Gold plating is fading

A. Hi cousin Naif.

You've sent us this request for help 6 times now. The problem is not that the readers are unwilling to help, but that you have given us no detail at all about what you did, no indications of who you are and what facilities and technologies are available to you, nor what knowledge and experience you possess -- and thus no limitations at all on suggestions. 90% of potential suggestions may be inapplicable or impractical for you to implement. Sorry, but reticent readers is not the problem.

Your plating is probably simply thin and wearing away. You may be able buy a gold plating process that applies a hard gold that wears a bit better, but I think the improvement will be marginal.

You can simply do heavy gold plating; this is very low technology that has been known for a hundred years or so, and many people have hundred-year-old gold plated pocket watches. But can you afford to put 20 microns of gold plating on the phone? I doubt it, but you have to tell us; we can't tell you.

You can apply a layer of TiN and a subsequent layer of gold by PVD processing to prevent wear. But do you have a million-dollar vacuum chamber or are you a small jeweler operating in a tiny stall?

You can protect a thin layer of gold plating with electrophoretic lacquer, but do you have an e-coating line, and will your customer consider this acceptable?

You can apply a UV cured lacquer with very inexpensive equipment, but will a lacquered gold-look finish satisfy your customer? My guess is that doubling the thickness of the gold plating (you haven't told us how thick it is), and then applying a UV cured lacquer will solve your problem, but to simply guess in lieu of getting real information isn't very satisfactory :-)

Best of luck.

Regards,

A. Hi Naif. The thickness of gold plating obeys Faraday's Law, i.e., that 96,485 ampere-seconds will deposit one gram equivalent weight of gold, but unfortunately the efficiency of aurous plating baths is so low that this won't help you much except after you have calculated the efficiency by trial and error. So perhaps you can plate a sample component for a given number of minutes at a fixed current, have it tested by a test lab, and scale up or down on the plating time based on that.

Recognizing that you want a very inexpensive solution occupying a small space, I think the UV lacquer may be the best solution. Pardon my ignorance of cultural issues, but here in the USA it is common for women to go to "nail salons" for professional application of fingernail and toenail polish. Those salons will use UV lacquer and a UV curing machine that will be very inexpensive. Getting what they use would be very inexpensive, and I have heard of small custom jewellers in the USA who do exactly that.

Regards,

A. Hi
Generally 178-180 mg gold on one square decimeter plated is 1 micron. Different plating solutions will give various plating speed from 1 ampere per DM2 for one minute will deposit from 20 mg of gold to 110 mg of gold depending up on the formulations.
Regards

A. Hi Naif. Please see

www.radtech.org/buyers/?cat=53

or contact RadTech

Regards,