High-strength and high-conductivity Cu-(Ni, Co, Fe)-Si copper alloy for use in leadframes

A process for preparing copper alloy comprising the following steps:

• (a) preparing a metal mixture consisting essentially of
• (i) from 0.5 to 2.5 wt % of Ni;
• (ii) from 0.5 to 2.5 wt % of Co;
• (iii) from 0.5 to 0.8 wt % of Si;
• (iv) from 0.05 to 0.15 wt % of either Mg or P or both;
• and
• (v) the balance of Cu;
• (vi) wherein the amounts of Co, Ni, and Si satisfy the following equation:
• 2%≦(Ni+Co)≦4%, and 0.8≦(Ni/4+Co/6)/Si≦1.2.
• (b) melting constituting metals using a high frequency induction furnace followed by rapid cooling to form ingots of desired sizes;
• (c) homogenizing said ingots at about 800 to 950° C. for about ½ to 5 hours;
• (d) hot working said homogenized ingots to form copper alloy plate at a hot reduction ratio of 70% or greater in thickness, followed by water quenching and then milled to remove oxide and scales;
• (e) cold rolling said copper alloy plate to a thickness reduction of 50% or greater, followed by annealing at about 800 to 950° C. for 30 seconds to 30 minutes then rapidly cooling said copper alloy plate;
• (f) cold rolling said copper alloy plate to a thickness reduction of 50% or greater;
• and
• (g) aging said copper alloy plates at about 300 to 600° C. for 30 minutes to 5 hours.

A process for preparing copper alloy comprising the following steps:

• (a) preparing a metal mixture consisting essentially of:
• (i) from 0.5 to 2.5 wt % of Ni;
• (ii) from 0.5 to 2.5 wt % of Co;
• (iii) from 0.5 to 0.8 wt % of Si;
• (iv) from 0.05 to 0. 15 wt % of either Mg or P or both;
• and
• (v) the balance of Cu;
• (vi) wherein the amounts of Co, Ni, and Si satisfy the following equations:
• 2%≦(Ni+Co)≦4%, and 0.8≦(Ni/4+Co/6)/Si≦1.2.
• (b) melting constituting metals using a high frequency induction furnace followed by rapid cooling to form ingots of desired sizes;
• (c) homogenizing said ingots at about 800 to 950° C. for about ½ to 5 hours;
• (d) hot working said homogenized ingots to form copper alloy plates at a reduction ratio of 70% or greater in thickness, followed by water quenching and then milled to remove oxide and scales;
• (e) cold rolling said copper alloy plates to a cold reduction of 50% or greater;
• and
• (f) aging said copper alloy plates at about 300 to 600° C.