Hemp hurd based carbon template for reaction formed silicon carbide ceramic

Reaction formed silicon carbide (RF-SiC) and reaction bonded silicon carbide (RB-SiC) are both fabricated with silicon infiltration as sintering process, in which silicon infiltrated into the porous template and reacted with the carbon in it to form silicon carbide. Although RF-SiC has been invented by Hucke for more than 40 years and shows high mechanical properties than RB-SiC, it hasn't been produced in industrial scale due to its high cost and some technical issues whereas RB-SiC has been produced in industrial scale and applied in many different fields. In this paper, the carbonization of the pre-templates of hemp hurd powder, the pore structure of the corresponding carbon templates, and the microstructure of the resulted ceramics were studied to evaluate their suitability for the fabrication of RF-SiC. The carbonization study shows that the carbon templates from pre-templates of hemp hurd powder have controllable density because the pretemplates have stable linear shrinkages in three directions and weight residual while carbonization. The cracking of pre-templates in carbonization is also evitable. The pore size distribution of the resulted carbon templates is narrow and ideal for the fabrication of RF-SiC. The microstructure of the resulted RF-SiC ceramic testified the suitability for RF-SiC fabrication of pre-templates of hemp hurd powder