Fabrication Of Lead Free Piezoelectric Ceramics For Energy Harvesting Applications

• Main Author: Mohd Radzi, Muhamad Haffiz
• Format: Thesis
• Language: English; English
• Published: 2017
• Subjects: T Technology (General); TK Electrical engineering. Electronics Nuclear engineering
• Online Access: http://eprints.utem.edu.my/id/eprint/23291/1/Fabrication%20Of%20Lead%20Free%20Piezoelectric%20Ceramics%20For%20Energy%20Harvesting%20Applications.pdf; http://eprints.utem.edu.my/id/eprint/23291/2/Fabrication%20Of%20Lead%20Free%20Piezoelectric%20Ceramics%20For%20Energy%20Harvesting%20Applications.pdf; http://eprints.utem.edu.my/id/eprint/23291/; https://plh.utem.edu.my/cgi-bin/koha/opac-detail.pl?biblionumber=112725

Energy harvesting is a process by collecting a small amount of energy from the ambient environment.In this research,the concept of energy harvesting system was implemented using thick film piezoelectric ceramics transforming mechanical vibration energy into electrical energy.In line with the growing awareness of the environmental hazards with the present of lead,this thesis proposed two types of lead free ceramic material: barium titanate (BaTiO3) and potassium sodium niobate (KNN).The major challenges for energy harvesting from a lead free piezoelectric device are that the electrical output power is relatively small compared to the minimum requirement of electrical power for operating small electronic devices.The main objective of the project is to fabricate thick film lead free piezoelectric ceramic which able to produce high output power for the application of energy harvesting.In order to fabricate lead free thick film piezoelectric ceramics,thick film technology is selected due to its simplicity and low cost compared to thin film technology.One of the performance indicators for a piezoelectric energy harvesting material is the measurement of the piezoelectric charge coefficient,d33.Two of the materials,BaTiO3 and KNN were characterized and studied to compare its performance.The fabrication process involves the development of lead free piezoelectric paste,thick film screen printing and electrical polarization.The lead free piezoelectric paste was developed by mixing a composition of functional element and permanent binder in the powder form and pine oil as the temporary binder to make the paste printable. The lead free piezoelectric ceramic was fabricated by screen printing a few layers of piezoelectric film,which stack on top of an electrode layer on a substrate and finished with another layer of electrodes on the top of the sandwiched structure of electrode-piezoelectric-electrode.The polarization was performed by applying high DC electric fields at ranges of up to 2 kV at an elevated temperature of around 250 C using hotplate.The performance of each of the lead free thick film piezoelectric ceramic was evaluated based on its charge coefficients,voltages output,and power output.The parameters of the film were varied with different screen printing process,co-firing duration and controlled temperature rate to determine the optimum lead-free piezoelectric ceramics.The result shows that the piezoelectric charge coefficient of KNN is 38 pC/N for a thickness of 140 μm which is able to generate a maximum power of 12.25 nW at external resistive load of 25 kΩ which is better performed compared to BaTiO3 with d33 of 25 pC/N and maximum output power of 0.423 nW for the similar thickness and external resistive load.In conclusion from this experimental result,it shows that KNN thick film performs better compared to BaTiO3 thick film as an energy harvesting material.