Posted by Gordon England on March 10, 2004 at 03:06:53:
In Reply to: Re: Hydrochloric acid posted by joe on March 10, 2004 at 01:05:14:
: : : Can you tell me what would be the best sealer to use on a HVOF coating, Stellite JK 6189 or JK 135, used in the envirement of Hydrocholic acid? And is there an alternative, or more cost effective one, like some kind of every day household wax or such? Thanks in advance.
: : Hi Joe
: : Microcrystalline wax is a very good sealer as long as the service temperature is kept below the wax melting point (80 C max)and hydrocarbon solvents and oils are not present. The part/coating is heated to above the wax melting point and the wax is then melted onto the coating. Metco did have a product called Metcoseal 185, it may still be available from Sulzer Metco. Household candle wax might work, but its melting point will be much lower and I'm not sure of the effect of the various other components of that wax.
: : Be aware that Stellite JK 6189 or JK 135 coatings will not be totally resistant to Hydrochloric acid environments.
: : Hope this helps.
: : Rgards Gordon
: In your opinon, what would be the best resistance in Stellite JK powder for the hydrochloric acid aplication? Not exactly sure on the operating temp. Thanks again for your help. Joe
Hi Joe
Difficult one to answer. Factors such as temperature, concentration and other chemicals will influence corrosion rates. There are few standard metallic thermal spray coatings that are totally resistant to hydrochloric acid. Metals like titanium, molybdenum, tungsten and alloys inconel 625 and hastelloy C are fairly resistant, but in the form of coatings containing oxides their resistance is lowered somewhat. Plasma sprayed ceramic coatings of aluminium oxide or chromium oxide are resistant if completely sealed.
Can you give more information on what the coating needs to do and the environment it will be working in?
Regards Gordon
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