Surface segregation on Fe-Si single crystals: the effect of crystallography

The kinetics of solute segregation was measured at the (001), (0 1 14), (01 7), (015), (014) and (013) surfaces of an Fe-6 at% Si alloy at 873 K. Indiv idual stages of segregation kinetics can be explained on the basis of mutua l interaction among the principal segregants (silicon, nitrogen, sulfur and potassium). Strong attractive interaction between silicon and nitrogen res ults in the formation of stable SixNy two-dimensional surface compounds at all surfaces studied including (001). Formation of these Si-N bonds is acco mpanied by a shift in the kinetic energy of the Si LVV Auger peak. Analysin g the segregation behaviour of individual surfaces indicates that it can be considered as a combination of the tare principal (001) and (013) planes. (C) 1998 Elsevier Science B.V. All rights reserved.