Solid-state reactive sintering of Nd:YAG transparent ceramics: The effect of Y2O3 powders pretreatment

• Heat-treatment in oxygen may decrease the internal porosities of Y2O3 powders.
• Heat-treatment of Y2O3 improved the size matching with Al2O3 after milling.
• Pretreatment of Y2O3 powders optimized the microstructure of Nd:YAG ceramics.
• Heat-treatment of Y2O3 powders improved the transparency of Nd:YAG ceramics.

Influence of Y2O3 commercial powders preheat-treating in oxygen atmosphere on solid-state reactive sintering of Nd doped yttrium aluminum garnet (Nd:YAG) transparent ceramics was investigated. The ceramics were fabricated by solid-state reactive sintering of commercial α-Al2O3, Nd2O3 and either untreated or heat-treated Y2O3 powders. It was found that the preliminary heat-treatment of the Y2O3 powders in oxygen atmosphere may reduce the internal porosities of the Y2O3 powder and optimize the matching with α-Al2O3 powder, increases relative density of the green body and transparency of ceramics. The highest transparency was achieved when the Y2O3 powder was pretreated at 1000 °C. The in-line transmittances are 83.7% and 82.1% at the wavelength of 1064 nm and 400 nm, respectively. Basic reasons of the Y2O3 powders preheat-treatment influence on the microstructure and optical transmission of Nd:YAG transparent ceramics were established.