Liquidmetal Technologies Inc (LQMT)

[JoTu]

One surface treatment that Liquidmetal R&D has recently had success with is a mixed oxide finish.

Mixed oxide finish is intriguing to the Liquidmetal team because it provides a coloring option that is both cosmetic and functional. The process creates a very thin layer of the native metal alloy atoms in their oxidized states. The approximate thickness of this layer is about 2 µm, but extremely hard (1400 Vickers), making the material, even more, scratch and wear resistant than usual (530 Vickers).

Mixed Oxide Finish

The oxidized metal layer is transparent with a dissimilar index of refraction to that of?the substrate amorphous alloy. Because the thickness of this very hard and transparent ceramic-like layer is on the order of the visible wavelengths of light, slight changes in the oxide layer thickness produce chromatic wavelength interference effects which result in pronounced reflected/refracted wavelengths (colors). The physics behind the perceived color is the same thin-film effect produced by a layer of oil on water as shown in Figure 1.

Zirconium-based amorphous alloys can have a functional and often colorful Mixed Oxide Finish. This finish is not a coating, paint, plating, or deposited layer of dissimilar material, but rather a very thin layer of the native metal alloy atoms which convert to their oxidized states.

In our commercial Liquidmetal LM105 alloy, the chart in Figure 2 (on the next page) shows an illustration of the approximate colors that can be produced through this mixed oxide finish along with photographs of as-molded parts with the Mixed Oxide Finish.
Although thin (approximate thickness is 2 um depending on the color), the mixed oxide layer is extremely hard (around 1400 Vickers) and can be effectively used to resist scratching, wear, or other abrasive environments.