Decomposition behavior of $ferro-Si_3N_4$was investigated with varying temperature and holding time in mud components for high temperature refractory applications. Porosities gradually increased with increasing temperature and holding time due to the carbothermal reduction of $Si_3N_4;and;SiO_2$. Silicon monoxide (SiO) as a intermediate resulted from evaporation of $Si_3N_4;and;SiO_2$ reacted with C sources to generate needle-like ${eta}-SiC$ and Fe in $Si_3N_4$ acted as a catalyst in order to enhance growth of SiC grain with the <III> preferred orientation. SiC generation yield increased with increasing holding time, all of the $Si_3N_4;and;SiO_2$ affected on SiC formation up to 2h. However, SiC generation was only dependent on residual $SiO_2$ over 2h, because the carbothermal reduction reaction of $Si_3N_4$ was no longer possible at that time.