Preparation And Electromagnetic Property Of Fe SiAlTi Flaky Powders

Entering the 21 st century, science and technology are going to an era of explosive growth. At the same time, it bring convenience with some trouble. The popularity of electronic equipment produces the increased amount of electromagnetic wave.Electromagnetic wave of electronic devices and biological effects are not allowed to ignore.Solution for this problem is mainly used to attenuation of electromagnetic wave absorbing material at present. Absorbing material, metallic powder alloy has better absorbing performance than ferrite for its higher saturation magnetization and wider absorption spectrum.Research for metallic alloy powder, absorbing material is much.Ti can increase the resistivity of material. Then it can reduce eddy current loss and improves permeability. FeSiAlTi alloy powders were prepared by two methods that are mechanical alloy and melting with ball milling. The influence of electromagnetic wave absorption performance was studied on two different preparation technology and different Ti content to the structure of powder. On this basis,MgO was covered on the surface FeSiAlTi alloy powder by two methods of high-energy ball milling and vapor deposition.FeSiAlTi flake powder was prepared by mechanical alloy method. After ball milling for 50 h, powder becomes to a few microns.When Ti content is 3.6wt%. Complex permittivity is the lowest among the four powders. The minimum value of reflection loss is-30.95 dB. The FeSiAlTi flaky metallic powder was pepared by melting and ball milling after 40 hours. As the increasing of Ti content, the lattice of powders increased at first and then starts to drop. According to their atomic size, it is found that Ti will replace the position of Al in the alloy with the increasing of Ti content. When Ti content is 1at% or 1.5at%, there is a new phase Fe0.975Ti0.025 in the alloy powder. When Ti content is 1at%, there was appropriate spacing and matching between the atoms. The complex permittivity and complex permeability have obtained the very good matching relationship. The minimum reflection loss is- 21.13 dB.A method of MgO covered in the surface of FeSiAlTi alloy powder was high-energy ball milling. The permittivity became bigger because MgO was not well coated on the surface of powder. This leads to a wave absorption performance becoming bad. Maximum absorption peak moves to low frequency. Another method was after FeSiAlTi powder surface oxidation, through the way of evaporation, let the Mg vapour and the surface oxide reaction at high temperature. The surface of powder will be coated MgO film. Quality factor of the powder increased with the increasing of frequency. ?? was good stability with the frequency.When Ti content is 1.5at %. ?? is the largest.The FeSiAlTi alloy powder prepared by mechanical alloy method,when Ti content content is 3.6wt%. It achieved best matching relations and best wave absorption performance.The FeSiAlTi alloy powder prepared by melting with ball milling, when Ti content is 1at%, the powder obtain the best wave absorption performance.