Variable infrared emittance of Sr-incorporated Sm1−xSrxCoO3 (0.1 ⩽ x ⩽ 0.9)

Sm1−xSrxCoO3 ((0.1 ⩽ x ⩽ 0.9), SSC) with perovskite-type structure is successfully prepared by the conventional solid-state reaction method. The phase structure, optical property, electrical conductivity and infrared emissivity are all closely related to the samarium-to-strontium ratio in the SSC system. X-ray diffraction results show that the perovskite structure has an orthorhombic symmetry for 0.1 ⩽ x ⩽ 0.5 and a cubic symmetry for 0.6 ⩽ x ⩽ 0.9. The incorporation of Sr2+ can first contribute to an increase in electrical conductivity and then to a decrease; in contrast, the infrared emissivity declines at the beginning, then rises and goes through a minimum at x = 0.5, showing a U shape. Optical reflection results show that the SSC system has a high spectral reflectance in the near infrared band, and reflectivity at 1.06 µm is lower than 0.5%, with infrared emissivity less than 0.25 in 3–30 µm infrared bands. This will satisfy the laser and infrared compatible stealth in the near, middle and far infrared bands. (paper)