Method for Manufacturing a High-Temperature Ultrasonic Transducer Using a Lithium Niobate Crystal Brazed with Gold and Indium

摘要

A process for manufacturing a high-temperature ultrasonic transducer, said transducer comprising a steel or metal top electrode, a piezoelectric converter, a steel or metal support ensuring the interface between the converter and the propagation medium of the acoustic waves, a first joint between the support and the piezoelectric crystal, and a second joint between the converter and the top electrode, comprises, to produce said gold-and-indium-based joints, a brazing and diffusing operation comprising the following steps: a first step of increasing temperature to a first temperature comprised between about 150° C. and about 400° C. and of maintaining this first temperature for a first length of time corresponding to a first plateau; and a second step of increasing temperature to a second temperature comprised between about 400° C. and about 1000° C. and of maintaining this second temperature for a second length of time corresponding to a second plateau.

主权项

1. A process for manufacturing a high-temperature ultrasonic transducer, said transducer comprising a steel or metal top electrode, a piezoelectric converter, a steel or metal support ensuring the interface between the converter and the propagation medium of the acoustic waves, a first joint between the support and a piezoelectric material, and a second joint between the converter and the top electrode, comprising the following steps to produce said joints:
depositing a gold layer then depositing an indium layer on one of the faces of the top electrode, on both faces of the converter, and on one face of the steel support; stacking the support, the converter, and the top electrode, this stack being maintained under pressure; and producing the indium-and-gold-compound-based first and second joints via a brazing and diffusing operation, said brazing and diffusing operation comprising the following steps:
a first step of increasing temperature to a first temperature comprised between about 150° C. and about 400° C. and of maintaining this first temperature for a first length of time corresponding to a first plateau; anda second step of increasing temperature to a second temperature comprised between about 400° C. and about 1000° C. and of maintaining this second temperature for a second length of time corresponding to a second plateau.