A solid-state electrochemical cell with yttria-stabilized ZrO2 was used to determine the O ion conductivity, and thereby the O ion diffusivity, by means of impedance measurements at temperatures ranging from 500 to 850C. The activation energies for O diffusion were between 1.2 and 1.25eV at temperatures ranging from 500 to 750C, and between 2.52 and 2.69eV at temperatures ranging from 800 to 850C. It was found that O diffused faster in sintered samples (table 13) than in hot-pressed ones (table 14). The c-direction texturing of the latter, and the resultant slow diffusion in that direction, were suggested to be responsible. In the low temperature range, O ion diffusion in the grain boundaries controlled diffusion whereas, at high temperatures, diffusion in the grains was the controlling process.

W.Zhu, P.S.Nicholson: Journal of the Electrochemical Society, 1995, 142[2], 513-8

 

 

 

Table 13

Diffusivity of O Ions in Sintered Cu3Ca2Bi2Sr2PbOx

 

 

Temperature (C)

 

D (cm2/s)

 

 

500

 

4.08 x 10-10

550

1.27 x 10-9

600

3.34 x 10-9

650

9.11 x 10-9

700

2.06 x 10-8

750

3.65 x 10-8

800

6.38 x 10-8

810

8.89 x 10-8

820

1.11 x 10-7

830

1.38 x 10-7

840

1.86 x 10-7

850

2.03 x 10-7

 

 

 

 

Table 14

Diffusivity of O Ions in Hot-Pressed Cu3Ca2Bi2Sr2PbOx

 

 

Temperature (C)

 

D (cm2/s)

 

 

500

 

2.70 x 10-10

550

6.67 x 10-10

600

1.66 x 10-9

650

4.48 x 10-9

700

1.10 x 10-8

750

1.98 x 10-8

800

3.71 x 10-8

810

5.03 x 10-8

820

7.25 x 10-8

830

9.48 x 10-8

840

1.14 x 10-7

850

1.32 x 10-7