Characterization by CEMS, XRD, and XPS of oxidized layers formed on the surface of carbonitrided low-carbon steel

Journal Article · Thu Jun 01 04:00:00 EDT 1995 · Materials Characterization

DOI:https://doi.org/10.1016/1044-5803(95)80080-8· OSTI ID:85932

Kurosawa, Kazuyoshi; Li, H L; Ujihira, Yusuke; Nomura, Kiyoshi ^[1]; Mochizuki, Eiichi ^[2]; Hayashi, Hiroki ^[3]

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1. Univ. of Tokyo (Japan)
2. Kogakuin Univ., Tokyo (Japan). Analytical Lab.
3. Central Research Labs. of Nihon Parkerizing Co. Ltd., Hiratsuka (Japan)

The surface structure and oxidation characteristics of carbonitrided low-carbon steel, prepared by oxidizing the surfaces in salt-baths after the carbonitriding process, have been studied using conversion electron Moessbauer spectrometry, X-ray diffractometry, and X-ray photoelectron spectrometry. The formation of an iron oxide layer in the carbonitrided surface improved the corrosion resistance significantly. The steel surface after carbonitriding for 3600 s consisted of {var_epsilon}- and {gamma}{prime}-nitride, {var_epsilon}-carbonitride, and cementite. After the oxidation, two sextets and one doublet were observed, attributable to the presence of magnetite, Fe{sub 3}O{sub 4}, and of fine crystals of ferromagnetic iron oxides such as {alpha}-Fe{sub 2}O{sub 3}, {gamma}-Fe{sub 2}O{sub 3}, and Fe{sub 3}O{sub 4}. Cross-sectional analysis or depth profiling of the carbonitrided layer revealed the presence of iron oxides not only in the outermost oxide layer but also in the carbonitrided layer. Oxygen diffused deep into the carbonitrided layer and formed fine crystals of iron oxides there, distorting the crystal lattices of {var_epsilon}-carbonitride and {gamma}{prime}-nitride.

• OSTI ID: 85932
• Journal Information: Materials Characterization, Journal Name: Materials Characterization Journal Issue: 4 Vol. 34; ISSN 1044-5803; ISSN MACHEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CARBON STEELS
CARBONITRIDES
CEMENTITE
CORROSION RESISTANCE
CRYSTAL LATTICES
IRON OXIDES
MICROSTRUCTURE
OXIDATION
SURFACE TREATMENTS
X-RAY DIFFRACTION
X-RAY SPECTROSCOPY