Powder injection molding of PNN-PMN-PZN doped low temperature sintering PZT ceramics

A complete process of powder injection molding was developed and optimized for the low temperature sintering PZT ceramics. A commercialized PNN-PMN-PZN doped PZT ceramics was used for the process development. The torque rheometer experiment was conducted to determine the optimal solids loading to injection molding rectangular type specimen. Appropriate debinding conditions were developed by thermogravimetry. Holding temperatures were determined based on the decomposition behavior of binder system and the volatilization temperature of Pb. Due to the fine particle size and low solids loading, a slow thermal debinding rate was required to prevent the crack defect. The densification behavior during sintering was analyzed by dilatometry. Low temperature sintering PZT ceramics shows a strain rate peak point at 1015 °C which is relatively lower than the peak point of conventional PZT ceramics. Even though a relatively long (3 h) holding time was required to achieve 98% of relative density, the powder injection molded low temperature sintering PZT ceramics showed 7.66 (103 kg/m3) of density and 635 (pC/N) of piezoelectric charge constant which are 98 and 99% of reference value of powder.