HCl and HV*F coatings
03-12-2012, 10:05 PM,
#1
HCl and HV*F coatings
Hi All,
Just a preliminary question here to find out if anyone can point me in the right direction.

Some of the guys in our shop were experimenting with different high velocity coatings to find out about resistance to hydrochloric acid.

Two samples of WCCrCNi (one sprayed with HVOF, one sprayed with HVAF) have both completely fallen off a mild steel backing plate after less than 24 hours of submersion. This is just standard hardware store grade HCl, nothing too concentrated. The HCl was used to try and speed up corrosion of the mild steel backing plate, to see how the coating stood up. It appears that the entire coating has lifted off in large pieces.

However, one sample of HVOF applied WCCo (88/12) appeared to suffer no degradation after several days of submersion.

Can anyone suggest reasons for this?

Much appreciated.
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03-13-2012, 09:14 AM,
#2
RE: HCl and HV*F coatings
Who need to strip a tungsten carbide HVOF thermal spray coating be glad to you, because every material has its strip method, you choice the media in order to perform WCCrCNi striping, but you must get an approval for an alternative striping method, quite every material has his own strip media, it means that as we know WCCo is indicated for chemical corrosion at low and high temperature, thats why WcCo performed better.
Best regards
Luigi
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11-02-2012, 09:37 AM,
#3
RE: HCl and HV*F coatings
(03-13-2012, 09:14 AM)loriolo Wrote: Who need to strip a tungsten carbide HVOF thermal spray coating be glad to you, because every material has its strip method, you choice the media in order to perform WCCrCNi striping, but you must get an approval for an alternative striping method, quite every material has his own strip media, it means that as we know WCCo is indicated for chemical corrosion at low and high temperature, thats why WcCo performed better.

Hello, all!
In our company we need to strip carbides coatings, like WC/Co/Cr, Cr3C2/NiCr and other. And we don't have galvanic baths. If coatings was stripped with some chemicals they wouldn't damage steel substrate? I know that use solutions rochelle salt and soda ash, tartar acid with sodium carbonate. What solution will strip coating better? May be there are another methods of stripping carbide coatings without current. When may impregnate coating with something, it will soften a coating and coating would be removed using abrasive blasting?
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