SUN Jian, MAO Chunlin, WANG Yanxiang, CHANG Xuepeng, QUAN Junwei

(Jingdezhen Ceramic Institute, Jingdezhen 333403, Jiangxi, China)

Abstract: The copper-based biporous capillary wicks for loop heat pipe were successfully fabricated by powder metallurgy sintering coupled with the addition of the pore forming agent, using copper powder as raw material and CaCl₂ as pore forming agent. X-ray diffraction (XRD), scanning electron microscope (SEM), aperture analyzer and corresponding physical tests were used to characterize the phase composition, microstructure and properties of capillary wicks. The effects of sintering temperature and pore forming agent on porosity, permeability and pumping performance of capillary wicks were systematically investigated. The results show that CaCl₂ is fully dissolved, and the capillary wick samples present biporous structure. The porosity and permeability of the capillary wicks increase with the increase of the pore forming agent content, and decrease with the increase of the sintering temperature. The capillary pumping amount is positively correlated with the pore forming agent content and negatively correlated with the sintering temperature. Moreover, the pumping performance of the capillary wicks depends on the interaction between porosity and permeability. The higher the porosity of the capillary wicks, the greater the permeability and the better the capillary pumping performance.
Key words: sintering temperature; pore forming agent; porosity; permeability; pumping performance