高能球磨制备NdFeB纳米晶粉末

利用湿法球磨制备了NdFeB纳米晶粉末，并通过对比发现湿法球磨比干法球磨效果好。研究结果表明，当湿法球磨超过210h，粉末变成细小、均匀的圆球状的小颗粒，颗粒直径在80～120nm之间，在本实验条件下颗粒尺寸已经趋向极限。粉末最终变成以Nd2Fe14B为基体相的合金。     

反应高能球磨制备纳米WC/MgO复合粉末

将WO3、C和Mg粉末按摩尔比为1∶1∶3混合,在室温下用高能球磨法对其进行球磨,经XRD、SEM和TEM分析表明,在球磨到4.7 h时,WO3、石墨和镁之间发生氧化还原反应直接生成了WC和MgO粉末,之后随球磨时间的延长,粉末不断细化.球磨50 h后,得到WC晶粒度和颗粒度分别约为25 nm和100 nm的WC/MgO复合粉末.实验结果和热动力学分析表明,WC/MgO的合成是一个自蔓延反应过程,此反应可以在很短的时间内完成.     

球磨WC-8Co粉末的放电等离子烧结

对WC-8Co粉末不同球磨时间后进行放电等离子烧结,研究了球磨时间及烧结温度对WC-8Co硬质合金微观结构及性能的影响。结果表明:球磨时间延长,粉末颗粒变细,晶格畸变增加,衍射峰强度降低,并随时间延长,团聚现象严重;采用放电等离子烧结,在1 200℃时,可以得到接近全致密的烧结样品,烧结温度低于传统方法的烧结温度;球磨时间在2 h以下时,样品的致密度、硬度和断裂韧性达到最佳,晶粒较小且分布均匀;延长球磨时间,性能显著下降且出现较多粗晶、空洞、Co池等缺陷。     

球磨法制备(Gd0.9Dy0.1)5Si4粉末及分析

采用行星式球磨机进行磁制冷材料（Gd0.9Dy0.1)5Si4的纳米粉末制备，在一定的球磨条件下，一定范围内颗粒粒度与球磨时间成正比，并最终制备出纳米级颗粒，但在此过程中，磁性材料的磁性完全消失，估计是由于材料的晶体结构转变为非晶状态和应力共同作用所致。     

混料工艺对Al＋Fe2O3铝热剂反应原料性能与微观形态的影响

采用双螺旋和球磨两种混料方式,研究不同混料时间对铝热剂性能及颗粒微观形态的影响,结果表明：混料过程中球磨混料颗粒平均粒度比双螺旋混料大,松装密度比双螺旋混料小,在双螺旋混料4h,球磨混料6h 时混合最为均匀,球磨混料物料均匀性好于双螺旋混料,微观形态显示双螺旋混料颗粒主要以Fe2O3粉末团聚形成,球磨混料颗粒以Fe2O3和Al接近化学配比团聚在一起长大形成。     

球磨工艺对Ti／HA复合材料原始粉料细化的影响

在不同球磨介质中对Ti 30％HA配比的原始粉料进行高能球磨，通过TEM，SEM和EDX对球磨前、后的粉末进行观察，研究球磨工艺时Ti／HA复合材料原始粉料细化的影响．研究结果表明：随着球磨时间的延长，采用干磨工艺时，HA粉明显细化，Ti粉的细化程度不明显，HA粉堆积覆盖在Ti粉大颗粒上；采用湿磨工艺时，HA粉和Ti粉都明显细化．表明湿磨工艺可以提高球磨的细化效果，提高HA粉在Ti粉中的均匀弥散分布程度．     

机械合金化法制备W-Cu合金粉末的研究

将W80Cu20（n（W）：n（Cu）=4：1）混合粉末在QM-BP式行星式高能球磨机中球磨进行机械合金化,研究了不同球磨时间对W-Cu混合粉末组织的影响.采用XRD和SEM对不同球磨时间的粉末进行分析,结果显示随着球磨时间的增加,混合粉末产生合金化效果不断增强,Cu固溶于W中,并且晶粒尺寸得到一定的细化.     

机械球磨对土豆淀粉颗粒特性的影响

利用球磨处理对土豆淀粉进行机械损伤,研究机械球磨对土豆淀粉颗粒特性的影响.结果表明:球磨处理可显著提高土豆淀粉中损伤淀粉含量和直链淀粉含量,且损伤处理2 h后,直链淀粉含量升高趋势变缓;球磨损伤会使土豆淀粉出现颗粒表面光滑度下降和偏光现象趋于模糊等变化;球磨处理后,土豆淀粉X-射线衍射图谱出现衍射峰强变弱、尖峰宽度下降和弥散性增加等变化,到达6 h时,尖峰变成馒头峰,结晶度消失;球磨处理使得土豆淀粉颗粒D10、D50、D90和平均粒径增加,同时土豆淀粉粒度曲线出峰位置后移,粒度分布带宽变窄.     

Ni—Al及Ni—Ti的机械合金化研究

对Ｎｉ－Ａｌ及Ｎｉ－Ｔｉ的机械合金化进行了研究,结果表明：Ｎｉ５０Ａｌ５０ａｔ％混合粉末球磨３ｈ后形成ＮｉＡｌ－金属间化合物,Ｎｉ７５Ａｌ２５ａｔ％混合粉末球磨后没有产生相变,Ｎｉ５０Ｔｉ５０ａｔ％混合粉末球磨２０ｈ后基本形成非晶合金     

机械合金化制备Fe-Co-C系非晶合金粉末

采用机械合金化方法制备出Fe—Co—C系的非晶态合金粉末。在球磨过程对合金粉末进行取样,通过X射线衍射的分析,发现合金粉末在球磨15～20h后开始部分非晶化,随球磨时间的增加晶粒尺寸减小。研究结果表明：在Fe—Co合金中加入C可促使其形成非晶;在一定的机械合金化条件下可获得Fe40Co40C20和Fe60Co20C20的非晶粉末,在球磨过程中,通过控制合理的球磨时间,可制备一系列晶粒尺寸的非晶材料。     

Preparation and characterization of stainless steel/TiC nanocomposite particles by ball-milling method

A stainless steel/10wt%TiC nanocomposite particles were prepared by high-energy ball-milling method using stainless steel, carbon and titanium as raw materials. The evolution of phase composition, microstructure and specific surface area of the stainless steel/TiC nanocomposite particles with increasing ball-milling time in the range of 0–100 h were investigated by XRD, SEM, TEM and BET techniques. The results showed that the stainless steel/TiC nanocomposite particles were fabricated when the ball-milling time was longer than 20 h. However, the nanocomposite particles were soldered and agglomerated again when the ball-milling time was longer than 60 h. The microstructure of the composite particles transformed from lamellar structure to nanostructure during the repeated process of the cold welding and cracking. TEM image reveals clearly that the in-situ TiC nanoparticles with grain size of 3–8 nm are in the interior of the stainless steel/TiC nanocomposite particles obtained by ball-milling 100 h. Funded by the Natural Science Foundation of Hubei Province (No. 2006ABA304)     

以石油焦和高温煤沥青制备各向同性石墨材料的研究

以煅后石油焦为骨料,高温煤沥青为黏结剂,采用冷混捏球磨,经过冷等静压工艺在不同压力下制得各向同性石墨材料,并对不同成型压力下制备所得材料的微观结构和物理性能进行分析. 结果表明,当骨料颗粒平均尺寸d50约为21μm,黏结剂含量为33 % 时,其适宜的成型压力为80 ～100 MPa;在不同的成型压力下制备各向同性石墨材料,应采用不同的焙烧和石墨化升温曲线;提高成型压力、减少骨料石油焦中大尺寸片状结构颗粒的数量及增强骨料和黏结剂混捏的均匀性,均有利于提高所制备各向同性石墨材料的物理性能;采用高温煤沥青作为黏结剂,有利于提高各向同性石墨材料的导热率和电学性能.     

Microwave sintering of Al<Subscript>2</Subscript>O<Subscript>3</Subscript>-ZrO<Subscript>2</Subscript>-WC-Co cermets

Composite powders of nanocrystalline WC-10Co (15wt%),Y2O3 (8mol%) stabilized nanocrystalline ZrO2 (30wt%),industrial cobalt powder (4.5wt%) and submicron Al2O3 (55wt%) composite powders were fabricated by high-energy ball-milling process.The nanocomposite powders were consolidated by microwave sintering process at temperature ranged 1300℃-1550℃ for 15min,respectively.The optimum consolidation conditions,such as temperature,were researched during microwave sintering process.Vickers Hardness of the consolidated cermets was measured by using a Vickers indentation test,and density of specimens was also determined by Archimedes’ principle.Microwave sintering process could not only increase the density of Al2O3-ZrO2-WC-Co cermets and reduce the porosity,but also inhibit abnormal grain growth.     

硅灰石球磨过程中晶体结构的变化

研究了湖北大冶硅灰石精矿粉经不同时间刚玉球干磨后,晶体结构的变化特点。初期以多型转变为主,后期以晶体结构破坏为主,晶格畸变效应贯穿变化的全过程。在球磨过程中晶粒的剥离方向并不总是平行于{100}解理方向而是变化的,变化的剥离方向平行于晶体结构中单四面体的某些边棱方向。     

锐钛型介孔纳米TiO2粉体的制备与机理研究

采用沉淀法．以水溶液为反应体系，无机物（硫酸氧钛和氢氧化钠）为主要原料，加入少量模板剂，制备出了锐钛型介孔纳米二氧化镳粉体，并对产物的生成机理进行了探讨。采用比表面仪、原子力显微镜（AFM）、高分群场发射透射电镜等仪器对产品的结构进行了表征，得到具有比表面积121m^2/g、晶粒尺寸12nm、介孔平均孔径10nm、多孔粒径〈100nm等特征的锐钛型介孔纳米二氧化钛粉体。     

ODS HT9钢的制备及其性能研究

用氮气雾化的HT9粉末和Y₂O₃粉末为原料,通过机械球磨的方法制备ODS(oxide dispersion strengthened, 即氧化物弥散强化)合金钢粉末,采用SPS(spark plasma sintering, 即放电等离子烧结)的方法制备不同烧结温度下的ODS HT9钢,通过光学显微镜、XRD、SEM、维氏硬度计和拉伸试验机等试验设备,研究不同球磨工艺(球磨时间及球料比)和烧结温度分别对ODS合金钢粉末特性和性能的影响。结果表明:球磨时间30 h以及球料比为10:1时,粉末颗粒大小均匀且晶粒尺寸趋于稳定,在烧结温度1 000 ℃和1 050 ℃;ODS HT9钢中只有铁素体-马氏体相,在烧结温度为1 000 ℃时,其抗拉强度、致密度和硬度分别达到了955 MPa、98.6%和460 HV1;其抗拉强度和硬度比普通类似成分的316不锈钢分别提高了48%和52%,获得了较好的性能。     

Preparation,Characterization, and Formation Mechanism of Calcium Sulfate Hemihydrate Whiskers

Calcium sulfate hemihydrate whiskers were synthesized successfully via one-step hydrothermal crystallization method using phosphogypsum at 130 °C for 240 min with an initial slurry mass fraction of 2.5 wt%. The phase compositions, microstructures, thermal properties and molecular structures of asprepared samples were analyzed by XRD, ESEM, EDS, TG-DTA, and FT-IR. The influence of raw materials' ball-milling time on the morphologies of whiskers was investigated. The effects of impurities on crystallization morphologies and length to diameter ratio(L/D) of calcium sulfate hemihydrate whiskers were studied. The results indicated that the calcium sulfate dihydrate crystalline could be translated directly into fibrous calcium sulfate hemihydrate whiskers. It was beneficial to form fine fiber structure when the ball-milling time of the raw material was 15 min. Aspect ratio of calcium sulfate hemihydrate whiskers decreased with increasing content of impurities. Moreover, the relative growth mechanism of whisker crystals via one-step hydrothermal crystallization method was discussed in detail.     

ZnO/CeO2 复合纳米材料的Rietveld 全谱拟合物相表征

通过非均相沉淀法合成ZnO/CeO₂ 复合纳米材料,并利用XRD 粉末衍射法对其进行物相分析、Rietveld全谱拟合法对其进行结构精修。拟合结果表明,该法制备样品为六方相ZnO 与立方相CeO₂ 混合相,平均晶粒尺寸分别为20.0nm 和6.9nm,质量分数分别为28.2%及71.8%。精修结果的数值判据为Rwp=5.95%、Rexp=4.06%、GOF=1.47,数值均在正常范围且计算结果可靠。TEM 表征进一步证明计算结果可靠。研究结果表明,Rietveld全谱拟合法在研究复合纳米材料的物相比与晶粒大小时更加合理。     

Analysis on the Difference between Synthetic Hydroxyapatite and Bone Apatite

1Introduction Boneistheimportantstructuralmaterialusedtocarrymajorloadsofhumanbody.Itisakindofcompositemateri alwhosecomponentsareprimarilycollagenandhydroxyapa tite[1].Boneisacompositematerialinseveralways.Firstofall,itisporousmaterialcomposedofasolidmat…     

Analysis on the Difference between Synthetic Hydroxyapatite and Bone Apatite

The composition and structure of bone apatite and synthetic hydroxyapatite powder prepared by precipitation method, sol-gel method was studied by FTIR, EMPA, AFM in this paper. The results showed that the composition and phase structure of apatite powder prepared by sol-gel method was most similar with that in the bone. The caleium phosphate ratios of apatite prepared two kinds of wet precipitation was 1.69, and 1.73 respectively. The culcium phosphate ratio of apatite prepared by sol-gel method was 1.66. The apatite powder prepared by sol-gel nwthod was hoped to be more bionctive and biocompatible compared with apatite powder prepared by wet precipitation method. The EMPA results prored thor the bone consisted of Ca, P,O, Na, Mg , K, Cl, etc elemeuts. The amount of aptaite decreased while amount of collagen increased from the outer layer to inner layer of the bone. AFM results showed that HA particle, with the size about 150-450 nm in length, 100- 150 nm in width, 15-40 nm in thickness, grown layer upon layer regularly. The long axis was not always parallel to the eollagen fiber. The angle between eollagen fiber and aputite lamellar was about 30-45 degree.