Synthesis of the in-Situ Si3N4-SiC Composite Nano Powders by Carbothermal Reduction

Si3N4-SiC micro-nano composite powder has been studied by a group of authors during the last decade.Previous works have shown that SiC-Si3N4 ceramics exhibits good mechanical properties and high corrosion resistance at elevated temperatures.In this study, we have tried a new approach to obtaining SiC-Si3N4 ceramic composite powder by changing the conditions in the carbothermal reduction process.Starting powders were quartz mineral, received from Ege-Sil Co., as silicon-source and, carbon, as silica-reducing and carburizing agent.These powders were ground in the ring mill, separately and together.Carbothermal reduction-nitridation/carburization reactions were carried out in a tube furnace at > 1400 • C for 4 hours under N2 and Ar gas, used as nitriding and shielding atmosphere.The synthesized powders were characterized by X-ray diffraction, SEM, and EDS.Results have shown that production of Si3N4-SiC micro-nano composite powder was achieved in the modified nitrogen and argon atmosphere above 1400 • C. Determination of the Si3N4/SiC ratio was possible with sensitive control of the system conditions.