Hardness Hardness Hardness is a measure of the resistance to localized plastic deformation induced by either mechanical indentation or abrasion. Some materials (e.g. metals) are harder than others (e.g. plastics, wood). Macroscopic hardness is generally characterized by strong intermolecular bonds, but the behavior of solid materials under force is complex; therefore, there are different measurements of hardness: "scratch hardness", "indentation hardness", and "rebound hardness". Hardness is dependent on ductility, elastic stiffness, plasticity, strain, strength, toughness, viscoelasticity, and viscosity. Common examples of hard matter are ceramics, concrete, certain metals, and superhard materials, which can be contrasted with soft matter. There are three
Indentation hardness used to quantify material characteristics at smaller scales. Measuring mechanical properties for materials, for instance, of thin films, can not be done using conventional uniaxial tensile testing. As a result, techniques testing material "hardness" by indenting a material with a very small impression have been developed to determine to estimate these properties. Hardness measurements quantify the resistance of a material to plastic deformation. Indentation hardness tests compose the majority of processes used to determine material hardness, and can be divided into two classes: "microindentation" and "macroindentation" tests. Microindentation tests typically have forces less than . Hardness, however, cannot be considered