碳预制体中BN粉引入及其SiC基复合材料性能研究

Fabrication and Properties of C_f/SiC Composites with Introduction of BN Powder

通过真空浸渍和压力注射的工艺方法向三维针刺整体碳毡中引入了质量分数为50%的BN亚微米粉,采用PIP工艺,以含乙烯基的液态聚碳硅烷(LPVCS)为先驱体,制备了Cf/(BNp-SiC)复合材料,并对其性能及微观形貌进行了表征,与未加粉的Cf/SiC复合材料进行了对比。结果表明:BN粉的引入能有效缩短复合材料的制备周期,且对材料的力学性能影响较小。经过8次PIP工艺后,Cf/(BNp-SiC)复合材料开孔率仅为4.4%,Cf/SiC复合材料经9次PIP工艺后开孔率为6.5%。Cf/(BNp-SiC)复合材料抗弯强度达到269.6MPa,断裂韧性为10.26MPa·m1/2,Cf/SiC复合材料抗弯强度和断裂韧性分别为257.8MPa和13.51MPa·m1/2。

Micro BN powder was introduced into a three-dimensional needled carbon fiber perform by vacuum infiltration and pressure injection, which could introduce 50% (mass fraction) of the carbon fiber perform. Then Cf/(BNp-SiC) composites were prepared with the precursor LPVCS by precursor infiltration and pyrolysis. Cf/SiC composites with the same precursor were prepared in the similar way. Results show that the period of fabrication is decreased effectively by the introduction of micro BN powder. The open porosities of Cf/(BNp-SiC) and Cf/SiC composites are 4.4% and 6.5% respectively. The average flexural strength and fracture toughness of Cf/(BN p -SiC) composites are 269.6 MPa and 10.26 MPa·m 1/2 , respectively, while that of Cf/SiC composites are 257.8 MPa and 13.51 MPa·m 1/2 , respectively.