Method for coating strip-shaped material with black aluminium oxide

摘要

Method for vacuum coating of a substrate, moving as a continuous band of material, with a layer of black aluminum oxide (A) by evaporation of aluminium and supplying oxygen to the vapor that includes controlling the amount of aluminum deposited and on-line measurement of color parameters. Method for vacuum coating of a substrate, moving as a continuous band of material, with a layer of black aluminum oxide (A) by evaporation of aluminium and supplying oxygen to the vapor. The new features are that (i) the amount of Al deposited is adjusted to at least 15 mu g/cm 2>and (ii) on-line with deposition, the color parameters L *>, a *>and b *>(or parameters that correlate with them) are determined. At essentially constant Al loading, the amount of oxygen supplied is regulated and at essentially constant supply of oxygen, the Al evaporation rate is regulated, so that, after a post-oxidation stage, L *>is below 12; a *>is -2.5 to 2.5; and b *>is -2.5 to 5.5.