Preparation And Morphology Control Of Erbium Oxide Powders Via Sol-gel Routes

In order to prepare erbium oxide powders and to control the powders’morphologhy, chelate sol-gel method and monodisperse colloid system were used toprepare erbium oxide powders and modify the powders’ morphologhy.Microstructure of powders were characterized using XRD, SEM, EDS and thespecific surface area was detected by nitrogen adsorption specific surface area tester.Experimental results show that species and the ratio of chelate agent were themain factors determining the erbium oxide powders’morphologhy in chelate sol-gelprocess. It has been shown that citric acid and EDTA gave an porous and spongepowders and the specific surface area of erbium oxide powders calcined at800°Cwere13.47m~2/g and11.70m~2/g respectively, tartaric acid and benzoic acid led to theamorphous or sand stone shape material. The particals synthesized by sol-gel routeusing oxalic acit as chelate agent were cuboid or cube, particals size decreased from10-20μm to2-5μm when the ratio of oxalic acid and Er increased from2:1to10:1.The calcine temperature did little affect erbium oxide size nor shape. Precursor pHand drying control chemical additive have great impact in size and shape of erbiumoxide powders. With the increase of precursor pH, the size of particle weredecreases. Add drying control chemical additive in the sol-gel process can obtainpowders size between200nm-5μm.Monodispersed colloidal particles prepared using urea were uniformlyspherical, their size and shape were mainly depends on the concentration ofreactants ratio, reaction time, temperature and precursor pH. The size ofmonodispersed colloidal particles prepared in different experimental parametersrange from35nm to240nm,and agglomeration there were serious agglomerationbetween particles. Particles size would change while sol transformed into gel,colloidal particles size reduced or raised a total range about20nm. Morphology oferbium oxide powders synthesized by monodisperse system were quite different,sponge、platelets and sand stone shape powders were prepared. The temperature andtime of sol formation have little effect on powders’ morphology, but the pH ofprecursor has a greater impact on it, particle size decreases with the increase of Ph.The particle size decreases when adding OP emulsifier as a surfactant.The concentration of reactants and drying control chemical additive andprecursor’s pH have severe impact on erbium oxide powders’ morphology preparedby adding agarose. Largest specific surface area of powders synthesized in differentoncentration of reactants was14.06m~2/g, the size of nanoparticals obtained by usingformamide and N,N-dimethyl formamide as drying control chemical additive was about200nm. The sol that contain colloid particals was prepared through thereaction of oxalic acid solution and gel of citric acid erbium, particals of erbiumoxide powsers size between500nm-1μm were prepared via sol-gel process and themorphology of particals mainly depend on precursor pH and reaction temperature.