Ultrasonic Contact Impedance 

UCIUltrasonic Contact Impedance is the name of a portable technique used for measuring the hardness of a material. Hardness is the resistance of a material to localised deformation. The hardness is often derived by measuring the deformation achieved when applying an indenter with a known geometry and under a predetermined load to the surface of a material. Hardness is not a fundamental physical property but a composite one, which is related to tensile strength, wear resistance, work hardening and other factors. There are many different methods for quantifying hardness (see link).

The UCI meter is a surface hardness tester based on the measurement of change in the resonance frequency of a mechanical resonator brought into contact with a surface. The UCI technique converts the measurement to common hardness values such as the Rockwell or Vickers hardness scales. The UCI technique is limited to the measurement of surface hardness, but it is portable and can be applied to positions that are difficult to access, such as the roots and teeth of gears.

For more information on UCI, see:

For more information on hardness measurements, see:

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