Location

La Jolla, CA

Start Date

1-1-1998 12:00 AM

Description

The phases in magnetic materials can be studied ultrasonically. Magnetic phase transition points can be determined from discontinuities in ultrasonic velocity as a function of temperature. Conventionally this is done using piezoelectric transducers (normally quartz) pulsed with a tone burst generator. Very accurate velocity measurements are required as the change in velocity is typically 1 part in 104 [1]. A common problem experienced with contacting transducers is the fracturing of the acoustic couplant bond at low temperatures. Non-contacting acoustic techniques have no problems with bond failure, electromagnetic acoustic transducers (EMATs) can be used for measurements on rare earth magnetic materials.

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

17B

Chapter

Chapter 6: Materials Characterization

Section

Materials Properties

Pages

1451-1456

DOI

10.1007/978-1-4615-5339-7_187

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

The Detection of Magnetic Phase Transitions in ER-TM by Electromagnetic Acoustic Transducers

La Jolla, CA

The phases in magnetic materials can be studied ultrasonically. Magnetic phase transition points can be determined from discontinuities in ultrasonic velocity as a function of temperature. Conventionally this is done using piezoelectric transducers (normally quartz) pulsed with a tone burst generator. Very accurate velocity measurements are required as the change in velocity is typically 1 part in 104 [1]. A common problem experienced with contacting transducers is the fracturing of the acoustic couplant bond at low temperatures. Non-contacting acoustic techniques have no problems with bond failure, electromagnetic acoustic transducers (EMATs) can be used for measurements on rare earth magnetic materials.