Lead-free thick-film ultrasound sensors for industrial process monitoring /

Abstract

Sol-gel high-temperature ultrasound transducers (HTUT) have been developed to compensate for the limitations present in many commercial ultrasound sensors, such as limited temperature durability and limited frequency ranges, etc. The most common HTUTs are lead-based and more environmentally friendly options are desired. For industrial process monitoring, ideally HTUTs can be fabricated directly onto machine tools, dies, vessels and moulds to create information-rich but minimally invasive sensors. In this study, two lead-free sol-gel composites are compared with a common lead-based HTUT material for the feasibility of spray-coating as a thick film on a steel substrate. The general procedure and key information for the preparation of the precursors for each composite have been outlined. The firing and annealing procedures necessary for the successful creation of films with good mechanical stability and surface adhesion are also outlined. The characterisation of the film properties demonstrates reasonable adhesion and mechanical stability for each film.