Phase transitions in a two-component site-bond percolation model

A method for analyzing a N-component percolation model in terms of one parameter p₊ is presented. In Monte Carlo simulations on 16³, 32³, 64³, and 128³ simple cubic lattices the percolation threshold p₊^c is determined for N=2. Continuous transitions of p₊^c are reported in two limits for the bond existence probabilities p₌ and p_≠. In the same limits, empirical formulas for the percolation threshold p₊^c as a function of one-component concentration f_b are proposed and links to existing percolation models are established. In the limit p₌=0 a different site percolation model is proposed and its threshold, f_b^c≃0.145, is reported.