Development of nano-scale porous and non-equilibrium materials by chemical dealloying process and application for catalyst

在用化学脱合金法制备细骨架银的过程中，银在铝相中的溶解度对银的产率的影响还鲜有报道。在Al-Ag二元合金系中，溶解度随温度变化较大。本文制备了不同溶解度的前驱体，并对其进行了化学脱合金处理。将不同成分的合金在氩气保护下熔化，然后采用雾化-水雾化工艺进行快速凝固。得到平均粒径约200μm的雾化颗粒。粒子的平均冷却速率估计在10^4-10^5K/s之间。为了控制溶解度，进行了两种热处理。其中一种是溶解处理，以获得最高的溶解度，另一种是沉淀处理，以获得最小的溶解度。两种治疗均归类为固态操作。另一方面，快速凝固属于液相操作， ...更多信息 n.对三种溶解度不同的前驱体进行了脱合金实验。在快速凝固前驱体的情况下，它几乎是α相的单相。在固溶处理后，从固溶温度开始进行水淬，观察到大量的Ag_2Al相，由于Ag_2Al相的析出速率很高，因此在淬火过程中很难抑制Ag_2Al相的析出。沉淀处理后溶解度可忽略不计。通过化学脱合金化，Ag在α相中形成了细小的骨架Ag，而没有Ag_2Al相分解形成骨架Ag。快速凝固法是一种有效的方法，可提高骨架银的生产率，约80%的银以骨架银的形式回收。另一方面，在其他两个前体中。回收率很低，不到10%。前驱体制备的快速凝固根源非常优异。比表面积约为25m_2/g。所得骨架银对2H_2O_2→2H_2O+O_2的分解具有较高的活性。在其他反应中的高性能将是预期的。少

There was few reports on the effect of the solubility of Ag in the Al phase on the productivity in synthesize of the fine skeletal Ag by the chemical dealloying process. In Al-Ag binary alloy system, the *olubility widely changes with temperature. In this work, some precursors with different solubility were prepared and they were chemically dealloyed. The alloys with various composition were melt in Ar atmosphere and then were rapidly solidified by the rotating-water atomization process. Thus atomized particles were obtained and their mean diameter was about 200μm. The mean cooling rate of the particles was estimated in the range of 10^4-10^5K/s. To control the solubility, two kinds of heat treatments were carried out. One of them was solution treatment for the highest solubility and the other was precipitation treatment for the minimum solubility. Both treatments were classified to a solid state operation. On the other hand, the rapid solidification was classified to a liquid operatio … More n. Three kinds of precursors wuth different solubility were dealloyed. In the case of the rapidly solidified precursor, it was almost a mono phase of the α phase. After the solution treatment followed by water quenching from the solution temperature, a significant amount of Ag_2Al phase was observed and it was difficult to suppress the precipitation of Ag_2Al phase during the quenching due to the quite high precipitation rate. The solubility was negligible small after the precipitation treatmnnt. By the chemical dealloying, fine skeletal Ag was formed from Ag in the α phase and no Ag_2Al phase was decomposed and contributed to the formation of the skeletal Ag. The rapid solidification was *e effective to high productivity for the skeletal Ag and about 80% of the addition of Ag was recovered as the skeletal Ag. On the other hand, in both other precursors. the rate of the recovery was quite low and less than 10%. The rapid solidification root for the precursor preparation was quite excellent. The specific surface area was about 25m_2/g. The obtained skeletal Ag showed high activity for decompostion of 2H_2O_2→2H_2O+O_2. High performance in another reactions will be expected. Less