Polyvinyl acetate (PVAc) composites were loaded with varying amounts of nano-metal alloy (Ag–Sn–Cu–Pt) and stearic acid. They are used as backing materials for ultrasonic transducers to prevent back-echoes from reverberating into the piezoelectric element and to reduce noisy echoes. The novelty of this work is the usage of these newly prepared PVAc/alloy composites as backing material in ultrasonic transducers with a polyvinylidene fluoride (PVDF) active element. The X-ray diffraction (XRD) technique was used to examine the structure of the composites. The ultrasonic technique investigated the ultrasonic attenuation coefficient, the acoustic impedance, the mechanical properties, and other parameters. The transducers with the new backing composites gained high sensitivity, broadband, short ringing, and so on. These characteristics were improved by increasing the nano-metal alloy content in the backing composites. The study also proved the efficiency of the PVAc/alloy composite as new backing material in ultrasonic transducers. Graphical abstract Sketch of fabricated ultrasonic transducers with backing materials from PVAc/alloy composites (B1, B2, B3, B4, B5, and B6) and their important features (BW is transducers’ band width and S is transducers’ sensitivity).

Nano Er-doped TiO₂ thin films prepared by sol-gel technique at different doping concentrations (5%, 7%, 9%, and 11%). The prepared thin films were studied through ultrasonic and ellipsometric measurements. Mechanical properties are known from the ultrasonic method that investigated the effect of the Er-doped amount on the cross-link density, bond strength, elastic properties, and stress-strain relation between atoms of TiO₂ thin films. Ellipsometric measurements studied the variation of optical transmittance, energy band gap, refractive index, Urbach energy roughness, and porosity with changing Er-doped amount. Finally, contact angle measurements are done to ensure the self-cleaning property of the prepared thin films. Results deduced that Er-doped enhanced greatly TiO₂ thin films, to be used in many industrial applications as self-cleaning glass fabrication.

This paper investigates the impact of different matching layers on the ultrasonic transducers’ performance. Matching layers are mostly used to solve the acoustic impedance matching problem between the piezoelectric element and the test specimen. To design good matching layers, we merged the metal–polymer and mass–spring systems. Their thickness was also optimized using the quarter-wavelength approach. Silver, alumina, and copper served as mass components, while parylene served as the polymer spring component. This was the first time to use such matching materials with lead zirconate titanate (PZT) transducers. The transducers’ sensitivity increased, the beam diameter broadened, the signal-to-noise ratio reduced, and the echo-height increased. According to the findings, the developed matching layers were extremely efficient in upgrading PZT transducers, making them ideal for a variety of non-destructive ultrasonic applications such as identifying defects in various materials. In addition, the new developed transducers may be useful in calibration.