Conservation Science

The oxide so produced is then treated as for the oxide-bearing ores. There is very little iron found in copper obtained from cha ...

The introduction of mechanically-operated bellows and taller shaft furnaces allowed higher temperatures to be achieved. These we ...

It is possible to produce alloys from ores. Archaeological bronze is an alloy of copper and tin and the alloys were made by mixi ...

to temperatures in excess of 200°C. This is called annealing and if the shaping of metals was performed at these elevated temper ...

If the two metals that form the alloy are insoluble in one another, then they will exist as two separate phases, often in altern ...

and then tempering at 200–300°C. This produces the ideal mechanical prop- erties for cutting instruments such as knives, blades, ...

separate metallic phases present on a single metal surface. Consider a strip of copper (copper electrode) joined to a strip of i ...

Electrolyte – to complete the electrical circuit. Electrical contact between anode and cathode – to allow the transfer of elect ...

sites. Lead artefacts form relatively insoluble compounds as corrosion products in marine environments such as PbSO 4 , PbCl 2 a ...

to achieve in most circumstances in museums or storage rooms. Finally, cor- rosion reactions involving chlorides can produce aci ...

rapidly in these strong alkali solutions. Aluminum artefacts, such as old engines, would have to be treated in a solution with a ...

Metals 137 Figure 2Concretion and mud on a split ring gun recovered from the Mary Rose As stated in the corrosion section, metal ...

the Solent, they were in very good condition and were protected by a thin 1–3 mm of corrosion products. Once the artefacts are b ...

occur but none of the problems mentioned above will commence. Very large artefacts such as the cannons from the Mary Rose, could ...

on the exposed metal. For example, wrought iron will form a passive film in a solution above pH 9. Hence sodium hydroxide, sodiu ...

Sometimes the artefact may be brought to the surface from the sea-bed and the shape of the artefact may be readily apparent even ...

X-rays are not very good for thick objects and the equipment is not portable. Radioisotopes such as Co^60 , Ir^192 and Cs^137 in ...

ferrous artefacts, as has 2.5 M H 3 PO 4 , which leaves a film of ferric phosphate on exposed iron. A 1–2% HCl solution has been ...

4.2 Aqueous Washing The principle of this method of conservation is to immerse the artefact in a tank containing a suitable solu ...

as these will corrode the metal at an alarming rate. A pH in the range 4–8 is required to form a passive film on aluminium. Sodi ...