Effect of Ti Content on Microwave Absorbing Properties of Nd-Fe Alloys

Abstract

The Nd7.69Fe92.31-xTix (x = 0, 4, 8, 12) alloy were prepared by arc smelting and high energy ball milling method. The morphology and phase structure of the powders were analyzed by Scanning Electron Microscope (SEM), X-ray diffraction (XRD) and the effect of the Ti content on microwave absorbing properties of the powders were measured by a vector network analyzer (VNA). The results reveal that the samples mainly consisted of Nd2Fe17 and α-Fe crystal structure. The minimum absorption peak frequency shifts to lower frequency region firstly and then shifts to higher frequency region with the increasing amount of Ti content. The minimum reflection loss of Nd7.69Fe84.31Ti8 powder is-31.35 dB and the bandwidth of R < -5 dB reach 3.6 GHz when the coating thickness is 2.0 mm. With the increasing of the coating thickness, the minimum reflectivity peak value of the Nd7.69Fe84.31Ti8 moves to lower frequency region and the minimum reflection loss increase firstly and then decrease. And the minimum reflection value of Nd7.69Fe84.31Ti8 alloy can reach to-38.74 dB (microwave absorption rate 99.99%) at 5.68 GHz, and the bandwidth of R < -10 dB reach 1.12 GHz with the best matching thickness of 2.2 mm.