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键距(或晶格)畸变与晶粒尺寸、晶界结构一样都是纳米晶体结构研究的重要方面.有关晶格畸变对纳米晶体性能的影响已有较多研究工作发表,但关于纳米晶体的键距(或晶格)畸变特征则未见专门报道.本文从Fitzer炭键键距公式出发,建立一种键距畸变的Raman光谱分析方法.应用这种方法可以测量玻璃炭纳米晶体sp~2杂化键的最可几键距b_g、平均键距(?)_g、键距畸变△b_g以及键距膨胀率α等参量.指出,畸变可能主要存在于晶粒边界附近形成畸变键距过渡层,并对过渡层中的键距膨胀现象从电子结构角度进行了初步探讨.1 实验过程通过控制炭化温度制备具有不同晶粒尺寸的玻璃炭试样.试样的X射线分析在D/max-rA衍射仪上进行.分析结果表明经800℃至2300℃炭化得到的玻璃炭均具有乱层石墨微晶结构.试样晶粒尺寸(六元环炭原子面大小)L_a的X射线测试结果列于表1,L_a的测量误差为0.04nm.Raman光谱分析在Spex-1403型谱仪上完成.Ar~+激光器的波长为488nm、功率为500mW.试样环境为室温大气环境.测试结果如图1所示.由于玻璃炭Raman谱中G线与D线略有重叠,故图中的G线谱形已经过计算机分峰处理.
The key (or lattice) distortion and the grain size and grain boundary structure are all important aspects of nanocrystal structure research.Many studies have been published on the influence of lattice distortion on the properties of nanocrystals. However, There are no special reports on the characteristics of the key (or lattice) distortion.This paper starts from Fitzer’s carbon bond distance formula and establishes a Raman spectrum analysis method of key-pitch distortion.With this method, we can measure the glass nanocrystalline sp ~ 2 The most probable key bond spacing b_g, the average bond distance (?) _ G, the bond pitch distortion △ b_g and the bond expansion rate α and other parameters of the hybrid bond.It is pointed out that the distortion may exist mainly in the vicinity of the grain boundary to form the distortion bond transition layer , And the electronic structure of the transition from the electronic structure of the key expansion phenomenon was discussed.1 experimental process by controlling the carbonization temperature of glassy carbon samples with different grain size sample X-ray analysis of the D / max- rA diffractometer.The results show that the glassy carbons obtained by carbonization from 800 ℃ to 2300 ℃ all have the chaos graphite microcrystal structure.The results of the X-ray measurement of the crystal grain size (the atomic area of six-membered ring carbon) L_a In Table 1, L_a measurements The error is 0.04nm.Raman spectrum analysis is done on a Spex-1403 spectrometer.The wavelength of the Ar ~ + laser is 488nm and the power is 500mW.The sample environment is at room temperature and the atmospheric environment.The test results are shown in Figure 1. As glassy carbon Raman spectrum in the G line and D line slightly overlap, so the G line spectral shape of the computer has been processed by the computer sub-peak.