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Test Method

Knoop and Vickers Hardness of Materials (Microindentation Hardness) - ASTM E384 - Test Method

The purpose of this standard is to specify how to measure the Knoop and Vickers hardness of materials.


Knoop or Vickers hardness numbers are determined based on the formation of a relatively small indentation made on the test surface of the sample being evaluated. A Knoop or Vickers indenter, made from a diamond of a specific geometry, is pressed into the test specimen surface by an accurately controlled applied force using test machines specifically designed for such work. The size of the indentation is measured using a light microscope equipped with a measuring device. Materials or cross-sections of materials are typically metallographically prepared (mounted and polished) prior to testing.

Applications and Benefits

Lucideon provides quantitative microindentation hardness results of materials in compliance with ISO 17025, 10 CFR 50 Appendix B and 10 CFR Part 21 quality management system requirements.

Typical applications include verifying surface hardness treatments, measuring coating hardness, measuring the hardness of thin films and foils, and characterizing the hardness profiles of welded materials.

Form of Results

A Knoop hardness number (HK) is based upon the force divided by the projected area of the indentation.  Test loads are typically in grams-force (gf) and indentation diagonals are in micrometers (μm).

Vickers hardness (HV) test loads are typically in grams-force (gf) and indentation diagonals are in micrometers (μm).

Related Tests

  • Rockwell Hardness of Metallic Materials – ASTM E18
  • Brinell Hardness of Metallic Materials – ASTM E10, E110
  • Durometer Hardness – ASTM D2240.