Ultrasonic Spectroscopy and the determination of physical Properties

Ultrasonic Materials Characterisation

Ultrasound is the propagation of a mechanical wave through the molecular, microscopic and macroscopic structure of a material or materials. 

Ultrasonic Spectroscopy is the measurement of the frequency dependant ultrasonic response of a material. It is closely related to rheology however operates at higher frequencies and shorter length scales. Since with all waves it can be described by a characteristic propagation wave number containing frequency dependant phase and magnitude changes. The interaction of the wave with the material is modifies the wave character through exchange of energy with through a range of physical process.

Ultrasonic Spectroscopy can measure the absolute frequency dependant velocity and attenuation of
mainly liquids over a wide range of frequencies. As it is a non optical methods is not limited by the opacity of the material. It is an ideal process senor technology as it is not affected by fouling of windows. Hence, there has been significant interest in the use of Ultrasonic Spectroscopy for the characterisation of materials in particular:

• Measurement of density in solids and in pure/
  mixed liquids
• Determination of thermal properties of liquids
• Rheological characterisation of liquids and soft
• solids through phase velocity
• Particle Sizing of colloids using attenuation
• Relaxation phenomena in biomaterials and soft
  solids