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 1600oC and 47 MPa, respectively, while heating rates varied between 100oC/min and 400oC/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.

[1]  Y. Bando,et al.  Low-Temperature Pressureless Sintering of alpha-SiC with Al4C3-B4C-C Additions , 2004 .

[2]  M. Toriyama,et al.  Silicon carbide ceramics prepared by pulse electric current sintering of β–SiC and α–SiC powders with oxide and nonoxide additives , 1999 .

[3]  M. Tabuchi,et al.  Preparation of Dense BaTiO3 Ceramics with Submicrometer Grains by Spark Plasma Sintering , 1999 .

[4]  M. Nygren,et al.  Superfast Densification of Oxide/Oxide Ceramic Composites , 1999 .

[5]  Hidehiko Tanaka,et al.  Low temperature sintering and elongated grain growth of 6H-SiC powder with AlB_2 and C additives , 1999 .

[6]  K. Niihara,et al.  Rapid Rate Sintering of Nano-grained ZrO2-based Composites Using Pulse Electric Current Sintering Method , 1998 .

[7]  M. Mayo.  Processing of nanocrystalline ceramics from ultrafine particles , 1996 .

[8]  Koji Tanaka,et al.  Effect of Spark Plasma Sintering on Densification and Mechanical Properties of Silicon Carbide , 1995 .

[9]  Moon J. Kim,et al.  Retention of nanostructure in aluminum oxide by very rapid sintering at 1150 °C , 1995 .

[10]  T. Nishimura,et al.  Fabrication of silicon nitride nano-ceramics by spark plasma sintering , 1995 .

[11]  S. Risbud,et al.  Clean grain boundaries in aluminium nitride ceramics densified without additives by a plasma-activated sintering process , 1994 .

[12]  M. Tokita.  Trends in Advanced SPS Spark Plasma Sintering Systems and Technology , 1993 .

[13]  N. Iyi,et al.  Simple Calculation of SiC Polytype Contents from Powder X-Ray Diffraction Peaks , 1993 .

[14]  H. Kleebe,et al.  Core/Rim Structure of Liquid‐Phase‐Sintered Silicon Carbide , 1993 .

[15]  K. Yamazaki,et al.  Plasma activated sintering of additive-free AlN powders to near-theoretical density in 5 minutes , 1992 .

[16]  D. Johnson.  Microwave and plasma sintering of ceramics , 1991 .

[17]  K. Upadhya.  An innovative technique for plasma processing of ceramics and composite materials , 1988 .

[18]  N. A. Mckinnon,et al.  Sintering in Gas Discharges , 1968, Nature.