Nanoporous metals similar to paper in form are developed using Japanese washi paper as a template to create hierarchical porous electrodes. This method is used to create a trimodal ­nanoporous Au electrode, as a well as a hierarchical NiMn electrode that achieves high electrochemical capacitance and a rapid rate of oxygen evolution.

The production method of micro sacrificial plastic mold insert metal injection molding, namely μ-SPiMIM process has been proposed to solve specific problems involving the miniaturization of MIM. The sacrificial plastic mold (SP-mold) with fine structures was prepared by injection-molding polymethylmethacrylate (PMMA) into Ni-electroform, which is a typical LIGA (Lithographie-Galvanoformung-Abformung) process. Stainless steel 316L feedstock was injectionmolded into the SP-mold which had micro structures with multi-pillars. The green compact was demolded as one component with the SP-mold, which was decomposed along with binder constituent of feedstock in debinding process. This study focused on the effects of metal particle size and processing conditions on the shrinkage, transcription and surface roughness of sintered parts, which were evaluated by SEM (Scanning Electron Microscope) observation.

Polymer electrolyte fuel cells (PEFCs) have recently increased in popularity in domestic and automobile use. However, the spread of miniature fuel cells doesn’t advance though they are expected to be the power supply of mobile electronic devices. Though a carbon is generally used to make the PEFC separator, it is unsuitable as the separator material for micro-PEFCs because complex shapes cannot be processed into it. However, a metal injection molding (MIM) method can achieve the complex gas channel formation to the micro-PEFC separator. Therefore, we have developed the four types of metallic separators for a micro-PEFC separator using the MIM method since 2011. We evaluate I-V performance of a new micro-PEFC of the same shape as C size battery (Type-C). As a result, although the cell voltage of Type-C is improved at low fuel rate, it decreases drastically after operating 3 hours. When we disassembled Type-C after testing, both gas channels were plugged by generated water. Therefore, it is necessary that the new Type-C separator has to be redesigned to improve drainage.

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This study aims to reveal the behavior of debinding and sintering in metal powder injection molding (MIM) process using copper powders with varied particle sizes. The feedstock composed of micron-and submicron-sized copper powders and polyacetal-based binder was adequately prepared. Oxidation process was added between debinding and sintering steps for decarburizing. The effects of processing temperature in debinding, oxidation and sintering were evaluated from the changes in weight, dimension, and residual carbon and oxygen contents in addition to microstructure.From the results obtained using micron-and submicron-sized copper powders, it was clarified that the oxidation conditions was very important for stably-obtaining the high dense sintered parts with lower carbon and oxidation contents. This is considered to be due to the mechanism that the binder was removed from green compacts at 873K in