机械合金化制备纳米Cu-Zn-Al2O3复合粉末的研究

采用X射线衍射仪、电子扫描电镜和透射电镜等研究了Ar气氛保护下Cu-Zn-Al2O3复合粉末在高能球磨过程中发生的机械合金化反应,分析了不同球磨时间对a-Cu(Zn)的晶格常数、晶粒尺寸以及复合粉末粉体形貌、颗粒尺寸的影响.结果表明,球磨初期,Cu的晶格常数增大,但75h后由于γ相的析出,a-Cu(Zn)晶格常数减小;高能球磨120h后,可获得氧化铝颗粒弥散分布的纳米级Cu(Zn)复合粉末.     

机械球磨制备快速铁系吸氧剂

以铁粉、石墨粉和X粉末为原料,用机械球磨法制备了铁基复合粉末。研究了碳粉种类、球磨时间和X粉末对复合粉末吸氧速率的影响,并用SEM对复合粉末微观形貌进行了研究。结果表明,X粉末的加入显著提高了铁基复合粉末的吸氧速率,可迅速降低包装空间内氧气含量。     

机械合金化过程中粉末变形与形成复合粉的工艺条件

本文将镍与钛单质混合粉在搅拌式高能球磨机中球磨。采用电子探针研究了粉末组织随球磨时间的变化。测定了了片状粉末的厚度以及复合粉分数随球磨时间的变化，并根据粉变形模型研究了球磨时形成复合粉所需时间与工艺条件的关系。     

高能球磨制备Mo-3%Cu纳米晶复合粉末特性

利用机械合金化法制备出Mo-3%Cu(质量分数,以下同)超细复合粉末,采用X射线衍射、BET氮吸附法和DTA差热分析方法对球磨后的Mo-6%Cu纳米晶复合粉的组织结构变化、表面特性和热稳定性进行了系统的研究.结果表明,高能球磨可以制取纳米晶复合粉末,晶粒内部产生很大的晶格畸变,同时球磨产生的晶体缺陷使原子扩散加快,形成Mo-Cu超饱和固溶体和扩大Mo在粘结相中的溶解度,BET氮吸附结果证实了球磨使粉末产生大量微孔,且比表面、中孔表面和孔径降低.     

球磨时间对TiB_2-Ni(Al)复合粉末组织结构影响研究

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。     

机械球磨对Ti-Al复合粉扩散反应的影响

研究了粉末烧结制取Ti-Al金属间化合物过程中,机械球磨对Ti、Al混合粉扩散反应的影响.结果表明,机械球磨使Ti、Al混合粉形成具有层片结构的复合粉,且球磨时间越长,层片越薄越均匀.在固相下对不同球磨时间的Ti、Al混合粉压坯试样进行烧结后,通过X射线衍射、扫描电镜及能谱分析,结果表明,球磨时间越长,越有利于Ti、Al之间的扩散反应,越容易形成Ti-Al金属间化合物,并有利于组织的均匀化.     

高能球磨Mg/B复合粉末的特性

对化学计量比的Mg/B原始粉体进行高能球磨,通过扫描电镜SEM和能谱分析EDX对球磨前后的粉末进行观察,对球磨过程中复合粉末的组织形貌和成分分布的变化进行了研究.结果表明:随着球磨时间的延长,Mg粉明显细化,B粉在Mg粉中的均匀弥散分布程度很好.     

机械球磨3%C-Cu复合粉末的微观组织

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.     

机械球磨与包套挤压制备Al-Pb合金

采用机械球磨(MM)制备了Al-20(Wt.%)Pb复合粉,通过X射线衍射和电子探针分析了Al20Pb复合粉及其层片状组织.为得出最佳球磨工艺参数,对复合粉进行了压制和烧结实验.结果表明:球磨6 h得到的Al-20Pb复合粉具有均匀细小的层片结构,既保持较好的塑性,易于致密,又能在烧结后得到均匀细小的显微组织.     

机械化学合成Ni2Al3/Al2O3去合金化制备Raney-Ni/Al2O3复合粉体

以NiO粉和Al粉为原料,采用机械球磨诱发化学反应制备了Ni_2Al_3/Al_2O_3复合粉体。利用X射线衍射仪(XRD)和附带能量色散谱仪(EDS)的扫描电子显微镜(SEM)对复合粉体球磨过程中的固态反应过程、表面形貌进行表征。将Ni_2Al_3/Al_2O_3复合粉体用浓度为20%的NaOH溶液腐蚀2h,可得到纳米晶结构的Ni/Al_2O_3复合粉体。利用XRD和TEM对其物相和结构进行了表征。结果表明,球磨1h后混合粉末仍为NiO粉和Al粉,球磨3h后NiO粉和Al粉在机械力的作用下反应形成Ni_2Al_3和Al_2O_3粉体,机械力诱发的NiO和Al之间的反应属于突发型反应,继续球磨10h后形成Ni_2Al_3/Al_2O_3复合粉体。Ni_2Al_3/Al_2O_3复合粉体在70℃、质量比为20%NaOH溶液中刻蚀2h,可获得Ni/Al_2O_3复合粉体。     

高能机械化学法制备微纳米Mo—Si粉体

以Mo粉和Si粉为原料,通过自行设计的高能机械化学球磨机在室温下制备出了微纳米Mo-Si粉体,利用X射线衍射（XRD）和扫描电子显微镜（SEM）进行物相分析和粒度分析,结果表明,在不同的反应阶段会生成MoSi2和Mo5Si3,并且生成物之间相互有一定的转化,反应生成率接近100％,制备出的微纳米Mo—Si粒度在100nm左右,在Mo和Si的高能机械化学反应中,适当地提高球料比和转速可以加快反应的进程。     

The effect of particle size of iron powder on α to γ transformation in the nanostructured high nitrogen Fe-Cr-Mn-Mo stainless steel produced by mechanical alloying

In this study, the effect of particle size of iron powder on α to γ transformation in the nanostructured high nitrogen Fe-18Cr-10Mn-4Mo stainless steel, produced by mechanical alloying (MA) was investigated. For this purpose iron powders with two different particle sizes were used. MA was performed under nitrogen atmosphere, using a high-energy planetary ball mill. X-ray diffraction (XRD) patterns and nitrogen analysis revealed that by decreasing the iron mean particle size, a higher transformation rate is obtained due to increase in the rate of nitrogen absorption. Moreover, nitrogen solubility in both milled samples was increased noticeably by increasing the milling time. This is believed to be due to the increase of lattice defects and development of nanostructure through MA. Variations of grain size and internal lattice strain versus milling time, for both iron particle sizes, showed that the critical ferrite grain size for austenite nucleation is less than 10 nm.     

Ball milling of stainless steel scrap chips to produce nanocrystalline powder

Nanocrystalline stainless steel powder was produced by ball milling of austenitic stainless steel scrap chips. The structural and morphological changes of samples during ball milling and after subsequent heat treatment were investigated by X-ray diffractometery, scanning electron microscopy and microhardness measurements. During ball milling the austenite in as-received chips partially transformed to the martensite phase with nanoscale size grains of ∼15 nm. This structure exhibited high microhardness value of about 850 Hv which is much higher than that for original samples. The deformation-induced martensite partially transformed to austenite after annealing at 700 °C for 1 h reducing the hardness of powder particles.     

Si3N4和52100钢对磨副材料对CrN薄膜干摩擦学行为的影响

利用阴极电弧离子镀技术在316L不锈钢基体上制备了CrN薄膜。采用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、纳米压痕仪对CrN薄膜的形貌、成分和力学性能进行了表征。为了研究Si_3N_4和52100钢对磨副材料对CrN薄膜和316L不锈钢干摩擦行为的影响,在2N、5N、8N三种载荷下,将CrN薄膜和316L不锈钢基体与Si_3N_4陶瓷球和52100钢球分别进行了往复式滑动干摩擦实验。采用扫描电子显微镜观察了磨痕的微观形貌,并对CrN薄膜和316L不锈钢基体的磨损机制进行了分析。结果表明:CrN薄膜表面平整,缺陷较少;CrN薄膜的纳米硬度约为28GPa,弹性模量约为350GPa;与Si_3N_4陶瓷球相比,CrN薄膜与52100钢球摩擦时摩擦因数相对较小(保持在0.7左右)且更加稳定;316L不锈钢的摩擦因数远大于CrN薄膜且波动较大;对磨球为Si_3N_4陶瓷球时,CrN薄膜的主要磨损机制为磨粒磨损,伴有少量的氧化和黏着磨损,316L不锈钢的磨损机制主要为磨粒磨损和塑性变形,伴有少量的氧化和黏着磨损;对磨球为52100钢球时,CrN薄膜的主要磨损机制为黏着磨损,伴有少量的氧化,316L不锈钢的磨损机制主要为黏着磨损,伴有少量的氧化和磨粒磨损。CrN薄膜与两种对磨球的磨损量均小于316L不锈钢基体的磨损量,说明CrN薄膜有效提高了基体的耐磨性。     

Application of mechano-chemical synthesis for protective coating on steel grinding media prior to ball milling of copper

One of the major sources of contamination during mechanical milling/alloying is from the surface erosion of the container and the grinding medium. This can either be prevented by using grinding medium and container of same material of the milled material or by adding a coating of the milled material on them. The paper describes the observations made during a mechano-chemical reaction, being used for coating the balls and vials in a planetary ball mill. Visual observation, XRD, optical micrography and EDS analysis were used to understand the progress of the reaction. Copper was successfully coated on the steel balls and vials. The method can easily be adopted in daily production purposes, prior to mechanical milling of a Cu-based powder for prevention of Fe contamination.     

高能球磨法制备铁、钨金属微粉的研究

用高能机械球磨法制备了金属铁、钨微粉，对振动磨的结构及破碎原理作了简要介绍，分析了铁、钨粉末产品的粒度分布特性、比表面积变化情况，讨论了原料性质、球磨时间、球磨强度、球料比等因素对高能球磨过程的影响。     

湿法机械球磨制备片状镍粉研究

以类球形镍粉为原料,进行了湿法机械球磨制备片状镍粉的试验,考察了乙醇体积、球料比、球磨转速、球磨时间及助剂用量等因素对镍粉形貌的影响,采用XRD、SEM等对镍粉结构形貌进行了表征分析,确定了最佳工艺条件:乙醇体积60mL、球料比30:1、球磨转速450r/min、球磨时间3.5h、助剂A用量2%。在该条件下,得到的片状镍粉径厚比89,表面光滑平整,碎片粘附少,具有良好的金属光泽;其微观结构表明,球磨过程中,镍粉的微观内应力逐渐增加,晶粒不断细化;而且产品的片状化程度与<200>择优取向度有关。     

采用振动磨制备中药微粉

采用振动磨对三七和水蛭两种中药材进行粉磨实验,研究振动磨工艺参数对粉磨效果的影响。结果表明:水蛭的粉磨效果很好,在短时间内就能达到所要求的微粉粒度;而三七的粉磨效果较差,粉磨时间长且存在无法磨细的中间颗粒。增大磨介填充率、减少物料填充量、减小入磨粒度、增加粉磨时间都可以有效降低最终中药微粉的粒度。     

Non-firing ceramics: Effect of adsorbed water on surface activation of silica powder via ball milling treatment

“Non-firing” ceramics have recently attracted much attention because many functional ceramics can be achieved by this method without the sintering process. The underlying idea of this method is to activate the surface of the particles by ball milling. In this study, the effect of adsorbed water on the surface of raw silica powder was investigated. Amorphous silica powder was mechanically treated by a rotating ball mill system and the surface activity of the raw and treated silica powders was measured based on the water adsorbed volume on the powder surface. The results showed that the surface activity of the silica powder increased with the increasing adsorbed water volume on the surface of the silica powder. In addition, better mechanical properties evaluated by the Vickers hardness test were achieved for the silica with more water adsorbed on its surface. The effect of milling energy and ball to powder ratio on activation of the silica was also investigated.     

轧制力与不锈钢多孔板孔隙性能的关系

本文用60-100目的316L不锈钢粉末为原料,在不同轧制力的条件下,研究了轧制力与轧制不锈钢多孔板孔隙性能的关系,得出轧制力在90-100KN的范围内,可以获得孔隙性能均匀一致的轧制不锈钢多孔板。