An investigation was made of mullite as a solid electrolyte at high temperatures. The predominantly ionic conduction of mullite was characterized by measuring the temperature dependence of the ionic transference number (tables 8 and 9). It was confirmed that mullite exhibited an ionic conductivity which was superior to that of CaO-stabilized ZrO2 solid electrolytes at temperatures ranging from 1400 to 1600C.

I.Rommerskirchen, F.Chávez, D.Janke: Solid State Ionics, 1994, 74[3-4], 179-87

 

 

 

Table 8

Ionic Transference Number of Mullite

 

 

PO2(bar)

 

Temperature(C)

 

Number

 

 

10-30

 

1400

 

0.00491

10-30

1600

0.000474

10-25

1400

0.0806

10-25

1600

0.00837

10-20

1400

0.609

10-20

1600

0.131

10-15

1400

0.965

10-15

1600

0.727

10-10

1400

0.998

10-10

1600

0.979

10-5

1400

1

10-5

1600

0.999

 

 

 

Table 9

Ionic Transference Number of Mullite

with 4mol% Excess Alumina

 

 

PO2(bar)

 

Temperature(C)

 

Number

 

 

10-30

 

1400

 

0.0375

10-30

1600

0.000802

10-25

1400

0.409

10-25

1600

0.0141

10-20

1400

0.925

10-20

1600

0.202

10-15

1400

0.995

10-15

1600

0.819

10-10

1400

0.9997

10-10

1600

0.988

10-5

1400

1

10-5

1600

0.999