best replacment for Cr2O3

[ehsan]

Hi
I do not have APS system for spray of chromium oxide.but i have gas hvof and jp5000.
I have several customer for this coating.
what is the best coat replacment for chromium oxide that has same properties to Cr2O3.
Ehsan

[Gordon]

Hi Ehsan

Quote:what is the best coat replacment for chromium oxide that has same properties to Cr2O3.

Well if your HVOF systems can not spray oxide ceramics, then really there are no coatings with the same properties. That does not mean to say that for a certain application an HVOF alternative coating is not possible. Sometimes tungsten carbide based coatings can be substituted with good effect, but it really depends on the specific application - anilox rolls, certain seal faces, specific anti-corrosion applications, electrical insulation etc. are probably ones not covered.

[ehsan]

[quote='Gordon' pid='3406' dateline='1242173697']
Hi Gordon
Thanks.Do you have any hvof system that spray chromium oxide?
what is this and how it works?
regards
Ehsan

[Gordon]

Hi Ehsan

No, but I believe the Top Gun SM, Diamond Jet, Theta gun and a few others can use modified hardware to spray ceramic powders. HVOF wire (rod/cored) systems are less restricted.

With ceramic powders, I think the systems are detune velocity wise, use extra fine powders and maximise flame temperature (acetylene, propylene, hydrogen) to achieve this goal . While coating quality can be very good (better than plasma), efficiency and production rates tend to be poor and special powders are required.

[LEN WOOD]

Hi Ehsan,

Check out Melissa Riley's (TWI Limited) article on Ceramic coatings by HVOF spraying:

http://www.tssea.co.uk/pdf_files/coating...r-2003.PDF

As Dr. Riley points out the process is higher cost than plasma spraying, but superior wear resistance can be produced. Remember though that this was 2003 - things change!

Why don't you just buy a Plasma system you already have 2 HVOFs?

GlenB

[ehsan]

Hi gordon
thanks alots.
Is it possible that give me more detail and info for that process.
you know that we have flame gun(5pll) and hvof system.we have some project on ceramic coating but we should support this coating.
regards.
ehsan

[Gordon]

Hi Ehsan

Depends very much on required purpose/application for the coating. Your Metco 5P-II gun is capable of spraying some chromium oxide and other oxide ceramic coatings. OK, maybe not the best coatings of the tsc processes, but still capable of providing suitable coatings for certain applications without too much investment. Plasma spray I still think is the more versatile and best overall tool for applying oxide ceramics and refractory materials. HVOF I think is still in its early days of development for oxide ceramic ceramic coatings, though very high quality coatings are being produced, but at a cost.

I maybe getting out of touch with more recent developments, so it would be interesting if someone can argue the case for choosing HVOF over plasma for general commercial application of oxide ceramic/refractory coatings

[ehsan]

Hi Gordon
I know that charge of hvof is so higher that APS but in this conditions of my company we can not buy APS and we need to spray chromium oxide for some valuable parts then cost is not important!!
i tested with 5pll but i did not get good result i get very poros coating then very low hardness.
if it is possible please help me for spraying it with hvof!!!
Ehsan

[Gordon]

Hi Ehsan

Your JP5000 system as far as I know will not be capable of spraying Chromium oxide powder. Your gas fuel HVOF system may have a bit more potential, I would contact the supplier/manufacturer to see if they have addition hardware for spraying ceramics. Failing that, you will need to get an additional HVOF system capable of spraying ceramics. The Rokide ceramic rod combustion spray system may also be worth consideration, along with HVOF wire/rod spraying systems.

[ehsan]

Hi Gordon
ok if we should provide additional equipment for gas hvof we do not have any problem .i prefer to spray chromium oxide powder and i have different size of cr2o3 (+5-25,+25-45,+45-90).
Plz say me what is that additional equipments?
ehsan

[Stephen Booth]

http://www.gordonengland.co.uk/sef/info-...-t-31.html

back in post in 2006 I believe you were asking a similar question.

Try these links.
(links dead)

Both the Mogul and Rokide systems are viable alternatives to Plasma for WEAR Applications, seals, sleeves, etc.

[ehsan]

Hi stephen
He was EHASAN not ehsan!!
I joined to surface forum recently.
Thanks for your guide.
Ehsan

[Gordon]

Hi Ehsan

If HVOF is your only game, then I can only suggest contacting the various HVOF maufacturers and ask them about your specific requirements. I know a few companies in the UK using Sulzer Metco DJ gun commercially for alumina coatings ( not sure about chromium oxide) and the TWI work (see GlenB link). heard of a Japanese gun called Theta, which I think has something like an acetylene afterburner, thats about all I know.

[plasmajet1990]

(05-12-2009 09:29 PM)ehsan Wrote:  Hi
I do not have APS system for spray of chromium oxide.but i have gas hvof and jp5000.
I have several customer for this coating.
what is the best coat replacment for chromium oxide that has same properties to Cr2O3.
Ehsan

Hi,

Buy from here:
http://www.youtube.com/watch?v=JXlOvoSj5Cc

Ion

[ehsan]

Hi Gordon
Thanks for your contact with providers and please offer me best of requaierments.
Ehsan