The Euro is a Soft Currency!

Nanoindentation hardness tests carried out on a range of European coins have shown that the Euro is softer than the both the pound and the German mark. The Euro has a soft surface layer of about 60nm thick when compared to the other currencies. This is due to the fact that it is a new coin in circulation and the surface has not been able to work harden by repeated contacts with other surfaces and coins during use. There is little difference between the coins at greater depth. The Euro will become a harder currency with increased use.

Conventional microhardness testing will not show up these differences since, in order to achieve indentation depths of less than 60nm contact loads of less than 500mN (0.05gf) are necessary on a sharp Berkovich diamond indenter. The Hysitron Triboindenter at Newcastle is one of the few machines available worldwide for making precision measurements at such low loads.

This page was last modified on 20th February 2002.

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