Coating of Blasr Furnace Tuyeres
10-23-2008, 06:44 AM,
#1
Coating of Blasr Furnace Tuyeres
Hi Gordon and members,
We have a requirement to coat blast furnace tuyeres made of electrolytic copper. Suggest a suitable coating which would be applied using plasma spray.
Thanks
Girish
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10-23-2008, 06:34 PM,
#2
RE: Coating of Blasr Furnace Tuyeres
Hi Girish

Arc sprayed NiAl seems to sit well on copper, though as you probably know few coatings bond very well to copper and relies on mechanical key. Top coat alumina or zirconia based ceramic, it is important that these coatings are low stress and resistant to thermal shock. Porous and more friable ceramic coatings may be better than hard dense coatings.
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11-01-2008, 05:55 AM,
#3
RE: Coating of Blasr Furnace Tuyeres
Hi Gordon,
I was wondering since there will lot of thermal strees generated because of large difference between the substrate and the ceramic coating. How better it would be to have a buffer layer of another coating between the bond coat and the top coat to minimise spallation. Can you suggest any buffer layer.
Regards
Girish
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11-01-2008, 04:26 PM,
#4
RE: Coating of Blasr Furnace Tuyeres
Hi Girish

If you want to use an intermediate buffer layer, I would use a coating containing both bond coat and top coat materials. For instance NiAl bond coat + 50NiAl/50 alumina blend buffer layer + Alumina top coat. You may have to blend your own bond and top coat powders together yourself if you can't get the product from your powder suppliers. One step further, you could go for 4 or 5 step graded coating instead of 3, by blending say a 25/75, 50/50 and 75/25 bond/top coat materials and produce a smoother multi-graded coating. Ultimately, if you have a twin or two powder feeders, ideally on a computerised system, you could go for a smooth gradated coating system going from pure bond coat with a smooth gradual transition to pure top coat effectively removing any defined interfaces or layers within the coating.
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