Corrosion Resistance of Injection-Molded 17-4PH Steel in Sodium Chloride Solution

ABSTRACTThe corrosion resistance of 17-4PH powder injection-molded (PIM) martensitic stainless steel (SS) was evaluated in naturally aerated sodium chloride (NaCl) solution (3 wt%) at 25°C. This resistance was investigated by analyzing the curves of the evolution of open-circuit potential with time...

Full description

Saved in:
Bibliographic Details
Published in:Corrosion (Houston, Tex.) Tex.), 2006-04, Vol.62 (4), p.357-365
Main Authors: Costa, I., Franco, C.V., Kunioshi, C.T., Rossi, J.L.
Format: Article
Language:English
Subjects:
Aeration
Analytical methods
Applied sciences
Chloride resistance
Circuits
Corrosion
Corrosion environments
Corrosion mechanisms
Corrosion resistance
Corrosion resistant steels
Electrochemical impedance spectroscopy
Electrochemistry
Electron microscopy
Exact sciences and technology
Immersion
Immersion tests (corrosion)
Injection
Injection molding
Intergranular corrosion
Martensitic stainless steels
Metallurgy
Metals
Metals. Metallurgy
Nonmetallic inclusions
Polarization
Porosity
Precipitation hardening steels
Scanning electron microscopy
Sodium
Sodium chloride
Spectroscopy
Stainless steel
Steel
Submerging
Susceptibility
Citations: Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:ABSTRACTThe corrosion resistance of 17-4PH powder injection-molded (PIM) martensitic stainless steel (SS) was evaluated in naturally aerated sodium chloride (NaCl) solution (3 wt%) at 25°C. This resistance was investigated by analyzing the curves of the evolution of open-circuit potential with time (Eocp vs. time), electrochemical impedance spectroscopy (EIS), and surface observation by scanning electron microscopy (SEM) at increasing times of immersion. The susceptibility to pitting was investigated using cyclic potentiodynamic polarization curves and SEM observation after polarization. Additionally, the susceptibility to intergranular corrosion was evaluated by a modified procedure described in ASTM A 262 Practice A. The results of the 17-4PH PIM steel were compared to that of a 17-4PH steel produced by conventional metallurgy. The results showed that under steady-state conditions the PIM steel presented a behavior typical of passive metals during the whole test period (60 days of immersion). This was indicated by the Eocp vs. time curves, EIS results, and SEM observation of the surface at increasing periods of immersion. The steel showed a bright metallic surface and no signs of corrosion during the whole period of the test. Cyclic potentiodynamic polarization curves indicated that both 17-4PH steels, conventional and PIM, are susceptible to pitting but the PIM steel showed a slightly increased susceptibility to pitting, which was supported by posttest observation by SEM. In the PIM steel, pits seemed to be related to the porosity that had inner oxide inclusions. The 17-4PH steel, produced by both PIM technology and convenPrecipitation-hardenable (PH) steels are stainless steels (SS) that can be hardened by aging heat treatments. They are classified as austenitic, semiaustenitic, or martensitic steels. The 17-4PH (17Cr-4Ni) SS type belongs to the precipitation-hardened martensitic group.1 It has a martensitic structure with low carbon content. After aging treatments its microstructure comprises tempered martensite and extremely fine, copper-rich intermetallic precipitates, whose properties depend on the aging temperature used. Heat treatment is straightforward and, with the exception of the solution treatment, is usually carried out at relatively low temperatures. The alloy is ferromagnetic, in both the solution-treated and aged states. The 17-4PH steel is one of the most widely employed precipitation-hardened SS, being commonly used in nuclear power pl
ISSN:0010-9312
1938-159X
DOI:10.5006/1.3280667