Fig. 4: Mechanochemically induced phase transformation kinetics of RP to BP using the JMAK and DC models.

a XRD-based phase fraction versus logarithmic time showing representative S-curves for each rpm condition; higher rpm results in faster conversion while a dramatic reduction occurs at and below 300 rpm. An S-shape curve is typical of nucleation and growth dominated solid-state processes. Error bars represent one standard deviation, lines are visual aids. b JMAK linearization plots for extracting rate constants and exponents, lines are linear regression fits for each straight section; the slopes remain relatively constant indicating the conversion mechanism remains constant, while the kinks at higher phase fraction indicate a possible mechanism change. c DC model linearization plot excluding the 200 rpm data, lines are linear regression fits; the slopes become steeper (higher rate constant) with increasing rpm. d Linear regression fits for rate constants versus calculated impact energies; both the JMAK and DC models show the linear dependence of the rate constant on the impact energy confirming the assumption that a single impact is sufficient for converting the entrapped RP powder between media collisions to BP.