Preparation Of Lu₂O₃-MgO And Y₂O₃-MgO-ZrO₂ Nanocomposite Ceramic And Research On Their Properties

The Lu2O3-MgO nanocomposite window material has good infrared light transmission property,and its high theoretical density is suitable for impact temperature measurement of high density non-transparent metals.In this paper,Lu2O3-MgO nanocomposite powders were prepared by sol-gel method.The effects of different calcination temperatures on the properties of nanopowders were studied,the optimum calcination temperature was determined to be 600℃.After ball milling and sieving,Lu2O3-MgO nanocomposite powders with good dispersibility and fine grain size(grain size～18nm)were obtained.The prepared Lu2O3-MgO nanocomposite powders were dry pressed at 100MPa and then hot pressed.The effects of sintering temperature,sintering holding time,sintering pressure,sintering heating rate and annealing temperature on the microstructures and optical property of the nanocomposite ceramics were investigated.In the optimum hot pressing routine,the powders were heated at a rate of 20℃/min to 1300℃ and gradually pressurized to 40MPa at the same time.The pressure and temperature were kept for 8 minutes.The sintered nanocomposite ceramic was annealed at 1100℃.The Lu2O3-MgO nanocomposite ceramic prepared under this optimum routine was nearly fully dense(relative density is 99.9%),the grain size was about 1l0nm,the transmittance at 1.42μm was 75%and the transmittance in 2-6μm IR regions was over 80%.To prepare nanocomposite ceramics with excellent mechanical properties,the preparation of Y2O3-MgO-ZrO2 three-phase nanocomposite powders was explored.Zirconium acetate was added in three different ways:from the start of sol-gel,to the gel and during ball milling.The effect of different concentrations of zirconium on the phase composition was studied.The powder phase composition after calcination was MgO phase and Y2O3-ZrO2 solid solution phase.Zirconium acetate was added from the start of sol-gel,and in this method,the uniformity and dispersibility of the powders were better.With the increase of zirconium concentrations,the grain size of the nanocomposite ceramics decreased and the single-phase aggregation phenomenon became more obvious.Meanwhile,the addition of ZrO2 was found to be effective to improve the hardness of nanocomposite ceramics.