Методы измерения микротвердости для металлических материалов, методы физико-химического анализа, методы измерения плотности

Knoop (HK) hardness was developed by at the National Bureau of Standards (now NIST) in 1939. Knoop tests are mainly done at test forces from 10g to 1000g, so a high powered microscope is necessary to measure the indent size. Because of this, Knoop tests have mainly been known as microhardness tests. The newer standards more accurately use the term microindentation tests. The magnifications required to measure Knoop indents dictate a highly polished test surface. To achieve this surface, the samples are normally mounted and metallurgically polished, therefore Knoop is almost always a destructive test.