What is apparent hardness? How to measure apparent hardness, which is an important value in sintered materials?

Sintered metal materials generally have a porous structure. Therefore, their hardness should be evaluated as a combination of solid metal and pores.

Main structure and pores in scanning electron microscope

Short description
Apparent hardness is a macrohardness measurement that represents a combination of both solid particles and pores in sintered metallic materials.

The apparent hardness value is often used as a whole expression of the mechanical strength of the material.

Because the hardness value is a composition of pores and solid material, it is generally lower than that of solid material of the same composition and condition. However, this does not mean that the functional properties (for example, wear resistance) are low.

Relevant standards state that the range of 10N to 2000N can be used as macro measurement load in sintered metal materials.

Depending on the hardness of the solid phase,

• HV 5, HV 10 and HV 20

• HBW 2.5/15.625/30

• HRH

• HRF

• HRB

• HRA

• HRC

Surface topography of sintered metal material in JEOL scanning electron microscope