LI Haozhan 1, WEI Hongkang 1, QIU Huijuan 1, MAO Miaomiao 1, WANG Chang’an 2, XIE Zhipeng 2
(1. School of Materials Science and Engineering, Jingdezhen Ceramic University, Jingdezhen 333403, Jiangxi, China;2. State Key Laboratory of New Ceramics & Fine Processing, Tsinghua University, Beijing 100084, China)
Abstract: Ultra-fine boron carbide powders were synthesized in argon atmosphere, with phenolic resin and boron oxide as rawmaterials. The effects of C/B2O3 molar ratio and calcination temperature on phase composition and microstructure of thesynthesized powders were studied. It is found that an increase in the content of boron oxide in the starting powder is benefi cialto improve the purity of the boron carbide in the synthesized powders. In addition, the higher the boron oxide content and thehigher calcination temperature, the larger the particle size of the synthesized boron carbide powder would be. When theC/B2O3 molar ratio is 1.0:1.0 and the calcination temperature is 1700 ℃, the particle size of the synthesized boron carbide isabout 180 nm. Monodisperse boron carbide powder with an average particle size of 62 nm can be obtained after the removalof boron oxide and carbon. The treated boron carbide powder was hot-pressed at 1850 ℃ for 30 min in vacuum at 60 MPa,leading to ceramic sample with relative density, flexural strength and fracture toughness of 93.27%, 304 MPa and4.41 MPa·m 1/2, respectively.
Key words: boron carbide; phenolic resin; submicron; monodisperse