Rapid densification of SiC ceramic rollers by microwave sintering

Ultralarge silicon carbide (SiC) ceramic rollers are successfully prepared in a microwave multimode cavity at 2·45 GHz. The length of the rollers is 1220 mm with outer diameter of 62 mm and thickness of 7 mm. The optimised sintering temperature of microwave sintering is ∼980°C, which is ∼400°C lower than that of conventional sintering. Mullite was detected within microwave sintered samples, rather than conventional sintered ones, which preferentially appeared around SiC as well as inside the residual pores. This might be attributed to the unique features of microwave sintering of ‘hot spot effect’, plasma behaviour and high frequency electromagnetic fields.