Practical Ultrasonic Transducers for High-Temperature Applications using Bismuth Titanate and Ceramabind 830
Open Access
- Author:
- Xu, Janet Liang
- Graduate Program:
- Acoustics
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- July 26, 2017
- Committee Members:
- Bernhard R Tittmann, Thesis Advisor/Co-Advisor
Clifford Jesse Lissenden III, Committee Member
Stephen Thompson, Committee Member - Keywords:
- Non-destructive evaluation
Ultrasound
Structural Health Monitoring
Ferroelectric Composites
Piezoceramic
High temperature transducer
Transducer
Thick Films
Bismuth titanate
Ceramabind 830
Ultrasonic - Abstract:
- Non-destructive testing (NDT) using ultrasonic transducers can help detect and prevent largescale failures in high-temperature environments (>150 degC) such as power plants by using noninvasive techniques to determine the structural integrity of pipework. Practical piezoceramic ultrasonic transducers made using only bismuth titanate (BIT), a binding solution called Ceramabind 830, and a bit of water have been shown to withstand temperatures up to 330 degC and are painted directly onto the substrate, allowing for in-situ, real-time monitoring of high-temperature components. When fabricating these BIT/Ceramabind 830 transducers, it was found that the performance varied significantly when made with the same materials and procedures. Investigations were made to identify the effects of humidity during the drying process, binder concentration, water concentration, and deposition amount to optimize performance and reduce variation between transducers. The best samples were made in low humidity environments with a low binder concentration, water concentration dependent on substrate roughness, and by depositing as thin of a layer of film as possible. In addition, an optimal poling temperature of ≈200 degC was determined, high-temperature tests were performed, laser cutting was shown to be a good method for creating transducer elements, and three signal processing techniques were demonstrated to significantly increase signal-to-noise ratio.