What Does Scratch Hardness Mean?
Scratch hardness is the ability of a material to resist plastic
deformation, usually by scratches and abrasion.
One type of hardness test is the scratch hardness test, which measures the
hardness of a material with the aid of a sharp object. This test measures
how resistant a sample is to fracture or permanent plastic deformation due to
friction.
The Mohs scale is used to measure scratch
hardness.
Corrosionpedia Explains Scratch Hardness
Hardness is the resistance of a material to localized deformation. Hardness can apply to deformation from many factors, including:
- Indentation
- Scratching
- Cutting
- Bending
Hardness is dependent on:
- Ductility
- Elastic stiffness
- Plasticity
- Strain
- Strength
- Toughness
- Viscoelasticity
- Viscosity
Some of the most common hardness scales are:
- Mohs
- Knoop
- Vickers
- Rockwell
- Brinell
- Shore
Scratch hardness tests are used to determine the hardness of a material and its ability to resist scratches and abrasion. The 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 necessary to cut through the film to the substrate. The Mohs scale (or some other scale) is used to measure the scratch hardness with the help of a measurement device called a sclerometer.