Effect of post treatments on the corrosion resistance of plasma sprayed duplex stainless steel coating in salt water

Book · Sat Dec 31 00:00:00 EST 1994

OSTI ID:160499

Kinos, T; Siitonen, P; Kettunen, P; Laurila, V J ^[1]

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1. Tampere Univ. of Technology (Finland)

The uniform composition of a thermally sprayed duplex stainless steel coating is essential to ensure its good corrosion resistance in salt water. Stainless steel coatings made by atmospheric plasma spraying (APS) always contain pores and oxides accompanied with chromium-depleted zones which destroy the corrosion resistance of such coatings. To reduce porosity and oxidation of the coatings, several post treatments for the coatings sprayed by APS and by APS with gas shielding around the plasma jet (APS/S) were studied including resin impregnation, hot isostatic pressing (HIP), shot peening and vacuum annealing. Electrochemical corrosion tests revealed that the corrosion resistance of the APS coatings could not be improved by any post treatments because oxidation during spraying caused chromium-depleted zones in the coating. The best corrosion resistance was obtained by using the shielding gas shroud with APS. Such coatings had a very low oxide content and primarily ferritic structure. The corrosion resistance of these APS/S coatings can be further improved by shot peening to densify the coating or by post annealing, which balances the austenite/ferrite ratio of the coating as well as reduce porosity.

• OSTI ID: 160499
• Report Number(s): CONF-940684-; ISBN 0-87170-509-5; TRN: 96:006037
• Resource Relation: Conference: 1994 national thermal spray conference, Boston, MA (United States), 20-24 Jun 1994; Other Information: PBD: 1994; Related Information: Is Part Of 1994 Thermal spray industrial applications: Proceedings; Berndt, C.C.; Sampath, S. [eds.] [State Univ. of New York at Stony Brook, NY (United States). Dept. of Materials Science and Engineering]; PB: 816 p.
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
IRON BASE ALLOYS
PLASMA ARC SPRAYING
MICROSTRUCTURE
CORROSION RESISTANCE
CHROMIUM ALLOYS
NICKEL ALLOYS
MANGANESE ALLOYS
MOLYBDENUM ALLOYS
SILICON ADDITIONS
NITROGEN ADDITIONS
POROSITY
SURFACE TREATMENTS
RESINS
IMPREGNATION
HOT PRESSING
SHOT PEENING
ANNEALING
OPTICAL MICROSCOPY
SCANNING ELECTRON MICROSCOPY
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION
POTENTIOSTATS
SODIUM CHLORIDES
EXPERIMENTAL DATA