Letter 2027

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I am an electroplating jobber in Penang, Malaysia. My company provide gold, silver, palladium-nickel, tin, tin-lead and electroless nickel (EN) plating to the electronic and electrical industries.

I had lately doing some EN coating jobber that require heat treatment, the job pieces tarnished with rainbow colors in the heating chamber. What caused this? Could you share some experience with me?

After the EN coating we passivate the surface with dilute chromic acid. Then heated in nitrogen gas purging oven with the following profile:

  1. Ramp up from 140 degree F to 750 degree F in 30 minutes
  2. Soak at 750 degree F for 75 minutes.
  3. 60 minutes to cool down to 140 degree F
  4. Remove from oven.

Thank you and best regards,

Keat-Seng Ong
- Malaysia

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Rinsing before bake must be thorough. Consider using D.I. water.

Richard Painter
- Cleveland, Ohio

+++

I agree with the better rinsing. Also, is the 750F necessary. What are you trying to achieve, higher hardness?

Robert Sachs
- Canada

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