Microstructure evolution of SiO2, ZrO2-doped Y3Al5O12:Nd3+ ceramics obtained by reactive sintering

The evolution of microstructure, porosity and optical properties of SiO2, ZrO2-doped Y3Al5O12:Nd3+ laser ceramics obtained by reactive sintering have been studied. The relationship between the relative density and average grain size of garnet ceramics obtained in the 1500-1800 degrees C temperature range has been determined. It has been shown that anomalous behavior of sintering trajectory at T > 1700 degrees C may be due to the inhibition of ceramic grain boundaries mobility by Zr4+ ions. At the sintering temperature of 1800 degrees C a partial decomposition of Y3Al5O12:Nd-3(+), Si4+ Zr4+ solid solution occurs with precipitation of alumina along grain boundaries of ceramics. The relationships between the residual porosity, in-line optical transmittance and sintering conditions of Y3Al5O12:Nd-3(+) (4 at%) ceramics have been studied. Optical ceramics sintered at T=1750 degrees C for 12 h possess residual porosity of 0.0016 vol%, in-line optical transmittance of 82.9% at 1064 nm wavelength and laser slope efficiency of 33% under diode-pumping at 808 nm. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.