Ball milling and annealing graphite in the presence of cobalt

When graphite is ball milled, Raman spectra and X-ray diffractograms of the products show increasing graphitic structural disorder with 1% and 10% cobalt addition. However, if sufficient cobalt (10% weight for weight) is added, this process is reduced in rate. This process is attributed to the cobalt stabilizing the graphitic structure during ball milling, thus reducing the degree of lattice-disorder. When the mixture is annealed, well-ordered carbon strips encapsulating cobalt nanoparticles are observed in the presence of cobalt. Annealing reorganizes the disordered structures and 10% cobalt loading is more effective than a 1% loading in this process. Transmission electron microscopic (TEM) analysis showed the formation and high abundance of well-ordered carbon strips encapsulating cobalt nanoparticles in samples that have been annealed with additional cobalt loading. (C) 2004 Elsevier Ltd. All rights reserved.