High temperature thermal barrier coatings from recycled fly ash cenospheres

► New FAC thermal barriers with potentiality for high temperature applications (HTA). ► A thermal conductivity value as low as 0.17 W/m K for FAC was found at 1200 K. ► Low thermal expansion coefficient of 5.96 × 10−6 for FAC was found. This avoids microcracking at HTA. ► HT values of α and e guarantee a good performance during unsteady state operation.