空间粒子辐射环境下石墨膜力学性能的演变规律

Evolution Mechanism of Tensile Strength for Graphite Films under Space Particle Irradiation Environment

目的将石墨膜置于9×10^5~9×10^7 rad(Si)总剂量下获得辐射改性石墨膜材料,探讨空间粒子辐射作用下石墨膜拉伸强度的演变规律。方法采用SEM、XRD、煅烧分析及XPS等手段分析石墨膜的结构及成分。结果石墨膜为有序堆积的层状结构,层间距为0.3355 nm,碳的质量分数高达99.75%,挥发分的质量分数为0.04%,灰分的质量分数为0.21%,XPS只检测到C1s及O1s峰。石墨膜的平均热膨胀系数为负值,且其峰值仅为-1.33×10^-6/℃,具备出色的结构稳定性。空间粒子辐射环境模拟试验表明,随着辐射剂量的升高,石墨膜的拉伸强度逐渐衰减,在更高剂量辐射下,石墨膜的拉伸强度趋向稳定。通过Raman光谱仪对辐射石墨膜结构的分析,揭示了力学性能的演变机理。结论辐射石墨膜的拉伸强度与其缺陷含量有很大的相关性,未经过辐射的原始石墨膜的缺陷含量最低,其拉伸强度最大,随着石墨膜的缺陷含量逐渐增多,其拉伸强度逐渐降低。

The paper aims to obtain irradiated graphite films in the total dose of 9×10^5~9×10^7 rad(Si)to discuss the evolution of tensile strength of graphite film in the space particle irradiation environment.Composition and structure of graphite films were characterized by means of SEM,XRD,calcination analysis and XPS.The results showed that they possessed orderly stacked layers with interlayer spacing of 0.3355nm.The mass fraction of carbon,volatile matter and ash content were 99.75%,0.04%,0.21%,respectively.Only C1s and O1s peaks were detected by XPS.The average linear expansion coefficient of graphite film was negative with a peak value of-1.33×10^-6/℃,indicating excellent structural stability.The simulation test of space particle irradiation environment showed that the tensile strength of graphite films decreased gradually with the increase of total dose,and tended to be stable under high dose irradiation.The structure of graphite films was analyzed with a Raman spectra,revealing the evolution mechanism of the mechanical property.The tensile strength of irradiated graphite films is correlated with their defect content.Un-irradiated graphite films have the lowest defect content,thus owning the highest tensile strength.And with the increase of defect,the tensile strength decreases gradually.