Research On Microstructure And Properties Of Yttria Transparent Ceramics

Yttria(Y2O3) transparent ceramics is a excellent high temperature infraredmaterial, electronic material and fire-proof material because of its several favorableproperties, such as stability, optical clarity over a broad spectral region and highthermal conductivity. It is, however, extremely difficult to fabricate high quality Y2O3single crystal because of its high melting point(~2430℃) and the polymorphic phasetransformation at about2280℃. It makes rare earth ions doping yttria transparentceramics attracted widespread attention, because of the Thermal conductivity is twiceas large as that of YAG, their expansion coefficients are very similar, contemporaryY3+and other rare earth luminescent ions both belong to the lanthanides with a highconcentration of doping.The yttrium lanthanum oxide transparent ceramics is fabricated by carbonatecoprecipitation method, sintered by atmosphere sintering and microwave sintering athydrogen atmosphere as the research object. The properties of the powder, themicrostructure, mechanical property and optical property of the ceramics wereinvestigated.The results shows that the XRD diffraction peak of the Y1.8La0.2O3powdersfabricated by carbonate coprecipitation becomes more sharpen with the increase ofcalcinations temperature; calcined at900℃for2h produced Y1.8La0.2O3powders withnearly spherical, well-dispersed and approximate particle size30~60nm. Thediffraction peak of the Y2-xLaxO3(x=0~0.4) powders moves in the direction of smallangle with the increase of La2O3contents, it will exceed the La2O3solid solubilitylimit in Y2O3with the continue increase doping of La2O3contents, the formation ofLa2O3diffraction peak seems as the the second phase.The relative density reaches99.6%, hardness reaches809HV, transmittancereaches54%, the grain size is5~10μm Of Y1.8La0.2O3ceramics with good propertiesby atmosphere sintering at1600℃for480min that prepared Y2-xLaxO3(x=0~0.4)ceramics. The relative density reaches99.8%, hardness reaches819HV, transmittancereaches78%, the grain size is2~4μm Of Y1.8La0.2O3transparent ceramics with good properties when the sintered temperature is1450℃by microwave sintering. Therelative density, hardness and transmittance have a certain degree of increase, thegrain size become more finer that microwave sintering compared with atmospheresintering preparing Y1.8La0.2O3transparent ceramics.The XRD diffraction peak corresponds to the cubic Y2O3, grain size is moreuniform and the average grain size is2~4μm of the sintered sample preparingY1.8La0.2O3transparent ceramics doping2at.%Nd3+by microwave sintering. Thetransmittance has a level of decrease compared with Y1.8La0.2O3transparent ceramicsbecause of the electron transition effect comes with the doping of Nd3+. Thetransmittance reaches33%in the range of visible light.