Crystallographic alignment and magnetic anisotropy were studied for NdxFe94–xB6 （x=8,9,10,11） ribbons prepared via melt-spinning. Effect of Nd content and wheel speed on the crystal structure and magnetic propertie...Crystallographic alignment and magnetic anisotropy were studied for NdxFe94–xB6 （x=8,9,10,11） ribbons prepared via melt-spinning. Effect of Nd content and wheel speed on the crystal structure and magnetic properties of the ribbons was investigated. Both the free and wheel side of the ribbons could obtain strong c-axis crystal texture of Nd2Fe14B phase perpendicular to the ribbons surface at low wheel speed,but the texture weakened gradually with the increase of the wheel speed. Increase of Nd content led to better formation of crystal texture in the ribbons,indicating that the α-Fe phase might undermine the formation of crystal texture. Magnetic measurement results showed that the magnetic anisotropy of the ribbons exhibited corresponding behavior with the invariance of the c-axis crystal texture of Nd2Fe14B phase in the ribbons,and the coercivity of the ribbons rose with the increase of both Nd content and wheel speed during melt-spun process.展开更多
Nd-Fe-B permanent magnets doped with CuZn5 powders were prepared via conventional sintered method. The effects of CuZn5 contents on magnetic properties and corrosion resistance of the magnets were sys- tematically stu...Nd-Fe-B permanent magnets doped with CuZn5 powders were prepared via conventional sintered method. The effects of CuZn5 contents on magnetic properties and corrosion resistance of the magnets were sys- tematically studied. It shows that the remanence, coercivity, and maximum energy product decrease gradually with the increase in CuZn5 doping content. The magnet＇s corrosion kinetics in autoclaves environment and its electrochemical properties in electrolytes were also examined. It is interesting to see that the weight loss of 3.5 wt% and 4.5 wt% CuZn5 powders doping magnets is only 1 and 0 mg.cm^-2 after autoclaves test at 121 ℃, 2 × 10^5 Pa for 500 h, respectively, which is much lower than that of the magnets without CuZn5 doping. Electrochemical results show that the CuZn5 powders doping magnets display more positive corrosion potential （Eoorr） and lower corrosion current density （Icorr） than those of the original magnets without CuZn5 doping in sulphuric acid electrolyte and distilled water. It is, therefore, concluded that doping CuZn5 powders is a promising way to enhance the corrosion resistance of sintered Nd-Fe-B magnets.展开更多
Ternary Tb-Fe-B ribbons were prepared via melt-spun technique under different wheel speeds of 5-25 m/s.Effect of wheel speed on the crystal structure and microstructure of the ribbons was investigated.All the ribbons ...Ternary Tb-Fe-B ribbons were prepared via melt-spun technique under different wheel speeds of 5-25 m/s.Effect of wheel speed on the crystal structure and microstructure of the ribbons was investigated.All the ribbons quenched under different wheel speeds crystallized in single Tb2Fe14B phase with tetragon structure.Different crystallographic alignment evolutions were observed in the free side surface and wheel side surface of the ribbons.On the free-side surface,an in-plane c-axis crystal texture of Tb2Fe14B phase was found in the ribbons quenched at 5 m/s.However,with the increase in the wheel speed,the direction of the c-axis texture turns to perpendicular to the ribbon surface.On the wheel-side surface,a strong c-axis texture perpendicular to the ribbon surface was observed in the ribbons quenched at 5 m/s,and then weakened gradually with the increase in the wheel speed.Further investigation showed that the competition of the two types of temperature gradients during the quench process was responsible for the crystallographic alignment evolution in the ribbons.展开更多
基金Project supported by the National Natural Science Foundation of China (50871003, 20971116)the Key Project of the International Coopera-tion and Exchanges of Zhejiang Province (2006C14014)
文摘Crystallographic alignment and magnetic anisotropy were studied for NdxFe94–xB6 （x=8,9,10,11） ribbons prepared via melt-spinning. Effect of Nd content and wheel speed on the crystal structure and magnetic properties of the ribbons was investigated. Both the free and wheel side of the ribbons could obtain strong c-axis crystal texture of Nd2Fe14B phase perpendicular to the ribbons surface at low wheel speed,but the texture weakened gradually with the increase of the wheel speed. Increase of Nd content led to better formation of crystal texture in the ribbons,indicating that the α-Fe phase might undermine the formation of crystal texture. Magnetic measurement results showed that the magnetic anisotropy of the ribbons exhibited corresponding behavior with the invariance of the c-axis crystal texture of Nd2Fe14B phase in the ribbons,and the coercivity of the ribbons rose with the increase of both Nd content and wheel speed during melt-spun process.
基金financially supported by the National High Technology Research and Development Program of China (No. 2012AA063201)the National Natural Science Foundation of China (Nos. 51001002 and 51371002)+2 种基金the International S&T Cooperation Program of China (No.2015DFG52020)the Natural Science Foundation of Anhui Province (No.1408085MKL72)the 2011 Cooperative Innovation Center of Beijing University of Technology
文摘Nd-Fe-B permanent magnets doped with CuZn5 powders were prepared via conventional sintered method. The effects of CuZn5 contents on magnetic properties and corrosion resistance of the magnets were sys- tematically studied. It shows that the remanence, coercivity, and maximum energy product decrease gradually with the increase in CuZn5 doping content. The magnet＇s corrosion kinetics in autoclaves environment and its electrochemical properties in electrolytes were also examined. It is interesting to see that the weight loss of 3.5 wt% and 4.5 wt% CuZn5 powders doping magnets is only 1 and 0 mg.cm^-2 after autoclaves test at 121 ℃, 2 × 10^5 Pa for 500 h, respectively, which is much lower than that of the magnets without CuZn5 doping. Electrochemical results show that the CuZn5 powders doping magnets display more positive corrosion potential （Eoorr） and lower corrosion current density （Icorr） than those of the original magnets without CuZn5 doping in sulphuric acid electrolyte and distilled water. It is, therefore, concluded that doping CuZn5 powders is a promising way to enhance the corrosion resistance of sintered Nd-Fe-B magnets.
基金Project supported by the National Natural Science Foundation of China (50871003)
文摘Ternary Tb-Fe-B ribbons were prepared via melt-spun technique under different wheel speeds of 5-25 m/s.Effect of wheel speed on the crystal structure and microstructure of the ribbons was investigated.All the ribbons quenched under different wheel speeds crystallized in single Tb2Fe14B phase with tetragon structure.Different crystallographic alignment evolutions were observed in the free side surface and wheel side surface of the ribbons.On the free-side surface,an in-plane c-axis crystal texture of Tb2Fe14B phase was found in the ribbons quenched at 5 m/s.However,with the increase in the wheel speed,the direction of the c-axis texture turns to perpendicular to the ribbon surface.On the wheel-side surface,a strong c-axis texture perpendicular to the ribbon surface was observed in the ribbons quenched at 5 m/s,and then weakened gradually with the increase in the wheel speed.Further investigation showed that the competition of the two types of temperature gradients during the quench process was responsible for the crystallographic alignment evolution in the ribbons.
