碳钢被覆金属碳化物过程中碳迁移扩散行为的探讨

Study of Carbon Diffusion in the Process of Coating Carbide on Steel Surface

本文对碳钢被覆金属碳化物过程中碳原子的迁移扩散行为进行了讨论。由于碳从基体向表面扩散形成碳化物,在基体与被覆层之间形成一假想的脱碳区△L,该区脱碳前的碳含量正好等于被覆层获得增量dl所需的碳原子总量。如果在被覆层获得增量dl的时间dt内,该区的碳能与远基体达到均匀化,则认为基体中的碳含量已足以维持被覆层的正常生长。本文对此进行了定量分析,导出了被覆金属碳化物钢中所需碳含量的数学表达式。

In the process of coating layer's growing, carbon atoms diffuse from the inside of steel to the surface and react with external metal atoms to from a metallic carbide.At the same time, there exists an imaginary decarbonizing zone between the carbide layer and steel base, because some carbon atoms diffuse toward the outside.The width of the decarbonizing zone is ΔL, in which the carbon content is just equal to the amount necessary for the coating layer to obtain an increment dL.It has been considered that if the carbon distribution between the zone and the steel base can be homo genized during the time dt when the coating layer will be well grown.In this paper, all problems concerned have been discussed quantitatively, and a mathematical expression has been found, by means of which the process of coating titanium carbide and niobium carbide can be calculated.