Integrated Piezoelectric Ultrasonic Receivers on Metals for Laser Generated Ultrasound

Thick (>50μm) piezoelectric ceramic films have been deposited directly onto metal substrates as integrated ultrasonic transducer (IUT) receivers to detect the laser generated ultrasound. The film fabrication is based on a sol-gel spray technique. In this investigation IUTs intrinsically acting as bulk longitudinal wave receivers use various mode conversion approaches and serve as longitudinal, shear, symmetric, anti-symmetric and shear horizontal plate wave receivers. Steel and aluminum having different sizes, shapes and thicknesses and coated with IUTs have been used for the study. Different laser generation conditions such as point and line sources of different sizes are also applied to investigate the capabilities of IUT receivers. Ultrasonic measurements up to 400°C of metal substrates with planar and curved surfaces using laser generated and IUT received ultrasound are demonstrated.