Physicists shed light on rarely seen 16th-century metal-working technique

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Physicists shed light on rarely seen 16th-century metal-working technique
by Hayley Dunning
04 August 2017
http://www3.imperial.ac.uk/newsandeventspggrp/imperialcollege/newssummary/news_28-7-2017-10-15-56


The gauntlets from a suit of armour - the left one was analysed.
Image: Trustees of the Wallace Collection

Imperial researchers have tested a 'blued' gauntlet from a 16th-century suit of armour with a method usually used to study solar panels.

Metalworkers have used various techniques to prevent steel from rusting, some of which turn the metal black-blue. This ‘blueing’ effect can be created in several different ways, including by applying heat or (in later years) chemicals.

However, it can be difficult to know which method was used in older metalwork like armour or weapons, because the blueing is oxidised over time, and because many armourers kept their methods protected as trade secrets.

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The method used is called spectroscopic ellipsometry, and involves studying the reflections of light from the surface of a material. A monochromatic light beam is bounced off the material, and then analysed to see what changes occurred to the beam.

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Excerpt.  Read more at http://www3.imperial.ac.uk/newsandeventspggrp/imperialcollege/newssummary/news_28-7-2017-10-15-56