Anodic behaviour temperature effect

Myers, J. R., Crow, W. B., Beck, F. H. and Saxer, R. K., Observation on the Anodic Behaviour of Nickel and Chromium Surface Topography and Temperature Effect , Corrosion, 22, 32 (1966)... 

Fig. 4.21 Effect of temperature on the anodic behaviour of nickel in 0 025 m H2SO4 -I-0-025 M K2SO4 (pH 1 -3) de-aerated with H2. The curves were determined potentiokinetically at a scan rate of 2 V/h and proceeding from negative to positive (after Cowan and Staehle )...

Anodic oxide formation Lakhiani and Shreir have studied the anodic oxidation of niobium in various electrolytes, and have observed that temperature and current density have a marked effect on the anodising characteristics. The plateau on the voltage/time curve has been shown by electron microscopy to correspond with the crystallisation of the oxide and rupture of the previously formed oxide. It would appear that this is a further example of field recrystallisation —a phenomenon which has been observed previously during anodisation of tantalum" . No significant data on the galvanic behaviour of niobium are available however, its behaviour can be expected to be similar to tantalum. 

Since the chemical reactivity of a cyclopropane ring is sometimes compared with that of a carbon-carbon double bond, it is interesting to study the electrochemical behaviour of silyloxycyclopropanes. Torii et al. described the anodic oxidation of silyloxycyclopropanes in the presence of Fe(N03)3 which resulted in the opening of the cyclopropane ring as shown in Scheme 27 [61]. The reaction temperature has a profound effect on the yields of the products the best resuls are obtained at —13 to —10 °C. 

Another way to decrease the anodic overpotential is to intercalate a mixed conductor between the yttria stabilized zirconia electrolyte and the metallic anode. Such a combination enlarges the reaction area which theoretically lowers the anodic overpotential. Tedmon et al. [93] pointed out a significant decrease of polarization when ceria-based solid solutions like (Ce02)o.6 (LaO, 5)04 are used as anode materials for SOFCs. This effect is generally attributed to the mixed conductivity resulting from the partial reduction of Ce4+ to Ce3+ in the reducing fuel atmosphere. A similar behaviour was observed in water vapor electrolysis at high temperature when the surface zirconia electrolyte is doped with ceria [94, 95]. 

As a conclusion, the effect of fuel utilization distribution on the anode exchange current density is predominating, while the temperature distribution attenuates this behaviour. 

Lin et al. [60, 61] have meshed a planar, intermediate-temperature three-cell stack based on anode supported-cells and a glass-ceramic sealant, with linear continuum shell elements (see Fig. 11). The maximum principal stress in the PEN reaches 170 MPa at room temperature and decreases to 70 MPa in operation, because of the smaller temperature difference with the reference state. The MIC undergoes significant plastic deformation. In operation, the elastic modulus of the glass-ceramic sealant has been reduced by two thirds for a first assessment of the effects of the viscous behaviour. It results in a decrease of the stress of 10 % in the cell. Few studies have been carried out on the overall deformation of a SRU embedded in a functional stack. In the conditions of their simulations, a limited influence of the stack support conditions and position in the stack on the stress profile has been highlighted (see Fig. 11). 

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