Scalable and tunable Y2O3-MgO composite for infrared transparency applications

The process-structure-property correlationships in yttria-magnesia (YM) composite have been investigated. YM composite was synthesized using commercial powders via ball-milling route with three different grinding balls (Si3N4, Al2O3, ZrO2) having two different sizes (2 and 5 mm diameter). The alteration in grinding ball material and size produces sintered ceramic having different grain sizes (420-560 nm) and degree of phase mixing homogeneity (0.40-0.70). The contamination induced by the milling ball resulted in changes in Y2O3 and MgO defect chemistry, which influenced the grain growth behavior in the YM composite. The hot-pressed composite prepared using 2-mm Si3N4 ball-milled powders exhibited the finest grain size (420 nm) and better phase mixing homogeneity (0.63). The subsequent impact was seen on transmittance efficiency (71%) over the 3-7-mu m wavelength range, which is similar to 85% of the theoretical limit. The findings show that the selection of the right size and type of grinding ball for milling commercial powder is a simple and cost-effective way for scalable production of YM composite with high transmittance efficiency for infrared windows and dome applications.