Crystallization kinetics and glass transition kinetics of iron borophosphate glass and CeO2-doped iron borophosphate compounds

Abstract

Effects of CeO2 doping and the preexisting formed CePO4 crystallite on the crystallization kinetics and glass transition kinetics of the 36Fe2O310B2O354P2O5 glass (IBP glass) have been investigated by differential thermal analysis (DTA). The results reveal that a well defined glass transition peak and two crystallization peaks are observed in DTA curve of the IBP glass. The crystallization activation energies for the first crystallization peak (Ec for P1) and the second crystallization peak (Ec for P2) of the IBP glass are 211.77 KJ mol−1 and 564.31 KJ mol−1 respectively. And CeO2 doping insignificantly affects the Ec for P1 but increases the Ec for P2. Moreover, the preexisting CePO4 crystallite increases the Ec for P1 and the activation energies of glass transition peak (Eg). However, the CePO4 crystallite obviously decreases the Ec for P2. In addition, the crystal growth in the IBP glass occurs in two dimensions. Due to the preexisting CePO4, the dimensions of crystal growth in CeO2-doped IBP compounds change to three. The conclusions offer some useful information for the disposal of high-level radioactive wastes using iron borophosphate glasses and iron borophosphate based glass-ceramics.