Faculty of Physics, University of Vienna, Strudlhofgasse 4, 1090 Wien, Austria.
Sci Rep. 2013;3:1840. doi: 10.1038/srep01840.
Mirrored carbon-spirals have been produced from pressured ferrocene via the bilateral extrusion of the spiral pairs from an iron core. A parametric plot of the surface geometry displays the fractal growth of the conical helix made with the logarithmic spiral. Electron microscopy studies show the core is a crystalline cementite which grows and transforms its shape from spherical to biconical as it extrudes two spiralling carbon arms. In a cross section along the arms we observe graphitic flakes arranged in a herringbone structure, normal to which defects propagate. Local-wave-pattern analysis reveals nanoscale defect patterns of two-fold symmetry around the core. The data suggest that the bilateral growth originates from a globular cementite crystal with molten surfaces and the nano-defects shape emerging hexagonal carbon into a fractal structure. Understanding and knowledge obtained provide a basis for the controlled production of advanced carbon materials with designed geometries.
通过从铁芯双侧挤压螺旋对，从加压二茂铁中生成镜像碳螺旋。表面几何形状的参数图显示了用对数螺旋生成的锥形螺旋的分形生长。电子显微镜研究表明，核心是一种晶状渗碳体，随着它挤压出两个螺旋碳纤维臂，它会生长并改变其形状，从球形变为双锥形。在沿着臂的横截面中，我们观察到石墨片以人字形结构排列，缺陷沿其传播。局部波型分析揭示了核心周围具有两倍对称性的纳米级缺陷模式。这些数据表明，双侧生长起源于具有熔融表面的球形渗碳体晶体，纳米缺陷形状将六角形碳塑造成分形结构。所获得的理解和知识为具有设计几何形状的先进碳材料的受控生产提供了基础。
