科技英语作业

1、Magnetic microstructures of high Magnetic microstructures of high performance permanent magnetic performance permanent magnetic materialsmaterials 材化材化1202班班 070512xxxxxwilliam 班级班级 学号学号 姓名姓名班级班级Contentsmagnetic force microscopy high coercivity Nd-Fe-B sintered magnets hot-deformed Nd-Fe-B magnets 2

2、:17-type Sm-Co sintered magnets 4123Magnetic domains are strong correlated to the macro-magnetic propertiesof magnetic materials. . the process轻敲模式轻敲模式抬起模式抬起模式 magnetic force microscopy (MFM)1.第一次扫描采用轻敲模式，得第一次扫描采用轻敲模式，得到样品在这一行的高低起伏并记到样品在这一行的高低起伏并记录下来；录下来；2.然后采用抬起模式，让磁性探然后采用抬起模式，让磁性探针抬起一定的高度针抬起一定的高度(

3、通常为通常为10200nm)，并按样品表面起伏轨，并按样品表面起伏轨迹进行第二次扫描，由于探针被迹进行第二次扫描，由于探针被抬起且按样品表面起伏轨迹扫描，抬起且按样品表面起伏轨迹扫描，故第二次扫描过程中针尖不接触故第二次扫描过程中针尖不接触样品表面（不存在针尖与样品间样品表面（不存在针尖与样品间原子的短程斥力）且与其保持恒原子的短程斥力）且与其保持恒定距离（消除了样品表面形貌的定距离（消除了样品表面形貌的影响），磁性探针因受到的长程影响），磁性探针因受到的长程磁力的作用而引起的振幅和相位磁力的作用而引起的振幅和相位变化，因此，将第二次扫描中探变化，因此，将第二次扫描中探针的振幅和相位变化记录下

4、来，针的振幅和相位变化记录下来，就能得到样品表面漏磁场的精细就能得到样品表面漏磁场的精细梯度，从而得到样品的磁畴结构。梯度，从而得到样品的磁畴结构。 high coercivity Nd-Fe-B sintered magnetsEvolution of magnetic domains for sintered Nd-Fe-B magnets upon temperaturematerials magnetic microstructures ContentsThe different microstructures of different temperature,120，170，270

5、respectivelyHigh coercivity NdDyFeCoBAl permanent magnets were prepared by powder metallurgy procedures. Description of the contentsText in hereDifferent crystals appear white or dark in color,Nevertheless, these crystals are still in single domain stateThere is almost no contrast in them, indicatin

6、g that they are single domain .Text in herea number of crystals have already had plate-like domain structures (Fig. 2(c), which are formed by nucleation and growth of reversal domains.Text in hereThe magnetic contrast of the single crystals increases compared to Fig. b1b1abchot-deformed Nd-Fe-B magn

7、etsMagnetic domains of hot-pressed and hot-deformed Nd-Fe-B magnetsmaterials and environment sample surfaces ContentsOne is with surface normal parallel (/) to the press direction; the other is with surface normal perpendicular () to the press direction. 1、Nd13.62Fe75.70Co4.45B5.76Ga0.47 melt-spun r

8、ibbon powders2、 in argon atmosphere at temperatures about 850 C with different height-reduction (h) of 60% - 88%热压热压(Hot-press)和热变形和热变形(Die-upset)。热压阶段将。热压阶段将Nd-Fe-B粉末压成高密度、各向同粉末压成高密度、各向同性坯块。热变形阶段将性坯块。热变形阶段将Nd-Fe-B等轴晶转变为片状晶，片状等轴晶转变为片状晶，片状晶的堆垛方式为垂直压缩方向，晶的堆垛方式为垂直压缩方向，c轴轴(易磁化轴易磁化轴) 沿着压力方向沿着压力方向排布，形成各向异

9、性磁体，从排布，形成各向异性磁体，从而大幅度提高磁体的磁性能而大幅度提高磁体的磁性能.2:17-type Sm-Co sintered magnetsmaterialsprocessenvironment1、The Sm(Co,Fe,Cu,Zr)z (z = 7.0 -8.5) permanent magnets2、 sintering at about 1200 for 0.5h, solid-solution treatment at about 1180 for 5 h, isothermal aging at 830 for 24 h, slow cooling at a rate o

10、f 0.7 /min to 400, and then soaking for 10 hA stripe domain pattern is presented. we gradually quenched specimens from 1200, 1180, 830 and 400 to room temperature, sequentially. Takes on typical corrugation and spike domains (i.e., black and white dots). Detected by magnetic tips as coarse domains o

11、r wide stripe domains.the domain structures are actually an aggregation of many single domains, or so-called coupling interaction domains(a)(b)(c)(d)Summary The influence of temperature, fabrication procedure parameters The thermal demagnetization process consists of four stagesTheir magnetic domains can be named as interaction ones.The domain configurations change from plate-like for the as-sintered magnet to corrugation and spike-like for the homogenized one, and then to a coarse, and finally to a finer domain structure .Nd-Fe-