Hybrid mica seals

Seal type (compressive pressure in parentheses) Leak rate (seem cm length of seal)  

Ag-mica (12psi) 0.03 after 1000 h 0.04 after 2000h 0.03 after 4000h 0.04 after 50 cycles (aged 1000 h) 0.03 after 30 cycles (aged 200 h) 0.03 after 42 cycles (aged 4000 h) [62] 

Ag-mica (12psi) 0.03 after 1000 h 0.03 after 40 cycles (aged 1000 h) [63] 

G-18-phlogopite (bpsi) 0.05 after 1000h 0.32 after 21 cycles (aged 1000h) [64] 

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Figure 11.4 Schematic diagrams of (a) a conventional and (b) a hybrid mica seal.

Chou, Y.S., Stevenson, J.W., Hardy, J., and Singh, P. (2006) Material degradation during isothermal ageing and thermal cycling of hybrid mica seals under solid oxide fuel cell exposure conditions. J. Power Sources, 157, 260-270. 

Recently, mica and hybrid mica seals have been developed as a viable technology. Mica seals were found to have many desirable characteristics, such as the ability to withstand thermal cycling, but exhibited unacceptable leak rates. When a thin layer of glass is inserted on either side of the seal to fill the voids between the seal and the other stack components, the leak rate was substantially reduced while other desirable properties were retained. 

Fig. 5.6 a Mica seal, b mica powder with corrugated alloy (glass ot metal), c hybrid mica seal with compliant layer and d infiltrated mica seal (Fta-gus 2005)... 

YS. Chou, J.W. Stevenson, and L.A. Chick, Ultra-low leak rate of hybrid compressive mica seals for solid oxide fuel cells. Journal of Power Sources, 112 (2002) 130-136. 

Figure 7-8 Structure of Mica and Mica-Glass Hybrid Seals and Performance...

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