RoHS restrictions on Hexavalent Chrome
I am an engineer for a large auto supplier. Most of my division's products are zinc-alloy plated and then we add a hexavalent chrome conversion coating. My division of Dana manufactures fuel rails, brake hose assemblies, and power steering components.
We have found a piece of information that may significantly impact the way we manufacture our products. The European Parliament is or was planning to restrict the total allowable weight of hexavalent chromium to no more than 2 grams per vehicle for anti-corrosion coatings on various vehicle components by the year 2003. The purpose of this restriction is for the recycling of end-of-life vehicles. We guess that if this restriction is passed into law, it would affect automotive standards globally since having a different specification for European parts only would be too complicated and expensive.
That brings me to the point of this message! Has anyone else heard of this supposed regulation? Is anyone doing anything about it? I know trivalent chrome and non-chrome conversion coatings are out there but that they are not nearly as effective as hexavalent chrome. I am curious as to what everyone else's opinion on this subject is. Thanks in advance for your discussion!
Rochester Hills, Michigan
The directive as far as I am aware is still at the draft stage, the trade association here in the UK (SEA website http://www.sea.org.uk) has been lobbying hard on this one, and in the february issue of the association health, safety & environmental newsletter had this to say. "The european directive on end of life vehicles now recognises that some hexavalent chromium is permissible. In the latest draft a maximum of of 2g per vehicle of hex cr is permissible which means that no special measures need to be taken to reduce the hex cr content of metal finishing processes" and they give these calcs.
Max SA with possible hex Cr 11 M2
Max hex Cr = 0.1g per M2
therefore max hex cr per vehicle = 1.1g
Thats about as much as I know perhaps someone with a more detailed knowledge could help out.
I can see there not being a lot of surface area in underbonnet parts, brackets, etc. but how about Zinc coated sheet for bodywork is this chromated ? if so is it included ?
- Lowestoft, U.K.
Timothy: Finding a trivalent chrome conversion coating that will provide protection equivalent to hex-chrome shouldn't be too much of a problem. It might be tough to get it here in the states but Europe has been dealing with the problem for a while.
I would think that your best bet is to start with a supplier from Europe. Since Dana is so large, you prob. have a facility there you can call to get some good leads. Good Luck.Robert Holderman
- Tulsa, Oklahoma
The procedure that you recommend regarding how to efficiently look for substitutes sounds right on target, Mr. Holderman!
But trivalent chromium is not hexavalent chromium, and the "trivalent chrome conversion coating that will provide protection equivalent to hexavalent chrome" has been the subject of a desperate search for 3 decades, still hasn't been invented yet, and may never be.
The environmental and health impacts of hexavalent chromium may be serious enough that we ought to abandon the use of hexavalent chromium in conversion coatings, and accept the reduced corrosion-fighting power of trivalent chromium or other more benign materials. If society wants to make that choice, okay -- but let's be conscious that it's a choice with consequences, and not allow ourselves to be talked into believing that we can make silk purses out of sows' ears. (Love those barnyard metaphors ).
Ted Mooney, P.E. RET
Pine Beach, New Jersey
We were recently informed by one of our large customers that they anticipate a need for chromium free (hex- & tri-) protective coatings by Jan 2004. Whether this need actually bears out, time will only tell but thanks for opening the conversation Timothy.
What I've been looking for is a suitable replacement for zinc chromate. The replacement has to provide 96 hours protection to white rust and 300 hours to red rust in a 5% salt spray. Electrical conductivity is also necessary. There are, of course, other plates that can meet these needs (EN) but cost is also a driver. So for now I'm sticking to zinc with a suitable post-treatment. When talking zinc, PAVCO comes to mind since zinc is what they do. I know they've been looking to develop chrome-free or hexCr-free products and they probably have some to market by now. Schloeter may also be a good source as they are a major Euro player.
I will be working on this search for the next few weeks and will share my findings as they develop.
- Syracuse, New York
If both hexavalent and trivalent chrome are to be eliminated, it may be time to look more closely at alternatives to plating, such as spray techniques (plasma or thermal)for applications where thick coatings are needed, and vacuum deposition techniques for thin coatings. There's an article on spray deposition as a replacement for hexavalent chrome in this month's issue of Advanced Materials and Processes.
- Vista, California
Thank you for the suggestions and discussion so far. I am investigating some of these non-hexavalent technologies. I am also in the process of contacting our European facilities.
Since my company produces fuel rails, brake system components, and power steering components, our salt spray requirements are a little higher with these high-safety systems. Our salt spray requirements typically range from 96 to 200 hours to 5% white corrosion and from 500 to 1200 hours to 5% red rust.
Here is something else to consider. Even if current hex-chrome usage is below 2 grams per vehicle, would proving it and monitoring it prove to be too costly? I still think that this European restriction could be the beginning of the end for hex-chrome.
Rochester Hills, Michigan
Tim: I think hex chrome is gradually on the way out too. The reason is that the parts themselves have hex chrome on the surface--which the public touches.
Toxic waste is an issue with technical solutions; the same with wastewater treatment, exposure to fumes, and other industrial containment issues. But if we start accumulating data, even anecdotal data, that shows increased risk of skin cancer among workers, it will become unacceptable to put that material on the surface of an item touched by the public. The platers can lobby as they like, but they can't win.
It should play out similarly to the cadmium issue but on a faster time-frame. 35 years ago cadmium plating was used everywhere; then people felt vaporized fumes were harmful, so it was gradually eliminated from parts that were often torched; then people came to realize that zinc could replace it on most hardware, so it might as well; gradually, its usage was reduced, easy applications first. Directives not withstanding, there is still cadmium on European autos, but very little of it.
People will start to say that trivalent chromates are good enough for many mildly corrosive applications. And trivalent chromates with lacquers will replace other applications where conductivity isn't needed. And some parts that were plated will be painted. And, as suggested above, electroless nickel will replace some of it, and spray and vacuum techniques will apply ceramics in other applications. And 15 years from now there will still be some very limited use of hex chromates for critical applications.
So I agree with you that we are at the beginning of the end, but I think it will be because of public reaction to a reality or perceived reality, not because of European directives.
Ted Mooney, P.E. RET
Pine Beach, New Jersey
Mr. Timothy Neveau
I would like to add some remarks about hexavalent chromium :
1) The Directive of the Council of European Communities COM(97)358 dated 07.09.1997 says that, starting of 01.01.2002, it will be forbidden to use, in the manufacture of vehicles, the following dangerous substances : lead, mercury, cadmium, PVC and hexavalent chromium.This is to avoid the pollution of the environment during the destruction or recycling of the vehicles, at the end of their life. If, for the first 4 elements, there is nothing to say, one may however wonder how a steel part, zinc plated and chromated, may pollute the environment after being granulated and introduced in metallurgical furnaces? But, in the absence of any right of contestation the electroplaters have no choice but to be submissive. Maybe the Council of European Communities lacks of good electroplating specialists and is not much bothered by elemental rules of democracy.
Would it be possible to imagine an action like that of the AESF Society beside U.S.Congress, described by Mr.Michael Murphy in his Editorial of Metal Finishing of Nov.1999 ?
2) In despite of the affirmation of Mr. Ted Mooney, a trivalent chromium conversion coating that provides protection equivalent to (iridescent) hexavalent chromium has well been invented in Europe and it is called chromiting (as it uses chromites in place of chromates) and is even object of a Specification of General Motors Europe (GME 00252). In plus, this coating resists to the thermal shock.
3) On the way to get rid of hexavalent chromium in conversion coatings, a yet unsolved problem, is the, so much beloved by designers, black passivation of zinc deposits, which needs the use of high concentrations of chromic acid. Many times this finish is specified for cosmetic, but non functional, reasons. Some new patents describe black passivations of some zinc alloys (Zn-Fe, Zn-Ni). As for the total elimination of hexavalent chromium in surface treatments, I think that we have to wait for the replacement of hard chromium plating by equivalent non-toxic processes.Emmanuel Popesco
I am not advocating the continued use of hexavalent chromate coatings, Mr. Popesco. After all, what we are talking about is coating parts that the public will touch with a toxic, carcinogenic jelly! Not only that, but totally losing control of it in the environment as well -- who knows how many people inspect chromate coatings and remove 'stains' with an eraser, only to eat a sandwich at the same desk full of eraser shavings?
But dozens of independent research projects over a period of decades have shown that nothing is as good as hex chromate yet. The way to show that chromites are as good would be to dig out a dozen or so of those articles, go through the lists of advantages cited for hex chromates, and challenge them ALL as no longer accurate. I maintain that nobody has done that, and nobody can do it, and that what we are doing instead (because we desperately want a less toxic substitute) is erecting a strawman who does not represent all of the advantages of hexavalent chromate but instead is simply "hours to salt spray failure under idealized wishful-thinking conditions".
Please give me your take on
http://www.jgpp.com/jtr-hugh.htm because I would like to be wrong and to learn that there really is a viable drop-in replacement for chromate conversion coatings.
Ted Mooney, P.E. RET
Pine Beach, New Jersey
Ed. note: Sorry, that link no longer works.
All users of hexavalent chromium should pay attention to what is going on in Willits, California -- a very serious long history of toxic waste dumping and carelessness with manufacturing chemicals.
See the following story in the 4 May 2000 Santa Rosa Press Democrat for details
http://www.pressdemo.com/local/news/04remcoempireb.html I would be interested in hearing from others about their experiences with situations like that in Willits. From what I have been told, this may end up being the biggest yet toxic waste lawsuit.
- Rohnert Park, California
Ed. note: Sorry, that link no longer works; but searches including terms like "Willits chromium" and "Remco hydraulics" will be productive. This was a VERY big chrome plating installation with five vertical in-ground plating tanks, one of which was 4 foot dia. x 70 foot deep, plus a couple of horizontal tanks.
Concerning the EU now Ford's ban on hex chrome, we have been working on a replacement since 1993. Since the patents are about to issue, our lawyers are allowing us to share our discovery. We have learned to form a thin, angstrom-thick mineral on steel, zinc, stainless steel, lead and some zinc-aluminum alloys. The coating is formed in an electrolytic bath, replacing the chromate bath in our plating line. Secondary rinses are required to seal the mineral. The process is similar to the epithermal metasomatism process found in nature. It appears the mineral can tolerate temperatures to 350° C and works as an inorganic tie coat with good adhesion properties for top coats. Since the minerals we form are different than what is found in nature the patent office has allowed patents on the minerals and now the process patents are soon going to issue.
Two universities, specializing in surface oxides are characterizing the different minerals. Our approaching method was similar to phosphate but rather than building a mineral on the surface we modified the existing oxide or sometimes create a uniform oxide and the convert it to a complex oxide.
We have a pretty good handle on the electrolytic method but are seeking collaborators for large surface mineralization. The ASTM brush plating method has been tested and seems to work. However we are not pursuing this method as our business is hardware not coils. I was the Chief Jailable Officer (CJO) for a couple of years . From that vantage point, I don't foresee any reduction in regulations, but rather the continuing ratcheting down of discharge allowables. For the long term, it's best for those generations following as we must be stewards of the resources.Bob Heimann
- Moberly Missouri
This may not be completely applicable to your needs but 5 years ago while a Captain in the US Air Force, I started a team called the Hard Chrome Alternatives Team (HCAT). The Air Force, Army, Navy & Industry Canada needed a replacement for hex-chrome on its landing gear components & hydraulic actuators. The environment was much more rigid that the automobile industry needs. Anyway I noticed your comments about stringent salt spray requirements. The Navy did our tests and it turned out very well using high velocity oxy fuel technology. It may be a fit for your situation? Recommend that you check out the website at www.hcat.org. The best industry contact is Keith Legg (his address is on the site). Best Regards & Oh ya, I agree it will be completely eliminated. With movies now being made about it ("Erin Brockovich" [link is to movie info at Amazon]), perception is reality & the public will demand its removal.
P.S.-Tri-Chrome never had the properties that hex-chrome did; but note, HVOF using tungsten carbide cobalt was better or equal to hex-chrome in many categories including corrosion, fatigue, etc.Brian Klute
- Austin, Texas
The European Parlament had a standard saying all the substances that will be forbidden. This will start on July 2003, but it says that may be some exceptions, when forbidden hexavalent chromium. The goal of this standard is to reach a 95% recyclability of the car's parts.Irantzu Muguerza
Ford has informed me that they are undergoing an initiative to eliminate all Hexavalent Chrome from their supplier's products for all NEW product launches. I have an Electrical background and need to evaluate where if any that Hexavalent Chrome is used in my products.
From reading the replies from the many people above, I have 'assumed' that the material in question is the shiny, metallic finish used on car bumpers in the 50's. As I am not directly involved with ALL of the subcomponents used in my products, my immediate concern is that Hexavalent Chrome can come in a 'non-shiny' form, that I personally would not recognize. If anyone has a moment to share their method of detecting Hexavalent Chrome I would be forever grateful.
Sincerely,Gregory C Messer
- Troy, Michigan
No, Mr. Messer, the shiny chrome on bumpers is metallic chromium with a valence/oxidation state of zero not six. Although there is some pressure to reduce the use of metallic chrome for various reasons, that is not what Ford is talking about.
Zinc and zinc alloys and some other metals are plated onto components to give them sacrificial corrosion protection, but the zinc is itself subject to corrosion (white rust). The traditional way of giving corrosion protection to zinc parts has been with a chromate conversion coating where the zinc plated part is immersed in a proprietary bath which includes chromic acid (Cr03) to apply a thin corrosion-fighting chromate gel. You would recognize this as the iridescent yellow (brass-like) coloring you often see on parts. It is also possible to have a clear or bluish or black chromate which contains hexavalent chrome. Aluminum parts are also often treated with a similar chromate conversion process.
Although laboratories can test for the presence of hexavalent chromium on the conversion coated parts, the crux of the problem is that you need to specify that your zinc plated and aluminum parts be processed in hexavalent-free solutions. Virtually all plating shops are aware of the issue, and many of them can now offer hexavalent-free conversion coatings (although they are more expensive because they involve more steps, and may be inferior in performance depending on how well the substitution process is done). My statements from 1999 that there are no substitutes yet that are as good still has truth to it, but aren't quite as true in 2004 as they were 5 years ago. Today's problems are lack of self-healing, poor adhesion of powder coatings and paints, and poor resistance to process chemicals rather than "salt spray hours".
Ted Mooney, P.E. RET
Pine Beach, New Jersey
Per EU ROHS's requirement, Hex Chrome should be less then 1000 PPM in homogenous material. We are facing a problem on how to inspect the parts' actual PPM of Hex Chrome.
Some of our suppliers claim their screw or fastener is Hex Chrome free. And their test report shows PPM of Hex Chrome in the whole parts. Supposedly they should just check the PPM of hex chrome in the zinc plating layer or just Chromate layer. But it is difficult for them to just check the zinc plating layer.
Do you know any good method to check hex Chrome's PPM in the plating layer?
The presence of hex-chrome I think can be detected by using 'dimethylcabazide'
However the exact ppm cannot be measured.
Do you know how to measure/ detect the presence of tri-valent chrome in passivation.
- Gurgaon, Haryana, india
December 6, 2008
I would like to comment on the hex chromium in the Willits area that has been ignored, and intentionally hidden for years. This is like straight poison to a human, animals, or anything living, My whole family has been very ill with many different medical problems; any community like Willits should be legally cleaned up in order to make it safer for the community.Kristie L Cartwright
- Willits, California
Best of luck to you and your family, Kristie. Yes the chromium issue was largely ignored until about 2000, but has been exhaustively covered ever since. "Escape from Suburbia" and Willits' environmental problems from the Remco Hydraulics plant, seem only roughly related to the topic at hand (European restrictions on chemicals including hexavalent chromium), but your community is at the forefront of changes in a rapidly changing world, and you and your townspeople are an interesting story for many reasons.
Ted Mooney, P.E. RET
Pine Beach, New Jersey
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