Preparation And Properties Of Y₂O₃-MgO Ceramic Nano/Nano Composites

Y₂O₃-MgO nanocomposite ceramic is mainly used in the infrared windows.The preparation of Y₂O₃-MgO nanocomposite powder is prepared by solid phase and sol-gel and the ceramics are prepared by normal atmosphere sintering,hot-pressing sintering and spark plasma sintering?SPS?seperately.The comprehensive performance of samples are described by scanning electron microscopy?SEM?,relative density,hardness,transmittance etc.The conclusions are as follows:Titrate the 0.25 mol/L Na2CO3 solution with 0.25 mol/L MgCl2 and then centrifugal the precipitation with stilled water and alcohol.TG-DSC curves indicate that the crystallinze water is removed at 126 ? and the MgCO3 decomposition at 392 ?.The XRD curves indicate that crystal of MgO can be get at 700?,800? and 90?C,but in order to get low shrinkage rate of ceramic,we adopted 900? to get MgO powder.Y₂O₃-MgO nanocomposite ceramic prepared by solid-phase method is get by normal atmosphere.The optimal process is 1400?for 2 h.The density of sample can be as 96.5%and the transmittance of it can be 24%at 6.9?m wavelength.The optimal process of preparation of Y₂O₃-MgO nanocomposite material by sol-gel are as follows:drying under a high temperature to get dry gel,and then calcined at 600 ? for 10 hours.The grain sizes of Y₂O₃ and MgO calculated by XRD are both 14 nm.The optimal process of sol-gel powder by SPS are as follows:at 1250? for 5 min.Two-step sintering are also performed.Three systems are tested:the first of two-step process is that ti is 1350? and t2 is 1200? for 24 h;the second of two-step process is that ti is 1400? and t2 is 1250? for 24 h;and the third of two-step process is that 1300? for 24 h.And they can contain the transmittance as high as 83%,83%,81%and they can get the relative density separately 98.3%98.5%99.7%.The optimal process of sol-gel powder by hot-pressing are as follows:dwelling press 30MPa and 1400? for 30 min,and then sintered for two-step sintering the ti temperature is 1400? and the t2 temperature is 1250?.The sample can get the transmittance 86%at 5.5 ?m wavelength.