AVS 50th International Symposium
    Surface Science Friday Sessions
       Session SS1-FrM

Paper SS1-FrM1
Surface Chemistry of Carburization and Embrittlement of Fe

Friday, November 7, 2003, 8:20 am, Room 327

Session: Catalysis IV: Reactivity of Complex Systems
Presenter: D.E. Jiang, University of California, Los Angeles
Authors: D.E. Jiang, University of California, Los Angeles
E.A. Carter, University of California, Los Angeles
Correspondent: Click to Email
High temperature and pressure, as well as reactive gases such as CO and H@sub 2@S, erode steel. Experimental observations of eroded steel show that carburization and embrittlement are potential causes for the erosion. We investigate the surface chemistry behind this problem via spin-polarized periodic density functional theory. In this talk, we will discuss C and H adsorption on Fe(110) and C and H diffusion into and through bulk Fe. Static properties including site preference, solution enthalpies, and adsorption energies, are predicted with increasing system size and compared with experiment. For adsorption, different 2-dimensional structures will be compared. Barriers for diffusion of C and H into and through bulk Fe will be presented. Our predictions generally agree very well with experiment, though we do make some predictions which suggest further experimental studies. C and H show very different behavior both in bulk Fe and on Fe(110). For example, H prefers the tetrahedral site in bulk Fe, while C prefers the bulk octahedral site. H prefers the quasi three-fold site on Fe(110), while C prefers the long bridge site. Our study provides a clear picture of structures and energetics of C and H in bulk Fe and on Fe(110).