What is scratch hardness?

Scratch hardness is the ability of a material to resist plastic deformation, usually caused by scratches and abrasion.

One type of hardness test is the scratch hardness test, which uses a sharp object to measure the hardness of a material. This test measures a sample's resistance to fracture or sustained plastic deformation due to friction.

The Mohs scale is used to measure scratch hardness.

Hardness is the resistance of a material to localized deformation. Hardness can be applied to deformation from a variety of factors, including:

indentation

• scratching

• to cut

• bending

Hardness depends on:

Extensibility

• Elastic stiffness

• plasticity

• tension

• strength

• toughness

• Viscoelasticity

• viscosity

Some common hardness scales are:

• Mohs

• Knoop

• Vickers

• Rockwell

• Brinell

• Shore

Scratch hardness testing is used to determine the hardness of a material and its ability to resist scratches and abrasions. This test uses an object made of a harder material to scratch an object made of a softer material.

When testing coatings, scratch hardness refers to the force required to cut through the film to the substrate. The Mohs scale (or other scales) is used to measure scratch hardness with the help of a measuring device called a durometer.