The effect of weight percent on the properties of ultrasonic transducers fabricated though a sol-gel deposition process

Open Access
Author:
Sinding, Kyle Matthew
Area of Honors:
Engineering Science
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Bernhard R Tittmann, Thesis Supervisor
  • Robert Allen Kimel, Honors Advisor
  • Clifford Jesse Lissenden Iii, Faculty Reader
  • Reginald Felix Hamilton, Honors Advisor
  • Clive Randall, Thesis Supervisor
Keywords:
  • Composite Transducers
  • PZT-Bismuth Titanate
  • Composite Ferroelectric Modeling
  • Sol-gel Spray-on Deposition
  • Ceramic
Abstract:
Applications for non-destructive evaluation (NDE) and structural health monitoring (SHM) in principle can be performed at various temperatures provided the transducer can reliably operate under those conditions. For are high temperature materials such as Lithium Niobate that can be used for NDE a coupling medium is required to aid in wave propagation between the transducer and system of interest. Traditional methods require either pressure contacts or a high temperature bonding medium, which can deteriorate over time. The sol-gel spray-on technology eliminates the need for this coupling medium and allows for an actuator that can be custom tailored to the specific application of interest. As nuclear reactors reach the end of their projected lifetime it is critical that the systems within the containment structure be continuously monitored. This spray-on technology allows for efficient on-line monitoring of a system at any operating temperature providing the proper transducer selection. The current objective is to develop a class of spray-on ferroelectrics that do not require a bonding medium and enable custom tailoring of composite transducers adapted for different combinations of efficiency and temperature. For example, if a high-temperature application is anticipated, the composition of the sol-gel can involve constituents that favor ultrasonic properties, while the powder could involve constituents that still function ultrasonically at high temperature. This paper presents details of the deposition method without requiring a bonding medium. It also shows results on the effects of varying the weight percent of the composite Lead Zirconate Titanate/ Bismuth titanate transducers on the Curie temperature and efficiency of the composite Piezoelectrics. Results for several composites are given with d33 values ranging from 20 to 60 x10-12 Coulomb/Newton along with temperature dependencies of the signal amplitude in pulse-echo experiments. These composite ferroelectrics are modeled using a micromechanics analysis code based on the “generalized method of cells” program.