Effect of silicon on intergranular corrosion of stainless steel in nitric acid solutions

Book · Mon Dec 01 04:00:00 EST 1997

OSTI ID:548567

Honda, T; Yokosuka, T; Arai, Y; Sukekawa, M ^[1]

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1. Hitachi Ltd., Ibaraki (Japan)

Corrosion mechanism of austenitic Fe-Cr-Ni alloys containing 0.06--3.76%Si in Highly oxidizing HNO{sub 3} solutions have been studied by exposure testing, electrochemical polarization, high resolution analytical electron microscopy (HRAEM), and Auger electron spectroscopy (AES) techniques. Results of these studies indicate that intergranular corrosion of {approximately} 1%Si alloy is caused by galvanic coupling effect between Si-rich grain boundaries and normal grain faces. Lower Si-content alloys have high corrosion resistance by an absence of the effect and forming Cr-rich oxide films. Corrosion tests using laser surface melted alloy and coupons simulating a galvanic couple support the identified mechanism.

• OSTI ID: 548567
• Report Number(s): CONF-970332--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHROMIUM-NICKEL STEELS
CORROSIVE EFFECTS
EXPERIMENTAL DATA
INTERGRANULAR CORROSION
METALLURGICAL EFFECTS
NITRIC ACID
PASSIVATION
SILICON