Structure properties and sintering densification of Gd2Zr2O7 nanoparticles prepared via different acid combustion methods

Gadolinium zirconate (Gd2Zr2O7) nanocrystals were prepared via two different combustion methods: citric acid combustion (CAC) and stearic acid combustion (SAC). The effects of the different preparation methods on the phase composition, microtopography, and sintering densification of the resulting Gd2Zr2O7 nanopowders were investigated by thermal-gravimetric and differential thermal analysis (TG-DTA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and transmission electron microscopy (TEM) techniques. The results indicated that both methods could produce Gd2Zr2O7 nanopowders with an excellent defective fluorite structure. The reaction time was reduced by the SAC method, compared with the CAC method. The nanopowders synthesized by the two methods were different in grain size distribution. The resulting nanoparticle diameter was about 50 nm for CAC and 10 nm for SAC. After vacuum sintering, the sintered bodies also had a different relative density of about 93% and 98%, respectively. Thus the preparation of Gd2Zr2O7 nanopowders by SAC was the first choice to achieve the desired sintering densification.