| 摘要 |
A coinage material comprises a ferritic blank, for example of mild steel, which has been surface-treated with an austenite-forming element such as nickel or manganese, and which has chromium diffused into the surface, such that a specific, marked difference, for example in electrical conductivity and/or magnetic permeability, which is electronically detectable exists between the surface and the interior. The coinage material may therefore be validated electronically using suitable detection means. |
