The microwave absorbents of Fe and C nanoparticles as magnetic loss and dielectric loss material respectively were composited with the polyvinyl alcohol(PVA)as binder by spray granulation method,The electromagnetic pa...The microwave absorbents of Fe and C nanoparticles as magnetic loss and dielectric loss material respectively were composited with the polyvinyl alcohol(PVA)as binder by spray granulation method,The electromagnetic parameters of Fe and C composite particles were analyzed by vector network.The complex permittivity and magnetic permeability of Fe and C composite particles matched well with increasing C nanoparticle content,and then the microwave loss property was improved.A minimum reflection loss(RL)of-42.7 dB at 3.68 GHz for a composite with 4.6 mm in thickness can be obtained when the content ratio of the C nanoparticles,the modified Fe nanoparticles and the PVA is 21:49:30(Sample 3).展开更多
The present paper reports the rapid surface alloying induced by the bombardment of high-current pulsed electron beam. Two kinds of substrate materials were examined to show this effect. The first sample was a pure Al ...The present paper reports the rapid surface alloying induced by the bombardment of high-current pulsed electron beam. Two kinds of substrate materials were examined to show this effect. The first sample was a pure Al metal pre-coated with fine carbon powders prior to the bombardment, and the second alloy is the D2-Crl2MolVl mould steel pre-coated with Cr, Ti, and TiN powders. The surface elements diffuse about several micrometers into the substrate materials only after several bombardments. Tribological behaviors of these samples were characterized and significant improvement in wear resistance was found. Finally, a TEM analysis reveals the presence of stress waves generated by coupled thermal and stress fields, which was considered as the main cause of the enhanced properties.展开更多
基金the support from the National Natural Science Foundation of China(No.51171033)the Fundamental Research Funds for the Central Universities(DUT15LAB05,DUT16LAB03)
文摘The microwave absorbents of Fe and C nanoparticles as magnetic loss and dielectric loss material respectively were composited with the polyvinyl alcohol(PVA)as binder by spray granulation method,The electromagnetic parameters of Fe and C composite particles were analyzed by vector network.The complex permittivity and magnetic permeability of Fe and C composite particles matched well with increasing C nanoparticle content,and then the microwave loss property was improved.A minimum reflection loss(RL)of-42.7 dB at 3.68 GHz for a composite with 4.6 mm in thickness can be obtained when the content ratio of the C nanoparticles,the modified Fe nanoparticles and the PVA is 21:49:30(Sample 3).
文摘The present paper reports the rapid surface alloying induced by the bombardment of high-current pulsed electron beam. Two kinds of substrate materials were examined to show this effect. The first sample was a pure Al metal pre-coated with fine carbon powders prior to the bombardment, and the second alloy is the D2-Crl2MolVl mould steel pre-coated with Cr, Ti, and TiN powders. The surface elements diffuse about several micrometers into the substrate materials only after several bombardments. Tribological behaviors of these samples were characterized and significant improvement in wear resistance was found. Finally, a TEM analysis reveals the presence of stress waves generated by coupled thermal and stress fields, which was considered as the main cause of the enhanced properties.
