Summary for tin plating adhesion Discussion
Tin plating adhesion on silver brazed inlay is the issue here: the company makes copper switch jaws with silver inlays brazed on the ends, then tin plates them for conductivity and corrosion protection, but the tin peels from the silver braze. Nathan Pace asked whether anything could prevent the failure and listed the cleaning and tin bath chemistry being used. David replied that if the silver inlay had an anti-tarnish coating, it could cause poor adhesion to tin unless it is completely removed during the plating process. The thread does not offer a full process fix, but it points to surface contamination or residual anti-tarnish treatment on the silver as a likely cause to investigate before replating.
Q. Hello, the company I work with manufactures switches for electrical substations. We need the jaws for our switches to be electrically conductive and protected from corrosion. We have copper jaws that have silver inlays that are brazed on the ends for improved conductivity. We then tin plate the jaws but the tin plating will peel off of the silver braze. Is there anything we can do to prevent this?
Chemicals used in process:
– Electro-Clean: Anodex NP2 8-16 oz/gal
– Acid: Metex M639 8-16 oz/gal
– Tin Bath: Sulfuric Acid 13.5 fl oz/gal, Stannous sulphate 4 oz/gal, MAT447: 10.2 fl oz/gal
Nathan Pace
Intern – Trafford, Pennsylvania, United States
January 31, 2019
February 7, 2019
A. Hi Nathan,
Was silver inlay anti-tarnish coated? If so, then may cause poor adhesion to tin if not fully removed during tin plating.
Regards,
David
David Shiu
– Singapore
Q. The inlays are not coated with anything prior to the tin plating procedure. They are polished with Scotch Brite to remove any heat scale or oxidation before plating, but poor adhesion with the tin still occurs.
Nathan Pace [returning]
Intern – Trafford, Pennsylvania, United States
February 8, 2019