Characterization of zirconium carbides using electron microscopy, optical anisotropy, Auger depth profiles, X-ray diffraction, and electron density calculated by charge flipping method
Characterization of zirconium carbides using electron microscopy, optical anisotropy, Auger depth profiles, X-ray diffraction, and electron density calculated by charge flipping method
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DOI：
10.1016/j.jssc.2012.04.047
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发表时间：
2012-10
影响因子：
3.3
通讯作者：
G. W. C. Silva;Andrew A. Kercher;J. Hunn;R. Martin;G. Jellison;H. Meyer
中科院分区：
文献类型：
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作者：
G. W. C. Silva;Andrew A. Kercher;J. Hunn;R. Martin;G. Jellison;H. Meyer
已经制造了具有五种不同碳化锆组合物（C/Zr摩尔比=0.84、0.89、0.95、1.05和1.17）的样品，并使用各种实验技术进行了研究。对每个样品进行区域精炼，以确保最终产品是晶粒尺寸为10-100μm的多晶。据发现，晶格参数是最大的x=0.89的组合物和最小的x=1.17的总C/Zr组合物，但不是线性的，这种非线性可能是解释使用电荷翻转技术计算的电子密度。在这五种样品中，ZrC 0. 89样品的晶胞显示出最高的电子密度，对应于最高的碳掺入和最大的晶格参数。ZrC0.84样品表现出最低的碳掺入，导致大量的碳空位和由此产生的应变。具有较大碳比率（x=0.95、1.05和1.17）的样品显示出晶格参数的轻微降低，这是由于电子密度的降低。光学各向异性测量表明，这三个样品中含有大量的石墨碳相，不结合的Zr原子。
Samples with five different zirconium carbide compositions (C/Zr molar ratio=0.84, 0.89, 0.95, 1.05, and 1.17) have been fabricated and studied using a variety of experimental techniques. Each sample was zone refined to ensure that the end product was polycrystalline with a grain size of 10–100μm. It was found that the lattice parameter was largest for the x=0.89 composition and smallest for the x=1.17 total C/Zr composition, but was not linear; this nonlinearity is possibly explained using electron densities calculated using charge flipping technique. Among the five samples, the unit cell of the ZrC0.89sample showed the highest electron density, corresponding to the highest carbon incorporation and the largest lattice parameter. The ZrC0.84sample showed the lowest carbon incorporation, resulting in a larger number of carbon vacancies and resultant strain. Samples with larger carbon ratios (x=0.95, 1.05, and 1.17) showed a slight decrease in lattice parameter, due to a decrease in electron density. Optical anisotropy measurements suggest that these three samples contained significant amounts of a graphitic carbon phase, not bonded to the Zr atoms.