Brainy Quote of the Day

Friday, August 16, 2013

When Disorder is a Good Thing...

A material’s nanostructure is decisive in determining how resistant it is against corrosion

August 08, 2013

Corrosion eats away 75 billion euros of economic output annually in Germany alone. But it may soon be possible to better assess which steels and other alloys will be affected, and how to limit the damage: An international team led by scientists from the Max-Planck-Institut für Eisenforschung GmbH in Düsseldorf analysed an amorphous steel comprising iron, chromium, molybdenum, boron and carbon. They found that the more ordered a material’s structure is, and the more uneven the distribution of its atoms, the more easily it is corroded by rust. If the elements of the alloy don’t form a regular crystal lattice and are distributed completely uniformly across the material, then, under corrosive conditions, a passivation layer forms on its surface and protects it from rusting. If, in contrast, ordered nanocrystals form that sometimes contain more chromium and sometimes more molybdenum, the corrosion quickly eats away the material because no protective passivation layer forms. These findings give materials scientists clues as to what they should pay attention to regarding the composition and production of materials.

Max Planck-Gesellschaft: Disorder creates rust protection

Note: On vacation. Blog will auto-post next Friday, 23 August 2013.

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