Transparent Aluminum

The process of making aluminum transparent apparently is comparableto the process that makes glass transparent. According to one Web sitethat describes that process, glass becomes transparent by messing withmolecular alignment via temperature changes: The process of heatingand cooling the glass ingredients transforms them into a molecular stewand solidifies them in that same liquidlike state with all of themolecules unaligned with one another, enabling light to pass throughthe hardened glass.

To create transparent aluminum, Raytheon starts with a powdercomprised of aluminum, oxygen and nitrogen. This powder is molded andbaked the way a ceramic is baked. The powder liquefies and then coolsinto a solid, creating a rigid crystalline structure. The resultingaluminum alloy molecules are arranged as if still in liquid form.Polishing strengthens the material and makes it clear.

Apparently, the heating and handling involved makes the process forcreating transparent aluminum prohibitively expensive outside thesurreal budgets of defense contracting. The substance has been layeredonto bullet-proof glass in vehicle-window size prototypes. The goodnews for soldiers is that transparent aluminum-coated glass weighs halfas much and is half as thick as conventional bullet-proof glass, buthas the ability to stop anti-aircraft fire.

Source: blog.mindtribe.comAdded: 16 February 2009