The H contents and H embrittlement (HE) of Zn- and ZnNi-electrodeposited SCM435 bolts were quantitatively evaluated before and after baking. The Zn-coated bolt possessed higher H contents than the ZnNi-coated bolt in as-electrodeposited and baked states. H atoms were strongly trapped inside the coating layers. The Zn-coated bolt underwent flaking of coating layer during baking at temperatures above 200 °C due to H effusion through the brittle δ phase. The Zn-coated bolt exhibited no HE regardless of baking despite of its high H content due to no permeation of H into the steel substrate during electrodeposition and tensile deformation.
Bibliographical noteFunding Information:
The authors gratefully acknowledge the support of the Metallic Materials Cell , Hyundai Mobis , Yongin, Republic of Korea.
© 2021 The Author(s)
All Science Journal Classification (ASJC) codes
- Ceramics and Composites
- Surfaces, Coatings and Films
- Metals and Alloys