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topic 18257

What is Distek / DiAv-93 / Unstain 1500 Thermodiffusion Sherardizing


RFQ: Hello,

I seek a company which could provide me equipment for sherardising. I sought some on the Web but I found none of it.

Thank you

Yohan Tremblay
- Quebec


RFQ: I am looking for Sherardizing Machinery or Sherardizing Jobshop. So far I haven't even met someone in India who has heard of this process. Can anyone help.

Mohandeep Singh Sodhi
- New Delhi, India
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Ed. note: Current, active RFQs are now on our "Looking for Products & Services for Our Finishing Shop" page, and our "Looking for a Finishing Service" page.


A. You don't have to seek a company that makes equipment. You will not find anyone. Just make the equipment yourself. If you need the machines you want, just go to a constructor and tell your wishes. I work in Holland in a small company that sherardizes. The owner just developed some machines, and some he could buy.

Leon Kloor
- Helmond, The Netherlands


Q. I would like to know about the corrosion resistance of sherardized parts. I have heard there is this new technology called sherardizing 2000 which can withstand up to 500 hours in the salt spray test. Has anyone heard about DiAv-93? It is a patented process of thermodiffusion galvanizing developed in Israel by Distek Ltd. They say it is similar to sherardizing in application, yet superior in corrosion resistance.

Sena Kiray
- Istanbul, Turkey

Ed. note-- Readers: to the extent practical, please try to keep this discussion about generic metal finishing technologies like sherardizing/thermodiffusion rather than the purported advantages of one particular brand or proprietary.
Also, keep in mind that salt spray testing of zinc coatings can be quite silly because their corrosion resistance depends upon the development of glassy tenacious self-sealing zinc carbonate corrosion products over the years; the zinc just dissolves away in a salt spray test :-)


Q. I'm aware of rumors about Distek, but I find a lack of information. Maybe someone can help me?


norbert seyfert
Dr. Norbert Seyfert
surface development - Olpe, Germany


A. Dear Sir,

Distek is an Israeli company who designs and sells lines for thermodiffusion zinc coating. Distek has today a better technology than Sherardising, but in principle it is the same technology of thermodifussion coating.

Best regards

Sigve Bø


A. You can try Distek web site or just google "Distek thermo diffusion".

Dorian Shifman
- Scarsdale, New York


A. I'm very familiar with this system. I know that DiSTeK® coated product is being sold under their American trademark UnStain® 1500 and is guaranteed for 1000 hours in ASTM B117 [link by ed. to spec at TechStreet] salt spray test.

Roded Leviathan
- New York, New York


A. I know that DiSTeK is the owner of the DiAv-93 process and that their American subsidiary have test results by independent 3rd parties, such as US EPA, Michigan State University, and Dade County (FL) approved lab. Their American company posts the test results on their web site. I am sure that through a search on Google you can find the information. Or you can contact them and they will send you copies of these test results.

Dorian Shifman
- Scarsdale, New York

December 28, 2008

A. Hi, Sena. Hi, Norbert.

1. If you search our site for "sherardizing" you will find several threads on what it is and its history.
2. The March 2004 edition of Metal Finishing Magazine contains an article by Dr. Benu Chatterjee on sherardizing, page 40.
3. Distek NA can probably help you with your questions or refer you to the proper contacts in Turkey.
4. You may wish to listen to our podcast interview with Martin Straus of Chemplate Industries about Sherardizing and the DiSTeK® process.


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

Improved Sherardizing

February 20, 2008

Q. I used to work for a company that utilised the original process to sherardize conveyor chain sideplates. Now I am doing consultancy for a company that builds aluminium ingot casting plants. This company makes their own conveyor chains and they wish to sherardize the sideplates. Unfortunately, nobody else does sherardizing in Australia.
Therefore I am looking at alternative suppliers elsewhere around the world.
Could you give me the contact details of the sherardizer in the USA?
Also, if it is not a trade secret, could you tell me how they achieve such surface hardness and what do they use in lieu of sand (if any)?


Yilmaz Gursoy
Mechanical Design Engineer - Melbourne, Victoria, Australia

May 1, 2008

RFQ: Where can I have parts sherardized in the USA?

Richard M [last name deleted for privacy by Editor]
- Houston, Texas, USA
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A. Hello Yilmaz; hello Richard.
Our supporting advertisers will contact you in private regarding their ability to fill your commercial needs. There is an Israeli company that offers what they claim is an improvement on sherardizing, which they call "thermodiffusion zinc coating". Other competitive technologies that you might consider include zinc electroplating, hot dip galvanizing, and mechanical galvanizing. Good luck.

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

February 28, 2008

A. DiSTeK (tm) is an improved Sherardizing (Sherardising) process developed in Israel (also Russia and Turkey). There is one U.S. applicator, Agritek (, 4211 Hallacy Drive, Holland MI 49424 . Your contact there is Bill Maddox ( 616-786-9200.

(Message from Tom Rochester : Bill Maddox, when you read this you should think about advertising on

Tom Rochester
Plating Systems & Technologies, Inc.  
supporting advertiser
Jackson, Michigan, USA
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Why did Thermal Zinc Coating shrink my fasteners?

April 16, 2010

Q. I had a sample coat made at Distek here in South Africa and it was perfect.
Now I hand in 500 M22 x 1.5 special studs with knurl etc and they come back I cannot get the nuts on but the size over the thread and even over the head has shrunk by 0.12 mm over the thread and 0.5 over the 35 mm head. This including the actual coating.

Apparently they were not happy with the first effort and "stripped" the coating off and now I have undersized studs but with clogged threads onto which the nuts cannot go. How is this possible. Does the Thermal Zinc deposit process then shrink the material or is the heat treatment the result or what could this be.

Should I not use this method then at all which means only remaining corrosion protection would be mechanical plating to avoid hydrogen embrittlement.

Please I need advice. Previously I used just normal zinc blue electroplating giving a great finish but not as corrosion resistant and I have to trust the plater will bake all hydrogen out of the bolts and I am not sure that that is the best process.

Chris Vermaak
machinist - Heidelberg, South Africa

April 30, 2010

A. Hello,

I guess you are not able to do the gauge fitment with nuts because of excess coating thickness in the thread roots. By the way what is the thread pitch and how much thickness you have deposited on it?

Maybe you can do the coating with controlled thickness and then nuts should fit easily.

All the best.

kalyan dhakane
Kalyan Dhakane
Mumbai, India

Threads on similar topics include:
- Letter 8591, "What is Sherardizing?"
- Letter 4917, "Sherardising: What is it? What are the important parameters?"

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