The Preparation And Characterization Of Nanocomposite Metal Oxide With Infrared And Millimeter-wave Radiation

Nowadays, with the rapid development of high technology, as the high technological weapons and equipment has been continuous improvement, in order to adapt to this new military threat, the interferential or camouflage materials with the single function has been difficult to be applied, which has been replaced by the multispectral compatible interferential or camouflage materials, which have become the main research direction in the field.In this experiment, Al3+, Mg2+ and Zn2+ ions doped LaFeO3, ZnFe2O4 and NiAl2O4 have been synthesized using a Sol-Gel method, and the properties of the samples have also been examined. The thermal analyzer (TG-DSC), X-ray diffraction analyzer (XRD), high-resolution scanning electronic microscope(FESEM), colorimeter, infrared emissivity meter and millimeter wave radiometer are used to describe the crystal structure, particle size, surface morphology, color characteristic, infrared and millimeter-wave radiation properties of the prepared samples.The results show that:(1) The XRD of LaFeO3 material sintering at different temperature, shows that 700℃is the best temperature to obtain LaFeO3 nanoparticles with an orthorhombic crystal structure, and the doping of Al3+ does not change the structure of LaFeO3 phase. The images of the samples reveal that all particles are of uniformly distributed diameters and spherical shapes and the average size is about 70-100nm. (2) The optimum calcination temperature of ZnFe2O4 particles is 800 ℃, the prepared sample is spinel structure with the standard pattern of face-centered-cubic, the space group is Fd3m(227), and the doping of Mg2+ does not change the crystal structure of the ZnFe2O4 substrate material, and the average size of the samples is about 80-200nm. prepared Zn1-xMgxFe2O4 particles exhibit a compact arrangement and show a spherical structure, and the prepared samples. (3) The optimum calcination temperature of NiAl2O4 nanoparticles is 800 ℃, the prepared sample is cubic crystal structure and the space group is Fd3m(227), and the doping of Zn2+ does not change the crystal structure of the NiAl2O4 substrate material. The obtained Ni1-xZnxAl2O4 particles are spherical structure and the average size is about 30-60nm. (4) The values of the infrared emissivity of the LaFe1-xAlxO3, Zn1-xMgxFe2O4 and Ni1-xZnxAl2O4 samples at the band of 3-5μm,8-14μm are between 26-87% and 85-98%, respectively. The prepared samples have high infrared emissivity at the band of 8-14μm, so they can be used as additive putted into the far-infrared decoy materials, which can enhance the 8-14μm infrared radiation characteristic, and the radiation energy can better simulate the radiation properties of the real target. (5) The magnesium powder, polytetrafluoroethylene powder and the synthesized powders are used as filler in the coatings, and the different coatings will be prepared. The results show that the values of emissivity of all the samples are between o.57-0.73 at 3 mm band, while between 0.44-0.60 at 8mm band. After different ions doped samples in the filler, the emissivity values are improved accordingly. So the prepared samples can be used for metal surface of the tank, vehicles and other military targets, which can improve the surface emissivity and keep a similar emissivity value with the surroundings, so as to obtain certain camouflage effect.In conclusion, this work not only brings some useful information for the infrared and millimeter-wave radiation research, but also gives some suggestions to the infrared and millimeter-wave radiation powders in the field interference or camouflage.