多种氧化物原位反应制备的Al2O3/Al复合材料

提出了多种氧化物与Al原位反应制备陶瓷颗粒增强铝基复合材料的新方法，并通过3种反应体系CuO／Al，(CuO SiO2)／Al，(CuO SiO2 TiO2)／Al制备了3种铝基复合材料。对原位反应过程进行了热力学分析。对复合材料的显微组织、硬度和力学性能进行了分析和研究。结果表明，多种氧化物与Al的原位反应能发生并自动进行下去，其反应状况良好。(CuO SiO2)／Al，(CuO SiO2 TiO2)／Al原位反应所获得的增强相颗粒分别是Al2O3和Al2O3 Al3Ti，增强相颗粒在复合材料中均匀分布，并且其所制得的复合材料的硬度与力学性能明显好于单一氧化物CuO所制得的复合材料。     

球料比对高能球磨固态还原燃烧反应的影响

在所研究的 Al/Cu O和 Si/Cu O体系中 ,不同球磨强度下 ,随球料比增大 ,燃烧点火时间存在一极小值。说明球磨固态燃烧反应的点火时间的长短取决于球磨粉末中已经发生部分反应的产物所占的比例和同时发生反应的活性位置数目。提出一新的、具有广泛适应性的球磨参量—占空比 VR,修正了传统采用球料比 CR在描述球磨强度与球磨燃烧反应点火时间时所存在的不足     

球磨条件对MoSi2形成的影响

通过对Ｍｏ、Ｓｉ混合粉末的机械球磨,研究了不同球磨条件对ＭｏＳｉ２形成的影响。用Ｘ射线衍射仪、透射电镜和扫描电镜对不同球磨时间的粉末进行了检测与分析,结果表明,在较低球料比的条件下（１０∶１）,不同转速的球磨均会使Ｓｉ固溶于Ｍｏ中,形成Ｍｏ（Ｓｉ）过饱和固溶体,但较低转速（１００ｒ／ｍｉｎ）的球磨不能发生合金化而形成ＭｏＳｉ２,只有较高转速（２２５ｒ／ｍｉｎ）的球磨才会通过机械诱发扩散固溶而逐渐形成ＭｏＳｉ２;在较高球料比的条件下（２０∶１）,ＭｏＳｉ２是通过机械诱发自蔓延反应而形成的     

反应生成α-Al_2O_3(p)/Al-Cu复合材料的化学反应的研究

利用X射线衍射仪和扫描电子显微镜对CuO／Al粉末预制块经不同条件反应后得到的材料进行了分析,探讨了CuO／Al体系的化学反应随温度和环境介质的变化情况,并利用该体系的化学反应制备了α-Al2O3（p）／Al—Cu复合材料     

高能球磨及热挤压制备亚微米结构Al基复合材料

借助高能球磨Al及5%CuO合成了纳米复合粉末,进而在退火后,通过热压和热挤制备出了组织均匀、致密、晶粒尺寸约为120 nm～150 nm的亚微米块体Al基复合材料.XRD和显微组织分析表明粉体球磨时,Al与CuO之间发生了还原反应,但生成物的热稳定性较差,在400℃退火过程中发生了与球磨时相逆的固态反应;复合粉末显微组织上的冷焊条纹其实质是球磨产生的高畸变区,退火使之逐渐消失;制备的亚微米块体复合材料主要以Al2Cu和Al2O3颗粒为增强相,室温下具有良好的压缩性能,但拉伸时表现出极大的脆性.     

高能球磨及热挤压制备亚微米结构Al基复合材料

借助高能球磨Al及5%CuO合成了纳米复合粉末,进而在退火后,通过热压和热挤制备出了组织均匀、致密、晶粒尺寸约为120 nm～150 nm的亚微米块体Al基复合材料.XRD和显微组织分析表明:粉体球磨时,Al与CuO之间发生了还原反应,但生成物的热稳定性较差,在400℃退火过程中发生了与球磨时相逆的固态反应;复合粉末显微组织上的冷焊条纹其实质是球磨产生的高畸变区,退火使之逐渐消失;制备的亚微米块体复合材料主要以Al2Cu和Al2O3颗粒为增强相,室温下具有良好的压缩性能,但拉伸时表现出极大的脆性.     

反应机械合金化/退火制备Al2O3/Fe3Si纳米复合粉体

以Fe2O3粉、Si粉和Al粉为原料,采用反应机械合金化/退火法制备出了Al2O3/Fe3Si纳米复合粉体。利用X射线衍射仪（XRD）和扫描电子显微镜（SEM）对复合粉体球磨以及退火过程中的固态反应过程、表面形貌进行表征。研究表明,Fe2O3-Si-Al混合粉体球磨5 h后发生反应生成Al2 O3、Fe5 Si3、Fe3 Si、FeSi,球磨20 h后生成Al2 O3/Fe3 Si,球磨20 h的粉体在900℃条件下退火1 h的组成物相未发生变化,复合粉体颗粒呈球形,其尺寸为5μm左右,分布均匀,组成相Al2O3和Fe3Si的晶粒尺寸分别为26.6 nm和28.3 nm。     

粉体聚集状态对自蔓延高温合成（SHS）反应喷涂A12O3-A12Cu3涂层的影响

采用SHS技术和传统氧-乙炔火焰喷涂技术，利用Al与CuO间的高能铝热反应，在钢的表面制备了A12O3-A12Cu3复相涂层。研究了粉体聚集状态对SHS火焰喷涂涂层物相组成、组织结构和反应机理的影响，结果表明：非团聚CuO—Al粉体分散在气流中缺乏发生SHS反应的条件，而团聚CuO-Al体，经历反应孕育、飞行燃烧、碰撞、结构转变与凝固4个阶段，形成层状结构。     

高能球磨制备Al3Ti/Al块体纳米晶复合材料

通过对Al Ti系和Al TiO2 系进行高能球磨和压制烧结制备了固态原位反应生成的纳米晶块体Al3Ti/Al复合材料。研究表明 :Al Ti合金系高能球磨后 ,各组元晶粒得到细化 ,并且Ti在Al中发生了强制超饱和固溶 ,烧结时原位反应形成纳米晶Al3Ti/Al复合材料 ;而Al TiO2 反应体系高能球磨仅发生组分晶粒细化 ,烧结时TiO2 部分还原并和Al原位反应生成纳米晶 (Ti2 O3 Al3Ti) /Al复合材料。     

W-Cu纳米复合前驱体粉末的机械合金化制备

采用机械合金化（MA）工艺，以W-25％CuO为原料，球磨参数设置为：球料比20：1、球磨转速500r／min，球磨时间范围1-40h，采用球磨20min、空气冷却30min的循环球磨方式。对不同球磨时间条件下制备的粉末进行了x射线衍射和透射电镜分析。结果表明，通过MA工艺可在较短时间内（lh）获得W-Cu纳米晶粉末，球磨时粉体中的CuO发生了还原，部分W被氧化成WOx（x=2～3），球磨后w粉的平均晶粒尺寸为12．5nm左右，最小晶粒5～6nm；W粉颗粒的最终形态为球形，并被Cu所包覆。     

高能球磨Si还原CuO的固态还原反应

通过对Ｓｉ和ＣｕＯ粉末进行高能球磨制备了Ｃｕ和ＳｉＯ２的复合材料。表明了一般条件下难以进行的固态还原反应，在高能球磨时可以发生；还原产物为纳米级的Ｃｕ和非晶的ＳｉＯ２，还原反应的进程有赖于高能球磨的条件；利用高能球磨可以直接制备纳米级氧化物金属复合材料     

Al-Si/Al_2O_3 in situ composite prepared by displacement reaction of CuO/Al system

Al2O3 particle-reinforced ZL109 composite was prepared by in situ reaction between CuO and Al.The microstructure was observed by means of OM,SEM and TEM.The Al2O3 particles in sub-micron sizes distribute uniformly in the matrix,and the Cu displaced from the in situ reaction forms net-like alloy phases with other alloy elements.The hardness and the tensile strength of the composites at room temperature have a slight increase as compared to that of the matrix.However,the tensile strength at 350 ℃ has reached 90.23 MPa,or 16.92 MPa higher than that of the matrix.The mechanism of the reaction in the CuO/Al system was studied by using of differential scanning calorimetry(DSC) and thermodynamic calculation.The reaction between CuO and Al involves two steps.First,CuO reacts with Al to form Cu2O and Al2O3 at the melting temperature of the matrix alloy,and second,Cu2O reacts with Al to form Cu and Al2O3 at a higher temperature.At ZL109 casting temperature of 750-780 ℃,the second step can also take place because of the effect of exothermic reaction of the first step.     

Effect of CuO Particle Size on the Microstructure Evolution of Al_2O_(3P)/Al Composites Prepared Via Displacement Reactions in the Al/CuO System

An Al2O3P/Al composite was successfully synthesized using a displacement reaction between 80 wt% Al and20 wt% Cu O powders at a heating rate of 5 °C/min. Two different sizes Cu O particles were used, and all the experiments were conducted under an argon atmosphere. To analyze the microstructural evolution during synthesis, the Al–20 wt%Cu O samples were heated to the temperatures selected according to the differential scanning calorimetry curve and then immediately quenched with water. The phase composites and microstructure of the water-quenching samples were investigated using X-ray diffraction, optical microscopy, scanning electron microscopy and energy-dispersive spectrometry.The results indicate that the Cu O particle size has a significant effect on the microstructural evolution of the samples during the heating stage and on the microstructure of synthesized composites. Smaller Cu O particles can decrease the reaction temperature, narrow the reaction temperature range at the different reaction stages during the heating stage and make the size and distribution of in situ Al2O3 particles more uniform. The reaction between Al and Cu O can be complete as the temperature rises to 900 °C. The size of the in situ Al2O3 particles is approximately 5 lm when the size of the Cu O particles is less than 6 lm. This sample has a relatively high Rockwell hardness of 60 HRB.     

Ignition and Combustion of Super-Reactive Thermites of AlMg/KMnO4

采用机械球磨法制备不同比例的Al-Mg合金,然后采用超声分散法制备AlMg/KMnO4铝热剂。通过DSC、点火温度和燃烧性能测试对AlMg/KMnO4铝热剂进行了性能表征。结果表明：随着镁含量的增加AlMg/KMnO4反应温度明显降低,表明其热反应活性优于Al/KMnO4;此外随着Mg含量（质量分数）从10%增加到50%,点火温度和燃烧速度分别从723 K降低至493 K和254 mg/s降至204 mg/s,其中Al0.5Mg0.5/KMnO4火焰溅射范围大幅提高     

STUDY ON THE THERMODYNAMICS OF CuO／Al IN SITU Al2O3 REINFORCED Al MATRIX COMPOSITES

Based on the experiment and the thermodynamics analysis for CuO/Al system, it is founded that the compounding reaction of CuO/Al under low temperature is available. The general equation of adiabatic temperature of the system is set up, and the influence of resultant concentration and temperature on adiabatic temperature is theoretically analyzed. The values of heat effect of CuO/Al system under different temperature are also caculated.     

CuO掺杂Ni0.4Zn0.6Fe2O4铁氧体的组织与性能探讨

采用传统球磨法制备了Ni0.4-xCu_xZn0.6Fe₂O₄（x＝0,0.12,0.20,0.28）铁氧体,并通过扫描电镜（SEM）、X-ray衍射（XRD）、综合热分析（TG-DSC）和振动样品磁强计（VSM）等手段研究掺杂CuO对Ni-Zn铁氧体的显微组织、相组成和磁性能。结果表明,随着CuO含量的增加,第二相Ni-Cu-Zn相生成,且 Ni-Cu-Zn铁氧体衍射峰强度逐渐增强;从显微组织形貌和能谱可以看出,Cu ^2＋参与了铁氧体的反应,CuO含量增加得越多,样品烧结性能越好,并促使Ni-Cu-Zn铁氧体的晶化温度降低;磁滞回线显示了Ni0.4-xCu_xZn0.6Fe₂O₄（x＝0,0.12,0.20,0.28）铁氧体的软磁特性,CuO原子分数x为0.2时的铁氧体的饱和磁化强度（Ms）最高,且具有较低的矫顽力（Hc）。     

高能球磨法制备SiC/Al复合粉末的工艺研究

采用高能球磨技术制备SiC和Al的复合粉末,研究了球磨时间、过程控制剂(PCA)、球料比以及SiC与Al混粉质量比对复合粉末粒度和包覆效果的影响。结果表明,复合粉末平均粒径的大小与PCA、混粉比、球磨时间和球料比有关,其影响程度依次为:PCA>混粉比>时间>球料比;复合粉末的粒径大小随着球磨时间、PCA和球料比的增加而显著减小,而随着混粉质量比的增加呈现先减后增的趋势。混粉质量比为3:7的复合粉末平均粒径达到最小值;球磨时间为9h、PCA添加量为1.5%、球料比为12:1和Al与SiC混粉质量比为3:7时,能制备出颗粒细小、包覆效果好的优质复合粉末。     

A study on mechanochemical behavior of B2O3–Al system to produce alumina-based nanocomposite

One possible route for producing the fine and homogenous distribution of hard particles in composite microstructure is the mechanochemical processing in which high-energy ball milling promotes the reaction in a mixture of reactive powders. In this study mechanochemical reaction of B₂O₃ and Al powder during ball milling was studied. The phase transformation and microstructure of powder particles during ball milling were investigated by X-ray diffractometry and scanning electron microscopy. The results showed that during ball milling the B₂O₃–Al reacted with a combustion mode producing Al₂O₃–AlB₁₂ nanocomposite. The crystallite size of Al₂O₃ and AlB₁₂ was 40 and 25 nm, respectively. This structure appeared to be stable upon annealing.