Influence of TiO2 doping on thermo-optical properties of pyrochlore Sm2(Zr1-xTix)2O7 (0≤x≤0.15) ceramics

Sm2(Zr1-xTix)2O7 (0≤x≤0.15) ceramics have been fabricated by pressureless-sintering method at 1973 K for 10 h in air. The influence of TiO2 doping on microstructure and thermo-optical properties of Sm2(Zr1-xTix)2O7 ceramics is investigated by X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy measurements. The partial substitution of Ti4+ for Zr4+ results in a significant increase in emissivity at low wavelengths contrasted with undoped Sm2Zr2O7. Sm2(Zr0.85Ti0.15)2O7 ceramic exhibits a high emissivity of above 0.70 at 1073 K in a wavelength range of 3-16 µm, where the highest value at this temperature is more than 0.90 especially in the wavelength range of 9-14 µm. FT-IR spectra and optical absorption spectra unveil the mechanisms of enhanced emissivity in Sm2(Zr1-xTix)2O7 (0.05≤x≤0.15) ceramics in the intermediate infrared range, especially at the wavelengths of 3-8 µm, due to Ti4+ ion substitution for Zr4+ ion.