Non-cadmium composite coating
AssigneeCSL Limited
InventorsNaishadh K. Saraiya, Mahesh Naik
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Abstract
A non-cadmium multi-layered composite coating is disclosed. Such coating achieves desirable lubricity, retains electrical conductivity, meets high performance industry standards for corrosion resistance, and avoids certain environmental and health hazards. Further disclosed are methods of applying such coating on various substrates using a combination of electrolytic and electro-less plating techniques. Such coating may be advantageously applied in machining and electrical interconnects, and are particularly useful in the defense and consumer electronics and appliances industries.
Claims19
A multi-layered composite coating for a substrate, comprising:
- a first layer of a first phosphorus electro-less nickel alloy on top of the surface of said substrate, said first layer comprising 9.5-13% phosphorus (w/w) and being 0.3-1.2 mil in thickness;
- a second layer of electrolytic nickel metal having a stress level below 7,000 psi compressive (−ve) or tensile (+ve) stress, wherein said second layer is on top of said first layer, and being 0.2-0.8 mil in thickness;
- a third layer of phosphorus electro-less nickel alloy on top of said second layer and having 9.5-13% phosphorus (w/w) and being 0.3-1.2 mil in thickness;
- a fourth layer comprised of one of:
- Ni—W-B, and Ni—Co—W, on top of said third layer and being 0.05-0.25 mil in thickness;
- a fifth layer comprised of a nickel/polytetrafluoroethylene composite on top of said fourth layer and being 0.2-0.5 mil in thickness;
- and
- a sixth layer of a sealing material on top of said fifth layer.
A multi-layered composite coating for a substrate, comprising:
- a first layer of a first phosphorus-nickel alloy on the surface of said substrate, a second layer of electrolytic nickel metal having a stress level below 7,000 psi tensile (+ve) or compressive (−ve), on top of said first layer, a third layer of a second phosphorus-nickel alloy on top of said second layer, a fourth layer of a nickel-tungsten-boron alloy or a nickel-boron alloy on top of said third layer, a fifth layer of a nickel/polytetrafluoroethylene composite on top of said fourth layer, and a sixth layer of material on top of said fifth layer, wherein no electric-magnetic-field cell is generated between each of said layers.
Dependencies are inferred from the claim text.