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在真空条件下采用高能球磨法以不锈钢粉末、钛粉和碳粉为原料制备了不锈钢-TiC超细复合粉末.X射线、扫描电子显微镜、比表面积评价等分析技术被用来对球磨过程中粉末的微观状态进行了分析.结果表明,随着球磨时间的增加,不锈钢复合粉末逐渐细化,用X射线衍射方法计算的最终晶粒可达到20nm.同时,钛粉和碳粉在球磨过程中发生反应形成TiC,可获得纳米级的不锈钢-TiC复合粉末. 相似文献
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为了获得具有良好微观组织的C-Cu复合粉末,以利于后续的压制、烧结和挤压等工艺,用机械球磨方法制备了3%C-Cu(质量分数)复合粉末.运用扫描电镜、背散射和X射线衍射等分析手段研究了该复合粉末的微观组织随球磨时间的演变规律.实验结果表明,随着机械球磨时间的增加,Cu颗粒由树枝状转变为层片状、块状,最后转变为近球形.球磨2 h,复合粉末中的石墨衍射峰消失.随着球磨的进行,复合粉末中Cu的微观应变逐渐增大.经3 h的机械球磨获得了晶粒尺寸约为20 nm的Cu纳米晶,说明该方法可以有效地细化晶粒组织. 相似文献
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以膨胀石墨和α-Al2O3微粉为原料,采用高能球磨制备了纳米碳包覆的α-Al2O3复合粉体,研究了高能球磨时间和球磨速率对复合粉体物相及形貌的影响。采用X射线衍射仪、场发射扫描电子显微镜和透射电子显微镜对复合粉体的物相、形貌和微观结构进行了表征。结果表明:按膨胀石墨与α-Al2O3质量百分比为1:2,球磨速率为600 r/min,球磨5 h可得到被粒度为20~50 nm碳颗粒包覆的α-Al2O3复合粉体;随着球磨时间延长,石墨(002)晶面特征峰逐渐消失,膨胀石墨中纳米片层会随球磨时间延长不断剥离脱落,并逐渐龟裂成纳米碳颗粒;相同球磨时间下,提高球磨速率可以促进纳米碳颗粒形成,但超过一定速率后纳米碳颗粒粒度不再减少;480 r/min速率球磨5 h未形成纳米碳颗粒包覆复合粉体,600和700 r/min速率球磨5 h后复合粉体形貌基本一致。 相似文献
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《材料导报》2016,(Z2)
在不同球磨时间条件下,采用机械球磨方法制备TiB_2-Ni(Al)复合粉末,其中Ni粉和Al粉的物质的量比为1∶1,TiB_2陶瓷相含量为40%(体积分数)。采用扫描电子显微镜(SEM)以及X射线衍射仪(XRD)分析球磨后粉末的显微组织结构及物相,研究不同球磨时间对制备TiB_2-Ni(Al)复合粉末物相演变、组织结构的影响。研究结果表明,随着球磨时间的延长,延性金属Ni和Al变形程度逐渐增大,粉末中呈现Ni/Al交替混合组织结构,此种结构有利于金属在球磨过程中扩散形成Ni(Al)固溶体,且逐渐细化的TiB_2相嵌入至金属Ni和Al颗粒中。通过物相分析发现,随着球磨时间的延长,Al衍射峰强度逐渐降低,并发现在球磨时间为36h时形成Ni(Al)固溶体。 相似文献
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Kinetics of solid-state reduction reaction during ball milling of CuO-Al and CuO-prealloyed Cu(Al) powder blends in dry and wet condition has been investigated by using X-ray diffraction (XRD), differential scanning calorimetry (DSC), and transmission electron microscopy (TEM) techniques. Direct reduction of CuO by Al has resulted into Al2O3 dispersed Cu-matrix composite through a self-propagating reaction only during milling in dry condition. However, indirect reduction of CuO by prealloyed Cu(Al) resulted into formation of nano-Al2O3 dispersed Cu-matrix composite either by continued ball milling in dry condition or by subsequent thermal treatment of wet milled powder precursor. The influence of milling conditions, that is, milling speed, and milling media, on the occurrence of reduction of CuO by elemental Al or Al in prealloyed Cu(Al) during ball milling have been explained by considering their effects on the rise of powder temperature due to collisions between balls and powder particles, and the rate of reduction of ignition temperature of the reaction due to microstructural refinement. TEM investigation has revealed that the size of Al2O3 particles in the composite power blend formed by the indirect reaction route (CuO-prealloyed Cu(Al)) is much finer than the same in case of direct reaction route (CuO-Al). It is suggested that the kinetics of the reduction reaction in the indirect reaction route is relatively sluggish in nature and amenable to processing of large amount of nano-Al2O3 dispersed Cu-matrix composite powder for industrial purpose. 相似文献
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Composites consisting of Al-Zn/Al2O3 have been synthesized using high energy mechanical milling. High energy ball milling increases the sintering rate of the composite powder due to increased diffusion rate. Owing to the finer microstructure, the hardness of the sintered composite produced by using the mechanically milled nanocomposite powder is significantly higher than that of the sintered composite produced by using the as-mixed powder. The mean crystallite size of the matrix has been determined to be 27 nm by Scherrer equation using X-ray diffraction data. The powders have been characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and differential thermal analysis (DTA). The effect of high-energy ball milling and subsequent annealing on a mixture of Al and ZnO has also been investigated. DTA result show that the reaction temperature of Al-ZnO decreases with the increase in the ball milling time. 相似文献
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干法球磨从废铝边角料中制取片状铝粉工艺研究 总被引:2,自引:0,他引:2
对在氮气惰性气氛下,利用废弃铝边角料生产片状铝粉的可行性进行了研究。发现在球磨过程中,废铝片通过钢球的微锻作用相互挤压分层,延展,细碎,最后形成片状铝粉,球罐中的钢球球径大小与片状铝粉的产出性能有着重要的关系,球径大的钢球研磨对铝粉的形成更有利;在球磨的前25h,适当次数的间歇停机冷却球罐可以提高铝粉的细度;硬脂酸的加入可以减少铝粉与铝粉,铝粉与钢球或罐壁的摩擦,降低球磨效率,加入3%的硬脂酸作为助磨剂球磨效果最佳。所得片状铝粉可用于指纹鉴定、加气节能混凝土等。 相似文献
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采用高能球磨法和溶胶-凝胶方法制备了碳纳米管掺杂的Ti02纳米复合粉体,通过扫描电子显微镜、X射线衍射、紫外分光光度计等方法对比分析了复合粉体的形貌、微观结构以及光催化活性.实验结果表明,5%碳纳米管掺杂的Ti02复合粉体的光催化活性得到了有效提高,其中高能球磨法制备的复合粉体颗粒细小、分布均匀,具有更好的光催化活性和... 相似文献
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《Materials Science & Technology》2013,29(8):960-964
AbstractA composite of copper powder and SiC particle reinforcement was prepared by mechanical ball milling and subsequent sintering. Proper choice of processing parameters ensured a homogenous distribution of SiC particles in the copper matrix. Microstructure, powder morphology and mechanical properties of the composite were investigated as a function of milling time. With increasing milling time, the dentritic copper powder became flattened, which subsequently became spherical shaped. Mechanical properties of the composites change with the distribution of SiC. 相似文献
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Based on two sets of TiAl powder, two kinds of porous TiAl were separately fabricated by powder metallurgical route including four stages. The porous TiAl with single pore structure (SPS) was prepared using pre-alloyed TiAl powder prior mechanical ball milling. Another porous TiAl with composite pore structure (CPS) was manufactured depending on composite mixture of Ti/Al elemental powders. The sintering was achieved at much lower temperature for the pre-alloyed power than for the elemental composite mixture. Compressive mechanical tests indicate that much higher mechanical strength can be obtained for SPS than for CPS at the same porosity. It was suggested that the difference of mechanical properties is ascribed to the variety of the compressive deformation process. 相似文献
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为获得高能球磨时间和退火温度对TiNi机械合金粉特性的影响机制,采用X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线能谱仪(EDS)、差示扫描量热法(DSC)等分析方法对TiNi合金粉进行了研究。结果表明,机械合金的相成分随着在氩气保护气氛中的球磨时间和退火温度的不同而发生变化。球磨22h的产物是非晶态TiNi合金、Ti的固溶体、Ni的固溶体,球磨27h的产物是非晶态TiNi合金粉和Ni固溶体相,球磨30h发生了明显的固相反应,生成了TiNi、Ni3Ti、Ti3Ni4等物相;在650℃/5h和1000℃/5h下的退火产物都是Ni3Ti、Ti2Ni、TiNi2、TiNi和TiC,但在上述2个退火温度下TiNi并不是主要物相,其中在650℃退火时TiNi的含量明显更低。 相似文献