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

Abstract

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.

Improved crystallisation of polysilazane‐derived Si3N4/SiC nanocomposites with Fe2O3catalyst

“…Si 3 N 4 /SiC composite ceramics have attracted increasing attention for many engineering applications, such as turbine engines, garbage incineration boilers, and rocket nozzle, because of their outstanding mechanical properties, excellent thermal shock resistance, and corrosion resistance [1,2]. Polysilazane, a class of inorganic polymers with silicon nitrogen bonds as a repeating unit in the main chain of the molecule, could be an appropriate precursor for Si 3 N 4 /SiC synthesis [3].…”