MCFC多孔隔膜烧结机理的研究

Sintering Mechanism of Porous Matrix for Molten Carbonate Fuel Cell

用电池内外隔膜最大孔径等物性测试,发现隔膜粉粒在烧结时发生重排和滑移.由此隔膜最大孔径逐步变小.组装压力促使隔膜粉粒重排和滑移,但又有效地抑制和减小隔膜内缺陷的发展.由于粉粒重排和伴随机理的联合作用,经烧结隔膜微孔变大,平均孔径增大,孔分布变窄,同时隔膜孔隙率有所增加.多孔(孔隙率≥50%)隔膜初期烧结主要机理是粉粒重排,其烧结模型为梯形模型.

In initial sintering stage of the porous （porosity≥50%） matrix impregnated fully with molten carbonate （46wt% electrolyte） and sintered under the cell stacking pressure, the sintering brought about the rearrangements and slips of powder particles by which the maximum pore diameter altered into a smaller one. Its maximum pore diameter and slip rate were smaller and oppositely higher respectively than those in the matrix impregnated with the less （5wt%）electrolyte and sintered under the ordinary pressure. The cell stacking pressure facilitated the rearrangements and slips of powder particles, but effectively suppressed and diminished defect developments in the sintered matrix. Porosity in the matrix increased, micro-pores altered into bigger ones, mean pore diameter increasing and pore-size distribution becoming narrowly with sintering time by the synergetic action of the rearrangements of powder particles and its accompanying mechanisms. As indicated above, the sintering behaviors and the alteration of some physical properties with sintering time in the porous matrix are different from those in traditional ceramics. So the rearrangement of powder particles dominates over the sintering mechanisms of the porous matrix, its sintering model conforms to the trapezium model.