【摘 要】
：
Silicon nitride based composites with different addition (0,2 or 5 wt%) of short carbon fibers (Cf) were prepared by hot-press sintering method,using rod-like Si3N4 powders as raw materials and Y2O3 a
【机 构】
：
State Key Laboratory of High Performance Ceramics and Superfine Microstructure,Shanghai Institute of
论文部分内容阅读
Silicon nitride based composites with different addition (0,2 or 5 wt%) of short carbon fibers (Cf) were prepared by hot-press sintering method,using rod-like Si3N4 powders as raw materials and Y2O3 as sintering additives.The morphological,structural,and compositional analysis and observation of the Cf/Si3N4 composites were carried out by XRD,SEM,and TEM.And also the thermal conductivity and mechanical measurements were performed.The results show that part of the Cf can react with Si3N4 or SiO2 on top of Si3N4 grains during sintering process,forming a intermedium layer of SiC.The highest value of thermal conductivity (k),45.8 Wm-1K-1,belongs to the sample of 2 wt% Cf/Si3N4,while the thermal conductivity of Si3N4 without Cf addition is only 37.1 Wm-1K-1.The addition of Cf can improve the thermal conductivity of the composites,while the degradation of Cf into transition layers of nano-sized SiC grains deteriorates k.The fracture toughness has a slight increase with Cf addition.And the measured hardness values for all samples are within a range of 16.6~16.8 GPa.
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