Ultrasonic Attenuation in Calcium Oxide

Jitendra Kumar,Devraj Singh,Virendra Kumar,Sanjeev Kumar Shrivastava,Kailash R

doi:10.4236/ampc.2011.12008

Abstract

Ultrasonic attenuation studies can be used to characterize material not only after production but during processing as well. The most important causes of ultrasonic attenuation in solids are electron-phonon, phonon-phonon interaction and that due to thermo elastic relaxation. The two dominant processes that will give rise to appreciable ultrasonic attenuation at higher temperature are the phonon-phonon interaction also known as Akhiezer loss and that due to thermo elastic relaxation are observed in calcium oxide crystal. At frequencies of ultrasonic range and at higher temperatures in solids, phonon-phonon interaction mechanism is dominating cause for attenuation. Ultrasonic attenuation due to phonon-phonon interaction (α/f2)p-p and thermo elastic relaxation (α/f2)th are evaluated in Calcium Oxide crystal up to an elevated temperature from 100 K - 1500 K along , and crystallographic directions. Temperature dependence of ultrasonic attenuation along different crystallographic direction reveals some typical characteristic features.

Highlights

Ultrasonic velocity and attenuation parameters are well connected to the micro structural and mechanical properties of the materials
The two dominant processes that will give rise to appreciable ultrasonic attenuation at higher temperature are the phonon-phonon interaction known as Akhiezer loss and that due to thermo elastic relaxation are observed in calcium oxide crystal
Ultrasonic attenuation due to phonon-phonon interaction (α/f 2 )p-p and thermo elastic relaxation (α/f 2 )th are evaluated in Calcium Oxide crystal up to an elevated temperature from 100 K - 1500 K along , and crystallographic directions

Summary

Introduction

Ultrasonic velocity and attenuation parameters are well connected to the micro structural and mechanical properties of the materials. The most important causes of ultrasonic attenuation in solids are electron-phonon, phonon-phonon interaction and that due to thermo elastic relaxation. The two dominant processes that will give rise to appreciable ultrasonic attenuation at higher temperature are the phonon-phonon interaction known as Akhieser loss [8,9] and that due to thermo elastic relaxation and are observed in calcium oxide crystal. In this work ultrasonic attenuation due to phonon-phonon interaction over frequency (α/f 2 )Akh and ultrasonic attenuation due to thermo elastic relaxation over frequency (α/f 2 )th are studied in calcium oxide at an elevated temperatures (100 K - 1500 K) along , and crystallographic directions. Mason’s theory relates the Gruneisen constants with SOECs and TOECs. The behaviour of ultrasonic absorption and other parameters as a function of higher temperature have been discussed as the characteristic features of calcium oxide

Formulation

Evaluation

Results and Discussion

Conclusions