Clean and oxidized surfaces of CoAl(10 0) were investigated by Auger electron spectroscopy (AES), low energy electron diffraction (LEED), high resolution electron energy loss spectroscopy (HREELS), and scanning tunnelling microscopy (STM). The regrowth or step flow of terraces was observed at 1150 K. The correlation between the growth of oxide and the step flow on the CoAl(l 0 0) surface is discussed in this paper. (c) 2006 Elsevier B.V. All rights reserved.