Formation of endothermic carbides on iron and nickel

The formation of endothermic carbides. on Fe and Ni is studied using X-ray photoelectron spectroscopy (XPS) by deposition of carbon films from the vapor phase and subsequent annealing steps. The reaction between carbon and metal substrates is measured by shifts in the C Is photoelectron peaks. By comparison with two elementary carbon photoelectron energies determined from carbon films on unreactive An substrates, a carbide peak in the C Is spectra on reactive Fe and Ni substrates is identified. The carbides formed after deposition of carbon films at room temperature are located at the interface between carbon film and metal substrate. We report on the behavior of elementary carbon films with respect to film thickness and thermal treatment leading to carbide formation and carbon diffusion into the bulk. (C) 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.