A few years ago, we wrote about the 10 futuristic materials that will be disrupting product design, and transparent aluminium was one of them. Since then, it's become more and more prevalent in the real world.
We weren't the first to talk about see-through metal, far from it. Transparent aluminium was famously referenced in Star Trek back in the 1980s. In one classic scene from Star Trek IV: The Voyage Home, Scotty attempts to trade sheets of plexiglass for the formula for transparent aluminium.
Here, we're taking a more in-depth look at the reality of see-through metal and answering the most common transparent aluminium questions.
Transparent aluminium is also known as aluminium oxynitride. It's a see-through polycrystalline ceramic made from aluminium, oxygen, and nitrogen, with the chemical formula Al₂₃O₂₇N₅, so it's aluminium-dominant rather than an even split between the three elements. It looks completely clear and is remarkably strong: roughly four times as hard as fused silica glass and about three times harder than steel of comparable thickness. It sits just below sapphire on hardness, at around 85% as hard.
It also has an extremely high melting point, above 2100 degrees Celsius, and resists oxidation in air up to around 1200 degrees Celsius, meaning it can be used for products that need to withstand extreme heat while staying transparent. Transparent aluminium also resists damage from radiation and offers good resistance to corrosion.
A lot of people who come across transparent aluminium wonder if it's really the same aluminium we know so well. The answer depends on how you define aluminium. Ordinary aluminium is abundant and used for countless day-to-day applications. It has the properties you'd expect from a metal, including being thermally and electrically conductive, and it can be melted and moulded into almost any shape, which is why it ends up in everything from cans to foil.
Transparent aluminium doesn't share these features. Aluminium oxynitride is a ceramic compound of aluminium, nitrogen, and oxygen rather than a true metal, one that's been around for decades. It's only in recent years that advances in production have made it viable for a wider range of applications.
Now that it's clear transparent aluminium isn't just see-through aluminium but an entirely different material, the next question is how it's produced. The ceramic is heated to extremely high temperatures, then ground down and heavily polished. It's this polishing stage that creates the transparency, while the grinding and polishing process together improve the material's strength and impact resistance, the same kind of precision shaping that 3D CAD Design work depends on, getting a material's final form exactly right before it's committed to.
Transparent aluminium has come a long way, but it's still an expensive material to produce at the volumes commercial manufacturing needs, exactly the kind of cost-versus-scale problem design for Manufacture exists to solve. While it has potential for everyday products such as electronic devices and packaging, the cost currently puts it out of reach for most manufacturers.
Right now, transparent aluminium is mostly used in defence applications: transparent armour, bulletproof glass alternatives, and sensor windows are all areas where it's being applied. For this industry, it brings clear benefits. A laminated pane of aluminium oxynitride just 1.6 inches thick can stop a 50-calibre rifle round, a claim traditional 3.7-inch bulletproof glass can't make. Unlike glass, it's also transparent to infrared waves, making it useful for heat-seeking missiles and other infrared technologies.
Every one of those applications came down to the same question: is the added cost, weight, and complexity worth what the material delivers for that specific use case? That's the exact kind of decision we work through with clients on far less exotic materials, and it's rarely as obvious as it looks from the outside.
Transparent aluminium isn't yet readily available for commercial products for everyday use or industrial product designs like mobile phones, but it's being adapted for exactly that kind of use, and that opens up a lot of potential for future products. Progress has continued in the last couple of years: Surmet, the material's primary manufacturer, now has FAA-certified ALON transparent armour flying on real aircraft, offering roughly half the weight and thickness of traditional glass-based armour, and in 2024 materials firm Nitride Global and Germany's Fraunhofer FEP institute demonstrated a new sputter-deposition method for AlON coatings aimed at semiconductor and power electronics applications, a sign the material's uses are stretching well beyond armour and optics. Defence still accounts for the large majority of current use, and the cost barrier hasn't gone away, but the direction of travel is toward wider accessibility rather than away from it.
Whether or not transparent aluminium ever makes it onto a supermarket shelf, the decision behind it, balancing cost, weight, optical performance, and durability, is the same one we work through with clients choosing far more everyday materials. Extreme cases like this one just make the trade-offs easier to see.
Every material choice on a product involves some version of that same balancing act. A custom Enclosure Design has to protect what's inside without adding unnecessary weight or cost, and the right material rarely announces itself, it's usually a compromise between several competing requirements. Sustainable Design adds another layer to that decision, since the most durable or highest-performing material isn't always the one with the smallest environmental footprint, and getting that balance right early avoids expensive rework later.
The structural side matters just as much. Materials like this hold their properties under extreme heat and impact because their internal structure has been engineered for it, and that's exactly the kind of problem mechanical Engineering Design exists to solve on a more everyday scale: choosing and shaping materials so a product performs reliably under the real conditions it'll face in use, beyond whatever it was tested against in the lab.
Deciding whether a material like this is worth its cost and complexity for a given application is ultimately a commercial Strategy question as much as a technical one, and it's the same question we help clients answer on every project: does this material earn its place at this price point, for this market?
We saw a version of this in our work with IMS's fluid cleansing monitor, where components needed to perform reliably in a demanding industrial environment without compromising on cost or manufacturability. If you're weighing up a similar trade-off between cost, performance, and manufacturability on your own product, book a call with our team, or find out more about us and how we work.