Engineering news
The research team, from Sandia National Laboratories in New Mexico, believe the material, which is 100 times more durable than high-strength steel, is the most wear-resistant metal in the world.
“We showed there’s a fundamental change you can make to some alloys that will impart this tremendous increase in performance over a broad range of real, practical metals,” said materials scientist Nic Argibay, an author on a recent paper reporting the findings in Advanced Materials.
Although metals are strong, they wear down over time when they rub against other metals, unless equipped with a protective barrier or coating such as motor oil. For electronics, this coating is usually made of gold or another precious metal, and it too wears out over time.
Sandia’s platinum-gold coating could save the electronics industry more than $100m a year in materials alone, said Argibay, and make products more durable and dependable.
“These wear-resistant materials could potentially provide reliability benefits for a range of devices we have explored,” said Chris Nordquist, a Sandia engineer not involved in the study. “The opportunities for integration and improvement would be device-specific, but this material would provide another tool for addressing current reliability limitations of metal microelectronic components.”
Although their mixture of 90% platinum and 10% gold isn’t new, the theory behind it is. Argibay and his co-author Michael Chandross went against conventional wisdom, which dictates that a metal’s ability to withstand friction is based upon how hard it is. Instead, they theorised that wear was related to how well a metal could withstand heat, and they engineered their alloy with that in mind.
“Many traditional alloys were developed to increase the strength of a material by reducing grain size,” said John Curry, a postdoctoral appointee at Sandia and first author on the paper. “Even still, in the presence of extreme stresses and temperatures many alloys will coarsen or soften, especially under fatigue. We saw that with our platinum-gold alloy the mechanical and thermal stability is excellent, and we did not see much change to the microstructure over immensely long periods of cyclic stress during sliding.”