Nano Hardness - What it is and How to Measure it

Nanoindentation is vital for revealing the quantitative mechanical properties of small volumes of materials. Currently, this method is a standardized method for determining plastic, elastic, and visco-elastic properties of materials such as ceramics, biological materials hard thin films, soft films, multi-phase metals, semiconductors, and plastics on a micron to nanometer scale.

Nanoindentation Test

Precision load-displacement curves are offered by a nanoindentation test for performing tests on both soft and hard surfaces as well as rough surfaces, such as those deposited by industrial processes. These processes include the formation of thermal spray coatings through quantitive measurement of the mechanical properties of small volumes of materials. Apart from other applications, multi-phase metals and ceramics, thin films and biological materials are the main applications for such instruments; however, they can also be used for flexure testing of MEMS, visco-elastic measurements of polymers, and any application that involves mechanical measurement on the sub-micron scale. The material properties that can be measured are yield strength, elastic modulus and hardness, and depending on the sample, fracture toughness, storage and loss moduli, scratch and wear properties.

IND-1000

The design of the IND-1000 instrument enables it to apply a controlled load and deformation of the material under test. Force and displacement sensors are used for measuring the material’s mechanical response. The resolution and range of the force, actuator, and displacement sensors are considerably small (in the μm and mN range with nm and nN resolution). The precise nature of the measurement enables recording of events on the micro- to nanoscale. As a result, macro-scale damage can be interpreted and elucidated by events on the sub-micron scale, thereby enabling the study of the basic properties of the sample and allowing the properties to be customized for particular applications.

IND-1000 instrument

IND-1000 employs robust LVDT sensors for both depth and force measurements. AC amplification offers a millivolt noise floor in this advanced package. Advantage of the full range of the analog-to-digital interface is taken by offsetting the signal with the help of a special circuitry.

In the late 1980s, CSIRO pioneered the use of the LVDT measurement sensors for nanoindentation applications. From that time, the technique has been proven to offer low-noise sub-nanometer resolution and a highly robust package. In contrast to competitor instruments in which a capacitance sensor is used, the IND-1000 system is nearly resistant to mechanical breakage due to the overloading of the indenter shaft since the indenter shaft passes right through the sensor and can withstand several millimeters of accidental deflection without any problem.

The force sensor is totally isolated from the load actuator and has the ability to directly measure the force applied to the indenter without any attenuation of the signal from the support springs. The depth and force sensors are independently calibrated against international standards. It is possible to select the closed loop feedback either from the depth sensor or from the force sensor. Open-loop operation mode can also be selected for high-speed data acquisition.

Benefits

  • Sub-nanometer depth resolution and highly linear response LVDT
  • Material properties such as yield strength, elastic modulus, fracture toughness, storage and loss moduli, hardness, scratch and wear properties can be measured (based on the sample)
  • The technology is based on the successful nanoindentation system of Fischer-Cripps Laboratories
  • High-quality PZT expansion element, without heat generation
  • Closed-loop force/depth feedback
  • Precise sample positioning can be guaranteed by video microscope and automated X-Y-Z-movement
  • No need for periodic calibration
  • Easy indenter tip changeover
  • Real-time feedback control over application of depth- or load-independent force and displacement measurement
  • Reliable performance for several years
  • Low-compliance load frame, enclosure, and mountings
  • Nearly resistant to mechanical breakage in contrast to competitor instruments
  • Traceable calibration
  • Robust design with the ability to endure considerable abuse

Optional Features

  • Atomic force microscope
  • Lateral force (scratch testing module)
  • Integrated finite-element analysis module

This information has been sourced, reviewed and adapted from materials provided by Semilab Semiconductor Physics Laboratory.

For more information on this source, please visit Semilab Semiconductor Physics Laboratory.

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