New technique builds super-hard metals from nanoparticles

Metallurgists have all kinds of ways to make a chunk of metal harder. They can bend it, twist it, run it between two rollers or pound it with a hammer. These methods work by breaking up the metal’s grain structure — the microscopic crystalline domains that form a bulk piece of metal. Smaller grains make for harder metals.

Now, a group of Brown University researchers has found a way to customize metallic grain structures from the bottom up. In a paper published in the journal Chem, the researchers show a method for smashing individual metal nanoclusters together to form solid macro-scale hunks of solid metal. Mechanical testing of the metals manufactured using the technique showed that they were up to four times harder than naturally occurring metal structures.

For this study, the researchers made centimeter-scale “coins” using nanoparticles of gold, silver, palladium and other metals. Items of this size could be useful for making high-performance coating materials, electrodes or thermoelectric generators (devices that convert heat fluxes into electricity). But the researchers think the process could easily be scaled up to make super-hard metal coatings or larger industrial components.

Read more at Brown University

Image Credit: Chen Lab / Brown University

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