Based on Al–Pbbinary phase diagram, there is no intermetallic compound between
Al and Pb, indicating the particles shown in Fig. 2a and Fig. 3a are
lead phase which is a reaction product between BPOp and Al.The
existence and particle size of Pb phase are in good agreement with
XRD results. Furthermore, the gray region near certain lead particles
was analysed using selected area electron diffraction (SAED)methods.