Thermal decomposition behavior and modeling of PMN-PZT ceramic feedstock with varying binder compositions

The thermal debinding process is one of the most crucial steps in powder injection molding because it consumes a great deal of the processing time and may introduce defects into the component. To enhance production efficiency and increase defect avoidance, debinding conditions including maximum temperature, heating rate, and holding time should be determined based on the analysis of thermal decomposition behavior. The thermal decomposition behavior of lead magnesium niobate-lead zirconate titanate (PMN-PZT) ceramic feedstock with varying binder compositions was investigated in this paper using experimental analysis and modeling. In this study, the powder volume fraction in the feedstock was fixed at 45 vol% in order to isolate the effects of binder composition on thermal decomposition behavior. Each feedstock was divided into three groups depending on the variation in the filler binder (first), the backbone binder (second), and the entire binder system (third), respectively. Thermal decomposition behaviors for the feedstocks were analyzed by thermogravimetric analysis experiments at heating rates of 2, 5, and 10 °C min−1. All of the TGA graphs showed two sigmoidal curves due to the difference in the molecular weights of the binders. The apparent activation energy for binder decomposition was calculated based on the Kissinger approach. A remarkable change in activation energy was derived from the variation in the entire binder system. Based on the acquired decomposition parameters, master decomposition curve was constructed and verified experimentally in order to provide a predictive design tool for identifying optimal debinding conditions based on the intrinsic kinetics of binder pyrolysis.