13-In-situ synthesis of YAG@Si3N4 powders with enhanced mechanical properties
writer：Chaochao Ye, Xinyan Yue, Hui Zong, Guangfu Liao, and Hongqiang Ru*
keywords：Si3N4 powders, Yttrium aluminum garnet, Precipitation method
source：期刊
specific source：https://doi.org/10.1016/j.jallcom.2017.10.064
Issue time：2017年
In this paper, a simple precipitation method has been developed for the preparation of yttrium aluminum garnet (YAG) precursor coated Si3N4 powders (YAG@Si3N4) without resorting to either titration or uncontrollable pH value. Yttrium aluminum garnet (Y3Al5O12) precursor was prepared via urea homogeneous preparation technology by using urea as precipitant. This method solved a problem that Y3+ and Al3+ exhibited different precipitation in the conventional method. The pH value would be maintained at 7.9 during the reaction process. This phenomenon could be explained that the heated urea could be decomposed continuously to keep the pH value stable. After sintering, the composition and microstructure of samples were analyzed by X-ray diffraction (XRD analysis), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). These results indicated that the microstructure of the precursor exhibited a core-shell structure, and the thickness of the shell was ranging from 37 to 66 nm. Moreover, the flexural strength was up to 817 ± 46 MPa via hot pressing at 1750 °C. The Si3N4 matrix by utilizing urea homogeneous co-precipitation coating might be a potential adding sintering aids method for reinforcing ceramic densification.