FABRICATION AND CHARACTERIZATION OF Cu-SiC_p COMPOSITES FOR ELECTRICAL DISCHARGE MACHINING APPLICATIONS

Abstract

Cu-SiC_p composites made by the powder metallurgy method were investigated. To avoid the adverse effect of Cu-SiC_p reaction, sintering was controlled at a reaction temperature less than 1032 K. Electroless plating was employed to deposit a copper film on SiC_p powder before mixing with Cu powder in order to improve the bonding status between Cu and SiC particles during sintering. It was found that a continuous copper film could be deposited on SiC_p by electroless copper plating, and a uniform distribution of SiC_p in Cu matrix could be achieved after the sintering and extrusion process. The mechanical properties of Cu-SiC_p composites with SiC_p contents from 0.6 to 10 wt% were improved evidently, whereas electrical properties remained almost unchanged as compared with that of the pure copper counterpart. In the electrical discharge machining (EDM) test, the as-formed composite electrodes exhibited a character of lower electrode wear ratio, justifying its usage. The optimum conditions for EDM were Cu–2 wt% SiC_p composite electrode operating with a pulse time of 150 μsec.

Keywords:

• Copper-based composite
• Density
• Electrical discharge machining
• Electrical resistivity
• Electrode wear ratio
• Electroless copper plating
• Fracture surface
• Hardness
• Material removal rate
• Metal matrix composite
• Porosity
• Powder metallurgy
• Silicon carbide
• Tensile strength
• Thermal expansion coefficient

5.0 ACKNOWLEDGMENTS

The authors thank the National Science Council of the Republic of China for the financial support under Grant NSC86-2216-E-009-016 for the experimental aspect of the study. Special thanks are acknowledged to one of the reviewers, who reviewed carefully and made many valuable suggestions on the paper.