MICROHARDNESS

Hardness testing is defined as ‘a test to determine the resistance a material exhibits to permanent deformation by penetration of another harder material’.

The process of evaluating a coating or materials hardness using a hardness tester, typically performed by pressing a specifically dimensioned object (indenter) into the surface of the material you are testing. The hardness is determined by measuring the depth of indenter penetration or by measuring the size of the impression left by the indenter.

Micro-hardness testing provides precise, accurate information for materials that have fine microstructures.

Microhardness is frequently used to assess the properties of coatings or thin layers of materials at lighter loads compared to macro hardness tests such as Brinell, Rockwell and Vickers.

Aerofin utilise microhardness testing to assess a material or coatings suitability for function in service e.g. chrome, nickel and hard anodise where impact and wear resistance (rotational and reciprocal) are important.

Micro-hardness testing can also be used to determine:

  • Surface hardening.
  • Case hardening depth.
  • Hardness of fragile or brittle materials.
  • Microstructure hardness variations.
Contact us today

Vickers Microhardness

Vickers microhardness testing: the process of indenting a pyramid shaped diamond with equal diagonal lengths into a material or coating with a constant load. Similar to macro-Vickers under low load. Vickers microhardness is utilised on coatings and coating cross sections with small area requirements to indent & materials that require low force loads.

  • Test methods include:
  • ASTM E 384 – Standard Test Method for Microindentation Hardness of Materials
  • ASTM E92 – Standard Test Methods for Vickers Hardness and Knoop Hardness of Metallic Materials
  • ISO 6507-1 – Vickers hardness test
  • ISO 4516 – Vickers and Knoop microhardness tests
microhardness-testers - Aerofin Laboratories - Materials testing for the aerospace industry

Knoop Hardness

Knoop testing: the process of indenting a diamond with one elongated diagonal length into a material or coating with a constant load creating an impression, which is then measured to give a defined hardness result.

Due to its long and narrow shape Knoop hardness is employed where area is significantly reduced such as thin coatings & very brittle materials.

  • Test methods include:
  • ASTM B 578 – Standard Test Method for Microindentation Hardness of Electroplated Coatings
  • ASTM E384 – Standard Test Method for Microindentation Hardness of Materials
  • ASTM E92 – Standard Test Methods for Vickers Hardness and Knoop Hardness of Metallic Materials
  • ISO 4516 – Vickers and Knoop microhardness tests
Microhardness