What type of indenter is used in the Vickers hardness test?

In the Vickers hardness test, a diamond indenter is utilized due to its exceptional hardness and durability. The diamond indenter takes the form of a square pyramid with an angle of 136 degrees between the opposite faces. This design allows for a precise and consistent indentation of the material being tested, as well as the ability to measure the size of the indentation accurately.

The hardness value is determined by calculating the diagonal length of the indentation left in the material after the indenter has been pressed into it under a specified load. Because diamond is the hardest known material, it can penetrate a wide range of materials without deforming, ensuring reliable results across different tests.

In contrast to the diamond indenter, other materials such as steel balls, cones, or aluminum would not provide the necessary hardness or precision required for accurate Vickers hardness measurements, making them unsuitable for this specific test.