Research Of Microwave Electromagnetism Property Of Flattened Metal Magnetic Powder

With the widespread use of microwave-absorbing materials in the field such as radar microwave stealth technology, electronic countermeasure, microwave comunic- ation and electromagnetic compatible, it becomes an important issue to research and develop microwave-absorbing materials for the demand above.Magnetic metal particle material has become main develop way for its stability of temperature, high permeability,higher Curie temperature and more way of produce.The absorber of magnetic metal particle material which has been flattened has attain abroad application in magnetism industry for their high permeability and high magnetic loss under broadband microwave frequency.Flaky morphology of magnetic metal particle material can raise its natural resonance frequency because of strong shape anisotropy, which is advantageous to acquiring high microwave permeability .According to this, Flattened metal magnetic particle were adopted to manufacture microwave absorber with high permeability and magnetism loss 2-18 GHz. Thus, it is possible to design and prepare thin layer absorber material with broad bandwidth and strong absorption.Firstly, domestic and international development of microwave absorber was described. And then, the problems of microwave absorber development in our country were discussed. Then, the absorbability mechanism of metal powder absorber,and the magnetic connotation of alloy flakes with particular shape anisotropy having high microwave permeability were presented.The relation between aspect ratio of flatten metal magnetic particle and electromagnetic parameter of the absorber is declared theoretically. The atomized powder was improved by high-energy ball milling,then the radar absorbent of flattened magnetic alloy powder was made. The absorbent was analysed by SEM and XRD and the magnetic alloy powder-paraffin sample was made a complex permeability measurement in the radar frequency. Effects of the high-energy ball milling technics on grain size decreasing,the particle size of the powder and the aspect radio and the changing law of complex permeability with the particle size of the flattened metal powder absorbent were discussed. And the result of prove that the absorbency of the flatten alloy particle material alloy is excellent in the frequency of 2-18 GHz.Thus, it can be applied for designing and preparing microwave absorber operating in broad bandwidth.