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-μm wavelength range, which is ∼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.