A review of the structure of metals used to form cultural objects and artifacts is used as a base for studying their corrosion. Corrosion is defined and quantified. The various agencies of corrosion are examined by studying the corrosion mechanisms of the metals used in antiquity. By understanding corrosion processes, students are able to  assess the current condition of a metal and predict its stability.

To define the physical and chemical structure of metals.

To examine how physical and chemical changes are caused in metals, by

corrosion in the atmosphere and  within burial environments.

To identify the nature of the changes caused by corrosion and quantify the physical condition of archaeological and historical metals which have corroded.

To identify causes of deterioration and assess their current activity status.

To demonstrate and ability to ;

     assess the condition and stability of metals

     recognise the changes which have taken place due to deterioration

     identify the likely causes of deterioration

     assess the stability of metals and identify the agencies of decay which are capable of continuing the corrosion of the metal in question

Lectures and Seminars : 11 hours total

Students will be able to critically interpret relevant corrosion publications and identify problems associated with corroded metal objects.

One essay (50%) and exam (50%).

Lecture 1. What is a metal? General overview of module.

Structure of metals; review of their properties; metallurgy; alloys; surface finishes.

Lecture 2. Phase diagrams and alloys

Alloying; energy in metals and the use of phase diagrams to explain compositional differences in metals

Lecture 3. Electrochemistry: Definitions and basic reactions associated with corrosion

Definition of corrosion; electrochemical reactions; corrosion cell; anode and cathode reactions ( hydrogen evolution; oxygen reduction; metal ion reduction); redox; potential difference; current; general corrosion; local corrosion; standard electrode potentials; thermodynamics; kinetics; polarisation (anodic, cathodic, activation, concentration, resistance); dry corrosion; oxide properties.

Lectures 4.  Types of corrosion.

Galvanic corrosion; influence of electrode area, electrolyte composition, cathode reaction and oxide coatings on galvanic corrosion; Selective corrosion attack on metals (metallurgical structure and corrosion, intergranular corrosion, lamellar corrosion, selective leaching); Differential aeration corrosion ( waterline corrosion, crevice corrosion, filiform corrosion); Pitting corrosion; hydrogen corrosion; environmentally induced cracking; microbial corrosion.

Lecture 5. Predicting corrosion by calculation: Thermodynamics in more detail and Potential-pH diagrams

Corrosion of a non alloyed metal; thermodynamics in more detail; chemical equilibrium; solubility product; concept of stability; energy changes in reactions; free energy; linking free energy to electrochemical potential; Nernst equation; Potential / pH diagrams (construction, predictive possibilities and limitations); Examples of potential / pH diagrams; limits of oxidation and reduction in nature.  Potential/ current diagrams (usefulness in conservation and predictive possibilities).

Lecture 6.  Burial environments and iron corrosion

Corrosion variables in burial environments; why and how iron corrodes during burial; predictive corrosion and actual corrosion; concept of original surface.

Lecture 7.  Role of chloride in the corrosion of iron during burial and post excavation

This lecture contextualises much of the corrosion theory that has been addressed in earlier lectures and identifies the role of chloride in iron corrosion.

Lecture 8. Copper alloys and their corrosion

Examines the corrosion of copper alloys during burial and following excavation. Also considers corrosion in the atmosphere for historic copper alloys. Differences with iron corrosion are contrasted.

Lecture 9. Corrosion of lead and tin and their alloys

A brief overview of these metals to compare and contrast their corrosion problems with the detailed assessments of iron and copper alloys.

Lecture 10. Corrosion of zinc, aluminium and selected modern alloys

Corrosion of zinc and alloys of zinc not covered in the lecture on copper alloys will be dealt with here. Aluminium is discussed and the many problems associated with its corrosion. Some reference will be made to modern museum collections.

During the course you may be provided with handouts to facilitate the teaching.

At the end of each lecture general recommended reading is provided. [To obtain the full reference follow the authors name back to the bibliography]. An in depth knowledge and lateral understanding of the subject can only be attained by reading more references, both from the bibliography and from your own researches. One of the aims of a university degree is to develop independent means of study. This means that you find your own information and make informed decisions on its usefulness and quality. Credit is given for widely read and well developed answers to essays. In general, it is not  necessary to read references prior to lectures, although some students may find that it helps them to follow the lectures more closely and aids their contribution to any discussion which may develop.

This will be provided during teaching.