Preparation Of BiMg₂VO₆,BaMg₂V₂O₈ And BaZnV₂O₇ Materials

The microwave dielectric ceramics of vanadate system materials have attracted much attention because of their low sintering temperature.BaZnV₂O₇,BaMg₂V₂O₈ and BiMg₂VO₆are all vanadate materials of microwave dielectric ceramics.They have low dielectric constants and exhibit excellent microwave dielectric properties,and are widely concerned by scholars.These three materials are in the early stage of research,and most of them are prepared by the solid-state method.The calcination temperature is very high.The calcination time required for the synthesis of the target product is longer,and the particles are bound together to form large-sized particles.The solid-state method directly affects the density,grain size,grain boundary and internal stress of the resulting ceramic material,which in turn affects the dielectric properties of the ceramic,so different preparation methods need to be studied.In this paper,BaZnV₂O₇ and BaMg₂V₂O₈ were prepared by sol-gel method,and BiMg₂VO₆ was prepared by improved precipitation method.The preparation conditions are investigated for obtaining products with smaller particles and higher purity.The precipitation method is widely used in the preparation of various ceramic materials.Firstly,the BiMg₂VO₆ material was prepared in a shorter calcination time with an improved precipitation method in this paper.The influences of preparation conditions on BiMg₂VO₆material were investigated,such as the amount of complexing agent,calcination temperature,calcination time and etc.BiMg₂VO₆ materials with small particle morphology,and better uniform particle size distribution were obtained.Secondly,BaMg₂V₂O₈ was prepared by sol-gel method in this paper.Experiments were carried out with citric acid and acetic acid as complexing agents.We explore the main factors influencing the preparation of BaMg₂V₂O₈ by sol-gel method;analyze and compare XRD spectram and SEM to investigate the preparation conditions of sol-gel method,such as the type and amount of complexing agents,calcination temperature and calcination time influences.BaMg₂V₂O₈ material was prepared successfully.Lastly,BaZnV₂O₇ was prepared by sol-gel method in this paper,which lowered the preparation temperature and sintering temperature.The amount of complexing agent citric acid,calcination time,calcination temperature,and sintering temperature were investigated during the preparation process by the sol-gel method.The typical BaZnV₂O₇ XRD pattern was refined.The experiment conditions for preparing high purity samples were obtained.To obtain better microwave dielectric properties,the influences of sintering temperature and sintering time on some sintering samples were investigated.The experimental results show that the sample calcined at 550?for 2h has good purity and morphology.When the amount of citric acid is 1.5 times,the best desired product can be obtained by the sol-gel method.The sintered samples exhibits better microwave dielectric properties.