Abstract High quality silicon nitride ceramics were fabricated by an oscillatory pressure sintering (OPS) process and the effect of sintering temperature on the microstructure and mechanical properties of Si3N4 ceramics was investigated. Different from the specimen fabricated by the conventional hot pressing (HP) method, only β-Si3N4 grains were detected in all the OPS-fabricated specimens. Driving forces of densification and grain growth were accelerated aided by oscillatory pressure. The optimum sintering temperature for silicon nitride ceramics under oscillatory pressure is considered to be 1770 °C; the highest average aspect ratio of β-Si3N4 grains (4.74) was achieved from the highly densified compact (99.86% of theoretical density). The specimen prepared at this temperature accompanied with the highest flexural strength, hardness and fracture toughness of 1348 MPa, 16.04 GPa and 12.8 MPa m1/2, respectively. The presence of oscillatory pressure is detected to promote the elimination of defects and accelerate the densification and grain growth kinetics of grains, thus contributing to the improvement of mechanical properties.

中文翻译：

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振荡压力下优质氮化硅陶瓷的最佳烧结温度

摘要 采用振荡压力烧结（OPS）工艺制备了高质量氮化硅陶瓷，研究了烧结温度对Si3N4陶瓷显微组织和力学性能的影响。与通过传统热​​压 (HP) 方法制造的试样不同，在所有 OPS 制造的试样中仅检测到 β-Si3N4 晶粒。在振荡压力的帮助下，致密化和晶粒生长的驱动力得以加速。氮化硅陶瓷在振荡压力下的最佳烧结温度被认为是1770℃；β-Si3N4 晶粒的最高平均纵横比 (4.74) 来自高度致密的压块（理论密度的 99.86%）。在该温度下制备的试样具有最高的抗弯强度，硬度和断裂韧性分别为 1348 MPa、16.04 GPa 和 12.8 MPa m1/2。检测振荡压力的存在以促进缺陷的消除并加速晶粒的致密化和晶粒生长动力学，从而有助于机械性能的改善。