HUANG Gangxiang XU Qingzhen GAO Huimin YU Shanfu HUA Hongci WANG Geya Shanghai Iron and Steel Research Institute
,
Shanghai
,
200940
,
China.Shanghai Institute of Metallurgy
,
Academia Sinica
,
Shanghai
,
200050
,
China.
材料科学技术（英）
The microstructures of melt-spun Nd_135- Fe_81.74B4.76 ribbons have been investigated by means of X-ray diffraction,Mossbauer spectroscopy and HREM.Experimental results show that optimal magnetic properties of the bond- ed magnet can be obtained by melt-spun alloys at wheel velocity of 24m/s,the microstructure of which was single phase Nd_2Fe_(14)B crystallites,and no other phases,such as Nd-rich,B-rich or x-Fe phase,were present.It is considered that the high intrinsic coercivity ~iH_c can be attributed to the sin- gle-domain behaviour of Nd_2Fe_(14)B crystallite phase.
关键词:
coercivity
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null
ZHANG Henghua MA Ruzhang SU Shizhang CHANG Ruqin JIN Huijuan XU Guiqin ** Beijing University of Science and Technology
,
Beijing
,
100083
,
China*** Shanghai Iron and Steel Research Institute
,
Shanghai
,
200940
,
China+ To whom correspondence should be addressed
材料科学技术（英）
The retained austenite in high speed steel of two different heat treatment regimes was quantitatively,determined by transmission Mssbauer spectroscopy (TMS),backscattering X-ray geometry,Mossbauer spectroscopy (BXMS) and X-ray diffraction technique.The results meas- ured by these methods were in agreement with each other.It was demonstrated that the concentration of carbides in high speed steel could be measured by transmission Mossbauer spectroscopy or Mossbau- er spectroscopy in backscattering X-ray geometry accurately.
关键词:
Mssbauer spectroscopy
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null
,
null
Lijun CHEN Yuzhi LIU Gingzhen XU Haisheng SHI Shanghai Iron and Steel Research Institute
,
Shanghai
,
200940
,
China
材料科学技术（英）
The relationship between the high-frequency magnetic properties and surface structure of the amorphous [Co_(0.94-x)Fe_(0.06)(MnMo)_x]_(77)(SiB)_(23) alloys annealed at 400-500℃ then control-cooled was investigated using XRD,TEM and XPS techniques.The results have shown that the high-frequency losses of the present alloys ob- viously reduced after suitable treatment.A crystalline layer with ultrafine grains of γ-Co formed on the surface of the amorphous ribbons.The size of the grains is 10-20 nm.The thickness of the layer is less than 0.1 μm.The sur- face of the crystalline layer is covered with an extremely thin oxide film which is very uniform and dense with thickness of less than 30 nm,the size of grains of the oxide is less than 10 nm.These ultrafine grains and the dense oxide film effectively refine the magnetic domains and increase the resistance of the layers of the magnetic core,consequently the losses at high frequency are fairly reduced.
关键词:
magnetic property
,
null
,
null
