氧化硼-磷酸浸渍对中间相炭微球复合材料抗氧化及力学性能的影响

以原位缩聚法制备的中间相炭微球/碳纳米管(MCMB/CNTs)复合微球为原料, 通过添加氧化硼(B₂O₃)粉体和磷酸浸渍对该复合材料进行了基体和表面改性。采用扫描电子显微镜(SEM)、三点弯曲法、热重分析(TG)以及恒温氧化测试方法对复合材料的表面形貌、弯曲强度以及抗氧化性能进行了表征与测试。结果表明: 添加适量的B₂O₃可以有效提升复合材料的抗氧化性能和弯曲强度, B₂O₃含量超过2%时, 复合材料的弯曲强度逐渐下降。将含有2% B₂O₃的复合材料试样进行磷酸浸渍处理后, 试样的弯曲强度可达66 MPa, 初始氧化温度520℃, 经过500℃恒温氧化60 min后其氧化失重率仅为5%, 弯曲强度仍达到50.3 MPa。

Effect of B2O3 Doping and Phosphate Impregnation on Oxidation Resistance and Mechanical Properties of Mesocarbon Microbead Composites

Mesocarbon microbead/carbon nanotubes (MCMB/CNTs) composites were modified by adding B₂O₃ powders and phosphate impregnation and the MCMB/CNTs were prepared using in-situ thermal polymerization. The morphology, flexural strength and oxidation resistance behavior were studied using scanning electron microscope (SEM), three-point bending tests, thermo gravimetric analysis (TG) and isothermal oxidation method. The results show that the oxidation resistance and flexural strength of the composites are enhanced with proper amount of B₂O₃. When the ratio of B₂O₃ is beyond 2%, the flexural strength of the sample begins to decrease. The sample with 2% B₂O₃ impegnated with phosphate reachs the highest flexural strength of 66 MPa, and the initial mass loss temperature of the samples is 520℃. After isothermal oxidation at 500℃ for 60 min, the mass loss and the flexural strength of the sample are 5% and 50.3 MPa, respectively.