Corrosion Engineering Assignments
Corrosion Engineering Companion

Corrosion engineering consultant

Corrosion Doctors site map

Alphabetical index of the Corrosion Doctors Web site

Corrosion Engineering Assignments

The recent Corrosion Engineering publication by McGraw-Hill was designed as a textbook to accompany the education of undergraduates, graduates and other technical trainees during their discovery of the modern world of corrosion engineering. The book contains many equations and principles that lend themselves to the production of assignments and questions that are so important to evaluate newly acquired skills.

Chapter One: The Study of Corrosion (Visual aids)

  1. Discuss the evolution of the knowledge of metallic corrosion over the past centuries

  2. Elaborate on the roles of a corrosion engineer.

  3. What are the main responsibilities of a corrosion engineer? ... of a corrosion scientist? ... of a corrosion technologist?

  4. Explain the purpose and chemistry of a ferroxyl indicator.

  5. Explain what are the main differences between direct and indirect costs associated to corrosion damage. Provide some examples from your own experience.

Chapter Two: Corrosion Basics (Visual aids)

  1. Describe the main ore species associated with iron, copper, aluminum, and zinc.

  2. Compare the energy required to produce one metric ton of magnesium from its oxide to the energy required to convert enough copper oxide to produce one ton of metallic copper.

  3. Discuss the energy values presented in Table 2.2 in relation to the order in which metals and associated alloys appeared in the history of mankind.

  4. Compare the order in which metal oxides are arranged in Table 2.2 to the order in which the parent metals are organized in the electromotive series presented in Tables 4.1 and 4.2.

  5. Compare the chemical arrangement in salts with the main crystal structures of the main metals used in engineering.

  6. Discuss the unit cell concept to describe metals.

  7. Describe a detailed procedure to reveal austenite boundaries in tempered steels; ... carbides in cold rolled and annealed steel; ... the general structure of stainless steels.

  8. What is the ASTM grain size number of an alloy for which we count 16 grains per square centimetre in a photomicrograph taken at magnificationX100.

  9. The yield strength of mild steel with an average grain diameter of 0.05 mm is 140 MPa. The yield strength of the same steel with a grain diameter of 0.007 mm is 280 MPa. Use Hall-Petch relation to estimate an average grain diameter for the same steel with a strength of 210 MPa.

  10. Estimate the ASTM grain size number of the 70 Ni 30 Cu alloy shown in Figure 2.6b.

  11. A solution is made up to contain 0.01 M HCl. What is its pH?

  12. A solution is made up to contain 0.01 M NaOH. What is its pH?

  13. A solution contains a mixture of sodium bicarbonate (0.05 M) and sodium carbonate (0.2 M).What is its pH?

  14. Would you add and acid or a base to increase the carbon dioxide (CO2) pressure in the solution described in the previous question? Explain your answer and relate this situation to the pH that exists in a pop (soda) bottle.

  15. 24 g of zinc are dissolved in 1 M HCl solution. How many moles of hydrogen gas would be produced during this corrosion reaction? (see equation 2.10 and the periodic table in Appendix B)

  16. 24 g of iron are dissolved in 1 M HCl solution. How many moles of hydrogen gas would be produced during this corrosion reaction? (see equation 2.15 and the periodic table in Appendix B)

  17. Provide an explanation for the patterns of oxidation states, in Figure 2.9, that are repeated between rows 4, 5 and 6 of the periodic table.

  18. Describe some possible manganese oxidation products.

Chapter Three: Corrosion Electrochemistry (Visual aids)

  1. Describe the principles of a Daniell cell and elaborate on the usefulness of the Daniell cell when it was introduced.

  2. Why is a separator commonly used between the anodic and cathodic half cells of a Daniell cell?

  3. Elaborate on the effect the absence of a separator would have on the potential generated by a Daniell cell. Make reference to the Nernst equation described in Chapter 4 to support your arguments.

  4. Why is the zinc electrode of a Daniell cell also called 'the negative' in battery parlance. Are there similarities between the anode material of a Danielle cell and anodes of some batteries or cells commonly used today?

  5. Write a short-hand description of the reactions involved in the corrosion of zinc as illustrated in Figure 3.3.

  6. Why are there always a minimum of two electrochemical reactions to explain even the simplest corrosion reaction?

  7. What is an anodic process in a corrosion reaction? Provide some examples.

  8. What is an cathodic process in a corrosion reaction? Provide some examples.

  9. 24 g of zinc metal are dissolved in a 1 M HCl solution. How many coulombs have been produced by the anodic process?

  10. If the previous reaction occurs over a thirty minute period, what current would have been produced?

  11. A sheet of carbon steel one meter wide by three meter long has lost 40 g to corrosion over the past six months. Convert that mass loss to a penetration rate of the steel in mm units. What would be the total corrosion current associated with such a corrosion rate? (carbon steel density = 7.8 g/cm3)

  12. Repeat the previous problem for a sheet of aluminum A96061. (A96061 density = 2.7 g/cm3)

Chapter Four: Corrosion Thermodynamics (Visual aids)

  1. Explain what is meant by 'the free energy of an electrochemical cell'.

  2. What is the significance of a negative cell potential?

  3. Propose a simple experiment to estimate the entropy change (DS) associated with an electrochemical reaction.

  4. Define the standard conditions associated with a gas? ... with a solid species? ... and with an ionic species?

  5. Explain why it is much easier to use molarity instead of activity to describe the presence of an ionic species.

  6. Is it possible to use the power coming out of a half cell? Explain your answer.

  7. Why are electrochemical cells described using typically two half cells?

  8. Define the purpose of what is called the 1953 Stockholm convention in the context of electrochemistry.

  9. Rank the following ions in order of their thermodynamic ease of plating out of a solution: Cu2+, Ca2+, Fe2+, Fe3+, Na+, Pb2+, Fe3+, Cu+

  10. Rank the following elements in order of their thermodynamic ease of being oxidized in solution: Hg, Al, Fe, Au, Cr, Zn, Ag, Mg

  11. Using standard potentials and molarity for ion concentrations calculate the open circuit potential of the following electrochemical reactions (balance the equations with water relater chemical species when necessary):

    1. H2O2 + Ni « H2O + Ni2+

    2. H2O2 + Mg « H2O + Mg2+

    3. Ni2+ + PbO2 « Pb2+ + Ni2+

    4. Al + O2 « Al3+ + OH-

  12. What does a measured potential value of 0.8 V vs. SHE would be if the potential had been measured with a saturated silver chloride electrode? ... with a saturated copper sulfate electrode?

  13. What does a measured potential value of -0.4 V vs. SCE would be if the potential had been measured with a saturated silver chloride electrode? ... with a saturated copper sulfate electrode?

  14. Propose and explain your choice of a reference electrode for measuring the corrosion potential of a piece of metal buried in soil.

  15. Propose and explain your choice of a reference electrode for measuring the corrosion potential of a piece of metal immersed in a very alkaline environment.

  16. What is the principle of a Luggin capillary and what are the main functions of such a device?

  17. What is the electrochemical principle of a pH glass electrode?

  18. What instrument would you use to measure directly the pH of a soil?

  19. Can one predict the corrosion rate of a metal in a given environment with E-pH diagrams?

  20. Can one predict which corrosion products will form on a metal in a given environment with E-pH diagrams?

  21. Some fuel cells operate by oxidizing hydrogen gas on an anode while reducing oxygen from ambient air in contact with a cathode. What would be the maximum voltage produced by such a cell running on pure hydrogen and air in an acidic environment? Would it be different if pure oxygen was used instead of ambient air?

  22. Repeat question 21 for an alkaline environment.

  23. Use the E-pH diagram for aluminum shown in Figure 4.13 to answer the following questions:

    1. What are aluminum dominant species at a potential of -0.5V vs. SHE and pH values of 2, 4, 6, 8, and 10?

    2. Define the predominance domain of aluminum metallic element in terms of pH and potential.

    3. Define the predominance domain of aluminum oxide in terms of pH and potential.

  24. Use the E-pH diagram for iron shown in Figure 4.15 to answer the following questions:

    1. H2O2

Chapter Five: Corrosion Kinetics and Applications of Electrochemistry to Corrosion (Visual aids)

  1. Describe in your own words the significance of what is meant by 'overpotential'.

  2. What is the relation between the overpotential and standard potential of an electrochemical reaction?

  3. What is the relation between polarization and overpotential?

  4. Describe the principles of a potentiodynamic scan.

  5. Describe in your own words the significance of what is meant by the 'exchange current density' in reference to a corrosion reaction.

  6. Propose an alloy modification that would possibly disfavor the production of hydrogen at an electrode. ... and one that would favor it.

  7. Would steel be a good electrode material for the production of hydrogen in an electrochemical cell? Considering what has been discussed in Chapter four would you suggest that such a process would be easier on the steel in an alkaline or an acidic environment?

  8. What is the chemical significance of a polarization branch? Explain your answer.

  9. Describe a simple method to verify if an electrochemical reaction is limited by a concentration polarization effect.

  10. How many grams of dissolved oxygen are present in one liter of aerated water at 5ºC? ... at at 30ºC?

  11. Describe a simple method to reduce the quantity of dissolved oxygen in a water container or vessel.

  12. Calculate the thickness of the Nernst diffusion layer for the electrochemical reduction of dissolved oxygen in water at 25ºC if the limited current density for that reaction is 0.01 mA/cm2. ... if it is 0.5 mA/cm2.

  13. Explain the main differences between the ohmic drop in an aqueous environment and the ohmic drop in an electrical conductor.

  14. Can one use direct current to measure the ohmic drop in an electrochemical cell? Explain your answer.

  15. How can a Luggin capillary improve the polarization measurement at an electrode?

  16. Describe, in your own words, the methodology applied to estimate the ground resistivity for various soil depths.

  17. What is the role of the two central pins in the Wenner method?

  18. Describe the main advantages of each of the soil resistivity methods that have been used to measure soil resistivity.

  19. Was is the purpose of graphing out an Evans diagram?

  20. How does one determine the corrosion potential from a mixed potential diagram.

  21. How does one determine the corrosion current from a mixed potential diagram.

  22. Describe the main components required to carry out some electrochemical polarization tests.

  23. Describe the main differences between potentiodynamic polarization, linear polarization resistance, and electrochemical impedance spectroscopy. Indicate what your arguments to propose one technique over another would be.

  24. Provide some application examples of corrosion monitoring techniques, Highlighting the advantages and costs associated with these practices.

  25. Describe the selection criteria that would make the choice of anodic protection a better choice than cathodic protection.

  26. Describe two electrochemical techniques that are used in corrosion studies but not mentioned in the book. Explain their principles and main uses.

Chapter Six: Recognizing the Forms of Corrosion (Visual aids)

  1. Search the Internet for examples to illustrate the inspectability of the forms of corrosion listed in the three groups described in pages 148 and 149.

  2. Corrosion problems can rarely be attributed to single forms of corrosion. Provide some examples to illustrate that statement.

  3. The seriousness of a corrosion situation is often directly related to the hidden nature of the specific corrosion defect that is progressing. Provide some examples in support of that statement.

  4. The actual importance of a type of corrosion may greatly vary between affected systems. Provide some examples in support of that statement.

  5. Provide some examples of uniform corrosion with pictures and general description.

  6. Where would general loss (uniform corrosion) be a concern. Provide examples and explanation.

  7. Provide some examples of pitting corrosion with pictures and general description.

  8. Why would pitting corrosion be much more prone to provoke a catastrophic failure than uniform corrosion generally does?

  9. Provide, from a basic search of the Internet, some details of the nature and chemistry of tubercles in water pipes.

  10. Where should pitting undercutting be a serious design consideration?

  11. Relate metallurgical features of a metallic material to the shapes of corrosion pits shown in Figure 6.11.

  12. Elaborate on the three types of pitting that have been observed on copper in water service.

  13. Why would stray currents be such a force to reckon with behind one of the most dramatic forms of pitting corrosion experienced in service? Use Faraday's law to support your arguments.

  14. Propose a simple algorithm to estimate the pit density obtained from micrographs taken on corroded samples.

  15. What would be the main purpose for using extreme value statistics for the evaluation of field coupons.

  16. Use the pKa of the following hydroxides to predict the acidity in crevices formed on their respective metals: Cr(OH)3, Fe(OH)2, Sn(OH)4, Fe(OH)3, and Al(OH)3.

  17. Explain in your own words the role played by dissolved oxygen in the general mechanism proposed to explain the various steps in crevice corrosion.

  18. Provide some examples of crevice corrosion different from those described in the book.

  19. Extend the crevice corrosion scenario to situations encountered with non-metallic materials.

Chapter Seven: Corrosion Failures, Factors, and Cells (Visual aids)

Chapter Eight: Corrosion by Water (Visual aids)

Chapter Nine: Atmospheric Corrosion (Visual aids)

Chapter Ten: Corrosion in Soils and Microbiologically Influenced Corrosion (Visual aids)

Chapter Eleven: Materials Selection, Testing and Design Considerations (Visual aids)

Chapter Twelve: Corrosion as a Risk (Visual aids)

Chapter Thirteen: Cathodic Protection (Visual aids)

Chapter Fourteen: Protective Coatings (Visual aids)

Chapter Fifteen: High Temperature Corrosion (Visual aids)

For questions or clarifications please send a note to our

Corrosion Doctors in action

Back to Publications