7440-45-1Relevant articles and documents
Study of the effect of cerium nitrate on AA2024-T3 by means of electrochemical micro-cell technique
Paussa,Andreatta,Rosero Navarro,Durán,Fedrizzi
, p. 25 - 33 (2012)
This work evaluates the effect of cerium nitrate as corrosion inhibitor for AA2024-T3 in the view of its introduction in sol-gel coatings able to provide self-healing ability. Since it is well established that deposition of Ce species is activated by the local pH increase, the objective of this paper is to investigate the behavior of AA2024-T3 (open circuit potential and polarization curves) in the presence of Ce species in aggressive solutions by means of a local technique, the electrochemical micro-cell. This technique enables the investigation of small areas with resolution in the micrometer range by the use of glass capillaries to define the working electrode area. The micro-cell results clearly displayed that the entire AA2024-T3 area exposed to the cerium-containing electrolyte was involved in the cerium precipitation mechanism. The heterogeneous electrochemical behavior of the microstructure is minimized by the formation of a cerium-containing layer able to protect the metal substrate.
Cerium deposition on aluminum alloy 2024-T3 in acidic NaCl solutions
Kolics,Besing,Baradlai,Wieckowski
, p. B512-B516 (2003)
We analyzed the interaction of cerium ions with surface intermetallics on Al 2024-T3 in NaCl media under open circuit conditions at pH 3 using scanning electron microscopic, Auger-electron spectroscopic (AES), and energy dispersive X-ray techniques (EDX), as well as electrochemistry. The results indicate that cerium deposition in a pH 3.0 NaCl solution is strongly surface-site specific. The cerium deposition was the highest on the S-phase particles, lower on the (Cu, Fe, Mn)Al6 sites, and minimal on the bulk matrix. In addition to the formation of a cerium-rich film on the intermetallics, we found that cerium incorporated into the porous structure of the dealloyed S-phase particles (Cu-Mg-Al intermetallics). Our analyses show that cerium does not prevent the dealloying of the intermetallic particles; in fact, the dealloying is necessary for local cerium deposition. AES and EDX data also revealed significant chloride enrichment on the cerium-rich sites. From our electrochemical measurements we conclude that the cerium-rich layer formed in acidic solution at short exposure times does not inhibit cathodic reaction on the intermetallics.
Mechanism of coke formation caused by catalytic nanochromium carbide particles from decomposition of CeCrO3
Li, Hao,Cui, Xinwei,Chen, Weixing
, p. 2578 - 2584 (2011)
Ce or CeO2 is often added to Fe-Cr-Ni base alloys to enhance protective Cr2O3 ceramic scale formation. In high-temperature carbonaceous reducing environments, however, it is still unsolved that Ce-containing alloys often exhibited increased carburization and coke formation. This research is aimed at understanding the mechanism of Ce-enhanced coke formation. It was found that CeO2 can cause catalytic activation of chromium carbide for carbon growth by first forming CeCrO3 and then decomposing CeCrO3 into CeO2 and active nanosize chromium carbide particles; the latter has proven to be conducive to coke formation. These findings can be helpful for the design of alloys with better ceramic coating resistant to carbonaceous degradation and for the growth of graphitic nanostructures using Cr-related catalysts.
Preparation of lanthanum and cerium metals by hydrometallurgy
Hasegawa,Sano,Aoshima,Shiokawa
, p. 246 - 249 (2008/10/08)
Lanthanum and cerium metals were prepared by electrolytic synthesis of amalgams in aqueous solutions followed by the thermal decomposition. The amalgamation yields were almost quantitative. The preparation yield of lanthanide metals, however, deteriorated during thermal decomposition due to a density difference between lanthanide and mercury. The gaseous impurities in the prepared metals were found to be comparable with those in commercially available ones.
