| Porous silicon carbonitride ceramics (SiCN) ceramic materials have promising applications because of their superior high temperature properties. Sol-gel process is an ideal route to porous ceramics that has been applied for the fabrication of a variety of porous oxides such as SiO2, TiO2 and Al2O3. Recently, our group have fabricated porous SiCN ceramics from the non-oxygen sol-gel reactions of bis(trimethylsilyl)carbodiimide (BTSC) and mixed chlorosilanes through molecular design, gelation and pyrolysis. The present work carried out systematic studies on the fabrications of porous SiCN ceramics from the sol-gel reactions of BTSC and mixed chlorosilanes, and fabricated arrayed pores of SiCN ceramics through introducing polystyrene microspheres (PS) as templates into the sol-gel systems followed by gelation, drying and pyrolysis.The gelation reaction of CH2=CHSiCl3+CH3HSiCl2 and BTSC resulted in the formation of highly porous SiCN ceramic materials after pyrolysis of the xerogel. The pore size is 1μm30μm and porosity is 76.5 vol.%. Moreover, the replacement of dichlorisilanes with different functionalities yielded also porous SiCN ceramics with similar porosities. Structural observation shows the pores were formed during pyrolysis rather than from drying of the gel. They were formed from the decomposition of the dichlorosilane-condensed part in the gel during pyrolysis.The addition of silica coated PS spheres into the sol-gel system as a template provided arrayed pores of SiCN ceramics after gelation and pyrolysis, with pore diameter of 160 nm and porosity of 70 vol.%. In contrast, as pure PS spheres were used as the template, the pores in the resultant SiCN ceramics presented as irregular. Moreover, we found that as the presursors for the PS spheres were directly introduced into the ceramics it also allowed the formation of arrayed pores of SiCN ceramics after pyrolysis. Thus, the pore arrays of SiCN ceramics were produced by a one-step process.
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