The H2-H20, Ni/YSZ point electrode has been investigated using long-term potential step measurements and impedance spectroscopy at 1273 K. Morphological and structural changes at the electrode interface were evaluated by electron microscopy, energy dispersive X-ray analysis, and Raman spectroscopy ex situ. The anodic current was found to induce a self-catalytic effect on the electrode, and the anodic "steady state" current increased to more than twice the initial value with a time constant of about 40 h. In contrast, cathodic polarization reduced the performance of the electrode, and the cathodic current decreased significantly with a time constant of about 20 h. Redistribution of material in the reaction zone is suggested to control most of the changes in electrode activity. At anodic overpotentials it was observed that Ni was transported to the electrolyte surface, forming a "necklace" of Ni particles around the electrode/electrolyte contact. This is believed to increase the three-phase boundary (TPB) length and account for the higher activity of the electrode. At cathodic overpotentials the transfer of Ni to the YSZ was found to be restricted, and it is proposed that agglomeration of dispersed metal particles reduced the TPB length, and accordingly the cathodic current. In addition to the morphological modifications, the catalytic properties of the surfaces were significantly altered as the electrode was polarized.Transformation from cubic to tetragonal YSZ, due to segregation of the material, was observed on the surface of the electrolyte when the sample was kept at working conditions for long periods of time (135 days). The passage of current was not found to generate any permanent phase transformation in the YSZ.

Submicronic polypyrrole/polyethylene-oxide (PPy/PEO) latex particles have been produced using PEO as the steric stabilizer and either FeCl~ or K2S208 as the oxidizing agent for pyrrole. Scanning electron micrographs show that the two types of PPy/PEO latex particles are of approximately the same size. From electrochemical and optical characterization (UV-vis spectra) of these particles, it was found that these latex particles can be electrochemically oxidized and reduced in an electrolyte of acetonitrile with 0.1M LiCF~SO~. The electrochemical and optical measurements indicate that the latex particles formed when using K2S208 as the oxidizing agent are more easily switched than the particles which are the result of applying FeC13 as the oxidizing agent.When using electronic conducting polymer electrodes in combination with liquid or solid electrolytes it is, for many potential applications, important to have polymers that * Electrochemical Society Active Member. 1Current address: SINTEF Metallurgy, N-7034 Trondheim, Norway. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.210.126.199 Downloaded on 2015-06-16 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.210.126.199 Downloaded on 2015-06-16 to IP

Poly(3-methyl-thiophene) displays a pronounced sensitivity toward the dopant anions in aqueous solutions which is not observed in organic solvents. The voltammogram for the polymer in aquoeus solutions consists of two anodic peaks in the potential region 0-2 V. As demonstrated by in situ conductivity measurements, the first peak corresponds to the doping process, while the second peak, at more anodic potentials, is due to polymer degradation. The potential of the first current peak is strongly dependent on the type of anions present in solution. During potential cycling, the position of this peak is shifted several hundred millivolts in the negative direction. The specific response of the polymer electrode toward nitrate and perchlorate in aquoeus solutions may be associated with the oxidizing strength of these ions. However, polymer swelling, ion size, as well as more subtle polymer-ion and ion-solvent interactions may also play a crucial role in the observed ion sensitive doping process.

The solubility of aluminum carbide in cryolitic melts was determined as a function of the following parameters: (i) normalNaF/AlF3 molar ratio false(CRfalse) of normalNaF‐AlF3 melts at 1020°C, (ii) temperature of normalNaF‐AlF3 melts at CR=1.80 , (iii) alumina concentration at CR=1.80 normaland 1020°C , and (iv) CaF2 concentration of normalNaF‐AlF3‐CaF2 melts at CR=1.80 normaland 1020°C . At 1020°C, a maximum concentration of 2.1 weight percent aluminum carbide was found at CR=1.80 . The following model for the aluminum carbide dissolution reaction, based on activity data for normalNaF and AlF3 , was found to fit the experimental solubility dataAl4C3)(normals+5AlF3 )(normaldiss+9normalNaF)(l=3Al3CF83−+9Na+Carbon could be electrodeposited from normalNaF‐AlF3 melts saturated with aluminum carbide by electrochemical oxidation of the dissolved carbide species. Voluminous deposits of amorphous carbon were obtained on several different electrode substrates (graphite, vitreous carbon, iron, tungsten, and platinum).