The effect of composition on the tableting indices of binary powder mixtures.

The purpose of this study was to investigate the effect of the composition of a binary powder mixture on the bonding index, the brittle fracture index, and the strain index, as defined by Hiestand. The studies involved tensile strength and dynamic indentation hardness determinations of square compacts, the solid fractions of which were 0.83. The mixtures were such that both components consolidated by plastic deformation, both components consolidated by brittle fracture, or one component was brittle while the other was plastic. The measured quantities were then used to compute the bonding index, the brittle fracture index, and the strain index. The bonding indices and tensile strengths of the individual plastic materials were greater than those of the individual brittle materials. It was concluded that the bonding indices were linearly related to composition when both materials consolidated by the same mechanism. It was further concluded that the bonding indices were related to compact composition by a second-degree polynomial equation for mixtures with one brittle and one plastic component. This latter relationship was consistent for four pairs of components.