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topic 41517

How to make gold plating last longer?

Current questions and answers:

January 5, 2021

Q. Hello! This thread has been unbelievably informative, I read all the way from the beginning. I am just starting my own line of 'Demi fine jewellery' and I will be outsourcing production. Like many others, I want to do the next best thing after solid gold.

- My first option is Gold-filled. Ideally with silver base (so it's a much thicker vermeil)
- However, because gold-filled has limitations (for example, you can't cast), my other preference is vermeil.

My two options I'd like to try for my vermeil jewellery are:

1. 10 microns of 14k gold/rose gold on sterling silver base
2. An initial coating (say 2 microns) of TiN, followed by 2-3 microns of 14k gold/rose gold on sterling silver base. This may not be possible initially due to quantity, but I'm happy to pay a premium

My questions are:

a) Which of the two (1 or 2) do you think would give me jewellery the best chance at lasting as long as possible? Say 2 - 5 years?
b) Do I need a nickel coating on top of sterling silver for option 1?
c) I was considering going up to 20 microns for everyday necklaces for example. Will this have significant improvement over 10 microns?

Thank you in advance for your help!

FK Amaa
- London, UK

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December 24, 2020

Q. Hello, I am starting a jewelry business and I was looking at the jewelry I want to sell. My question is how long does a sterling silver coated with 0.25 microns gold last for?

Sylvanus Edi
- Anchorage, Alaska


December 2020

A. Hi Sylvanus. First off, I'm no jewelry expert and this is just 'book knowledge', I'm just trying to offer the courtesy of a reply -- so I certainly encourage others to chime in.

I don't think there is an answer to your question because rings suffer extreme wear; bracelets probably quite a bit less, but still an awful lot; necklaces and earrings less than that; and pins and broaches almost none. And that's before we even consider that different people treat their stuff much differently, for example, swimming and washing dishes with rings on vs. off.

But one answer is that 0.25 microns is ten millionths of an inch, and standard aluminum foil is 63X thicker. So without a clear coat it probably won't last long except in a very low-wear situation. A clear coat is probably called for.

Perhaps a better answer is by comparison to other jewelry. I believe that the cheapest gold plated jewelry you will find anywhere is about 0.06 microns; this is probably just enough for a gold color and is used under a clear coat. Your thickness of 0.25 is probably similar to most average quality costume jewelry these days. "Better quality" costume jewelry is sometimes called "micron gold" because it is 1 micron (4X your thickness) and that was probably the typical thickness several decades ago. Vermeil is about the highest quality non-karat jewelry you'll find, and is 2.5 microns thick on sterling silver. The gold plating on super premium watches was reportedly about 7 microns (although today they probably use titanium nitride as well as gold to prolong the life, so the gold thickness might be less).

So I think the question of how long will it last is not answerable, but the question of where you will fit in on the quality scale is :-)

Luck & Regards,

-->



Previous closely related Q&A's starting in:

2006

Q. Hello,
We import gold plated jewelry from various different countries including, China, India.

The gold plated jewelry usually doesn't last long and will tarnish within 12 months, Usually using 1 micron gold plating.

We want our jewelry to last longer, for at least 3 years wearing it everyday. I have heard about PVD process and using titanium nitrides, I have asked many manufactures about PVD on jewelry and they tell me its not suitable for jewelry as it doesn't give the right gold color for jewelry, they tell me its too bright and mainly used on door handles etc but not for jewelry.

Is this correct? Does anyone know of a manufacture that can do PVD Titanium nitrides over brass/copper for jewelry or any other suggestions for increasing the wearability/durability without a too heavy price tag?

Mat Johnson
Jewelry - Australia


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2006

A. Hello, Mat. Actually, I think it is a fairly well developed technology to combine titanium nitriding PVD processing and gold plating to provide a good gold color and a wear resistant surface. The thing is, it is rather inexpensive for a very small shop to do gold plating (especially if they don't have environmental regulators monitoring them), but a PVD vacuum chamber is major capital equipment. So you won't often find tiny operations offering titanium nitride assisted gold plating.

Ted Mooney, finishing.com Teds signature
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey


2006

A. Ted is exactly right. The technology for using titanium nitride and gold is well tried and tested. The titanium nitride is put down first as a "rough" deposit and then gold electrodeposited into the valleys of the rough surface. This gives a very high amount of gold on the surface, but it is protected by the "peaks" of TiN, so it doesn't wear away too fast.

trevor crichton
Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK


2006

A. Gold is soft, so it wears fairly fast. 1 micron is about enough to give it color. It also depends on what it is plated on. Copper and zinc will migrate thru a coating that thin in a few weeks.
You get what you pay for sometimes. Cheap will be cheap in most countries.

James Watts
- Navarre, Florida


2006

Q. Thanks for your reply, I wonder where I can find a suitable manufacturer to do the PVD Titanium Nitrides combined with gold electroplating?

Best Regards,

Mat Johnson
Jewellery - Australia
outdated

----


2006

A. One micron of gold should give a reasonable life for costume jewelry. Most costume jewelry is plated with a 'flash' of gold which is much less than a micron. Check the thickness; are you getting what you paid for?
Tarnish of thin gold deposits is associated with porosity or diffusion of the base coat. It is usual to apply an intermediate layer. In industrial applications this is usually nickel but some people are sensitive and can develop a form of dermatitis (do they never take their jewelry off?). Palladium/nickel is commonly used. Your supplier should know this.

P.S. 1 micron of gold cannot be accurately measured by microsection. You will need XRF - talk to a local plating house.

geoff smith
Geoff Smith
Hampshire, England



May 4, 2011

Q. I am very curious about the use of titanium nitride underneath gold plating for costume jewelry. I have customers who are using anywhere from 3-5 mils to 6-8 mils gold, often with e-coating on top.

Anyone familiar with the cost of e-coating and titanium nitride who can provide me with a comparison in cost? would replacing e-coat with titanium nitride be cost neutral? would it be a more effective option?

Also, does the color of titanium nitride work only with a shiny gold finish? Some of our customers use an oxidized or even matte gold. If the gold plating were to wear off, would the titanium nitride beneath be very obviously different in color?

Thank you in advance!

Rebecca Noveck
- New York, New York, USA


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June 21, 2011

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Q. Yeah, I have the same question. My jewelry coming from many sources, so I want to have a unique color of 18k jewelry in my show room. Could you please to share with me where I could buy the tools and material to do that?

Thank you very much!

Huan Nguyen
- HCMC, Vietnam


November 8, 2011

A. As per the series of experiments conducted by our company, the durability of depositing gold over titanium nitride would be as much as that of 1 micron. Sometimes the life term of the product can be 6 months also. To obtain a durability of nearly 3 years, it is recommended to do electrophoretic lacquer.

Amit Jain
- Mumbai, Maharashtra, India


October 2013

A. Hi Rebecca. Ideally, the titanium nitride is, as Trevor tells us, a rough surface with mountain peaks that protect the gold in the valleys from wearing off. Cost comparisons are difficult because non precious materials like TiN and e-coating lacquer are inexpensive, so you're usually looking at capital costs vs. labor costs. The capital cost of gold plating can be very low; jewellers can do it in a beaker with a stirrer on a hotplate. E-coating systems might cost $100,000 for a small setup to $1 million for a large one, and PVD systems cost something like $1 million and more. I believe it is relatively easy to incorporate 'contaminants' into PVD deposits to give a darker look.

41517

Hi Huan. The coloring of gold is an art more than a science, but Al Weisburg's "Gold Plating" chapter in the Metal Finishing Guidebook includes a "Table 1 "that will give you a start on formulations and operating conditions for different colors =>

Regards,

Ted Mooney, finishing.com Teds signature
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey


February 23, 2012 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. I'm a watch case manufacturer and also plater. We own PVD plant to coat ss 304 straps and brass watch cases using arc for TiN plating up to 0.5 or more micron and then followed by sputter 24k Gold plating (0.05 micron) to get gold finish.

I want to reduce the cost of PVD plating due to very high price in GOLD!

My question is can we do electroplating followed by TiN ? Or can we do gold electroplating after TiN and very thin layer or gold or nickel layer in PVD?

Any other suggestions are welcome

Thanks
Bhavin

Bhavin Sorathia
Owner - Rajkot, Gujarat, India


October 2013

A. Hi cousin Bhavin. It is possible to electroplate gold before TiN deposition by PVD. I think, but do not know for sure, that is is also possible to electroplate gold plating on top of a thin TiN layer. But it is probably more customary to apply the gold via PVD as you say you are doing.

Surely there is something wrong with your figures? 0.05 microns of gold cannot possibly be costly as it is incredibly thin. Light gauge aluminum foil is 320X thicker :-)

Regards,

Ted Mooney, finishing.com Teds signature
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey



May 1, 2012

Q. I'm an independent jewelry designer in NYC used to working with gold/silver. I've now created a line of costume jewelry in brass and would like to have them gold plated but have been quoted cost prohibitive prices for "micron plating". What I understand is called "flash plating" is at my price point (~$5-10 per piece) but doesn't last long.

Is there a coating I can apply that will extend the life of the gold plating (to at least 1 year but hopefully more) while maintaining a matte finish?

Hopefully either something I can apply myself (as a layman) or can be inexpensively be done by a professional in the NYC area?

Thanks and regards,

Jon

Jon Silo
- New York


May 4, 2012

A. Hello Jon,
The jewelry industry has their own jargon especially when it comes to electroplating. Micron plating is not a considered a flash plate in Au plating. A micron is about 40 microinches give or take. Flash plating is conventionally anywhere from 3 to 10 microinches. You would be lucky to get 10 from most decorative Au platers. If the Au plating thickness was 1 micron and was alloyed for some hardness your products would last a year and even more. If you can't find a plater to put down that much Au, coatings are available that will not change the appearance of the final finish. Obviously your price to have the items plated / coated will be more expensive. Good Luck.

Mark Baker
Engineering - Mesa, Arizona, USA


July 25, 2012

Q. I would like to know about the gold micron plating which can last at least one year. Can anybody suggest for the same? Thanking you.
Rohan

Rohan Kumar
- Mumbai, India


August 2, 2012

Q. We are importing sterling jewelry charms and would like to offer gold plated silver charms as well. I have been discussing the plating with suppliers but it is difficult to get an actionable answer. I am looking for a suggestion to point me in the right direction with regard to wearability. There is obviously some body contact with the charms. I'd like to offer pieces that will not wear through to the silver - at least for several years of occasional wear. 1 micron of 24k gold has been suggested and that's affordable, the charms are small, but I have not been able to determine what I should buy. Any suggestions will be greatly appreciated. Thanks.

John Anthony
- Phoenix, Arizona, USA


August 7, 2012

A. Hi, Rohan; Hi, John.
I'm not a jeweler, but since no answers have come so far, I'll provide my understanding, albeit not definitive answers.

Gold has been valued throughout history for its beauty, one aspect of which is that it doesn't tarnish or corrode. For that reason, no lacquer or topcoat is required to keep it bright, as is needed for copper or silver and other non-precious metals. So it has been customary to not topcoat gold or gold plating. That doesn't mean you can't put a clear topcoat on it; but it does mean that it may not be as well received, so you decide whether you will or you won't as a business decision depending upon how you want your jewelry perceived.

If you do topcoat it, with an electrophoretic lacquer for example, the thickness of the gold doesn't matter from a wear standpoint because it is underneath the clearcoat. If you don't clearcoat it, the gold itself will wear and must be thick enough to resist that wear for what you consider an acceptable life. 1 micron is probably sufficient to offer sufficient life for moderately priced jewelry if it sees little wear and no body contact. A ring would receive tremendous wear and body contact, a pin or brooch virtually no wear or body contact, a charm would probably depend on the exact design of the bracelet. Until I learn better myself, I don't think I'd do 1 micron without a clearcoat though if I wanted it to last several years.

Ted Mooney, finishing.com Teds signature
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey


August 29, 2012

A. A trick used by some jewellers is to coat the articles with titanium nitride and then put down a thin coating of gold. The TiN is relatively rough, and the gold fills the cavities (or valleys) as well as the peaks. However, as the gold wears off the peaks, the TiN offers a hard and wear resistant point that protects the gold further down the valley.

trevor crichton
Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK


January 31, 2013 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q1. In respect to jewellery items, what is the common understanding of the meaning of the term HARD GOLD PLATING (HGP)? What does HARD actually refer to?

Q2. Also, what are the recommendations for achieving HGP with very strong bonding (that is, won't wear off), when plating silver (925) and brass jewellery items? It seems that a barrier layer is required between the base material and the HGP layer, what is the consensus as to what layers be applied to each of 925 and brass items?

Q3. Does anyone have opinions on the use of Enthone additives and solutions? They seems a reputable supplier, or any other specific brands you have tried and have faith in?

Q4. Any views on the use of e-coating, as a final protective coat over the HGP? Is this necessary and recommended?

Many thanks for anyone sharing their views and experience.

Robert Killeen
Jewellery manufacturer employee - Brisbane, Queensland, Australia


February 9, 2013

A. Hello Robert,
Hard gold plating is a gold plating process whereas the plating solution contains gold salts (Potassium Gold Aurocyanide, conducting salts, buffer salts, and an alloy or brightener. Potassium citrate versions have been common for many years. The gold plating thickness is normally higher than standard "color gold flashes". Whatever the alloy is in conjunction with the gold metal concentration in the bath, determines the color and hardness of the plating deposit. pH and bath temperature play a role as well. Diffusion barrier coatings (between the substrate and the gold plating) vary. White bronze has become popular, palladium is also a good option, but more expensive. As you probably know, nickel had been the most widely used barrier plate in jewelry plating, but over the past 15 - 20 years usage of Nickel has been on a steep decline because of consumer allergies. There are reputable gold plating suppliers out there. This website can satisfy your search for a good supplier. Because jewelry is gold plated you have to expect the deposit to wear off over the years. The wear life will of course be dependent on the piece. Are you plating rings that will be worn daily, or necklaces that will be worn a few times a month. E-coating is an option to extend the wear life, but I am not familiar with possible drawbacks. Good Luck.

Mark Baker
Process Engineer - Mesa, Arizona, USA


February 6, 2013

Q. Hello, please please I need some help!

I'm doing the hardware metal for my handbags (logo, tags, o rings, metal plate) in China. I got the samples on Friday and they looked pretty good to my surprise. The only problem I have is the gold color. I asked them to do a 14k gold plating (they say they use IP plating which is better and more durable than micron plating, is this true?) and when I compared the pieces to the metal hardware that were done here in the USA, the gold color is a little bit lighter then the ones made in USA. I wonder why could this be?
Also, another thing that got to my attention. When I did the metal hardware here in the USA, the people that did it told me that to have the engraving on the metal (like the name of my brand that is engraved on the metal) to polished inside is really hard, so that's why it looked rough on the inside, not polished. But the hardware from China looks amazing on the inside! is completely polished and clean. Does anybody knows why is there such a difference? if there is something that this people in China might be doing differently? And if this is the case will that be compromising the quality of my metal hardware?
Thanks so much

Isabella Galli
- Snowmass Village, Colorado, USA


April 25, 2013

A. Hi Isabella. 14K gold is 10/24 non-gold, and the color depends on those other 10 parts. "Gold coloring" is both an art form and a trade secret for the fastidious: it's not easy to get consistent color, and quite difficult to specify it -- but you can study that topic in plating textbooks. "Gold Plating Technology" has quite a bit of info on gold coloring =>

I didn't understand your engraving description and problem, sorry; but is it possible that the engraving was done after the plating here, and before the plating there? Also, your Chinese supplier is doing "ion plating" -- but that's a method, like "electroplating" is a method; it may be gold plating but it may not be. Are you sure you specified "gold plating" rather than just "gold color"? Micron plating is neither a method nor a material; it's a gold plating thickness of one micron. I don't think you are getting from China what you thought you were asking for; but if what you actually want is only the appearance, and you're happy with the appearance, that's probably okay.

This is a forum of international camaraderie, so we naturally try to not stand in judgement of anyone's outsourcing choices. Still, a problem is that we receive hacking attempts every hour of every day from China, and so many thousands of pieces of spam from China every week, that we often must block large swaths of IP addresses from China, and in so doing we may inadvertently block a helpful response from China. So you probably can't expect much help from China. And you really can't expect domestic and other platers to spend their time for free here helping you cut them out of the loop. That would be like going to a Chevy dealer and expecting the salesperson to patiently spend her time helping you choose between a Honda and a Toyota. That's probably why you've received no responses in a couple of months. But best of luck.

Regards,

Ted Mooney, finishing.com Teds signature
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey


April 25, 2013

Q. Regarding Plating Cost and Plating Thickness recommendation

Hello,

I am talking to manufacturers in China about fashion jewelry, mainly ear studs, chains, pendants and rings. My market is very price sensitive and I need to consider cost versus benefit closely.

I understand ear studs have less exposure to sweat than rings.

Can anybody give a recommendation for each of those categories - chains worn around the neck, ear studs, pendants and rings - how many microns or fractions thereof you would recommend so that the plating holds for 0.5/1/1.5/2 years under normal usage in a table format for gold, rhodium and black colour plating ?

In addition, I was wondering what the actual cost differential for the plating factory is. The issue I have that I do not know how big the square centimeter surface of a ear stud (sizes 3 to 10 mm), ring, chain etc is depending on common sizes.

For example a table that would tell me that the average 4 mm/5 mm/6 mm ear stud costs x US$ per 0.1 micron of gold/rhodium plating.

I would like to use this when negotiating prices with my manufacturers.

Any help would be highly appreciated.

Another question I am pondering with is whether there are health concerns if the plating wears off and brass or zinc alloy is revealed and gets direct skin contact. Firstly, I cannot even find what exactly "zinc alloy" is versus brass. Are there any EU rules under REACH that mandate a specific minimum plating thickness in microns?

Many thanks again,

Daniel

Daniel Bihler
- Guangzhou, China



April 30, 2013

A. It isn't necessary to know all the costs involved in the manufacturing of the jewelry you are seeking to buy in order to get the best possible price but you will need detailed designs and exact specifications that you can give to multiple manufacturers for quotes. Based on some of your questions I'm guessing you have little experience and you should hire a consultant to help you write up the specifications you will want to use. A word of caution: we regularly receive jewelry items through our customers that have been gold plated in China and do not meet the specifications.

Neil Bell
Red Sky Plating

supporting advertiser
Albuquerque, New Mexico
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