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Q&As since 1989
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TiN, TiC, TiO2 practical problem
2007
Q. (1) Adhesion between Au and TiN is very poor, please advice any glue layer required between TiN and Gold.
Problem :
(a) no peel off when ion-plating 18K Au-Cu-Ag gold alloy on TiN, but the gold alloy peel off after 24 hours artificial sweat test.
(b) gold peel off when ion-plating 24k pure gold on TiN
(2) TiN could be produced by Arc PVD or Sputtering PVD, but I found that the TiN produced by using Sputtering will crack and peel off after few days. But it will not happen on Arc PVD TiN. Why ? Is it possible to produce TiN by sputtering with no crack or less internal stress ?
(3) How to remove or strip the TiC coating or TiO2 coating from the steel workpiece so that workpiece can be replated
(4) When doing the TiC coating, the dark grey color on workpiece of the lower rack and upper rack is difference. Why ? ANy advice to improve ?
Thanks for any advice
Engineer - ShenZhen, China
A. No one can really answer any of your questions without detailed knowledge of your process. I would suggest you hire a consultant and not rely on website-generated information. In the long run this will prove to be far more cost effective.
Jim Treglio - scwineryreview.com
PVD Consultant & Wine Lover - San Diego,
California
2007
A. In response to why a sputtered coating is flaking but the arc deposited coating doesn't. To the best of my knowledge (mostly literature), in arc PVD the target or coating material is highly ionized, 90% or more, where as sputtering ionizes only a small portion of the material. This ionization gives the coating a more energy as it transports/condenses on the substrate. the higher energy leads to better adhesion and a more dense film. Again this is from researching the processes not from performing them so this may not be 100% accurate.
Patrick McCarthy- Sarasota, Florida
2007
A. In adhering Au to TiN or TiC I suggest a suitable diffusion barrier such as TiW (80% W 20% Ti) to allow for proper adhesion between the Tin and Au. Cr or Ni may work as well.
Also, make sure when sputtering your Au you do not break vacuum on your Ti compounds as this will cause oxidation immediately.
To etch typical Ti compounds such as TiN, TiC, try a mixture of HNO3 + HF, 1 part each at room temperature. Go lighter on the HNO3 if the steel appears to be affected by it.
Good luck.
- Lompoc, California, USA
2007
TiC Sputter Coatings Not Adhering
Q. Hello,
We have had success with making blue TiO coatings for decorative purposes using Ti sputter targets (in a post configuration).
However, our black TiC coatings are often full of pinholes. Any suggestions for fixing this? We already blast the workpieces with Ar gas for 6 minutes in situ before plating.
When we purchased the machine, we were shown at the seller's factory how to make relatively durable TiC coatings, but the same method does not seem to work in our factory.
Our cleaning process is the same as we use for the TiO coating.
Cheers.
- Katikati, New Zealand
September 11, 2019
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