Preparation And Properties Of CeF₃ Optical Coating Material

CeF₃ crystal,which has high density,fast response,high ionic conductivity and unique optical properties,can be applied to chemical sensors and optical components.Cerium fluoride as a medium refractive index coating material,through the range from 300nm to 10μm,which is an excellent optical coating material,widely used in infrared and ultraviolet optics.As the coating material used in the fluoride material on the oxygen content requirements are very strict,but the fluoride is widespread in the high oxygen content of raw materials,it is difficult to meet the needs of the application.In this paper.CeO₂ was prepared by wet process using CeO₂ as raw material and used in the production of related coating materials.The phase,composition,morphology and coating properties of CeF₃ crystals were characterized by XRD,EDS,SEM and spectrophotometer.The factors such as heat preservation time,crystallization atmosphere,cooling system and crucible materials and additives were studied on the crystallization process of CeF₃.The results are as follows:（1）In the process of cerium oxide dissolution,the acid concentration had a great influence on it,and the optimum hydrochloric acid concentration was llmol/L.Dissolution temperature control at 80℃ is appropriate,the dissolution time of 3h.CeO₂ dissolved in the highest percentage of up to 80%.（2）During the fluorination process of cerium salt,CeF₃ obtained by direct fluorination is colloidal,which is not easy to be filtered and separated.The cerium fluoride obtained by transformation with cerium oxalate is easier to settle and wash than that obtained by direct fluorination.（3）Crystallization of cerium fluoride powder CeF₃ crystal preparation process,the crucible material on the crystal appearance of the performance of the crystal crucible crystal black,tungsten crucible crystal transparency is better.（4）As an additive,NH₄HF₂ can reduce the oxygen content of the crystallization product,and its oxygen content can be reduced from 0.45（wt%）to 0.1（wt%）.ZnF2 as an additive,the obtained CeF₃ has obvious porosity（5）The coating experiment shows that the CeF₃ film has a certain roughness,and the coating process splits obviously.From the residual analysis of the coating,it may be due to the influence of oxygen content on it.（6）The obtained Cep3 film was subjected to optical performance test.At a wavelength of 550 nm,the refractive index was 1.56 and the absorption coefficient was 1.56×10-4.