Marcus Hanke
[PuristSPro Moderator]
11515
Gold PVD - a Scam? - PART II
Modern gold PVD vs. traditional gold-plating
by Marcus Hanke
Remember the times when “gold plated” or “gold filled” watches were the “poor man’s gold watch”? It was rather common to wear timepieces that were encased in steel (well, sometimes even brass) and covered with thin layer of gold. However, there were different grades of this kind of “cheat”: from thinnest possible coats, that were ribbed off already by wiping the watch with a cloth, to rather thick gold layers that did not show signs of becoming thinner even after many years of use.
It was fashion that brought an end to this practice, at least as far as watchmaking is concerned. Golden watches became less common, stainless steel was the most popular case material. Even those cases made from precious metal resembled steel: white gold and platinum watches rose in sales, while the classic yellow gold practically disappeared from the watch market.
However, the recent trend shows gold to gain popularity again. In pink or red gold, elegant timepieces appear even more elegant and classy. While the dynamics of global gold prices caused golden watch cases to increase massively in sales prices (unfortunately, watch brands forget to lower the prices again, when the global gold rate drops, as is the case right now), a gold plated watch does not have enough gold on it to be really influenced by these dynamics.
This causes watches with gold coats to shift into the customer’s perspective again. Consequently, the recent watch brands’ catalogues, especially those of the lower to medium price range, feature an increasing number of watches that appear to be made from gold, but only have applied a layer of gold atop of a steel body. Steel or titanium watches that have some golden, or gold-looking parts on it, like crowns, pushers or bezel rings, also belong into this category.
Unlike earlier years, however, the accompanying texts disclose these watches to be treated with “PVD gold”. This is not limited to some obscure fashion brands the names of which we never had heard of. Even globally-known watch brands like Seiko, Tissot, Longines and many others are using it on a large scale. What is this “PVD gold”? And - more important: Is it inferior or superior to gold plating, cheaper or more expensive?
To begin with, I started a web research for statements on gold PVD and brands using it: how is this treatment communicated to the customers? How is it perceived?
The results were shocking, to say the least. Practically all information I found written in so-called “expert blogs” or watch-related sites, be they independent or funded by the industry, was completely wrong, sometimes even deliberately misleading. Self-acclaimed experts would convince their readers that PVD gold was the best and most advanced technology available, and far superior to traditional gold-plating.
I read that gold PVD is bonding the gold directly into the molecules of the stainless steel, thus making it completely unabrasive, much harder than gold, and - as a nice side-effect - the steel much harder and absolutely scratch-resistant.
I read the gold PVD is far more expensive than traditional gold-plating, and therefore more desirable.
I read that gold PVD is far less prone to corrosion from sweat and chemicals than gold-platings.
The only thing missing was the statement that gold PVD is the solution to the energy crisis and will restore the global climate.
I think it is important to get some facts straight.
1) What does “gold plated” mean?
Generally, the term “gold plated” describes any ordinary material, be it metal, plastic, wood, or whatever that is coated with gold in a layer of any thickness, by whatever means. The application can be by mechanical means, like hammering or rubbing gold foil to the base material, chemically (for example by means of quicksilver, a method applied already in the antiquity), galvanically (so-called electro-plating), or by “simple” condensation of vaporized gold on a surface. The latter is called “physical vapor deposition”, short: PVD.
So PVD is but a specific process of gold-plating. Why making a difference between gold-plated and PVD gold watch cases? The main difference lies in the thickness of the precious metal layer, and legal definitions.
2) Gold-plating and law
Any frequent traveller interested in bringing a piece of gold from abroad as a souvenir or gift knows: Asian gold is different from Arabian gold, European gold is different from African or American gold. Gold contents are different, content measure units are different, alloys are different, hallmarks (if any are present at all) are different.
Unfortunately, there is no globally accepted standard for the composition and designation of articles produced from precious metal (silver, gold and platinum, since recently, palladium counts as precious metal, too). Since 1972, there exists the “Convention on the Control and Marking of Articles of Precious Metals”, also called the “Vienna Hallmarking Convention”, trying to introduce standards on hallmarks and contents. Only very few states have ratified it since, among them Switzerland, what is important for us watch enthusiasts.
However, this convention only applies to articles solidly made from gold or gold alloys, but not to articles only covered by a layer of gold. For these goods, only national legislation can enforce any standards. Unfortunately, barely a state would do this. Switzerland, though, as a nation traditionally depending on exports, with a very strong jewellery and watchmaking sector, has an interest in defining rules, to assure the high quality of Swiss goods.
In Switzerland, the so-called "Edelmetallkontrollgesetz" (control statute for precious metals), is dealing with all kinds of objects either made from massive precious metals, alloyed precious metals, or unprecious materials coated with precious metals. Aside cutlery and jewellery, watch cases and their parts play a significant role in this statute, which demands very strict standards for composition and hallmarking.
According to it, only the terms “doublé” and “plaqué” are permitted for gold-plated watch cases that are offered as such. A gold, silver, platinum or palladium plating then has to be at least 5 microns (=micrometers) thick, and has to be stamped with a small sign confirming this, followed by a hallmark showing who is responsible for the article production.
Any watch case that is not marked, does not meet this standard, and is treated like a cheap plastic ball-pen with gold layer, called “Ersatzware” (substitute) in legal German. The hallmark is a sign of value, and Swiss law makes sure that a minimum gold value is the condition for the hallmark. Without this minimum gold value, no hallmark, it’s that simple. This is why, sometimes, we read about “Swiss gold layering”, or similar marketing terms, that in fact do not describe a specific procedure, but merely the fact that the Swiss legal standards are fulfilled.
As we all know, watch cases with a gold coat of 5 microns are not really durable. In fact, this thin coat is easily scratched, and the watch case will reveal the base metal, steel or brass. Better “plaqué” watch cases therefore traditionally employ a gold coat of at least 10 microns, which became somewhat a standard in the watch industry. Even better are cases coated with 20 microns, which in everyday use is good enough for an entire watch life, without the base metal ever shining through. Just for comparison: an average newspaper page is about 60 to 70 microns thick.
Since a while, however, plaqué watch cases seem to have disappeared from the market, to be replaced by gold PVD. Sometimes, even quite expensive watches have cases or case details with gold PVD ( I saw a 4,000+ Euro Seiko chronograph with gold PVD details on case and bracelet). What is this?
3) What does “gold PVD” mean?
Unlike traditional galvanical, chemical or mechanical procedures, PVD applies a metal coat by the condensation of the precious metal as a vapor in vacuum. For this, the solid precious metal has to be vaporized by means of energy, then the vapor is led to the base article, where it condenses into an extremely thin coat. This is the main reason for the PVD process: applying ultra-thin coats, mostly for technical purposes, in order to protect the base article against corrocion or abrasion, or to influence friction, without having to recalculate the dimensions of the entire base article.
Maybe some of you recall when several years ago, about a decade, some watch companies started using galvanically coloured movement parts aside the rotor, like Ulysse Nardin’s “Blue Max”:
The galvanical process added too much thickness, so the movement parts had to be adapted to this added material. With PVD, this is not necessary any more, since the thickness of a PVD layer is below the standard tolerances of the parts production.
A gold PVD layer is not more than 0.3 microns thick (less than a 1/30th of even a thin traditional gold plaqué layer!).
Normally, this extremely thin layer is rubbed away already in everyday use within a very short time. And yes, it is - but the wearer does not notice it. The reason lies in a trick, a gold-colored second layer below the gold, made from unprecious titanium nitride (TiN). This PVD layer, with an average thickness of 1 micron, is extremely hard and not likely to be scratched hard and deep enough to reveal the steel base below. So what the owner and wearer of a gold PVD watch actually is looking at, after prolonged daily use of his watch, is to a certain extent only the gold-colored titanium nitride, and not gold, which was rubbed away since long already.
Consequently, the Swiss law does not permit gold PVD articles to wear any designation of its gold content (carat, or something like 585), nor any hallmark.
4) Now what is better: gold-plated or “gold PVD”?
First of all, I have to repeat that I cannot speak for gold-plating as a general standard, so my conclusions are based on the gold-plating regulated by Swiss law, that is designated “doublé” or “plaqué” only.
Is gold PVD harder than gold-plating? No. Gold is gold, and gold is soft. Gold alloys normally are a bit harder than pure gold, which is why our common 18k (750) gold cases are more scratch-resistant than would watch cases from pure 24k (999) gold be. Consequently, Longines’ proud statement that its gold PVD layer is made from pure 24k gold makes clear that this 0.3 microns layer will vanish even quicker.
Longines gold PVD statement
However, we have to keep in mind the TiN (titanium nitride) layer below the gold. It has some positive attributes. Not only is it extremely hard, a lot harder than steel, but also is it rougher than gold. A pure TiN finish is looking flat, not highly polished. The gold layer above it would settle especially in the recesses of the TiN surface, with the TiN “peaks” effectively protecting it - after, or course, the gold that had coated these peaks is worn off, which is likely to happen within a few weeks, if not days.
As a consequence, gold PVD APPEARS to be harder than plaqué, but it is pure sleight of hand.
Is gold PVD more resistant against sweat and chemicals? No, for the above reasons. Gold is gold. By the PVD process, it is not chemically changed. In theory, an 18k gold alloy is a bit more prone to corrosion, depending on the metals used in the alloy (copper, for example), but as we saw, a 24k layer is lost quicker. It is the TiN layer beneath that is the corrosion-protection for the steel.
Is gold PVD changing the steel molecules? No, of course not. It is a coat. Steel remains steel, gold remains gold.
Is gold PVD more expensive than gold plaqué? Let me think: Is a layer of 0.3 microns more gold than a layer of 5, 10 or even 20 microns? No, I don’t think so. Remember: Plaqué is entitled to signs and hallmarks BECAUSE it does represent a certain value, gold PVD is not. Is the base TiN (titanium nitride) layer more expensive than gold? For a single ounce of gold, you get 195 kilograms of titanium.
What in fact is more expensive is the basic equipment for the PVD process - which pays off within a very short time.
5) Is “gold PVD” on watch cases a scam?
Technically no, as long as no signs or hallmarks suggest it to be “plaqué”. However, I consider it bordering to a scam when producers and/or dealers try to create the impression of gold PVD being the more valuable gold plating method, superior to “plaqué” (according to Swiss law). I applaud companies like Frederique Constant that decided not to take the low road and stayed with the traditional gold-plating. All “plaqué” FC watches have a layer of 10 microns thickness. This could be improved, of course, but it is eons ahead of the gold PVD used by some other brands of high renown.
(c) Frederique Constant for PuristSPro
When blogs and self-acclaimed “experts” in fora state - contrary to better knowledge - that, for example, a gold PVD Seiko, Orient, or Armani timepiece represents a higher metal value than a “plaqué” watch, this is misleading. If these people act in own financial interest, be it that they are involved in the production of such timepieces, be it that they sell such timepieces, it might still not be scam in legal sense, but it is highly unethical.
Regards,
Marcus
Gold PVD - a Scam? - PART II
Modern gold PVD vs. traditional gold-plating by Marcus Hanke Remember the times when gold plated or gold filled watches were the poor mans gold watch? It was rather common to wear timepieces that were encased in steel (well, sometimes even brass) a...
Crystal Clear
Thanks for this. Very informative and crystal clear. I have just looked at how many we'll known respected brands use gold PVD, it was very surprising. Anyway, I do think most of us here have never considered buying a gold PVD, or even a gold plated watch....
In my experience...
Raymond Weil, who set 10 microns as a standard, back in 1976, had ruled this area for many years (they got away from it, but I think they're returning to it slowly, but with rose gold). Their 10m holds up MUCH better than any PVD I've ever seen. Frankly, ...
Fascinating!
Very interesting article, thanks for your research and well written report.
Thanks for sharing these information!
Now I understand the difference between Gold Plating and Gold PVD. Will be more careful about it in the future.
Reference post!!!
One more of many from dr. Hanke's Laboratory Thank you very much indeed Best r egards Damjan
Old gold plating...
...from an Omega bumper automatic from the late 1940's or early 1950's. Unbelievable that at that time 80 microns was considered a reasonable plating, versus 5 microns today! ...
Titanium Nitride...
Titanium Nitride must be the gold-plating industry's best friend! Thanks for sharing this Marcus!
TiN has some great physical properties
one of them being that it is extremely hard (2450 HV) and thus all the more resistant to scratching and wear. So why cover it with a thin layer of gold, which is not? Besides, I love the color on industrial tools! In the hands of the right (watch) designe...
Don't forget the Longines gold PVD is mostly on ladies' timepieces ...
... and I doubt that this customer group would be equally attracted to a watch if the golden colour is not the result of at least a thin golden layer, but of an unprecious metal. Technically-minded customers are more likely to accept the latter. Just look...
The PVD process is certainly more expensive than electroplating...
But why is only 0.3 microns deposited? It could be as thick as anyone desires. It is true that PVD is an expensive process due to the equipment used. I always thought gold PVD was only TiN anyway. We use this material whenever we want a nice gold coloured...
It depends on how you calculate the costs ...
ONe of PVD's big advantages is that it is easier to achieve a flawless surface. Any watchmaker, who had a galvanic lab coating some of his work pieces, perfectly knows what I am speaking about. It is extremely difficult finding able and careful enough for...
Very useful information
although I suspect that many people reading it prefer solid steel to plated gold of any thickness. Excellent investigation and clear write-up. Thanks.
Most Edifying!!!
Very interesting article. I feel much more educated on this topic now! Thanks, Dave
Dear Marcus. Thank you for a clear and very accurate
explanation of PVD as it pertains to watch making. I come from a semiconductor background and coatings are a day to day experience in our world as you are aware. My companies have 129 patents in coating or machines that make these coatings. Your article i...
Thank you kindly for your your great compliments!
I just read your comment after returning from vacation. Generally, I have the impression that "gold PVD" will disappear, at least from the marketing material. More recently, I have read only "gold-colored PVD", making clear that it is different from "real...
