Preparation And Microwave Electromagnetic Properties Of Flaky Reduced Iron Powders

With the development of socio-economic and electronic technology, more and more electronic products are used by people, more and more electromagnetic wave are brought by electronic products. Electromagnetic wave can severely influence human health and other electronic devices normal use. The demands from war also contribute to development of the absorbing material. Therefore, absorbing materials applied researches are becoming more and more important.In this article, flaky reduced iron powders were prepared by wet ball milling, the morphology and structure of flaky reduced iron powders were characterized by SEM、 XRD respectively. The 2-18GHz electromagnetic parameters of reduced iron powders/paraffin (sample) were measured by vector network analyzer. The influence of electromagnetic parameters of the sample by milling around, different milling time, ball material ratio and the mass fraction were researched. The reflection loss of the sample was calculated by Matlab, and the reflection loss was compared with the measured reflection loss. Different sizes of flaky reduced iron powders were get by size-fractionated. The morphology and structure were characterized. Electromagnetic parameters of sample were measured. The reflection loss of the sample was calculated. The reduced iron powders were heated treatment before and after milling. The morphology and structure were characterized. Electromagnetic parameters of sample were measured. The reflection loss of the sample was calculated, and was compared with the measured reflection loss.Results show that the flaky reduced iron powders were prepared after milling. The size of the flaky reduced iron powders was between 0-150p.m, and the thickness of flaky was several hundred nanometers. Compared with the reduced iron powders/paraffin, the s and μ of flaky reduced iron powders/paraffin increased, and the reflection loss decreased. With the milling time increased or the mass of reduced iron powders decrease in ball material ratio, the average particle size of the flaky reduced iron powders decreased. The ε and μ. of samples reduced, and the reflection loss of samples showed stronger absorption. With the increase of mass fraction of flaky reduced iron powders, the ε and μ of samples increased, and the reflection loss of samples showed stronger absorption.The different particle sizes flaky reduced iron powders/paraffin electromagnetic parameters were contrast. With the particle size decrease, the ε and μ of sample first increased and then decreased. The maximum were 150-200 mesh samples. The smaller particle size sample had the best absorbing. The electromagnetic parameters of the same particle size flaky reduced iron powders/paraffin were not consistent with the milling time.Compared with the original reduced iron powders, reduced iron powders were smooth and bond after the heat treatment. The ε of the sample decreased, and μ, increased. The reflection loss of samples showed stronger absorption. Compared with the flaky reduced iron powders, flaky reduced iron powders were also bond after the heat treatment. The ε and μ of the sample reduced, and the reflection loss of sample showed stronger absorption. Compared with the calculated reflection loss, the measured reflection loss showed poor results. It might due to absorbing materials contamination during preparation absorbing coating, resin matrix changed and flaky reduced iron powder reunion and so on.