气体渗硼层孔洞成因探讨

An Investigation for the Cause of theGaseous Boronizing Layer Voids

渗层易产生孔洞,是长期困扰气体渗硼发展的主要问题之一。本文通过对渗硼孔洞的电子探针扫描和气体渗硼的热力学分析证实:在BCl_3+H_2渗硼气氛中,孔洞主要是由Fe-Cl产物组成,气氛中的残留H_2O、O_2加剧了产物的形成。严格控制气氛中残留H_2O、O_2含量不仅可有效地防止孔洞的形成,而且可大幅度降低BCl_3用量。此外还讨论了B.Cl_2的扩散特点及温度对孔洞形成的影响。

Boronized layer voids are one of problems which hinders the development of gaseous boronizing for a long time. By means of microscope probe scan- ning and thermodynamics analysis, the paper proves that in the boronizing atmosphere of BCl_3+H_2, the layer voids are mainly composed by the product of iron chloride and the retained H_2O and O_2 in the BCl_3+H_2 atmosphere accelerates the formation of the voids. The strict controlling of the retained content of H_2O and O_2 in the atmosphere not only can efficientlly prevent the formation of the voids, but also have a big increase in lowering the dosage of BCl_3. In addition, the diffusion characteristic of B and Cl atoms and the boronizing temperature have the influence on the formation of the layer voids.