Synthesis of 1Y6Ce–ZrO2 nanoparticles with excellent sintering performance via novel Sol-Gel-Flux method

To alleviate agglomeration and refine the particle size, a novel sol-gel-flux method (SGFM) was applied to synthesise ZrO 2 (1Y6Ce–ZrO 2 ) nanoparticles (NPs) stabilised by 1 mol% Y 2 O 3 and 6 mol% CeO 2 . Both the NaCl and NaCl + KCl flux systems were investigated. The effects of calcination temperature and holding time on the phase composition and morphology of the NPs were studied, and the sintering performances of the 1Y6Ce–ZrO 2 NPs prepared in the two flux systems were compared. The results showed that the optimum temperature for the preparation of 1Y6Ce–ZrO 2 NPs by SGFM could be reduced from 800 to 700 °C if the NaCl system was replaced by the NaCl + KCl system. The lower calcination temperature resulted in well-dispersed tetragonal 1Y6Ce–ZrO 2 NPs with an average grain size of 14.5 nm and quasi-spherical morphology. 1Y6Ce–ZrO 2 NPs prepared in the NaCl + KCl system exhibited better sintering performance than 1Y6Ce–ZrO 2 NPs prepared in the NaCl system. The 1Y6Ce–ZrO 2 ceramics obtained by sintering the former showed higher stability at high temperatures, smaller grain sizes, and narrower grain size distributions, which are conducive to improving the mechanical properties of 1Y6Ce–ZrO 2 ceramics. Fully tetragonal 1Y6Ce-TZP ceramic with an average grain size of 0.68 μm and a relative density of 98.49% were obtained by pressureless sintering of the former at 1400 °C for 2 h.