Due to the different shapes of the diamond indenters used,

Microhardness is divided into two types: Vickers microhardness and Knoop microhardness.

Vickers microhardness is calculated using a diamond pyramid with an object of 130 ° as the indentation head, and its value is calculated according to the following formula:

HV＝18.18·P/d2

In the formula: HV Vickers hardness, Mpa； P - Load, kg；

D - diagonal length of the pit, mm。

The Knoop hardness is calculated using a diamond pyramid with angles of 170 ° 30 'and 130 ° as the indentation head, and its value is given by the following formula:

HK=139.54·P/L2

In the formula: HK - Knoop hardness, Mpa； P - Load, kg；

L - diagonal length of concave pit, mm。