The Knoop hardness test is used for microhardness testing (loads less than or equal to 1 kgf). Hence before putting the sample material into the microhardness tester, its surface should be highly polished or electropolished.

In the microhardness testing range, the Knoop hardness test is an alternative to the Vickers hardness test and can be carried out on the same universal or micro hardness testing apparatus. It is primarily employed to prevent breaking in brittle materials and to make it easier to measure the hardness of thin layers.

The indenter used in the Knoop hardness test is a pyramidal diamond, just like in the Vickers hardness test. However, the pyramid is extended rather than symmetrical. The length diagonal of the indent is measured optically to determine the Knoop Hardness (HK).

These are the standard dimensions of NextGen’s Knoop Hardness Test Blocks:

Micro Knoop – 1kg. or under
Range: from 80 KHN 700
Diameter: 1.25″

Heavy Load Knoop – from 1kg. – 50kg.
Range: from 80 KHN – 700
1.25″ Square

Looking for a quote? Click here to obtain a personalized quote!