EFC Working Party 7: Corrosion Education

Outlines of courses of study

The content of a course should be broadly based and should cover all the major aspects of corrosion and protection. However, it is recognised that some emphasis may be placed on the lecturer's field of interest and experience and on the specific objectives of the course. This latter point will be particularly true in the case of courses provided for groups C and D (Corrosion technicians and operatives).


For GROUP A (CORROSION SCIENTISTS) the aim has been to arrange the phenomena associated with corrosion and its prevention in a manner based upon the scientific principles involved. It will be necessary for persons belonging to this group to have taken appropriate courses in physical chemistry, electrochemistry, chemical thermodynamics, physical metallurgy etc. The depth and breadth of the course described below depend on the type and content of these other courses. Course A serves to a large extent to integrate the knowledge obtained from the other courses mentioned.

A common syllabus has been provided for GROUPS B and C (CORROSION TECHNOLOGISTS AND CORROSION TECHNICIANS), but it is apparent that the depth of approach and emphasis will not be the same. Thus, in the case of the technologist a more fundamental approach will be required, and in addition courses in physical chemistry and physical metallurgy, which should precede the course on corrosion, will be necessary to enable the technologist to appreciate the electrochemical and metallurgical aspects of the subject. On the other hand, the technician will not be required to go so deeply into theory and emphasis will be placed on the practical aspects of corrosion protection and on corrosion monitoring and testing.


For GROUP D (OPERATIVES) treatments of the principles is confined to providing only a basic knowledge relevant to the special topics being taught. These courses will be highly specialised and directed to specific jobs. Special attention will be paid to carrying out the work effectively and the training supplemented with case studies. Three examples of such courses will be given.

GROUP A (CORROSION SCIENTISTS)

Economic and Technical Significance of Corrosion

Discounted cash flow, present worth, investment decision, total life cycle costing.

Fundamental Aspects of Corrosion:

Effects on Corrosion of Various Factors:

• Velocity, concentration and temperature
• Environment (atmosphere, aqueous solution, soil, organic solutions. biological media, fused salts, liquid metals, etc.)
• Mechanical (effects of stress, fatigue, erosion, cavitation, fretting)
• Metallurgical (composition and structure)
• Geometrical (shape, thickness, orientation).

Design for Corrosion Prevention:

• Selection of materials, fabrication and construction; geometry and economics.

Methods for Corrosion Protection:

• Change of environment (removal of aggressive constituents)
• Inhibitors
• Electrochemical methods (cathodic and anodic protection)
• Change of material (composition, structure or stress condition)
• Surface coatings (metallic, inorganic non-metallic and organic)
• Packaging and temporary protection in storage and transit
• Economics.

Corrosion Testing and Monitoring:

• Service tests (field, model, pilot plant and plant tests), accelerated tests
• Standardised testing procedures and monitoring
• Equipment and cells for electrochemical measurements (potentiostats, polarisation measurements)
• Statistical planning and analysis
• Economic; prediction of plant performance from laboratory tests; hazard analysis.

Analysis and Correction of Corrosion Failures (Case Studies)

Development of Expert Systems

Bibliographic sources.

GROUP B (CORROSION TECHNOLOGISTS) and GROUP C (CORROSION TECHNICIANS)*

Economic and Technical Significance of Corrosion

Corrosion Processes:

• Basic concepts (electric conductance, electrode potentials, polarisation) Thermodynamics (potential-pH equilibrium diagrams)
• Kinetics of electrochemical corrosion (polarisation diagrams, passivity)
• Hydrogen evolution, oxygen reduction, anodic metal dissolution
• High temperature oxidation.

Corrosion Related to Environment:

• Atmosphere
• Fresh and sea water
• Soil

Other environments (fused salts and slags, dry gases, water-free organic liquids, molten metals).

Metallurgical Factors:

• Composition
• Structure, grain boundaries, dislocations, stress.

Use of Expert Systems
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* Note: The syllabus proposed should be of value in courses leading to qualifications in engineering, metallurgy, chemistry, etc. in which corrosion studies are important but subsidiary to the major theme, cf. Classification of personnel combating corrosion, second paragraph. The scope and depth of treatment will be dependent on the nature of the course and on the time available for teaching. The syllabus must therefore be taken as a guide to the teacher who will naturally interpret it with reference to the nature and objectives of the specific course.

GROUP C (CORROSION TECHNICIANS)

Some Important Types of Corrosion:

Uniform corrosion, pitting corrosion, bimetallic corrosion, intergranular corrosion and fretting corrosion, corrosion fatigue and stress corrosion cracking, crevice corrosion, deposit corrosion, selective corrosion.

Corrosion Properties of Some Metals and Alloys :

• Unalloyed and alloyed steels, copper, aluminium, magnesium and their alloys
• Tin, lead, zinc, nickel, titanium, etc.

Design for Corrosion Prevention:

• Corrosion prevention starts with design
• Establishment of basic prerequisites
• Choice of surface treatment or other corrosion protection
• Design principles with regard to corrosion, effects of shape and orientation
• Economics
• Monitoring facilities.

Corrosion Protection by Change of Composition, Structure or Stress Condition of the Metal

Corrosion Protection by Modification of the Corrosive Environment :

• Removal of aggressive constituents, for example oxygen/air and water (as liquid orvapour)
• Inhibitors.

Electrochemical Protection:

• Cathodic and anodic protection.

Environmental Aspects

• Effect of corrosion on the environment
• Leaching of toxic metals and chemicals into the atmosphere or potable waters.

Corrosion Protection by Means of Coatings:

• Pretreatment of metal surfaces before the application of coatings
• Metallic coatings
• Inorganic, non-metallic coatings (anodising, conversion coatings, etc.)
• Organic coatings (paints, plastics coatings, film forming types of temporary corrosion preventives)
• Packaging and corrosion protection in storage and transit
• Economics.

Corrosion Testing and Monitoring

Service tests (field and plant tests), accelerated tests:

• Standardised testing procedures
• Statistical planning and analysis
• Application of results to prediction of plant performance.

Analysis and Correction of Corrosion Failures (Case Studies)

Bibliography.

GROUP D (OPERATIVES)

Example No. 1: Protective painting of structural steel
Source - Bayliss D A and Chandler K A: Steel work corrosion control, 1991. Elsevier Applied Science, London.

• General principles governing successful protective painting
• Surface preparation
• Paint systems
• Painting procedure
• Repainting of old steelwork
• Practical examples
• Special cases
• Relevant national standards and similar specifications.

Example No. 2 : The protection of steel by metal coatings
Source - The Protection of Steel by Metal Coatings. No. 5 of a series of Corrosion Preventio
Booklets. Steel Users Advisory Service, British Steel Technical, Rotherham, UK.

Metal coatings used for the protection of steel

• Zinc
• Aluminium
• Titanium
• Stainless steels
• Nickel alloys

Methods of application

• Hot-dipping
• Metal spraying
• Electroplating
• Diffusion coating
• Cladding.

Choice of coating and coating method

• Painting of metal coatings.
• Relevant national standards.

Example No. 3 : The corrosion of steel and its prevention
Source - A Background to the Corrosion of Steel and its Prevention. No. 3 of a series of
Corrosion Prevention Booklets, as example 2 above.

• Introduction
• The electrochemical nature of corrosion
• Electrode potentials
• Corrosion of two metals joined together
• Corrosion of iron and steel
• Factors affecting corrosion rates in natural environments
• Preventive measures
• Appendix - Note on acidity and alkalinity.