Dear Umesh,

for aluminium oxide (Al2O3) the thermal expansion coefficient is:              

0.83.10-5 K-1 (othogonal to c axis)      0.9.10-5 K-1 (parallel to.c axis).

For iridium (metal): 6.4.10-6 K-1.

But it is for metallic iridium or for oxide?

Best regards.

Philippe.

You may want to check:

https://www.researchgate.net/post/Where-to-find-the-thermal-conductivity-of-alumina-in-the-range-of-300-K-to-2-000-K