| Piezoelectric ceramics are new kind of smart materials. Due to their piezoelectric and inverse electric effect, they have been used as sensors and actuators in smart structure. Many companies have achieved industrialization in ultrasonic transmitters, acceleration sensors and ultrasonic motors. The PZT piezoelectric ceramics is the most used piezoelectric ceramics currently. Though PZT is a kind of high-performance piezoelectric ceramics with excellent piezoelectric properties, over 60% weight of PZT ceramics is lead. As Lead is toxicity, In the near future, regulations on the use of lead will be strengthened .Therefore, research and development of lead-free piezoelectric materials with performances comparable to PZT has been an important issue.This study aims to fabricate high-performance, harmless to environment lead-free piezoelectric materials. Potassium sodium niobate (KNN) lead-free piezoelectric ceramics is seemed to be the candidate material substitute for PZT. As KNN ceramics has high Curie temperature and relative large electric-mechanic couple coefficient. In this study, ceramic fabrication methodology will be developed. This study will use solid-solution method to synthesize ceramics powder, use atmospheric sintering method to sinter ceramics, and cold-press method to press the ceramics compact. The condition of coating electrodes and polarization will also be discussed in this study. The ceramics powders will also been synthesized by hydrothermal method. The difference properties of ceramics with different synthesis method will also been discussed. |
