As for metallurgy, the smaller grains are known to be harder metals. But how exactly do you get these grains?
A group of researchers at Brown University have found a method to break individual metal nanocumulus that leads to metals up to four times harder than natural structures. This new method is quite different from conventional hardening techniques.
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“Hammering and other hardening methods are ways to alter the structure of the grain and it is very difficult to control the size of the grain you end up with,” Ou Chen, an assistant professor of chemistry at Brown, said in a press release. corresponding author of the new research.
“What we have done is create nanoparticle building blocks that fuse when you squeeze them. In this way, we can obtain uniform grain sizes that can be precisely adjusted to obtain improved properties. “
For this research, the team used nanoparticles of gold, silver, palladium, and other metals and chemically removed organic molecules called ligands, which generally prevent the formation of metal-to-metal bonds between the particles. The groups were able to merge with some pressure.
It was found that the new metal coins made with the technique had an electrically conductive and light reflectance virtually identical to standard metals, but their optical properties changed drastically.
“Because of what is known as the plasmonic effect, the gold nanoparticles are purplish black,” Chen said. “But when we applied pressure, we see that these purple clusters suddenly turn a bright golden color. That’s one of the ways we knew we had really formed gold in bulk. ”
Now researchers are looking to apply the technique to commercial products, as chemical treatment is relatively simple to perform. Currently, Chen has patented the technique and sees great potential in it “for both the industry and the scientific research community.”