Short derivation of the influence of particle size ratio on the conductivity threshold in binary aggregates

A model developed by R.P. Kusy for predicting the composition at which the sudden onset of conductivity occurs in polymer/metal powder compacts is shown to yield quantitative results practically equivalent to those given by a previously published solution to the same problem. Significant differences nevertheless exist in the two theoretical developments leading to the concurring results; both approaches are appraised with reference to these differences.