HVOF WcCoCr Sealant
04-01-2013, 11:42 AM,
#1
HVOF WcCoCr Sealant
Hey all,

I have recently had a customer request a part coated with WcCoCr and then to be surface sealed. This would be the first time we have had this sort of request and I'm sure it won't be the last.

I have read a few articles that stated using Linseed Oil is a viable option.

I am wondering is this the best method?
Are there other products that are readily available?

I realise that different products produce different results. From our understanding the customer wishes to decrease the already low porosity of the parts.

Any information would be very helpful.
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04-03-2013, 01:11 PM,
#2
RE: HVOF WcCoCr Sealant
Hi SSC

I've come across quite a few different sealers in use for HVOF WC-CoCr.

As you say Linseed oil in the form of Metcoseal AG
Metcoseal AP a phenolic resin
Loctite 290 anaerobic methacrylate
Epoxy resin
Wax
and no doubt a few others.

Depends really on the operating environment and whether the sealer is in itself resistant to it.
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04-03-2013, 02:09 PM,
#3
RE: HVOF WcCoCr Sealant
I agree with Gordon, the metal impregnation sealants choise is very important , It must penetrate the microscopic porous holes and must resist against working temperature and aggressive chemicals products on the piece operating environments and working temperature conditions, To apply sealers you must have a clean and dry surface, and before apply it, the coating must be preheated, in order to facilitate the sealer penetration, the choose of the sealer is very important, and must be used only products created for thermal-Spray applications, there are sealants that are resistant till 1200 °C and more.
Best regards
Luigi
Reply
05-23-2016, 12:52 PM,
#4
RE: HVOF WcCoCr Sealant
(04-03-2013, 02:09 PM)loriolo Wrote: I agree with Gordon, the metal impregnation sealants choise is very important , It must penetrate the microscopic porous holes and must resist against working temperature and aggressive chemicals products on the piece operating environments and working temperature conditions, To apply sealers you must have a clean and dry surface, and before apply it, the coating must be preheated, in order to facilitate the sealer penetration, the choose of the sealer is very important, and must be used only products created for thermal-Spray applications, there are sealants that are resistant till 1200 °C and more.

Hello everyone,

I know this thread is very old but i am currently working exactly on that subject.
My company currently uses the loctite 290 sealer on HVOF coatings but I am looking for something else which is able to cope with permanent exposure over 300°C min.
The Loctite 290 which is a thermoset polymer is able to reach 200°C and 150°C on a permanent way...
This sealer has to penetrate deeply and be permeable against gas on the same time.

Can you advice me ? Does a sealer exist with these features ?

Thank a lot in advance
Reply
05-25-2016, 05:24 AM,
#5
RE: HVOF WcCoCr Sealant
Hi Thomavia
Dichtol sealant are one of the best choise, there are many others, but I had very good result with this, Diamant has a wide sealant line, for all kind of thermal spray applications, even on cracked coatings and from -50 to 550 °C, with capillary active penetration up tu 20 mm, with very reliable protection against water, oils, chemicals agents, and with food and drinking water approvals, you can choise the one write for your application on www.diamant-polymer.de
Best regards
Luigi
Reply
06-14-2016, 12:11 PM,
#6
RE: HVOF WcCoCr Sealant
Hello,

Does someone already make a gas tight test after applying the dichtol WFT1532 on a WCCoCr coating ?
Which results did you get ?
On my side, it has been completely failed... Is that sealant is supposed to impregnate all microporosity and make the material impermeable against gas ?

Reply
10-22-2016, 07:32 PM,
#7
RE: HVOF WcCoCr Sealant
Hi, Thomavia

We tried to use Dichtol for gas tight applications with the same poor result.

it seals porosity for the normal environment, but when you apply pressure...
it fails.

Looks like the only way here is to make non-permeable HV coating.

Vig
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10-24-2016, 04:46 PM,
#8
RE: HVOF WcCoCr Sealant
UniqueCoat Technologies has been successfully applying non-permeable WC coatings with their M3 gun. The coatings have withstood tests at 15,000 psi.
Reply
10-25-2016, 11:48 AM,
#9
RE: HVOF WcCoCr Sealant
Sure, David

HVAF is good in providing non-permeable WCCoCr coatings;
Kermetico and UCT are the only two HVAF equipment manufacturers so far.

BR
Vig
Reply
10-28-2016, 04:06 AM,
#10
RE: HVOF WcCoCr Sealant
On a related subject, Kermetico has a very simple testing equipment for checking the coating permability http://www.kermetico.com/equipment-gastest.php

And of course HVAF is one of the optimum solutions to get a good coating system, to withstand these applications, and eliminate the use of sealants.

Primary function: The Coating Gas Permeability Tester (GPT-02) is used for measuring gas flow through a coating, which is directly correlated to the coating through porosity.

Principle of operation: The test coating is applied onto a flat surface of a standard porous disc sample. The sample is placed into the GPT-02 cell. The test gas (nitrogen, air) is delivered to the cell under the sample at a controlled pressure. The flow of gas through the coating is measured above the sample with a precise flowmeter. Original results are presented as the “Gas Flow – Pressure Chart”.
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08-21-2020, 01:15 AM,
#11
RE: HVOF WcCoCr Sealant
(04-03-2013, 02:09 PM)loriolo Wrote: I agree with Gordon, the metal impregnation sealants choise is very important , It must penetrate the microscopic porous holes and must resist against working temperature and aggressive chemicals products on the piece operating environments and working temperature conditions, To apply sealers you must have a clean and dry surface, and before apply it, the coating must be preheated, in order to facilitate the sealer penetration, the choose of the sealer is very important, and must be used only products created for thermal-Spray applications, there are sealants that are resistant till 1200 °C and more.

Dear Iorolo, can you tell me what is the sealant that resist 1200°C, I need once to aplly in this situation.
Tks.
Reply
08-21-2020, 01:41 AM,
#12
RE: HVOF WcCoCr Sealant
you might check out https://firesidecoatings.com/optecoat/ up to 1097C its more of a coating than a sealant, but used over the top of HVOF and Arc Coatings in boilers
Reply
08-21-2020, 02:50 PM,
#13
Thumbsup  RE: HVOF WcCoCr Sealant
(08-21-2020, 01:41 AM)Stephen Booth Wrote: you might check out https://firesidecoatings.com/optecoat/ up to 1097C its more of a coating than a sealant, but used over the top of HVOF and Arc Coatings in boilers

Tks, I will consult this sealant, by the way, it can be used in another application.
Reply
09-07-2020, 10:29 PM,
#14
RE: HVOF WcCoCr Sealant
Hi Wagner
Try Aremco 542 or Aremco Ceramacot 503-VFG-C, both are a single-part, alumina-filled, high-temperature, corrosion resistant
sealer for applications as thermal spray sealant up to 1.200 °C
Best regards
Luigi
Reply




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