Magnetic multilayer pigment flake and coating composition
AssigneeViavi Solutions Inc.
InventorsVladimir P. Raksha, Paul T. Kohlmann, Cornelis Jan Delst, Paul G. Coombs
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Abstract
The present invention provides a magnetic multilayer pigment flake and a magnetic coating composition that are relatively safe for human health and the environment. The pigment flake includes one or more magnetic layers of a magnetic alloy and one or more dielectric layers of a dielectric material. The magnetic alloy is an iron-chromium alloy or an iron-chromium-aluminum alloy, having a substantially nickel-free composition. The coating composition includes a plurality of the pigment flakes disposed in a binder medium.
Claims16
A method for making a multilayer pigment flake comprising:
- forming on a substrate a layer stack including two or more semi-transparent absorber layers of a ferromagnetic alloy, two or more dielectric layers, and one or more opaque reflecting layers of the ferromagnetic alloy;
- stripping the layer stack from the substrate;
- and
- grinding the layer stack to form a plurality of multilayer pigment flakes;
- and
- wherein the ferromagnetic alloy is a nickel-free composition, and consists essentially of about 5 wt. % to about 30 wt. % chromium, about 0 wt. % to about 18 wt. % aluminum, and a balance of iron.
Dependencies are inferred from the claim text.