Degradation current flow measurement

Essentially similar spectra were observed for other diborides. The only difference was a degradation of maxima with bias rise, taking into account their purity and increased EPI, which leads to the transition from the spectroscopic to the non-spectroscopic (thermal) regime of the current flow [33]. The positions of the low-energy peaks are proportional to the inverse square root of the masses of the d metals [33], as expected. For NbE>2 and TaE>2 the phonon density of states (DoS) is measured by means of neutron scattering [34], The position of phonon peaks corresponds to the PC spectra maxima (Fig. 5). Because Nb and Zr have nearly the same atomic mass, it is suggested that they should have similar phonon DoS. 

During S-cell stack performance test, the reformed gas with 6,820 seem flow rate and air with 13,000 seem rate were respectively used as fuel and oxidizer gas to complete l-V-P and durability tests. The reformed gas generated from methane and water vapor through the home-made reformer installed in the SOFC measurement system. According to our experiences about measuring the degradation rate of SOFC MSC cell stack, the most suitable applied current density is located around 400 mA/cm at 700 C. So, the constant current density is kept at 400 mA/cm in long term durability test. 

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