Problem With Shiny Centers in a Nickel Sulfamate bath
"The Sulfamate Nickel How-To Guide"
by David Crotty, PhD
& Robert Probert
Hot Off the Press -- published Oct. 2018
$89 plus shipping 2000
Q. I am having a problem with nickel sulfamate bath.I am getting a very shiny center of my electroformed parts. The parts then begin to warp. The bath is okay right after the carbon treatment, but never lasts too long before the same result is evident. I have changed the bath but the same thing keeps happening. the tank seems to check out okay electrically. If anyone has any suggestions I would appreciate your input. Thank you in advance and have a nice day. DennisDennis Ehret
- Pitman New Jersey
A. I am not an electroformer, but have done some very heavy build SN. My guess is breakdown product combined with a low current density area, giving a very smooth plate that is very probably thinner and of a different internal stress than the edges.
You might try repositioning your anodes to reduce the CD difference, possibly to the corners of the tank vs the middle. You may have to go to aux anodes very carefully placed. Robber strips is also an option. Shields, baffles or barrier is also a possibility. You may be able to get by with a slight drop in the amperage.James Watts
- Navarre, Florida
A. BY WHAT YOU WROTE,IT SEEM THAT YOU ARE FORMING STRESS RELIEF COMPOUNDS WITH YOUR ANODES. SHINY PARTS IS A COMPRESSIVE DEPOSIT AND THE BORDERS OF YOUR PARTS ARE IN TENSION. A COMPRESSIVE DEPOSIT ALWAYS LOOK SHINY WITH THIS STRESS RELEAF COMPOUNDS.
THERE ARE 3 TYPES OF ANODES OF NICKEL FROM INCO CORP: 1. POLARISED ANODES, 2. NON-POLARISED ANODES, 3. SEMI-POLARISED ANODES.
1. THEY ARE USED FOR ELECTROFORMING, THEY RELEASE NICKEL WITHOUT BREAKING THE SULFAMATE SOLUTION AND FORMING BY- PRODUCTS
3. USED TO CONTROL THE STRESS IN THE BATH BY FORMING STRESS RELEAF COMPOUNDS. THE PROCESS IS CALL NI-SPEED
SO CHECK OUT WHAT IS THE TYPE OF ANODES THAT YOU ARE USING AND ALSO TRY TO INCREASE YOUR ANODES AREA COMPARE TO YOUR CATHODE AREA
YOU CAN CHECK ALSO ON INTERNET THE SITE OF NICKEL INSTITUTEHUGO CHAGNON
- MONTREAL, QUEBEC, CANADA
Q. WILL ANY ONE SUGGEST A SUITABLE BATH COMPOSITION FOR ELECTROFORMING OF NICKEL SHIM FOR HOLOGRAPHIC HARD EMBOSSING WITH HIGHER CURRENT DENSITY AND CONTROLLED HARDNESS. ALSO SUITABLE OPERATING CONDITIONS ARE REQUIRED.S.PALANI RAJAN
- CHIDAMBARAM, TAMIL NADU, INDIA
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