**4. Conclusions**

136 Sintering of Ceramics – New Emerging Techniques

nano-powders ultrasonically dispersed in isopropanol with addition of butyral resin were deposited on half cells by air spray (perovskite + fluorite 10 microns thick nanocomposite functional layer, such as LSM-ScCeSZ or LSFN-GDC) and by painting (porous thick LSFN cathode layer) followed by drying and sintering at 900-1100C for 2 h using microwave or e-beam heating (Sadykov et al, 2011). The cell performance was evaluated using air at cathode side and humidified H2 at anode side with Pt current collectors adding Pt or Ar pastes on the cathode side. For these cells, the typical level of power density at 700C was in the range of 500 mW/cm2, which is promising for the practical application. Performance stability was demonstrated for short-term (~ 100 h) testing. No cracking or layers spallation was observed after testing. Decreased sintering temperature allowed to prevent any damages to anodic substrates during cells manufacturing as well as any undesired interaction between YSZ electrolyte and cathode layers leading to formation of

200 300 400 500 600 700

Fig. 16. Temperature dependence of the dynamic extent of exchange XV for LFN-GDC composites sintered by microwave heating at 1100C. PO2 = 4 Torr, heating ramp 5o/min.

 LFN (30%) - GDC (70%) LFN (50%) - GDC (50%) LFN (70%) - GDC (30%)

> T, o C

Fig. 17 presents the temperature dependence of oxygen flux through asymmetric supported oxygen separation membranes with Bi-containing perovskite-fluorite functional layers sintered by using microwave radiation (vide supra). As follows from these results, the values of oxygen flux are close to best results obtained with supported membranes in these

isolating pyrochlore layers.

0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7

XV

**3.5.2 Membrane performance** 

conditions (Sadykov et al, 2010).

Advanced sintering techniques based upon radiation-thermal sintering by e-beam action and microwave heating allow to provide required density and consolidation of thin functional layers in design of intermediate temperature solid oxide fuel cells and oxygen separation membranes. Due to decreased temperature and duration of sintering as compared with conventional sintering methods, such negative phenomena as variation of functional layers phase composition, their cracking and damage of metallic substrates were prevented. For oxide mixed ionic-electronic conducting composites advanced sintering provides developed interfaces which act as paths for fast oxygen diffusion required for considered applications. As the results, fuel cells and oxygen separation membranes manufactured using advanced sintering techniques demonstrate performance characteristics promising for the practical applications.
