Knoop hardness scale

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A hardness scale based on measuring indentations that was developed in 1939 by F. Knoop, a 20th century chemist. The Knoop hardness scale ranges from Glass (300-600) to Diamond (6000-6500). A Knoop hardness tester drops a pointed diamond indenter onto a material then examines the size and depth of the indentation to determine surface hardness. This test is generally used on brittle materials like ceramics.

Synonyms and Related Terms

Knoop-Härte (Deut.)

Resources and Citations

  • G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971
  • Theodore J. Reinhart, 'Glossary of Terms', Engineered Plastics, ASM International, 1988
  • Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993