Cerium chemical conversion coatings for corrosion protection of stainless steels in hot seawater environments

Abstract

In order to replace the hazardous chromate‐based surface treatment, a new cerium chemical conversion coating was developed on 316L stainless steel through a mixed solution of hydrated cerium nitrate, citric acid, and hydrogen peroxide. The chemical composition was characterized by energy‐dispersive spectroscopy, X‐ray photoelectron spectroscopy and atomic force microscope. The dense conversion coating is composed of CeO2 with a small amount of Ce2O3 and has small grain size lower than 50 nm. Its thickness is about 47.4 nm as determined by spectroscopic ellipsometry analysis. Potentiodynamic polarization was used to study the corrosion behavior of the coatings in the concentrated artificial seawater at 72 °C. In comparison with the conventional nitric acid‐chromate passivated specimens, the cerium conversion coatings show much higher pitting potentials. It is suggested that the cerium conversion treatment is more effective than the nitric acid‐chromate passivation to improve the pitting resistance of 316L stainless steel used in the hot seawater environments.

Facile preparation of self-healing superhydrophobic CeO2 surface by electrochemical processes

“…are composed of two multiplets (i.e., v and u), which correspond to the spin orbit split 3d 5/2 and 3d 3/2 , respectively. In accord with previous reports [30][31][32][33][34]…”

“…The intensity of all the Ce 3d peaks slightly decreases with time of air exposure. This is because of covering coating surface by hydrocarbon contaminants, as described below.The O 1s spectra reveal two peaks at 529.5 eV and 531.4 eV; the former is assigned to Ce-O-Ce and the latter to −OH/H 2 O oxygen, defective oxide or carbonate oxygen[30,35,36]. The presence of surface −OH/H 2 O species probably make the surface hydrophilic.…”

In Situ AFM and Electrochemical Study of a Waterborne Acrylic Composite Coating with CeO2Nanoparticles for Corrosion Protection of Carbon Steel

“…[36][37][38] The in situ AFM results demonstrate that the stability of the waterborne acrylic coating was significantly improved by the CeNP. The poor stability of the reference coating can be attributed to the high density of the nano-sized pinholes and opening up of the large defects during the exposure, providing an easy path for the electrolyte and leading to premature coating delamination.…”

A Detailed Molecular Dynamics Simulation and Experimental Investigation on the Interfacial Bonding Mechanism of an Epoxy Adhesive on Carbon Steel Sheets Decorated with a Novel Cerium–Lanthanum Nanofilm

“…As can be seen, the O 1s is deconvoluted into six peaks at binding energies of 534, 530.16, and 529.7 eV, corresponding to the presence of CeO 2 and Ce 2 O 3 oxides, 23,51 and at 533.26, 532.31, and 531.18 eV, which are attributed to the La(OH) 3 and La 2 O 3 compounds. These results confirm that the cerium oxides exist in both a trivalent state (Ce 3+ ) and a tetravalent state (Ce 4+ ).…”