Abstract:In this paper, Yb2Si2O7 precursor powders and ceramic bulks were respectively prepared by solid-state reaction method and sol-gel method. By solid-state reaction method, the mixed powder was calcined at 1500 ℃ for 5 h and turned out to be a mixture of Yb2Si2O7 and Yb2SiO5. After cold pressing and 1600 ℃ sintering for 10 h, loose bulk was obtained where a large amount of silicon oxide and Yb2SiO5 were found inside. By contrast, high purity Yb2Si2O7 powder could be obtained by the sol gel method after the dry gel was calcined at 1400 ℃ for 5h. After cold pressing and 1600 ℃ sintering for 10 h, a more dense and compact bulk with almost pure Yb2Si2O7 phase was obtained. These results indicate that the preparation of Yb2Si2O7 by sol-gel method has the advantages of low reaction threshold and easy preparation of high-purity homogeneous materials. The ultra-fine powder for low pressure plasma spraying was prepared by atomization granulation. The influence of PVA content and atomization pressure on the powder was investigated. The results showed that the powder morphology was determined by PVA content. Only when the PVA content was moderate (10 wt.%), a solid powder with good sphericity could beobtained. The atomization pressure strongly affected the powder particle size. The larger the atomization pressure, the smaller the powder particle size. When the atomization pressure was 1.2 MPa, the desirable powders with 1~30 μm could be obtained.