Preparation And Properties Of Composite Multiferroic Materials By Microwave-assisted Method

Multiferroic materials contain two or more iron basic properties simultaneously. In recent years, composite multiferroic materials have become a hot research at home and abroad,which have great application value in the magnetic sensor, data memory, piezoelectric transducers and so on. As a new generation of sintering method, microwave sintering is a rapid sintering of ceramic new technology in recent years. Compared with conventional sintering, it has the characteristics of low sintering temperature, short sintering time, high heating efficiency, safe and non-polluting. Microwave sintering is superior to conventional sintering in ceramic performance.In this paper, CoFe₂O₄/BaTiO₃ was selected as the research object, by microwave assisted sintering. The effects of different sintering temperature and different composition ratio on the structural properties of the composites were studied. The main contents and main conclusions are as follows:1. Ferroelectric phase BaTiO₃ powder and ferromagnetic phase CoFe₂O₄ powder were prepared by sol-gel method respectively. Change the calcination temperature, holding time,dispersant content and other factors to study. The optimum conditions for the preparation of BaTiO₃ powder were calcination temperature of 1000?, holding time for 1h, dispersant polyethylene glycol 6000 content 5%. The optimum conditions for the preparation of CoFe₂O₄ powder were calcination temperature of 700?, holding time for 2h.2. The CoFe₂O₄ powder and BaTiO₃ powder prepared under the optimum conditions were selected for the study of CoFe₂O₄/BaTiO₃. The ferroelectric properties and ferromagnetic properties of CoFe₂O₄/BaTiO₃ ceramics were studied by changing the calcination temperature and holding time. In this study, CoFe₂O₄/BaTiO₃ were prepared by microwave assisted sintering sol-gel method and microwave-assisted sintering powder mixing method.CoFe₂O₄/BaTiO₃ ceramic samples prepared in the two ways have some small pores, and the samples are not completely densified. Compared with the sol-gel method, the density of CoFe₂O₄/BaTiO₃ ceramics prepared by powder mixing method are slightly worse. However,the density of CoFe₂O₄/BaTiO₃ ceramics prepared by two different composite methods are higher than those of conventional sintering, and the sintering time is greatly shortened.Comparing the magnetic and ferroelectric properties of CoFe₂O₄/BaTiO₃ ceramics prepared by two methods, it can be seen that the magnetic properties and ferroelectric properties of CoFe₂O₄/BaTiO₃ ceramics prepared by powder mixing method are better under the same other conditions.