Study On The Preparation And Properties Of Fluorine Doped Cerium Based Composite Rare Earth Polishing Powder

In the polishing operation of advanced optical glass,the pure ceria rare earth polishing powder on the market generally has some defects,such as low polishing efficiency,easy to cause too many scratches on the polished surface and so on.It takes a long time to polish and it is difficult to meet the surface requirements of advanced optical glass.In order to solve this problem,the properties of cerium based rare earth polishing powder were improved by changing the preparation conditions or coating operation.The results were analyzed and summarized,and the optimal preparation conditions of cerium based rare earth polishing powder and its composite abrasive were obtained.The conclusion can provide theoretical guidance for the preparation,research and production of fluorine doped cerium based rare earth polishing powder and its composite abrasives.Cerium dioxide rare earth polishing powder was prepared by using cerium nitrate as cerium source.The main technological conditions of fluorination,reaction environment and roasting temperature were studied.The results show that fluorination can make the product obtain a regular and round shape,which is conducive to polishing.Microwave environment can make the sample obtain higher crystallinity,reduce agglomeration and refine particles.Simultaneous fluorination in microwave environment will make the suspension of the product worse.On the basis of the optimum preparation conditions,the roasting temperature was further studied.The results show that the samples can obtain better crystallinity and smaller grain size at the calcination temperature of 850??960?,and the best particle morphology and particle size distribution can be obtained at 900?.Rare earth polishing powder doped with fluorine cerium dioxide was prepared by precipitation method.The fluorinating agent and precipitant were studied.The characterization method is the same as above.The results show that the organic precipitant(oxalic acid)and inorganic precipitant(ammonium bicarbonate)not only affect the cerium based rare earth polishing powder by their inherent precipitation mechanism,but also affect the crystallinity,particle morphology and agglomeration degree of the prepared rare earth polishing powder when combined with different fluorinating agents(ammonium fluoride and potassium fluoride)There are obvious differences in grain size and dispersion in solution.The coating of cerium based rare earth polishing powder was studied.A core-shell composite abrasive polishing powder was prepared by coating the surface of polystyrene with modified ceria.The characterization method is the same as above.The results show that the composite abrasive polishing powder with core-shell structure is successfully prepared.The results show that the best preparation condition is that the concentration of cerium nitrate is1.00g/ml and fluorine is doped in the microwave environment,which is conducive to make the coating more uniform and complete,and the composite abrasive particles are more rounded,and have better suspension and dispersion in the liquid.The crystallinity of Ce O₂ particles on the surface of the sample is the highest,and the particle size of the sample is the most uniform.In this paper,the above conclusions and the reasons are discussed,and the possible research directions in the future are prospected.