Effect of RE/Ni (RE = Sm, Gd, Eu) addition on the infrared emission properties of Co–Zn ferrites with high emissivity

The RE/Ni doped Co–Zn ferrites were prepared by the ceramic method. X-ray diffraction, infrared absorption, scanning electrical microscopy and emission properties were used to investigate those ferrites. The IR spectra in the range from 400 to 1200 cm−1 were observed. Mainly, two bands were investigated. The band at around 587 cm−1 and the band at around 400 cm−1 were assigned to the tetrahedral and octahedral complexes, respectively. The peak intensity decreases with the increase of RE/Ni ratio. X-ray diffraction analysis confirms the formation of spinel-like structure. Lattice constants decrease slight distortions proportionally to RE/Ni ratio. The X-ray density of doped ferrites was found to be increasing. The grain sizes were estimated from the SEM micrographs. The addition of RE/Ni results in a decrease in grain size. The infrared emissivity for 8–14 μm wave bands seems to be increasing with increasing RE/Ni ratio. The highest infrared emissivity is 0.938 when Gd/Ni ratio is 0.20.