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Tacking and plating bits with diamond in nickel sulphate solution

 

What is the cause of nodules on the surface of tacked diamond after plating in a nickel sulphate solution consisting of nickel chloride, boric acid, and brighteners?

What is the cause of missing diamond after tacking bits in diamond using nickel sulphate solution as the medium (solvent) consisting of nickel chloride, boric acid, and brighteners attached to a power supply using 1 amp per rod.

Please reply thanks!

Karen Smith
- Dearborn, Michigan, USA

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I am not quite sure what you mean in the question but my guess is that you are seeing nodules rather like melted wax around a candle.

If you are this is called 'treeing' in the UK (and many other things).

It is caused by too much current going to one area and this causes a large build up of plate in a local area.

To stop this you need to use 'burners' (also called robbers and other things).

This is where science goes into black art.

To start try using copper wire aroung the outside of the job to take the excess current (ensure the wire is connected to the power supply the same as the job is).

An example of this was a tube we had for nickel plate - we used a burner that looked like a 'halo' (a ring floating above the end of the tube). This worked well.

The only way to go forward is by trying some wire and see if it is better. This is the black art the best platers can make up a burner first time and have it work perfectly, the rest try until they get an acceptable result.

Please can you be a little clearer on what the second problem is.

Martin Trigg-Hogarth
surface treatment shop - Stroud, Glos, England

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I have brass bits plated and tacked with diamond, nickel sulphate, nickel chloride, boric acid, and brighteners, which is attached to a power supply at 1 amp per bit. After tacking the bits with diamond, the surface is not completely tacked. What is the cause of those missing diamonds after tacking?

is this more clear to understand?

please reply!

Thank you in advance!

Karen Smith
- Dearborn, Michigan, USA

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There are many reasons you can be treeing and or having build up around your diamond particles.

1st) How clean is your diamond, you need to keep it clean.

2nd) Have you calculated the surface area or are you approx, I plate a rack of 75 burrs depending on the size way below 1 amp. correct current very important.

3rd) Low current dummy your bath and see what you get on the dummy, if it is dark you are contaminated and need to carbon and dummy out the bath. there are more reasons but this is a start.

Good luck,

Glenn Simms
abrasives - Pottstown, Pennsylvania, USA