Effect of Ce and Hf on the segregation of sulfur and the anodic polarization of nickel

Journal Article · Sat May 01 04:00:00 EDT 1993 · Scripta Metallurgica et Materialia; (United States)

DOI:https://doi.org/10.1016/0956-716X(93)90010-P· OSTI ID:6519571

Lee, M H; Park, Y W ^[1]

---

1. Univ. of Suwon (Korea, Republic of) Sungkyunkwan Univ., Suwon (Korea, Republic of)

It is known that sulfur segregates to grain boundaries even at low bulk concentration and embrittles nickel and nickel-based alloys or accelerates intergranular corrosion of this alloy. One way to reduce the sulfur segregation is to introduce strong sulfide forming elements into nickel such as, Ce, Cr, and Hf which can tie up sulfur in the nickel matrix. Another possible method would be to replace sulfur by segregating elements which help the cohesion of grain boundaries or improve grain boundary chemistry such as phosphorus or boron. Therefore, in this article, the authors investigated the surface segregation of sulfur in nickel doped with Ce, Hf and Mn by Auger electron spectroscopy, and the anodic polarization behavior of these alloys was examined to compare to that of pure nickel. Among the tested elements, Hf was found to be the most effective element in suppressing the sulfur surface segregation in nickel. However, Ni+470ppm Hf specimen showed pitting corrosion in 0.1 N H[sub 2]SO[sub 4] solution. All the elements (Mn, Ce, and Hf) added to nickel at the concentration of about 500ppm improved the ability to passivate the nickel but deteriorated the properties of the passive film. Ce addition into nickel might be the best choice among the examined elements to reduce the sulfur segregation in nickel-based alloys without deteriorating the corrosion characteristics.

• OSTI ID: 6519571
• Journal Information: Scripta Metallurgica et Materialia; (United States), Journal Name: Scripta Metallurgica et Materialia; (United States) Vol. 28:9; ISSN SCRMEX; ISSN 0956-716X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360105* -- Metals & Alloys-- Corrosion & Erosion
ALLOYS
ANODIZATION
AUGER ELECTRON SPECTROSCOPY
CERIUM
CHEMICAL COATING
CHEMICAL REACTIONS
CORROSION
CORROSION PROTECTION
CRYSTAL STRUCTURE
DATA
DEPOSITION
ELECTROCHEMICAL COATING
ELECTROLYSIS
ELECTRON SPECTROSCOPY
ELEMENTS
EMBRITTLEMENT
EXPERIMENTAL DATA
GRAIN BOUNDARIES
HAFNIUM
INFORMATION
INTERGRANULAR CORROSION
LYSIS
MANGANESE
METALLURGICAL EFFECTS
METALS
MICROSTRUCTURE
NICKEL
NICKEL ALLOYS
NICKEL BASE ALLOYS
NONMETALS
NUMERICAL DATA
PITTING CORROSION
RARE EARTHS
SEGREGATION
SPECTROSCOPY
SULFUR
SURFACE COATING
TRANSITION ELEMENTS