Aluminium: The Secret Recipe Of Tech’s Favourite Metal

Aluminium: The Secret Recipe Of Tech’s Favourite Metal

There’s a reason why Jony Ive has forged so much of Apple’s success from aluminium for the last decade or so.

Basically: You tell this metal what you need, and it’ll work it out. You want a perfectly cooked Thanksgiving bird? A beer that doesn’t taste like shit? A lighter automobile? Better all around electrical conductors? Computer bodies that don’t shatter into a million pieces when you drop them, yet don’t weigh a million pounds either? Aluminium’s the material for you.

The clincher is its unique combination of properties. Aluminium is only about one half as thermally conductive as copper and only about two thirds as electrically conductive. But the thing is, it’s much less dense, and it’s corrosion resistant, thanks to an oxide film that blankets its surface. So for electrical transmission lines, aluminium trumps copper. Its feather-weight status and corrosion combating also gives it a leg up against iron, which is heavier and prone to rust.

When it was first refined, an account in Mining Magazine admired how it had a better general utility than iron and was lighter, more durable than silver, while being more abundant than both. The article, published in 1854, predicted, “some of us now present may yet to live to eat with forks and spoons composed of aluminium on aluminium dishes, food cooked in aluminium utensils upon an aluminium stove, and possibly while seated on aluminium chairs in houses or ships composed of the same metal.”

But it wasn’t always so available. See, aluminium doesn’t appear in its metallic form in nature, so soft-drink cans, cooking utensils and building materials take a bit of chemical coaxing. Although aluminium shows up everywhere from rocks to plants to animals, it likes hanging out with other common elements like oxygen. Before we can use it, science needs to separate it from those it chemically combines with. And then combining it with small amounts of silicon and iron makes it the strong stuff found in aeroplanes and cars.

Figuring out how to do that took a long time. In 1807 an English chemist named Humphry Davy made an unsuccessful attempt to coax out the metal. Though it remained beyond his reach, he named this thing alumium, before renaming it aluminum. The US kept this name, but many other countries modified it to conform to the “ium” ending popular among other elements.

The coming out party was at the 1855 Paris Expo where a bar of the newly minted metal was on display aside the crown jewels. There was quite a bit of fanfare over this “scientific marvel” with a higher value than gold, but the breakthrough still wasn’t of much use for industry. Before mass production became viable, aluminium was used mostly for jewellery and trinkets.

All that changed with better access to electrical power.

As the 19th century was nearing its close, electrical power became more widely available and less expensive. Helpful when you’re trying to use electricity to make something big happen. As it turns out, two men on different continents landed upon a better refining method at exactly the same time. Charles Martin Hall, an American, and Paul-Louis-Toussaint Héroult from France both realised that if they hit aluminium oxide dissolved into molten cryolite with electricity, they could get aluminium in its metal form. And it’s basically still done like that, but today the industry is much, much bigger — $US40 billion in the US alone.

Take the venerable beer can. Before cans were made out of aluminium, beer came in tin. The beer sucked. First, brews sealed in tin required pasteurisation because the can was letting in outside elements, which negatively affected the taste. More than that, the tin itself imparts its own extra flavour. Tin is not delicious. So Bill Coors of the Adolph Coors Company was not pleased. In order to get the container to stop skunking up his beer, he needed to find a material capable of being truly sealed which would knock out the need for pasteurisation.

It took five years, but in 1959 the world’s first stamped, seamless, aluminium can arrived from a newly created division of Coors. Aluminium was lighter than tin and could be rolled into thin sheets. It also didn’t leak or offer an unintended metallic taste. Not only did it make drinking beer way more awesome, but it also kicked off a major recycling push. Recycled aluminium comprises some 30 per cent of our domestic aluminium needs today-and we can toast Bill Coors for that.

Of course, there’s more. aluminium is perfect for electrical transmission lines because it’s a great conductor without a lot of weight. And in the automobile industry, swapping aluminium parts in for heavier ones allowed cars to get lighter and faster.

Good thing there’s enough aluminium to go around.

Rachel Swaby is a freelance writer living in San Francisco. Check her out on Twitter.

Chris Madden is a New York-based illustrator and designer. You can see his work here, follow him on Facebook and on Twitter.