Fabrication of high-performance infrared-transparent 8YSZ nanoceramics through auto combustion powder synthesis followed by resistive-heating assisted microwave sintering

Abstract Infrared-transparent materials are specially manufactured ceramic materials indented to allow infrared rays in homing missiles to trail its trajectory. An auto combustion powder synthesis method followed by a resistive-heating assisted microwave (RHAM) sintering of 8 mol % yttria stabilized zirconia (8YSZ) ceramics for its utility as infrared-transparent application is presented in the paper. X-ray diffraction (XRD) investigation reveals that each of the peaks correspond to a face-centered cubic structure, exhibiting a mean crystallite size of 11.18 nm. High-resolution transmission electron microscopy (HRTEM) confirms the XRD findings. UV-visible absorption spectra, assesed between 200 and 800 nm, reveal maximal absorbance in the ultraviolet (UV) band, decreasing near the visible spectrum. Fourier transform infrared spectroscopy (FTIR) validates the phase homogenity of the specimen, while thermogravimetric (TGA) and differential thermal analysis (DTA) indicate high thermal stability. The 8YSZ sample achieved 96.7 % of theoretical density using a susceptor-assisted microwave (SAM) sintering method at 1530 ± 10 °C, with a thermal progression of 20 °C/min and a holding time of 30 minutes while it reached 98.2 % of theoretical density with the resistive-heating assisted microwave sintering process at a lower temperature of 1320 ± 10 °C, under the same thermal progression and holding time. The sample sintered using the RHAM method exhibited superior sintering behavior, resulting in an infrared transmittance of 71.13 % and a microhardness of 11.82 Gpa compared to the SAM sample with an infrared transmittance of 70.03 % and a microhardness of 9.90 GPa.