Characterizations of piezoelectric thick films made by screen printing

Screen printing provides a cost effective, high productivity and flexible method to achieve lead zirconate titanate (PZT) thick films for many sensor and actuator applications. PZT thick films with thickness of 5μm to 100μm can be easily obtained from screen printing and the thick film effectively fill the technological gap between thin film and bulk ceramics. However, screen printed thick films usually have poor densification due to high porosity resulting in inferior ferroelectric, dielectric and piezoelectric properties. To improve the density of the thick film, glass frit addition or sol infiltration to the thick film has been incorporated with the screen printing method. Nevertheless, inorganic binder like glass reduces the ferroelectric and piezoelectric properties of PZT thick films due to its low dielectric permittivity while spin coating sol-gel only managed to infiltrate the top part of the thick film therefore still leaving voids between powders. In this report, binder-less PZT composite thick film up to 50 μm on alumina substrate will be fabricated through the mixture of modified PZT powder of different sizes achieved through ball milling technique. Only organic vehicle is used to form the thixotropic paste for screen printing and no binder is added. Different composition of the PZT powder and processing techniques were explored to achieve thick films with satisfactory densification. Microstructures of the fabricated thick film will be evaluated using Scanning Electron Microscope. Thick films with dense microstructure will then be characterized and evaluated on their ferroelectric, dielectric and piezoelectric properties.Bachelor of Engineerin