Characterization of Sintered Copper Wicks Used in Heat Pipes

Rectangular porous wicks for use in flat plate heat pipes were fabricated using copper powder (63 µm) sintered at 800°C and 1000°C. These wicks were characterized in terms of their porosity and pore size distribution using the techniques of mercury intrusion porosimetry and scanning electron microscopy (SEM). A uni-modal pore size distribution was obtained with most pores having sizes in the 30–40 µm range. Comparison was also made with cylindrical wicks fabricated by injection molding technique with the same binder and sintered at the same temperatures. Calculated permeability values of the rectangular wicks are comparable with commercially produced cylindrical wicks. When compared with conventional heat pipe wicks such as those using wire mesh, the advantage of these sintered wicks appears to be the existence of smaller pores and the controllability of porosity and pore size to optimize heat pipe performance.