Porous W with spherical and directionally aligned pores was fabricated by the combination of sacrificial fugitives and a freeze-drying process. Camphene slurries with powder mixtures of WO3 and spherical PMMA of 20 vol% were frozen at −25 oC and dried for the sublimation of the camphene. The green bodies were heat-treated at 400 oC for 2 h to decompose the PMMA; then, sintering was carried out at 1200 oC in a hydrogen atmosphere for 2 h. TGA and XRD analysis showed that the PMMA decomposed at about 400 oC, and WO3 was reduced to metallic W at 800 oC without any reaction phases. The sintered bodies with WO3-PMMA contents of 15 and 20 vol% showed large pores with aligned direction and small pores in the internal walls of the large pores. The pore formation was discussed in terms of the solidication behavior of liquid camphene with solid particles. Spherical pores, formed by decomposition of PMMA, were observed in the sintered specimens. Also, microstructural observation revealed that struts between the small pores consisted of very fine particles with size of about 300 nm.

1. 서론
2. 실험방법
3. 결과 및 고찰
4. 결론
Acknowledgements
References

• 이한얼(서울과학기술대학교 신소재공학과) | Han-Eol Lee
• 전기철(서울과학기술대학교 신소재공학과) | Ki Cheol Jeon
• 김영도(한양대학교 신소재공학부) | Young Do Kim
• 석명진(강원대학교 재료금속공학과) | Myung-Jin Suk
• 오승탁(서울과학기술대학교 신소재공학과) | Sung-Tag Oh Corresponding Author