HOME FAQs BOOKS JOBS: Help Wanted Suggestions you are here: Hotline/Forum => Letter 52068
I want to plate copper jewelry with gold color via p.v.d. coating process
May 7, 2009
I want to plate gold on copper finish jewelry with high durability of gold plating with lower cost than real gold direct forming by rectifier .
Agrawal Abhishek- Khirkiya-M.P.INDIA
^- Privately contact this inquirer -^
May 15, 2009
Firstly, PVD is more expensive than conventional electroplating becuase you need a high capital expenditure on a vacuum system and chamber. Assuming you have access to a PVD system you need to deposit a thin layer of TiN (titanium nitride) - this will give you your gold colour. However, it may not be the right colour for you, so you can then plate the TiN with a thin layer of gold. If your TiN is too thick, you will have problems depositing the gold, becqause TiN is rather non conducting. The trick to it is to use the substrate's conductivity to deposit a thin layer of gold over the TiN, using discontinuities in the TiN layer to allow the current to pass through the TiN. You will get increased wear resistance this way, because the gold will be deposited over a rough TiN surface and it will fill in the "valleys" in the TiN. The gold on the "peaks" will wear away to expose the much harder TiN and this will then protect the gold still left in the valleys.
|
Trevor Crichton R&D practical scientist The Pheasantries - Chesham, U.K. |
May 18, 2009
Actually, TiN is a very good electrical conductor. As noted, you may have to add a gold layer on top to get the exact color that you want. Another way is to deposit an alloy nitride, mixing the titanium with zirconium. ZrN is more of a champagne gold. Addition of a little carbon to either will darker the hue. You have to be careful with the carbon, though -- too much and you get magenta.
|
Jim Treglio  Lakeside, California |
June 1, 2009
A layer of gold on TiN is generally deposited on watch straps, cases etc in the same chamber by PVD. However depositing gold by PVD requires huge investment in gold and recovery of unused gold is difficult. It would be ideal if gold can be electroplated on TiN. But it appears to be difficult.
H.R. Prabhakara
- Bangalore, Karnataka, India