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US 8,152,985 B2Granted
Method of chrome plating magnesium and magnesium alloys
AssigneeArlington Plating Company
InventorRichard Lee Macary
Life of this patent
Estimating the term…
Abstract
A process for chrome plating magnesium and its alloys. The process uses a combination of electroless nickel plating, a multi-stage copper coating transition system and multiple layers of electrodeposited nickel to form a corrosion resistant system of substantial impermeability and interlayer adherence suitable for direct chromium electroplating.
Claims8
A method of chrome plating a magnesium or magnesium alloy part, the method comprising the steps of:
- (a) treating the part with a fluoridating agent to develop a fluoridated surface layer including magnesium fluoride;
- (b) using electroless nickel plating to apply a nickel-phosphorous alloy layer across at least a portion of the fluoridated surface layer;
- (c) applying a copper coating at a position above the nickel-phosphorous alloy layer using a series of copper electrodeposition treatments, wherein said series of copper electrodeposition treatments includes at least one copper electrodeposition treatment using a cyanide solution, at least one copper electrodeposition treatment using a pyrophosphate solution of basic pH and at least one copper electrodeposition treatment using an acid solution;
- (d) electrodepositing a semi-bright nickel layer at a position above the copper coating;
- (e) electrodepositing a bright nickel layer at a position above the semi-bright nickel;
- (f) electrodepositing a layer of micro-porous nickel at a position above the bright nickel;
- and
- (g) electrodepositing a chromium layer at a position above the micro-porous nickel.
5 more elements
A method of chrome plating a magnesium or magnesium alloy part, the method comprising the steps of:
- (a) treating the part with a fluoridating agent to develop a fluoridated surface layer including magnesium fluoride;
- (b) using electroless nickel plating to apply a nickel-phosphorous alloy layer across at least a portion of the fluoridated surface layer;
- (c) applying a copper coating at a position above the nickel-phosphorous alloy layer using a series of copper electrodeposition treatments, wherein said series of copper electrodeposition treatments includes a preliminary copper strike electrodeposition treatment using a Rochelle salt solution, at least one copper electrodeposition treatment using a cyanide solution, at least one copper electrodeposition treatment using a pyrophosphate solution of basic pH and at least one copper electrodeposition treatment using an acid solution;
- (d) electrodepositing a semi-bright nickel layer at a position above the copper coating;
- (e) electrodepositing a bright nickel layer at a position above the semi-bright nickel;
- (f) electrodepositing a layer of micro-porous nickel at a position above the bright nickel:
- and
- (g) electrodepositing a chromium layer at a position above the micro-porous nickel,
- wherein said preliminary copper strike electrodeposition treatment using a Rochelle salt solution, said at least one copper electrodeposition treatment using a cyanide solution, said at least one copper electrodeposition treatment using a pyrophosphate solution of basic pH and said at least one copper electrodeposition treatment using an acid solution are carried out sequentially.
6 more elements
Dependencies are inferred from the claim text.