures and maintenance costs. Some problems caused by these considerations can be solved, or solutions simplified, by the use of anodic protection. Technical and scientific information is presented on applications to industrial equipment, economics, design and installation, operation and maintenance, electrochemical principles, laboratory tests and procedures. A historical summary, patent list, glossary of terms, and a subject index are included. It is important to acknowledge that much of the information has been from the original work of others, including the publications of many friends.

Spis treści

1 Anodic Protection of Metals—A Technique Whose Time Has Come.- Many Protective Methods Are Used.- Anodic Protection Used Effectively.- Protection of Alloy Steel Important.- Strategic and Absolute Factors Bearing on Materials.- Substitute Alloys for Chromium.- Prices of Substitute Alloys Increase.- Corrosion Protection Is Necessary.- Contamination Control Important.- Ecological Considerations Are Important.- Energy-Conservation Values.- Applications and Limitations.- Limitations Can Be Anticipated.- Installation Expense Factors.- Rapid Development Anticipated.- References.- 2 Anodic Protection of Industrial Equipment.- Sulfuric Acid Applications.- Sulfuric Acid Corrosion.- Hydrogen Attack Is Also a Problem.- Product Purity Is Important.- Protection of Sulfuric Acid Storage Equipment.- Application Details in Storage Tanks.- Spent Sulfuric Acid.- Heat Exchangers for Sulfuric Acid.- Transport of Sulfuric Acid.- Protection Provided for Barge.- Nitrate Fertilizer Container Protection.- Other Interesting Uses for Fertilizer Solutions.- Pulp and Paper Industry Applications.- Miscellaneous Applications.- Summary.- References.- 3 Equipment for Anodic Protection.- Characteristics of Electrodes.- Characteristics of the Cathode.- Platinum-Clad Cathodes.- Hastelloy C Cathodes.- Stainless (Cr—Ni) Steel Cathodes.- Reference-Electrode Designs.- Calomel Half-Cell.- Silver/Silver Chloride Half-Cell.- Mercury/Mercury Sulfate Half-Cell.- Metal Oxide Electrodes.- Metals As Reference Electrodes.- Electronic Control and Power Supplies.- Potential Controller.- Power Supplies.- Summary.- References.- 4 Design, Operation, and Maintenance of Anodic Protection Systems.- Design Requirements.- Electrochemistry.- Establishing Electrochemical Parameters.- Time Effects on Passivation Currents.- Electrodes.- Electronic-Hardware Selection.- Power-Supply Criteria.- Installation and Start-up.- Electrode-Installation Modes.- Electrical-Wiring Criteria.- Location of Power Supply and Controller.- Start-up Procedures.- Operation and Maintenance Parameters.- Corrosion-Rate Measurements.- How to Take Solution Samples.- Commercial Units Reliable.- Summary.- References.- 5 Economic Evaluation of Anodic Protection.- Known Costs of Anodic Protection.- Costs of Small Tanks.- Data on Larger Tanks.- Current Costs of Protecting Steel Tanks Against Sulfuric Acid.- Why Tanks Require Protection.- Cost of Internally Lining Tanks.- Sulfuric Acid Coolers.- Summary.- References.- 6 Principles of Anodic Protection.- Electrochemical Description of Passivity.- Characteristics of Anodic-Polarization Curves.- The Passive Metal Layer.- Proposed Mechanism of Iron Passivity.- Metal Passivity Breakdown.- References.- 7 The Potentiostat.- Potentiostat Mode.- Development of the Potentiostat.- Potential Control.- Control Amplifier.- Current Regulator.- Solid-State Potentiostats.- Commercial Electronic Potentiostats.- Portable/Field Potentiostat.- Summary Comments on Potentiostatic Mode.- The Potentiostat.- References.- 8 Laboratory Tests and Procedures.- Wiring Sequence for Potentiostatic Experiments.- Reproducibility of Potentiostatic and Potentiodynamic Anodic-Polarization Measurements.- Polarization Cells.- Elevated-Pressure Polarization Cells.- Proposed Experimental Procedure.- Experimental Procedure.- High-Temperature Polarization Cells.- Crevice Corrosion Testing Polarization Cells.- Summary.- References.- 9 Selected Examples of Anodic Protection.- Alloy Evaluation.- Alloy Effects.- Concentration Effects.- Temperature Effects.- Environmental Effects.- Preliminary Investigations Are Necessary.- Time Effects.- References.- 10 Future Uses for Anodic Protection.- A Realm of Probability.- Cooling-Tower Water.- Raney Catalyst.- Prosthetic Implants.- Stainless Steel Pickling.- Molten Salt—Metal Technology.- Metallography.- Coolant Systems.- Solution-Potential Concept.- Sulfide Minerals.- Enzyme Production.- Surface-Area-Ratio Concept.- The Sufficiently Real Possibilities.- Potentiostatic Conditioning of Electrodes.- The Cell Cathode.- The Electrochemical-Conditioning Concept.- References.- Appendixes.- I Electrochemical Principles of Corrosion.- Corrosion.- Electrode Terminology.- Potential Series.- Nernst Equation.- The Electrical Double Layer.- Free Energy.- Polarization Diagrams.- Electrochemical Equivalents of Metals.- Conversion Factors.- Partial Electrochemical Equivalent.- References.- II Glossary.- III Historical Development.- IV United States Patents Relating to Anodic Protection.- V Bibliography.