Dissertation > Industrial Technology > General industrial technology > Materials science and engineering > Functional Materials

Study on Manufacture and Microwave-Absorption Properties of the New Type Absorption Material Nd8-XYFe84.5+XB6.5 (x=0, 0.5, 1)

Author DuMinSheng
Tutor LiGuoDong
School Inner Mongolia University
Course Condensed Matter Physics
Keywords Rare earth doped Ball milling Alloy melting Annealed Absorbing materials
Type Master's thesis
Year 2008
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In this paper, alloy smelting, milling and appropriate by the star line obtained after annealing a new kind of absorbing material, and its microwave band absorbing characteristics were studied. The experimental results showed that: after different milling time, annealing treatment and iron content will be of a different impact absorbing properties of materials, including samples after annealing treatment was significantly higher than that without absorbing properties annealed samples; milling time and the iron content the optimum value only in the amount of absorption to reach max. Same article also rare-earth doped yttrium oxidation resistance of the material after the changes were studied. In Nd 8-x YFe 84.5 x B 6.5 (x = 0,0.5,1) three different proportions of materials, not After annealing treatment, x = 0.5 absorbing the best performance, the maximum absorption value reached 36.843 dB, relative to the x = 0 and x = 1 are significantly improved. So you can see: Material does not comply with the iron content increased absorbing performance improvement principles, but the best amount. After different times (t = 10min, 15min, 20min) after annealing the sample absorbing properties than annealed samples without absorbing properties were obtained very substantial increase, in which the sample after annealing 15 minutes maximum absorbing properties maximum absorption peak of 137.36dB, and the ratio of the mean absorption of microwave annealing section t = 10 and t = 20 min are higher than about 10dB, so there is also a sample annealing time optimum value. Samples were different times (t = 6h, 8h, 10h, 12h) milling, when t = 8h when the average sample in microwave absorption maximum at this time is not easy to see the smaller the particle milling longer absorbed by the sample volume the better, but there is a matching value. In our experimental conditions, the optimal sample size of 0.2 microns. Rare-earth doped Yttrium Yttrium undoped sample and compared to samples in the air for some time before its absorbing performance can be measured, the whole rare earth doped yttrium reduce the amount absorbed by the sample is relatively small amplitude , so the sample doped yttrium oxidation after a certain enhancements. To further investigate the mechanism of absorbing the sample, we tested the imaginary part of the dielectric constant of the sample, the imaginary part of permeability, and the XRD patterns. The experimental results showed: without annealing treatment, the imaginary part of the permeability frequency corresponding to the peak absorption peak corresponding to the frequency is very close, and their peak change with frequency similar laws. It can be seen, when the sample mainly through the impact of changes on the magnetic loss to change the microwave absorption. After annealing the samples absorption spectrum and permittivity spectra are very similar, and their peak frequency changes with the rules similar to the sample at this time mainly through the dielectric loss of the microwave to change its absorption rate. The XRD pattern shows that these new microwave absorbing materials, mainly through the metal oxide particles are spaced from each other to form aggregates insulated alloy particle dispersion, uniform distribution by volume compounded by the way, this is such a high performance absorbing agent provides better absorbing channels.

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