High efficiency synthesis of Nd:YAG powder by a spray co-precipitation method for transparent ceramics

A spray co-precipitation method was developed to efficiently synthesize Nd:YAG nano-powders. The effects of spray speeds and solution concentrations on the crystallization processes of calcined precursors have been studied. The results indicated that the pure phase of YAG could be obtained by three different crystallization processes owing to different homogeneity levels of Y and Al mixing. Pure YAG powder was obtained at 850 °C and the phase purity persisted to 1600 °C. Using the obtained powders, transparent ceramics with the in-line transmittance up to 80.2%@400 nm and 83.1%@1064 nm were fabricated by gel-casting method and hot isostatic pressing sintering. Furthermore, the microstructure and laser properties of the transparent ceramics have been measured. The maximum laser output of 7.015 W has been obtained with an oscillation threshold and a slope efficiency of 0.235 W and 59.4%, respectively.