Preparation of Protective Films Containing Molybdate for Self-Healing of a Scratched Iron Surface

CORROSION ◽  
2000 ◽  
Vol 56 (9) ◽  
pp. 901-909 ◽  
Author(s):  
K. Aramaki

Abstract Nonchromate, self-healing films protective against corrosion of Fe were assessed by polymerization of 1,2-bis(triethoxysilyl)ethane ([C2H5O]3Si[CH2]2-Si(OC2H5]3; BTESE) containing ammonium heptamolybdate ([NH4]6Mo7O244H2O), which was combined tightly with ferric ion (Fe3+) on the surface of an Fe electrode passivated in aerated 0.1 M sodium molybdate (Na2MoO4). After the electrode surface was scratched crosswise with a knife-edge, the electrode was immersed in an aerated 0.1 M sodium chloride (NaCl) solution at 30°C for > 4 h, and then polarization curves were measured in the solution potentiodynamically. The anodic process of Fe corrosion was suppressed markedly by passivation of the scratched surface with molybdate ion (MoO42−) oozing from the film and O2 diffusing through the scratch. The surface covered with the film was characterized by x-ray photoelectron spectroscopy, Fourier transform infrared reflection spectroscopy, and electron probe microanalysis.

1992 ◽  
Vol 259 ◽  
Author(s):  
J. Yota ◽  
V. A. Burrows

ABSTRACTChemical treatment of GaAs with sulfur-containing compounds has been shown to improve GaAs surface electronic properties. There is still considerable controversy, however, regarding the chemical nature of the surface film which results from the sulfidation, and of the basis of the electronic improvement and of the decay in the improved electronic properties with time. We have investigated the surface chemistry of the chemical sulfidation treatment of GaAs with Na2S.9H2O and (NH4)2S. Using surface infrared reflection spectroscopy (SIRS) and x-ray photoelectron spectroscopy (XPS), we have studied the GaAs surface and its behavior with time after such treatments. Results show that both of these sulfidation treatments removed the chemical oxide of GaAs, leaving behind a thin film on the surface. XPS results show that the Ga-O and As-O peaks were removed after treatment and that As-S and no Ga-S peaks were formed. Infrared results show that the film deposited after Na2S.9H2O treatment slowly reacted in air to form sodium carbonate and rhombic sulfur. In addition, this film contains compounds with sulfur-oxygen bonds, which most likely were arsenic sulfate, sulfite, and thiosulfate salts. The film deposited on the (NH4)2Streated GaAs surface was identified as ammonium thiosulfate and slowly decomposed with time. Rinsing with water removed the thin film formed after either sulfidation treatment.


2021 ◽  
Author(s):  
Steven H. Huang ◽  
Jiaruo Li ◽  
Zhiyuan Fan ◽  
Robert Delgado ◽  
Gennady Shvets

Infrared spectroscopy has found wide applications in the analysis of biological materials. A more recent development is the use of engineered nanostructures, or plasmonic metasurfaces, as substrates for metasurface-enhanced infrared reflection spectroscopy (MEIRS). Here, we demonstrate that strong field enhancement from plasmonic metasurfaces enables the use of MEIRS as a highly informative analytic technique for real-time monitoring of cells. By exposing live cells cultured on a plasmonic metasurface to chemical compounds, we show that MEIRS can be used as a label-free phenotypic assay for detecting multiple cellular responses to external stimuli: changes in cell morphology, adhesion, lipid composition of the cellular membrane, as well as intracellular signaling. Using a focal plane array detection system, we show that MEIRS also enables spectro-chemical imaging at the single-cell level. The described metasurface-based all-optical sensor opens the way to a scalable, high-throughput spectroscopic assay for live cells.


1994 ◽  
Vol 65 (8) ◽  
pp. 2731-2732 ◽  
Author(s):  
D. Bunimovich ◽  
E. Belotserkovsky ◽  
A. Katzir

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