Ultrasonic Interferometer

Non-Destructive Testing of Material is an important part of Education as it gives information without deformation in the shape and size of the material. One of the NDT techniques, Piezoelectric technique is widely used for the measurement of composition dependent properties such as ultrasonic velocity, compressibility, elastic constant, Young’s modulus and Bulk modulus. Its suitability for metals, plastics, polymers and crystals etc makes it versatile tool for Engineering Physics, Material Science and Polymer Science.

In this technique the specimen is cemented to a quartz rod of identical cross section and resonant frequency (fc) of the composite system is determined using the apparatus. The resonant frequency of the quartz rod (fq) is also determined. From the knowledge of fq, fc and the masses of the quartz (mq) and the specimen (ms), the resonant frequency of the specimen fs is evaluated using the relation


Using the value of the length of the specimen and the density of the specimen, the velocity of the ultrasonic waves in the specimen and compressibility can be calculated using relations where ? is density of specimen .


Young's Modulus of specimen is calculated using relation

Instrument: It consists of Piezoelectric Oscillator and R.F. meter, quartz crystal, quartz crystal with sample, holder , connecting cables.
Accessory: Any general purpose C.R.O.