Preparation Of Yttrium Oxyfluoride And Study On The Physical Performance

Yttrium oxyfluoride was synthesized in aqueous solution by reacting with yttrium chloride as theraw material, ammonium hydrogen carbonate as the precipitator, and hydrofluoric acid as the fluridizer.Study of the phase component and the rule of pyrogenation is used to find out the area of precipitationtemperature of yttrium oxyfluoride by using XRD and TG-DTA. XRD、particle size apparatus、TEMand EDS are used to analyse the influence of precipitation temperature for crystal structure、particlesize、appearance and chemical component of yttrium oxyfluoride. Particle size apparatus is used toanalyse the influence of fluorination temperature with the change of fluorination condition. Analysis ofrange is used to analyse the the influence of precipitation conditions (precipitation temperature, chlorinatedyttrium concentration, ammonium bicarbonate concentration, drops to fluoride acceleration) on the sizeof,and analysis of variance is used to do significance test qualitatively or not by orthogonalexperiment.Changing a experimental conditions is used to analyse the precipitation conditions on theinfluence of the size of yttrium oxyfluoride quantitatively after optimizing a set of data. combinating of thetwo methods, we draw up technology conditions of preparing small particles yttrium oxyfluoride which isprepared and characterized. Preparation technics of zirconium oxyfluoride is confirmed by exploringlyexperiment and small particles zirconium oxyfluoride is prepared and characterized. Using smallparticles fluorine yttrium oxide and fluorine zirconia as raw material,3Y-TZP powder is prepared viasolid-phase method pre sintering and characterized.3Y-TZP ceramic grain billet is prepared by drypressure method and sintered without pressure sintering, the sintered compact is characterized by XRDand SEM to study the influence of precipitation conditions on the the relative density、crystallingphase、topography and bending strength of3Y-TZP.Experimental results show:precursors of yttrium oxyfluoride consists of Y2(CO3)3、YCO3F andYCO3F。It has the best crystalling phase and the smallest particle size. With the increase of calcinationtemperature, particle size becomes smaller and smaller, topography becomes from loose to closely,chemical composition becomes more and more homogeneous. Precipitation temperature and drops tofluoride acceleration have bigger influence than concentration of ammonium bicarbonate and chlorinatedyttrium. Yttrium oxyfluoride of small(D50≤2μm) and stable size is prepared with expanded test.Zr7O8.79F9.71of small(D50≤2μm) and stable phase is prepared. the relative density and bending strengthof3Y-TZP increase at first and go down then with the increase of calcination temperature and reach thebest value respectively at1500℃：96.8％and790MPa. The results of SEM show that the the sizeofthe havoc of3Y-TZP with the increase of calcination temperature.