We report the structural transformations of carbon via the melt spinning and subsequent annealing of nickel-carbon alloys. We attained metastable solid solubility of carbon in nickel ribbon by achieving a rapid solidification rate of up to 1.6 × 10⁶ K/s. Excess carbon atoms were found to be dissolved in the nickel lattice causing up to 1.4% strain for an alloy spun at 70 m/s tangential wheel speeds. High temperature heat treatments led to precipitation of carbon from the nickel lattice on the ribbon free surfaces but also led to growth of spherical precipitates within the nickel matrix, an effect consistent with bulk diffusion-driven Ostwald ripening. Carbon was excavated from the ribbons via chemical dissolution of the metal and characterized by electron microscopy and Raman spectroscopy. We found that the microstructure of carbon precipitated from the rapidly quenched ribbon could be tuned by varying the carbon content from 4 to 12 at. % in the precursor and annealing the ribbon at temperatures that ranged from 400 to 1200 °C. Via the step-wise variation of these two parameters, we sequentially transformed amorphous carbon nanospheres with a high BET surface area of 203 m²/g into thick, highly crystalline flakes of graphite that conformed to the shape of the as-spun ribbon.

我们报告了碳通过熔体纺丝和随后的镍碳合金退火而发生的结构转变。通过实现高达 1.6 × 10 ⁶的快速凝固速度，我们实现了碳在镍带中的亚稳态固溶度 K/s。发现过量的碳原子溶解在镍晶格中，导致以 70 m/s 切向轮速度旋转的合金产生高达 1.4% 的应变。高温热处理导致碳从带状自由表面上的镍晶格沉淀，但也导致镍基体内球形沉淀物的生长，这种效应与体扩散驱动的奥斯特瓦尔德熟化一致。通过金属的化学溶解从碳带中挖掘出碳，并通过电子显微镜和拉曼光谱对其进行表征。我们发现从快速淬火带中析出的碳的微观结构可以通过改变 4 到 12 at 的碳含量来调整。% 在前体中，并在 400 到 1200 °C 的温度范围内对带进行退火。通过这两个参数的逐步变化，² /g 成厚的、高度结晶的石墨薄片，符合初纺带的形状。