树脂液相浸渍法制备3D针刺碳/碳预制体影响因素研究

STUDY ON INFLUENCE FACTORS OF PREPARING 3D NEEDLED C/C PREFORM BY LIQUID-PHASE RESIN IMPREGNATION

本文以3D针刺碳毡为增强体，热塑性酚醛树脂为先驱体，采用真空压力浸渍法多次浸渍一次碳化和一次浸渍一次碳化两种工艺制备碳／碳多孔预制体，以用于制备碳／碳化硅复合材料，研究真空度、增强体尺寸、浸渍液浓度、浸渍温度及压力等因素对浸渍效果的影响。结合试样碳化前后SEM显微结构变化，探讨了树脂液相浸渍机理。实验结果表明，树脂液相浸渍用真空度以稍高于浸渍液在浸渍温度下的饱和蒸气压为宜。树脂溶液浓度、浸渍温度和压力分别为80％、40～50℃和0.6MPa时浸渍效果最好。增强体尺寸越大，浸渍效果越差。

With three-dimensional needled carbon felt as reinforcement and thermoplastic phenol formaldehyde （PF） resin as precursor, multiple vacuum-pressure impregnations （VPIs） with one carbonization and one VPI with one carbonization process are employed to prepare porous carbon/carbon as preform for the manufacture of carbon/ silicon carbide composite. The influence of carbon felt size, PF resin concentration, vacuum degree, temperature and pressure on impregnation result is studied. Through analysis of SEM photographs of the samples before and after carbonization, the impregnation mechanism of liquid-phase resin is discussed. It has been found that the best impregnation results can be obtained when the vacuum degree is slightly higher than the saturated vapor pressure of the solution at corresponding impregnation temperature, and PF resin concentration, temperature and pressure are 80%, 40 - 50 ℃ and 0. 6MPa respectively. The impregnation result turns poor with the size of carbon felt increasing.