Abstract
The compression of spherical glass powders has been studied by static method in the pressure range 0-7.5 tons per cm2 (Fig.1). The results obtained are as follows.
(1) During the compression process, the following distinct steps are observed (Photo. 1, 2) : (a) Packing without crushing (Initial stage of Fig. 2, 5, 6). (b) Sudden breakage of the particles and rapid diminution of apparent specific volume (Fig. 2, 5, 6). (c) Compaction of the crushed particles (Fig. 2, 3, 4, 5, 6, 11).
(2) In the process of the compression of spherical glass powder, the relation between P, the applied pressure, and n, the porosity, is generally given by the following equation (Fig. 5, Table 1) :
-(dn/dP)=k·nx
where k and x are constants.
(3) The effect of particle size on the breakage phenomena has been studied (Fig. 6, 7, 8). (a) The breakage pressure is higher for small particles than for large ones (Fig. 8, 9). (b) The degree of rapid volume change accompanying the sudden breakage increases with increasing of the particle diameter (Fig.10).
(4) In the experiments of binary mixture which composed of two different particle sizes with different ratio of mixing, it has been observed that the rapid volume change accompanying the breakage of large particles occurs when the component of large particles is above about 70 percent by weight (Fig. 12, 13, 14).
