Study On Preparation And Properties Of Calcium Fluoride Ceramic

Calcium fluoride material has a series of excellent performance as a function of materia. Due to the unique structure of calcium fluoride and its performance, it has been received more and more attention., calcium fluoride is widely used the three major industries such as chemical industry, metallurgy and building materials with science and technology development, as well as optics, light industry and the defense industry. In recent years, the application of nano calcium fluoride become a hot spot due to the rapid development of nanotechnology. Therefore, the study of nano calcium fluoride powder preparation and its properties is necessary. On the other hand, the rare earth is often used as ingredients or additives in metallurgy, machinery and other sectors. Especially the rare-earth doped micro or nano fluoride materials are widely used in solid-state lasers, integrated optical systems, high-definition display, bio-analysis, medical diagnosis and scientific research in the field of military aviation, due to its unique excellent performance. Thus rare doped nano calcium fluoride is one of the elements of the study.In this paper, pure nano and doped nano yttrium calcium fluoride powder were prepared by direct precipitation method. X-ray diffraction (XRD), scanning electron microscopy (SEM) analysis and other characterization methods were carried out to performance the nano powder structure, morphology. Then the study explore the impact of different calcining temperature on calcium fluoride powder, and sintering temperature on the calcium fluoride ceramics to determine the optimum calcining temperature and the best sintering temperature on the powder and ceramic. Finally, the study explore the electrical properties of the doping calcium fluoride.The results indicated that:the grain size of calcium fluoride is between 40-50nm prepared by direct precipitation, prepared doped The grain size of 3mol%YF3-CaF2,5mol% YF3-CaF2 and 7mol% YF3-CaF2 is reduced to about 20 nm with the doping concentration increases. While the calcined calcium fluoride crystal powder after doping has also been reduced. The optimum calcining temperature for nano calcium fluoride and the one under different doping concentration is 500?Under different doping level, the research for calcium fluoride ceramics on sintering temperature indicates:With the doping concentration increases, the sintering temperature for calcium fluoride ceramic is reduced from 1000? to 800?. The results reveal that the doped powder is easier to aggerlarate, finer powders is easier to fuse and form ceramic.Because pure calcium fluoride is ion conductor, AC impedance spectroscopy is carried out to measure ionic conductivity of undoped and doped calcium fluoride ceramic samples between 350?-450 ?. Experimental results show that appropriate doping can effectively reduce the activation energy of the ion conductivity. However, in the case of heavy doping, the surface area of crystal increases due to the reduced size of the crystal. The interfacial area increased leading to ion relaxation component increases in impedance spectroscopy, thus multiple relaxation components are performanced in the impedance spectrum.