화학공학소재연구정보센터
Journal of the American Ceramic Society, Vol.83, No.3, 654-656, 2000
Very rapid densification of nanometer silicon carbide powder by pulse electric current sintering
Rapid densification of a nanometer SiC powder doped with 2.04 wt% Al4C3 and 0.4 wt% B4C was conducted by using a nonconventional sintering technique called pulse electric current sintering (PECS), In all experiments, the sintering temperature and applied pressure were kept to be 1600 degrees C and 47 MPa, respectively, while heating rates varied between 100 degrees C/min and 400 degrees C/min and the holding time was either 2 or 5 min, All of the specimens which were PECS-sintered under various conditions reached near-theoretical density. The microstructures of the rapidly densified SiC ceramics consisted of large elongated grains, and the grain size increased with the increase of heating rate. polytype transformation of SiC occurred during the PECS process, where faster heating favored the formation of 6H polytype while slower heating favored 4H polytype.