光コヒーレンストモグラフィーによるAl₂O₃顆粒の一軸加圧下における粉体層中の空隙の形態変化過程のその場観察

抄録

Uniaxial pressing is a utilized technique to prepare powder compacts in regions of ceramics, metal, drug, and functional food. On the other hand, it is known that the inhomogeneous structures are induced by stress distribution resulting from applying the anisotropic stress field to the powder bed and they become the origin which forms defect degrading the performance of products. However, the generation process of inhomogeneous structures has not been clarified experimentally. Directly understanding the formation mechanism of the internal structure during uniaxial pressing is very important to control the particle-assembled structure in the powder bed and the quality of products. In this work, the change process in void morphology under uniaxial pressing was observed dynamic-two-dimensionally and intermittent-three-dimensionally by the novel observation system composed of swept-source optical coherence tomography (SS-OCT) and material testing machine. Moreover, the detected voids were evaluated quantitively to directly clarify particle-packing behavior on the initial stage of pressing.