电泳沉积时间对SiC_f/SiC复合材料性能的影响

针对电泳沉积结合先驱体浸渍裂解的方法制备SiC_f/SiC复合材料过程,探讨沉积时间对SiC纤维及SiC_f/SiC复合材料性能的影响规律。实验结果得出:随电泳沉积时间的延长,SiC纤维逐渐被腐蚀,致使其单丝强度下降;而在SiC纤维表面覆盖PyC涂层可以有效地保护SiC纤维,由于悬浮液中的通电作用,Py C涂层与SiC纤维的界面结合强度略有降低,纤维单丝强度随电泳时间的延长先增大后减小。5 min的电泳沉积结合9个周期的PIP得到了SiC_f/SiC复合材料最大的弯曲强度为731 MPa,随后其力学性能随着沉积时间的延长先降低后略微回升;SiC_f/SiC复合材料的热导率随沉积时间的延长先增大后减小,10 min电泳沉积得到了常温下SiC_f/SiC复合材料的最大热导率为4.658 W/(m·K)(25℃)。

INFLUENCE OF ELECTROPHORETIC DEPOSITION TIME ON SiCf/SiC COMPOSITES PROPERTIES

This paper pays attention to the hybrid method of Electrophoretic Deposition (EPD) and Precursor Infiltration and Pyrolysis (PIP) for fabricating the SiCf/SiC composites.Influence of deposition time on SiCf/SiC composites is analyzed.It is concluded that SiC fibers would be gradually corroded with EPD time prolonged,and the fibers' peak strength would decrease as well.While,the existence of PyC interphases in front of the SiC fibers would effectively protect the SiC fibers.Because of the electric power of EPD suspension,interfacial strength between PyC interphases and SiC fibers would drop slightly.Therefore,the peak strength of SiC fibers would increase at first then decrease with EPD time.5 min EPD and 9 cycles PIP result in a maximum bending strength of 731 MPa for SiCf/SiC composites.After that,its mechanical property first dropped then grew a little with EPD time.Thermal conductivity of SiCf/SiC composites rose first and then fell with EPD time.With 10 min EPD,thermal conductivity of SiCf/SiC composites in room temperature reaches the maximum of 4.658 W/(m·K).