ION Engineering (United States)

A qualitative study was conducted to analyze degradation of CO2 capture solvents containing ionic liquids by GC/MS under a variety of conditions representative of the carbon capture process. Aqueous monoethanolamine (MEA) was used as a benchmark for solvent degradation and compared to two advanced CO2 capture solvents containing ionic liquids. Accelerated aging experiments were conducted in the laboratory by exposing solvents to various gases (N2, air, CO2, or SO2) at elevated temperature in sealed cylinders. Degradation products were analyzed by GC/MS and key pathways leading to their formation were elucidated. For all solvents, degradation was most rapid and lead to a wider array of products in the presence of CO2 compared to the other studied gases. The ionic liquid solvents showed enhanced degradation and a different set of degradation products than those observed for MEA. In one case, the anion of the ionic liquid was found to be reactive and led to a unique primary degradation mechanism not seen in ...

In the analysis of scanning tunneling microscopy (STM), a one-dimensional model is used to predict the tunneling spectrum of a quantum well structure. Investigations of the current-voltage characteristics for the double potential barrier structure are presented for a heterostructure (GaAs/AlAs/GaAs) -vacuum-STM tip (GaAs) system. The dependences of resonant tunneling current-voltage characteristics on the double-barrier structures are shown for the peak voltage of negative resistance and the shape of negative resistance.

Monolayer TiN films often display poor corrosion resistance due to localized weak spots, and multilayer film composed of several TiN and thin Cr2N layers was therefore studied in an effort to improve pitting corrosion resistance. A thin Cr2N layer with a mixing layer formed with the underlying materials was produced by N++N2+ ion implantation into the Cr layer. The multilayer film showed a dense, homogeneous rupture face, unlike the columnar structure observed in the monolayer TiN film. In an anodic polarization test in 3.5wt.% NaCl solution, austenitic SUS 304 stainless steel coated with the multilayer film showed better pitting corrosion resistance than specimens coated with the monolayer TiN film. After this corrosion test, many shallow corrosion marks were observed in the surface of the multilayer film in contrast to the deep pits observed in the surface of the monolayer TiN film. It is thought that the improved pitting corrosion resistance of the multilayer film was due to its stronger inter-column characteristics obtained by the interposing of the multiple thin Cr2N layers.