چكيده به لاتين
Microwave absorbing materials are one of the useful materials utilized in military and aerospace industries produced by various methods such as Sol-gel, Co-precipitation, etc.
In this research, the exchange-coupled hard/soft composites were produced by auto combustion method, forming Strontium hexaferrite as the hard phase and 〖MnFe〗_2 O_4, 〖Ni〗_0.3 〖Mn〗_0.2 〖Zn〗_0.3 〖Fe〗_2 O_4, 〖Ni〗_0.6 〖Zn〗_0.4 〖Fe〗_2 O_4 and 〖Ni〗_0.3 〖Mn〗_0.3 〖Zn〗_0.2 〖Fe〗_2 O_4 as the soft phase. Strontium nitrate, manganese nitrate, nickel nitrate, zinc nitrate and iron nitrate were distilled in different fuels such as EDTA, ethylene glycol and citric acid in stoichiometric amounts followed by combustion reaction. Then, the powders were annealed at different temperatures at 900, 800 and 700 centigrade degree.
The samples properties were measured by X-ray diffraction, Fourier transform infrared, field emission SEM, vibrating sample magnetometer and Microwave absorption tests to investigate morphological, structural and magnetic properties.
The sample that formed by Nickel-Manganese-Zinc ferrite and strontium hexaferrite as an exchange-coupled composite being calcinated at 900 Celsius degree. The saturation magnetization of this sample was about 60 (emu/g) with its coercivity of about 4500 (Oe).
