Synthesized Lead Zirconate Titanate Polycrystalline Research Articles

Effect on High-Intensity Fields of a Tough Hydrophone With Hydrothermal PZT Thick-Film Vibrator and Titanium Front Layer.

A novel tough hydrophone was fabricated by depositing hydrothermally synthesized lead zirconate titanate polycrystalline film on the back-side surface of a titanium plate. Our developed tough hydrophone resisted damage in a high-pressure field (15 MPa) at a focal point of a sinusoidal continuous wave driven by a concave high-intensity focused ultrasound (HIFU) transducer with up to 50 W of power input to the sound source. The hydrophone was suitable for the HIFU field, even though the hydrophone has a flat-shape tip of 3.5 mm diameter, which is slightly larger than the wavelength of a few megahertz. In this paper, experiments are performed to assess the effect on the HIFU field of changing the shape of the tough hydrophone, with the aim of developing a tough hydrophone. The spatial distribution of the acoustic bubbles around the focal point was visualized by using ultrasonic diagnostic equipment with the tough hydrophone located at the focal point of the HIFU transducer. From the visualization, the trapped acoustic bubbles were seen to arise from the standing wave, which implies that the acoustic pressure is reduced by this cloud of acoustic bubbles that appeared during hydrophone measurement. Although cavitation and acoustic bubbles may be unavoidable when using high-intensity ultrasound, the estimated result of evaluating acoustic fields without misunderstanding by acoustic bubbles can be obtained by the aid of visualizing bubbles around the tough hydrophone.

Development of anti-cavitation hydrophone using a titanium front plate: Durability test in the high intensity focused ultrasound field

Our research group has developed new anti-cavitation hydrophones by depositing a hydrothermally synthesized lead zirconate titanate polycrystalline film with 15 μm thickness on the back surface of a titanium front plate with 50 μm thickness and 3.5 mm diameter. A durability test of the anti-cavitation hydrophone was performed when the anti-cavitation hydrophone under test was placed at the focal point of a concave focused ultrasound transducer with 100 mm diameter and at a resonant frequency of 1.75 MHz. The amplified 80 Vp-p (calculated electric input power: about 40 W) signal was applied to the concave ultrasound transducer at the focal point of the focused ultrasound system and high-intensity ultrasound waves were irradiated in water. The irradiated sound pressure at the focal point was about 4 MPa. Through this research, we will report that the fabricated new anti-cavitation hydrophone was robust and was not damaged easily, even in a high intensity focused ultrasound field with sound pressure of where acoustic cavitation occurred. We will make a durability test by increasing the acoustic power at the focal point of the focused acoustic field with sound pressure higher than 15 MPa.

Development of anticavitation hydrophone using a titanium front plate: Effect of the titanium front plate in high-intensity acoustic field with generation of acoustic cavitation

Novel anticavitation hydrophones were fabricated by depositing a hydrothermally synthesized lead zirconate titanate polycrystalline film at the back of a titanium front plate. These anticavitation hydrophones were not damaged by the measurement of the acoustic field formed by a high-intensity focused ultrasound (HIFU) device. Their sensitivity was improved by approximately 20 dB over that of the conventional anticavitation hydrophone by modifying their basic structure and materials. The durability of the anticavitation hydrophone that we fabricated was compared by exposing it to a high-intensity acoustic field at the focal point of the HIFU field and in the water tank of an ultrasound cleaner. Therefore, the effect of the surface of the titanium front plate on acoustic cavitation was investigated by exposing such a surface to the high-intensity acoustic field. We found that the fabricated anticavitation hydrophone was robust and was not damaged easily, even in the focused acoustic field where acoustic cavitation occurs.

チタン前面板裏面に水熱合成チタン酸ジルコン酸鉛を成膜した耐音響キャビテーションハイドロホン

チタン前面板裏面に水熱合成チタン酸ジルコン酸鉛を成膜した耐音響キャビテーションハイドロホン

Frequency characteristics of receiving sensitivity and waveform of an anti-acoustic cavitation hydrophone

Novel anti-cavitation hydrophones were fabricated by depositing a hydrothermally synthesized lead zirconate titanate polycrystalline film on the back of a titanium plate. These hydrophones were not damaged by the measurement of the acoustic field formed by a high-intensity focused ultrasound (HIFU) device. The hydrophones were designed using Mason’s equivalent circuit and by numerical simulation to improve their receiving characteristics for the measurement of the HIFU device. High receiving sensitivity with flat frequency characteristics was obtained by using a backing material with a specific acoustic impedance of about 20 × 106 kg/(m2 s) [Rayl]. We developed a new type of hydrophone using a tin and titanium rods as backing materials, which have specific acoustic impedances of 24 × 106 and 27 × 106 kg/(m2 s), respectively. The fabricated anti-cavitation hydrophone showed wide frequency characteristics of the receiving sensitivity. Furthermore, we observed the output waveform with distortion due to nonlinear propagation using the fabricated anti-cavitation hydrophone. This hydrophone was not damaged by exposure to a high-intensity acoustic field of an ultrasound cleaner under acoustic cavitation for duration of about ten times longer than the conventional commercial hydrophone.