Laser Black is a multi-layer metallic oxide. Its deep velvety-black surface is somewhat fragile since it achieves its remarkable absorption by creating a micro-dendritic structure on the optical surface (see SEM Photo). Unfortunately, these dendrites will show evidence of being touched, however, the overall performance of the surface will not be degraded if this “touching” is performed in a small area. Being an inorganic coating, Laser Black does not outgas and when vibrated ultrasonically in acetone shows no flaking or chipping.
Because the application of the black requires emersion in a hot (greater than 100º C) caustic solution, coating aluminum parts require a protective layer of at least 12 ½ microns of electroless nickel. In addition, the black coating transforms a layer of a propriety copper electroplate. That copper layer adds another 12 ½ microns so that in summary, any aluminum part requiring Laser Black can be expected to add 25 microns of plating to each surface.
Another design consideration is masking. The hot caustic solution is not kind to masking materials and frequently we use a thin layer of gold as the masking material, since the black does not affect the gold.
If the substrate is stainless steel or copper, then the only overcoat required to achieve the black is a layer of our proprietary copper, 12 ½ microns thick. The black coating does not to this thickness, but functions by converting the copper surface itself.