TSA AISI316L against 22 Cr duplex 1

[MaxNeg63]

Hello everybody. Is there anybody who has any knowledge about the use of thermally sprayed alluminium coated AISI316L against bare 22 Cr duplex steel within an environment containing hydrocarbon and water?
thanks a lot
Max

 

[SJones]

It wouldn't be considered normal practice (by me anyway) to resort to applying thermal spray aluminium to a CRA material. It's horses for courses and if you have to adopt TSA then you have backed the wrong horse. What corrosion mechanism are you trying to protect against?

Steve Jones
Materials & Corrosion Engineer

http://www.pdo.co.om/pdo/

 

[MaxNeg63]

Thanks Steve. Supplier is proposing such solution to protect 316L against SCC at temperatures higher than 50 °C.
My doubts regard the inherent porosity of thermal spray coatings and therefore the contact between substrate material and aggressive environment.

 

[SJones]

Well, there is the possibility of cathodic protection provided by the TSA but, at some point, the TSA will be depleted. As to whether you need to worry about INTERNAL SCC, take a look at Bruce Craig's NiDI paper on CRAs in oilfield environments.

http://www.nickelinstitute.org/mult...erature_pdfs/10000_technical_series/10073.pdf

Steve Jones
Materials & Corrosion Engineer

http://www.pdo.co.om/pdo/