Yttrium Oxide‐Assisted CRN Synthesis of Silicon Oxynitride Powders with Controlled Morphology

Si 2 N 2 O powders were synthesized at low temperatures by a Y 2 O 3 ‐assisted‐carbothermal reduction nitridation ( CRN ) with mesoporous silica/carbon composite as raw material. Experimental results showed that with the addition of Y 2 O 3 , the CRN reaction temperature decreased from 1380°C to 1250°C. The mechanism for Y 2 O 3 reducing the CRN temperature was discussed in detail. It was found that the occurrence of Si 2 N 2 O at low temperatures was due to the formation of an eutectic intermediate phase as Y 2 SiO 5 , which was the reaction product of Y 2 O 3 and mesoporous SiO 2 . In addition, spherical and rod‐like Si 2 N 2 O powders were found to be readily obtained by selecting the mesoporous silica/carbon composite precursors with mesoporous silica spheres and rod‐like SBA ‐15, respectively.