Summary for silver plate adhesion Discussion
Silver plate adhesion problems on nitrided steel were traced by responders to likely issues at the copper strike/silver strike interface. Daniel Bemenderfer described small blisters in the silver that peeled away to reveal copper, after a process of cleaning, acid dip, copper strike, silver strike, and silver plate. James Watts said the copper strike may have holes or pits that trap impurities, suggesting a thicker strike. Tom Pullizzi questioned whether the copper was bonding well to the nitrided steel and suggested trying a Wood's nickel strike or Watt's nickel before the copper. Keith Ager recommended a potassium cyanide rinse between the copper and silver stages to activate the copper and prevent galvanic silvering, noting that plain water swilling is not enough. Victor Esteves believed the silver strike was contaminated with copper and said an extra rinse between copper and silver was needed.
2000
Q. I am having adhesion problems plating silver to a nitrided steel. The silver plate has small blisters, which when peeled away show a copper strike. The process is:
- Soak clean
- Rinse in running water
- Anodic alkaline clean
- Rinse in running water
- Muriatic acid dip
- Rinse in running water
- Copper strike
- Rinse in running water
- Silver Strike
- Silver Plate
- Rinse in running water
- Hot water rinse and blow dry
It appears that the silver is not adhering to the copper strike in small areas. What could be the problem?
Daniel Bemenderfer
– Indianapolis, Indiana
A. Since I can not see it, my first guess is that the copper strike has holes or pits in it that traps impurities which cause the later tiny blister. Try putting a thicker strike on it and see if that helps.
James Watts
– Navarre, Florida
2000
A. Yes, and I wonder if the copper is having trouble with the nitrided steel. How about testing with a Wood’s Nickel strike ⇦ huh? or Watt’s nickel before the copper?
Tom Pullizzi
Falls Township, Pennsylvania
2000
A. Have you tried putting a potassium cyanide rinse in between stages 8/9 to activate copper? This will also stop a galvanic silver taking place in silver strike. A water swill is just not sufficient.
Keith Ager
– Sheffield, S.Yorks, UK
2001
A. I think you have your silver strike badly contaminated with copper. If you see a small black point when it comes out of this bath, it’s copper. You need another rinse between copper and silver, only one is too few.
Victor Esteves
– Munich, Germany
November 8, 2014