Measurement of initial porosity distribution in a powder cell by x-ray radiograph

Homogeneous powder packing into a powder cell is one of the fundamental and also important problems which should be urgently elucidated in powder technology. For example, to get a sufficient mechanical strength of sintered powder chips in fine ceramics or electronics industry, a good homogeneous powder packing method should be developed. However, it has not been sufficiently established up to now. In this paper, from such a point of view, the initial powder packing states in different powder cells with one to five powder feeding points were systematically radiographed by X-ray, and their initial powder porosity (or powder bulk density) distributions were quantitatively analyzed by applying the analysis method presented by the authors. As the result, the following conclusions were obtained. (1) In every type of powder packing, the minimum porosity column was generated just under the powder feeding points. (2) The interference effect between two neighbouring powder feeding points changed remarkably depending upon test powder. That is, the porosity at the central region between two feeding points changed from the minimum value of the porosity distribution to the maximum one with the change of test powder. (author)