Copper alloy for electronic machinery and tools and method of producing the same

1. A method of producing a precipitate-type copper alloy material for electronic machinery and tools,

wherein the precipitate-type copper alloy material consisting essentially of 2.0 to 4.0% by mass of Ni and 0.4 to 0.8% by mass of Si, and either (a) 0.05 to 0.3% by mass of Mg or (b) 0.005 to 2.0% by mass in a total amount of at least one selected from the group consisting of 0.005 to 0.2% by mass of Ag, 0.005 to 0.2% by mass of Mn and 0.05 to 1.0% by mass of Zn, with the balance being Cu and inevitable impurities, and has a work affected layer in a surface layer thereof,

the producing method comprising the steps of:

casting the precipitate-type copper alloy material;

rolling the precipitate-type copper alloy material;

optionally buff polishing the precipitate-type copper alloy material;

annealing the precipitate type copper alloy material;

optionally degreasing the precipitate-type copper alloy material;

optionally pickling the precipitate-type copper alloy material by washing in an acid;

subjecting the work affected layer in the surface layer to a heat treatment at a temperature of 500 to 585° C. in a non-oxidizing atmosphere or a reducing atmosphere, thereby to make the work affected layer have a thickness of 0.2 μm to 0.02 μm, to repair crystallinity of the surface layer; and

subjecting the heat-treated copper alloy material to plating with Ag or Cu,

wherein the plating is in direct contact with at least a portion of the work affected layer whose crystallinity is repaired via the heat treatment.

2. The producing method according to claim 1 , wherein the work affected layer in the surface layer is subjected to a heat treatment at a temperature of 565 to 585° C. in the non-oxidizing atmosphere or the reducing atmosphere, thereby to make the work affected layer have a thickness of 0.05 μm to 0.02 μm to repair crystallinity of the surface layer.

3. The producing method according to claim 1 , wherein the heat treatment is conducted for 2 hours.

4. A method of producing a precipitate-type copper alloy material for electronic machinery and tools,

wherein the precipitate-type copper alloy material consisting essentially of 2.0 to 4.0% by mass of Ni and 0.4 to 0.8% by mass of Si, and either (a) 0.05 to 0.3% by mass of Mg or (b) 0.005 to 2.0% by mass in a total amount of at least one selected from the group consisting of 0.005 to 0.2% by mass of Ag, 0.005 to 0.2% by mass of Mn and 0.05 to 1.0% by mass of Zn, with the balance being Cu and inevitable impurities, and has a work affected layer in a surface layer thereof,

the producing method comprising the steps of:

casting the precipitate-type copper alloy material;

rolling the precipitate-type copper alloy material;

buff polishing the precipitate-type copper alloy material;

annealing the precipitate type copper alloy material;

optionally degreasing the precipitate-type copper alloy material;

optionally pickling the precipitate-type copper alloy material by washing in an acid;

subjecting the work affected layer in the surface layer to a heat treatment at a temperature of 500 to 585° C. in a non-oxidizing atmosphere or a reducing atmosphere, thereby to make the work affected layer have a thickness of 0.2 μm to 0.02 μm, to repair crystallinity of the surface layer; and

subjecting the heat-treated copper alloy material to plating with Ag or Cu,

wherein the plating is in direct contact with at least a portion of the work affected layer whose crystallinity is repaired via the heat treatment.

5. The producing method according to claim 4 , wherein the work affected layer in the surface layer is subjected to a heat treatment at a temperature of 565 to 585° C. in the non-oxidizing atmosphere or the reducing atmosphere, thereby to make the work affected layer have a thickness of 0.05 μm to 0.02 μm to repair crystallinity of the surface layer.

6. The producing method according to claim 4 , wherein the heat treatment is conducted for 2 hours.