Manufacturing and characterization of ceramic wick structures for capillary pumped loop

Abstract

Porous structures have been used in capillary pumped loop for thermal control in space application. For this application porosities of 50% and pore sizes of around 10 µm are suitable. The main objective of this paper is the manufacturing and characterization of porous wicks for capillary pumping. The wick structures were cast by slip casting. The slurry was prepared with Al2O3/Mullite ratio of 1:4 and chemical addictives. Activated carbon was added with a carbon/ceramic powder ratio of 1:10 and 4:10. After drying, the samples were calcined at 600º for 180 min in oxidizing atmosphere and latter sintered at 1600ºC for 120 min. The microstructure of the wicks was characterized by scanning electronic microscopy and image analysis with IMAGO® software. Porosities of 59% and 79% were obtained from the samples after calcination, and 48% and 68% after sinteriing for carbon/ceramic powder ratios of 1:10 and 4:10, respectively.