工业纯铁表面离子W、Mo、Co多元共渗扩散行为

采用双层辉光离子渗金属技术在工业纯铁表面进行W、Mo、Co多元共渗，分别采用0．5、1、2和3h等渗金属时间，研究了合金层中W、Mo、Co含量随渗金属时间的变化规律。研究表明：渗金属初期，合金层中W含量〉Co含量〉Mo含量；渗金属后期，合金层中Co含量〉W含量〉Mo含量。理论分析认为：在渗金属初期，W、Mo、Co扩散主要受各元素原子与空位交换难易程度以及基体表面各元素活性原子量的控制；在渗金属后期，W、Mo、Co扩散主要受各元素在基体中的溶解度的控制。

Diffusion behaviors of W, Mo, Co in pure iron

Pure iron was surface alloyed with tungsten, molybdenum and cobalt for various time from 0.5h to 3h by a double glow plasma surface alloying technique. Concentrations of W, Mo and Co in alloyed layer for different alloying time were studied and an important feature about W,Mo,Co contents in alloyed layer was found that in the initial stage of alloying W content was the highest in alloyed layer, but at the last stage of alloying Co content surpassed W content and became the highest. Based on above experimental results, the diffusion behaviors of W,Mo,Co atoms in alloyed layer were discussed.The diffusions of W, Mo, Co atoms in alloyed layer are controlled by the exchange of vacancies with W, Mo, Co atoms and the active atom quantities of W, Mo, Co on pure iron substrate surface in the initial stage of alloying,however,the diffusions of W, Mo, Co atoms are controlled by the maximum solubility of each element in pure iron at the last stage of alloying.