As the value of precious metals fluctuates over time, the U.S. Mint has to constantly find new ways to keep currency manufacturing affordable. A five-cent nickel that costs as much as seven cents to make is a problem, but so is a coin that suddenly looks and feels different because its metallurgic ingredients were changed. To solve this problem, the U.S. Mint turned to computer simulations to help it redesign a more cost-effective nickel.
Most coins are a strategically engineered mix of different metals that work together to give your pocket change a specific list of properties. They have to be durable enough to survive decades of use while still being recognizable, they can’t corrode when held in a sweaty hand, they have to maintain a certain color and sheen throughout their life, and modern coins also have to have a specific level of electrical conductivity so they can be properly identified by the millions of vending machines across the country.
To streamline the process of designing a nickel made of... less nickel, the U.S. Mint worked with a team of researchers at the National Institute of Standards and Technology’s Materials Genome Initiative. Their approach employed powerful computer simulations to model and predict the outcome of mixing various metallic alloys. This allowed the researchers to specify the specific properties and features of new nickels—prioritizing color, durability, and conductivity—before casting a single cent.
In the end, the researchers created a prototype five-cent piece made from a mix of copper, zinc, and nickel that was about 40 percent less expensive to produce than what’s banging around in your pockets right now. And the entire process took less than a year, significantly shortening the standard experimentation period.
Unsurprisingly, the researchers see great potential for their more modeling, less experimenting approach, which could be used to streamline the production of consumer electronics. For now, at least, their method seems like a clever way to make coins so that vending machines can’t tell the difference—and aside from the year stamped on the coin, neither can you.