Microstructure and IR transmittance of yttria–magnesia (50:50 vol.%) nano-composites consolidated from agglomerated and ultrasonic horn treated nano-powders

Yttria–magnesia (50–50 vol.%) nano-powder with large agglomerates was consolidated by Spark Plasma Sintering (SPS), and nano-composite ceramics with densities higher than 97.5% can be obtained at a temperature higher than 1200 °C. The microstructures and IR transmittances of the obtained nano-composite ceramics were characterized. In order to remove the large agglomerates from the original powder, the powder was treated by ultrasonic horn in a solution of ethanol and floated in the ethanol. Then, powder from the top part of the floated solution (treated powder) was collected and consolidated by SPS. The nano-composite ceramics from the treated powder exhibit broader peak and much better value (∼80%) in IR transmittances comparing with that of the original powder because of the small grain sizes (nano-size), homogeneous microstructures and phase distributions of the yttria–magnesia nano-composite ceramics.