硼在先驱体转化制备2DC_f／SiC材料中的应用

Application of Boron in Fabricating of 2D C_f/SiC Composites by Precursor Pyrolysis

研究了含硼(B)的聚碳硅烷(PCS)／二乙烯基苯(DVB)先驱体的裂解,并以B为活性填料,SiC微粉为惰性填料,PCS／DVB为先驱体制备了2D Cf／SiC-B材料。考察了B粉含量对材料力学性能和抗氧化性能的影响。结果表明,B的引入可以有效提高先驱体的陶瓷产率,缩短制备周期,当浆料中B含量为15(?)％时,6次浸渍-交联-裂解周期后,材料的弯曲强度达到301．3MPa,与不添加活性填料制备的材料9个周期后的性能基本相当。当浆料中B含量为5(?)％时,材料的力学性能和抗氧化性能均较好,9个周期后,材料的弯曲强度和断裂韧性分别达到351．3 MPa,13．7 MPa·m1/2,较不添加活性填料制备的材料力学性能有所提高,在1300℃马弗炉中氧化10 min后,弯曲强度和断裂韧性保留率分别达到了79．4％和80.3％,较未添加活性填料的Cf／SiC材料有明显提高。

Effects of boron on the pyrolysis of polyearbosilane （PCS）/divinylbenzene （DVB） were investigated in this paper, and the boron-eontsining two-dimensional carbon fiber cloth reinforced silicon carbide （2D Cf/SiC-B） composites, in which boron was used as active fillers and SiC as inert fillers, were fabricated by percursor pyrolysis. The effects of boron contents on the structures and properties of Cf/SiC composites were investigated. The results showed that the addition of boron enhanced the ceramic yield of the PCS/DVB, so addition of boron could decrease the manufacture cycles. Upon 15 volume percent boron in the slurry, the bend strength of the 2D Cf/SiC-B composites after 6 pyrolysis cycles reached 301.3MPa, which is closed to the strength of the 2D Cf/SiC composites with 0 volume percent boron after 9 cycles. It was found that upon 5 volume percent boron in the slurry the composites exhibited the highest properties, the bend strength and fracture toughness reached 351.3 MPa and 13.7 MPa · m^1/2, respectively. Furthermore, 2D Cf/SiC-B composites showed improved oxidation resistance than clearly compared to 2D Cf/SiC composites. After soaked at 1300℃ for 10min under static air, the 2D Cf/SiC-B composites retained 79.4% of original bend strength and 80.3% of original. Fracture strength while the 2D Cf/SiC composites without boron matrix retained only 69.8% and 69.3%, respectively.