A magnetic core of a reactor applied to the boost converter of hybrid vehicle was developed. The core is made of High-Density Magnetic Composite, which is a kind of the powder magnetic core. A great cost reduction was achieved while keeping the magnetic properties equal to conventional magnetic steel. In order to achieve both high magnetic flux density and mechanical properties of the core, high compaction density and high bending strength were coped with by developed warm compaction technique using die wall lubrication. The great decrease of a core loss was achieved by adopting the Fe-Si alloy, developing the particle shape of the raw material powder made by the new controlled atomization method and enabling the annealing at the high temperature.

Synchrotron X-ray nano computed tomography was employed to study how the microstructure changes during the co-sintering process of multi-layer ceramic capacitors (MLCC). MLCCs are composed of alternating Ni electrodes and BaTiO3 dielectric layers. When the thickness of the electrodes was reduced to submicron levels, on the order of a few particle diameters, it led to the development of defects in the inner electrodes, resulting in a loss of capacitance. The discontinuous electrode region contained circular holes and irregularly shaped channels. The creation of these gaps was linked to an increase in the characteristic length of the non-uniform electrode structure, which can be described as a coarsening process. The transformation of the electrode's shape through surface/interface diffusion triggered the separation of the material connecting two holes. This separation was driven by instability induced by surface tension and stress, causing the material to form sharp points as it broke apart. These sharp points could potentially enhance the local electric field and lead to dielectric breakdown. An explanation was provided for the generation of defects arising from the arrangement of heterogeneous particles in the electrode layer.

The properties of MAX phase ceramics that possess metallic and ceramic nature are anisotropic because of their hexagonal and layered crystal structure. Slip casting under a strong magnetic field followed by spark plasm sintering is one of the methods to control the orientation of the MAX phase ceramics. In this study, first, the textured Ti₂AlC-MAX phase was fabricated by slip cast under 12 T, where the direction of magnetic field was fixed to the slip cast direction after clarifying the easily magnetizable axis of Ti₂AlC. Second, the crystal orientation dependence of the room temperature deformation behavior was investigated by the Vickers hardness test from various orientations. It was found that the easily magnetizable axis of Ti₂AlC was the c-axis and the textured body could be obtained by applying the magnetic field from one direction. In the room temperature deformation, Vickers indents show an anisotropic shape and the hardness changed depending on the loading direction against the c-axis due to different deformation modes such as kink deformation and slip deformation. For 0°, since the slip deformation was unlikely to occur, linear crack growth was observed to form from the indent. For 45°, on the other hand, since the slip deformation occurred relatively easily, the crack growth was suppressed through the stress relaxation due to the slip deformation. For 90°, although the slip deformation is unlikely to occur similar to 0°, the crack propagation was suppressed through pile-up due to kink deformations along the c-axis. It can be concluded that kink deformation prevents crack propagation and increases the fracture toughness of the textured Ti₂AlC-MAX phase.