Aluminum windscreens. Yes, you read that correctly, ‘But aluminum is a metal, and a windscreen is made of glass?’ I hear you ask.
To help make this information easier to process, aluminum glass is actually, technically, transparent aluminum. A sample of transparent aluminum say, a tube, looks like a tube made of glass but it’s actually aluminum. Well, an asterisked aluminum; this is not elemental aluminum but rather a material made from it as the core ingredient.
Despite clearly not being a metal (and not a glass either; glasses are amorphous solids while ceramics are crystalline) transparent ceramics demonstrate impressive properties. Transparent aluminum is produced by a process called sintering. Powdered ingredients are poured into a mould, compacted under tremendous pressure, and cooked at high temperatures over long periods. The resulting translucent material is then ground and polished to transparency ready for use.
Aluminium Oxynitride ( “ALON” ) is a ceramic composed of aluminium, oxygen and nitrogen. .
Aside from being optically transparent (≥80%) in the near-ultraviolet, visible and midwave-infrared regions of the electromagnetic spectrum, ALON is four times harder than fused silica glass; 85% as hard as sapphire, and nearly 15% harder than magnesium aluminate spinel. Since it has a cubic spinel structure, it can be fabricated to produce transparent windows, plates, domes, rods, tubes and other forms using conventional ceramic powder processing techniques. Tests show that a laminated pane of ALON 1.6″ thick can stop a 50 caliber rifle round, something even 3.7″ of traditional “bullet-proof” glass can’t do. ALON also has better optical properties than regular glass in the infrared wavelengths; where most glasses absorb IR, ALON is essentially transparent to it. That makes ALON a great choice for the windows on heat seeking missiles and other IR applications.
ALON also demonstrates superior scratch resistance.
While the technology exists, there is currently no demand for automotive windscreens. Unbreakable and damage-resistant glass is undoubtedly a game-changer which could spell trouble for many AGRR businesses. However, in applications such as mobile phones, the increased demand for such a material will drive costs down, but windscreens might take a while longer.
An ‘aluminum windscreen’ presently could cost in the region of £30,000-40,000, a price tag which even Monty Brewster might balk at.