Synthesis of porous Cu–Sn using freeze-drying process of CuO–SnO2/camphene slurries
Porous Cu–Sn with controlled pore characteristics was synthesized by a freeze-drying and sintering process. CuO and SnO2 powders were selected as the source material, which are hydrogen-reduced to metallic Cu–Sn in the sintering stage. Camphene-based CuO–SnO2 slurries were prepared by milling at 60 °C with a small amount of dispersant. Freezing of a slurry was done at −40 °C with unidirectional control of the growth direction of the camphene. Pores were generated by sublimation of the camphene. The green bodies were sintered at 650 °C under a hydrogen atmosphere. The sintered bodies with Cu3Sn, Cu6Sn5 and β-Sn phases showed macroscopic aligned pores with an average size of 200 μm. The internal wall of the macroscopic pores is also porous, and there are a number of many small pores in it. The formation of macroscopic and microscopic pores was discussed in terms of solidification behavior of the liquid with foreign particles.
KeywordsPorous Cu–Sn Camphene-based slurry Freeze-drying Hydrogen reduction Pore structure
This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (Grant No. 2009-0089508).