The adsorption of carbon atom on Fe surface and in Fe subsurface with and without rare earth (La and Ce) substitution in the surface layer and subsurface layer was studied by first-principles calculations. The carbon atom is predicted to adsorb at hollow and long bridge site on Fe(100) and Fe(110), respectively. However, the carbon atom shifts to occupy preferentially hollow site on both Fe(100) and Fe(110) with rare earth atom doping at surface layer. The lower adsorption energies involved with stronger adsorption abilities were obtained for carbon atoms on Fe surface with rare earth doping at surface layer, which was determined by the electronic structure of the surface atoms. The La atom was pulled out the surface after carbon adsorption due to strong interaction of La–C, which is consistent with the more charge transfer. In the subsurface region, the carbon atom prefers to occupy at octahedral site with rare earth doping at surface layer in Fe slab. These strong adsorption energies of the carbon atoms on Fe surface and in Fe subsurface with rare earth pose relevant insights into the interaction between carbon and rare earth, which helps to understanding the influence mechanism of rare earth in carburizing.

通过第一性原理计算研究了碳原子在Fe表面和Fe亚表面的表面层和亚表面层有和没有稀土（La和Ce）取代的吸附。预计碳原子将分别吸附在 Fe(100) 和 Fe(110) 上的空桥和长桥位。然而，碳原子转移到 Fe(100) 和 Fe(110) 上优先占据空心位置，稀土原子掺杂在表层。Fe表面的碳原子在表层掺杂稀土时获得了较低的吸附能和较强的吸附能力，这是由表面原子的电子结构决定的。由于 La-C 的强相互作用，La 原子在碳吸附后被拉出表面，这与更多的电荷转移一致。在亚表面区域，碳原子优先占据八面体位置，在 Fe 板坯的表层掺杂稀土。Fe表面和Fe亚表面的碳原子与稀土的这些强吸附能对碳与稀土的相互作用提供了相关见解，有助于理解稀土对渗碳的影响机制。