Simulating study of atmospheric corrosion of Ni-advanced weathering steels in salinity environment: Formation and structure of magnetite rust particles prepared from FeCl2 solutions containing Ni2+ at neutral pH

• Published in: Advanced powder technology : the international journal of the Society of Powder Technology, Japan Vol. 35; no. 9; p. 104605
• Main Authors: Tanaka, Hidekazu, Nishitani, Ayaka
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.09.2024
• Subjects: Artificial magnetite rust; Atmospheric corrosion; Ni ion; Ni-advanced weathering steel; Salinity environment; Salinity environment; Ni ion; Ni-advanced weathering steel; Artificial magnetite rust; Atmospheric corrosion
• ISSN: 0921-8831
• DOI: 10.1016/j.apt.2024.104605

[Display omitted] •Rust formation on Ni-advanced weathering steel in salinity environment was simulated.•Fe3O4 particles were prepared from FeCl2 solutions in the presence of Ni2+ at pH=7.•Addition of small amount of Ni2+ improves crystallinity and particle growth of Fe3O4.•Large amounts of Ni2+ addition suppress Fe3O4 formation to produce α-FeOOH particles.•Added Ni2+ improves the crystallinity of Green rust(Cl-) as a precursor of the rusts. In order to elucidate the role of alloying Ni in Ni-advanced weathering steels on the formation of Fe3O4 (magnetite) rust particles by atmospheric corrosion in salinity environment, aqueous FeCl2 solutions containing various amounts of NiCl2 were aged under bubbling the air at 50 °C for 24 h. The atomic ratio Ni/Fe of the solution was 0 – 0.2 and the solution pH before aging was about 7 over the whole Ni/Fe ratios. Aging for 3 h generated the Green rust(Cl-) ([Fe3IIFeIII(OH)8]+[Cl·nH2O]-) as a precursor of Fe3O4. Added Ni2+ was incorporated into Green rust(Cl-) to form Ni2+-substituted Green rust(Cl-) ([Fe3-xIINixIIFeIII(OH)8]+[Cl·nH2O]-]), resulting in enhancement of crystallization of this material. After aging for 24 h, the Ni2+-substituted Green rust(Cl-) formed at Ni/Fe = 0 – 0.08 was mainly transformed into spherical Fe3O4 particles. The crystallization and particle growth of Fe3O4 were promoted on elevating Ni/Fe ratio. At Ni/Fe ≥ 0.12, Fe3O4 formation was suddenly impeded to generate rod-shaped α-FeOOH particles, of which the material possesses more stable crystal structure than Fe3O4. These results suggest that alloying Ni in Ni-advanced weathering steels accelerates the formation of stable rust layer composed of Fe3O4 and/or α-FeOOH particles by atmospheric corrosion in salinity environment such as coastal and marine zones to contribute to the formation of the protective rust particle layer.