Personal ornament covered with colored coating and process for producing the same

A personal ornament having its surface covered with a colored coating formed by dry-plating comprising:

• a basis material for the personal ornament, composed of a copper alloy or zinc,
• a nickel plating layer on a surface of the basis material, or a nickel plating layer on a surface of a copper plating layer on a surface of the basis material,
• a completely amorphous nickel/phosphorus alloy plating layer on a surface of the nickel plating layer, said amorphous nickel/phosphorus alloy plating layer formed in a plating solution which contains nickel sulfate in an amount, in terms of nickel atom, of 15 to 70 g/lit., sodium hypophosphite in an amount, in terms of phosphorus atom, of 10 to 50 g/lit., an electric conductive salt in an amount of 50 to 90 g/lit., a pH buffer in an amount of 20 to 50 g/lit. and a complexing agent in an amount of 5 to 30 g/lit., and
• at least one colored coating layer on a surface of the amorphous nickel/phosphorus alloy plating layer, the colored coating layer formed by dry-plating,
• said amorphous nickel/phosphorus alloy plating layer formed by electroplating or by electroless plating, and having a phosphorus content of 12 to 16% by weight.

A personal ornament having its surface covered with a colored coating, the colored coating formed by dry-plating, which personal ornament comprises:

• a basis material for the personal ornament, composed of a copper alloy or zinc,
• a nickel plating layer on a surface of the basis material, or a nickel plating layer on a surface of a copper plating layer on a surface of the basis material,
• a completely amorphous nickel/phosphorus alloy plating layer on a surface of the nickel plating layer, said amorphous nickel/phosphorus alloy plating layer formed by electroless plating in a plating solution which contains a nickel salt in an amount, in terms of nickel atom, of 1 to 15 g/lit., sodium hypophosphite (reducing agent) in an amount, in terms of phosphorus atom, of 5 to 30 g/lit., a complexing agent, a buffer and a pH regulator, or by first electroplating in the plating solution and thereafter electroless plating in the same plating solution, and
• at least one colored coating layer on a surface of the amorphous nickel/phosphorus alloy plating layer, the colored coating layer formed by dry-plating,
• said amorphous nickel/phosphorus alloy plating layer formed by electroplating or by electroless plating and having a phosphorus content of 12 to 16% by weight.

A process for producing a personal ornament having its surface covered with a colored coating, the colored coating formed by dry-plating, which process comprises the steps of:

• electroplating a surface of a basis material for the personal ornament composed of a copper alloy or zinc to thereby form a nickel plating layer on the surface, or first electroplating a surface of the basis material to thereby form a copper plating layer on the surface and thereafter electroplating a surface of the copper plating layer to thereby form a nickel plating layer on the surface of the copper plating layer,
• electroless plating a surface of the nickel plating layer in a plating solution which contains a nickel salt in an amount, in terms of nickel atom, of 1 to 15 g/lit., sodium hypophosphite (reducing agent) in an amount, in terms of phosphorus atom, of 5 to 30 gilit., a complexing agent, a buffer and a pH regulator, or first electroplating a surface of the nickel plating layer in the plating solution and thereafter electroless plating the surface in the same plating solution, to thereby form on the surface of the nickel plating layer a completely amorphous nickel/phosphorus alloy plating layer formed by electroplating or by electroless plating and having a phosphorus content of 12 to 16% by weight, and
• subjecting a surface of the amorphous nickel/phosphorus alloy plating layer to dry-plating so that at least one colored coating layer is formed on the surface.