Microstructure and properties of ultrasonic assisted copper coated graphite foams

Mesophase pitch based graphite foams were electroplated with copper to obtain the improved mechanical and thermal properties and to extend their applications in heat sinks. A nickel interlayer was electroplated prior to copper to improve the wettability and bonding between copper and the graphite foams. An ultrasonic oscillation device and a rotary cathode were applied to enhance the mass transfer and to ensure the more even coatings throughout the foams from inside. Microstructure and properties of the copper coated foams were studied. Results indicated the copper coatings greatly improved the mechanical and thermal properties of the foams. With the prolonged timescale of plating, the foams possessed enhanced mechanical and thermal properties. After 16 min. of plating, the bending strength of the foams increased from 1.1 to 7.6 MPa, and the thermal conductivity of the foams reached 100.2 from 81.6 W m(-1) K-1, while the porosity was reduced only by 4.2%.