EMC spring get bubbled after zinc plating, look for solution, thank you!

We have a metal EMC spring(material:spring_steel_D 1.1200/DIN_2076), thickness 0.4mm, this EMC spring will weld on a metal box(Material:DC01 1.0330/EN10130), after the welding, will process blue zinc plating, but after the zinc plating, we find the EMC spring is easy get bubbled, can you please advise what is the problem and how to improve it, thank you very much!

Unfortunately, I am not familiar with your metal codes. Some springs have a high carbon % and are sensitive to BOTH under and over cleaning and BOTH under and over activation. The results will vary by metal, but undercleaning tends to have fewer but larger blisters. Over cleaning and Over etching both tend to have hundreds of tiny blisters. Under etching normally results in peeled plating, possibly in small areas and edges.

Hello,

please check your pre-treatment and adjust to material. It seems that you a hydrogen diffusion into your material caused by excessive pickling and electrolytic degreasing times. Also might you have adjust your chemical composition with your supplier. Some inhibitors which reduces or eliminates completely the diffusion of hydrogen.

Heat treatment also would could be applied