Enhancing infrared emissivity of GdCoO3 with Ca doping: Potential for advanced thermal control materials

The high infrared emissivity material Gd1-xCaxCoO3 was synthesized using the sol-gel method. The structure and composition of Gd1-xCaxCoO3 were investigated through X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), specific surface area analysis, Brunauer-Emmett-Teller (BET) method for void analysis, and Ultraviolet–Visible-Near-Infrared (UV–Vis–NIR) diffuse reflection spectrum were employed to analyze the surface morphology, elemental composition, specific surface area, pore size distribution, and band gap of the prepared powders. The average infrared emissivity of samples with different doping concentrations at various temperatures (8–14 μm and 3–5 μm) was determined using a dual-band emissivity meter. At room temperature, the infrared emissivity of the doped powders is generally higher, exceeding 0.75 in comparison to the undoped sample powder. As the test temperature increases, the infrared emissivity of all samples shows a significant rise. The infrared emissivity of all samples surpasses 0.91 at 500 °C, with the emissivity of the samples reaching as high as 0.988-14μm (0.993-5μm) with a Ca doping concentration of 5 %. These findings indicate that Ca-doped GdCoO3 powder represents a promising high-emissivity material with broad potential in spacecraft thermal control applications.