Production of Non-Equilibrium Transition Metal Fine Particles by Mechanical and Chemical Fragmentation

在这个项目中，我们尝试用机械研磨和化学反应相结合的方法制备非平衡态金属复合细粉，并观察其结构和磁性能。下面是我们实验结果的总结。1)机械铣浸联合工艺采用机械铣法制备了Ni-Al、Mn-Al、Ru-Al、Ni-Fe-Al和Cu-Fe-Al等非平衡前驱体颗粒。铝的主要部分在碱性溶液中从这些磨粉中浸出。x射线衍射测量表明，即使在浸出后，Cu-Fe粉被高度氧化的情况下，bcc Ni、α - mn、bcc Ru、bcc Ni- fe和bcc Cu-Fe等非平衡结构仍然存在。由于非平衡相转变为平衡相，这些粉末的DSC示踪显示出放热峰。磁性测量表明，bcc Ni和bcc Ru具有顺磁性，而α - mn和bcc Ni-Fe（25at%Fe）具有铁磁性。这些结果清楚地说明了非平衡相的形成。2)超声波增强化学溶液的分解用高强度超声探头辐照十烷中的五羰基、Fe(CO)_5溶液，用干戊烷过滤、漂洗得到煤烟粉末。x射线衍射实验显示出晕状图案，表明这些粉末是无定形的。这些粉末的磁化强度比块状铁小一个数量级。这表明羰基溶液的分解不足，与化学分析检测到的C和O的存在一致。通过x射线衍射、DSC、NMR和EXAFS验证了氧化铝和二氧化钛水凝胶形成络合物的过程。^<27>Al的Knight位移和对称到不对称的变化以及Ti-K边缘的EXAFS谱的修饰清楚地表明，Al- o - ti是在加工过程中形成的化学键。少

In this project, we tried to produce nonequilibrium metal and compound fine powders using the combined process of mechanical milling and chemical reaction, and observed their structures and magnetic properties. The following is the summary of our experimental results.1) Combined Process of Mechanical Milling and LeachingNonequilibrium precursory particles of Ni-Al, Mn-Al, Ru-Al, Ni-Fe-Al and Cu-Fe-Al were produced using mechanical milling. The main portion of Al was leached out of these milled powders in basic solution. The X-ray diffraction measurements indicate that the nonequilibrium structures, bcc Ni, alpha-Mn, bcc Ru, bcc Ni-Fe and bcc Cu-Fe, retain even after leaching, where Cu-Fe powders are highly oxidized. The DSC traces of these powderes show a exothermic peak owing to nonequilibrium-to equilibrium-phase transformation. Magnetic measurements indicate that bcc Ni and bcc Ru are paramagnetic, while alpha-Mn and bcc Ni-Fe(25at%Fe) are ferromagnetic. These results clearly demons … More trate formation of nonequilibrium phases.2) Enhanced Decomposion of Chemical Solution by Ultrasonic IrradiationPentacarbonyl, Fe(CO)_5 solutions in decane were irradiated using a high-intensity ultrasonic probe and sooty powders were obtained by filtereing and rinsing with dry pentane. The X-ray diffraction experiment show a halo pattern, indicating these powderes are amorphous-like. Magnetization of these powders is one order smaller than that of bulk Fe. This indicates insufficient decomposion of carbonyl solutions, being consistent with presence of C and O detected by the chemical analyzes.3) Homogeneous Complex Formation in Mixed Hydrogel by Mechanical MillingProcesses of complex formation between alumina and titania hydrogels was verified by X-ray diffraction, DSC, NMR and EXAFS.The Knight shift and symmetric to asymmetric change in the of ^<27>Al as well as modification of Ti-K edge EXAFS sepctra clearly demonstratethe chemical bonding, Al-O-Ti is formed during the millig process. Less