Analysis on thermal debinding kinetics of iron-based powders by warm flow compaction

Cross-shaped parts were prepared by flow warm compaction using iron-based powders as raw material and paraffin wax-based polymer as binder, the polymer binder was removed at different debinding rates. The thermogravimetric analysis (TGA) was used to study the thermal debinding behavior of binder under N₂ atmosphere, and the kinetic parameters were investigated by derivative thermogravimetric method. The parts prepared by the optimized debinding parameters were sintered at 1300℃, and the shrinkage, density distribution, and microstructures of the sintered parts were studied. Results show that, the thermal debinding processes can be divided into two stages, the activation energy and pre-exponential factor are ranging from 31.3 to 72.7 kJ·mol^-1 and 0.96×106 to 1.14×1010 min^-1, respectively. The activation energy of stage 1 is lower than that of stage 2, which means that it is easier to remove low molecular polymer binder in stage 1. The key factor of debinding quality is to control the heating rate of stage 1.