Temperature‐dependent mechanical and oxidation behavior of in situ formed ZrN/ZrO₂‐containing Si₃N₄‐based composite

In this work, Si₃N₄ and Zr(NO₃)₄ were used as raw materials to prepare ZrN/ZrO₂‐containing Si₃N₄‐based ceramic composite. The processing, phase composition, and microstructure of the composite were investigated. Hardness and fracture toughness of the ceramics were evaluated via Vickers indentation in Ar at 25°C, 300°C, 600°C, and 900°C. During spark plasma sintering, Zr(NO₃)₄ was transformed into tetragonal ZrO₂, which further reacted with Si₃N₄, resulting in the formation of ZrN. The introduction of ZrN enhanced the high‐temperature mechanical properties of the composite, and its hardness and fracture toughness reached 13.4 GPa and 6.1 MPa·m¹/² at 900°C, respectively. The oxidation experiment was carried out in air at 1000°C, 1300°C, and 1500°C for 5 h. It was shown that high‐temperature oxidation promoted the formation and growth of porous oxide layers. The microstructure and phase composition of the formed oxide layers were investigated in detail. Finally, it was identified that the obtained composite exhibited a higher thermal diffusivity than that of monolithic Si₃N₄ in the temperature range of 100°C–1000°C

Temperature‐dependent mechanical and oxidation behavior of in situ formed ZrN/ZrO2‐containing Si3N4‐based composite

In this work, Si3N4 and Zr(NO3)(4) were used as raw materials to prepare ZrN/ZrO2-containing Si3N4-based ceramic composite. The processing, phase composition, and microstructure of the composite were investigated. Hardness and fracture toughness of the ceramics were evaluated via Vickers indentation in Ar at 25 degrees C, 300 degrees C, 600 degrees C, and 900 degrees C. During spark plasma sintering, Zr(NO3)(4) was transformed into tetragonal ZrO2, which further reacted with Si3N4, resulting in the formation of ZrN. The introduction of ZrN enhanced the high-temperature mechanical properties of the composite, and its hardness and fracture toughness reached 13.4 GPa and 6.1MPa center dot m(1/2) at 900 degrees C, respectively. The oxidation experiment was carried out in air at 1000 degrees C, 1300 degrees C, and 1500 degrees C for 5 h. It was shown that high-temperature oxidation promoted the formation and growth of porous oxide layers. The microstructure and phase composition of the formed oxide layers were investigated in detail. Finally, it was identified that the obtained composite exhibited a higher thermal diffusivity than that ofmonolithic Si3N4 in the temperature range of 100 degrees C-1000 degrees C