Knoop hardness scale

Description

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 indentor 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.)

Authority

• 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

• Encyclopedia Britannica, http://www.britannica.com Comment: Knoop Hardness." Encyclopædia Britannica. 8 Sept. 2004 .