Microhardness Tester Technical Information
(Vickers & Knoop) The Fundamentals of Microhardness Scale Testing The Microhardness test method according to ASTM E-384 specifies a range of loads using a diamond indenter to make an indentation which is measured and converted to a hardness value. It is very useful for testing on a wide type of materials as long as test samples are carefully prepared. There are two types of indenters, a square base pyramid shaped diamond for testing in a Vickers tester and a narrow rhombus shaped indenter for a Knoop tester. Typically loads are very light, ranging from a few grams to one or several kilograms, although "Macro" Vickers loads can range up to 30 kg or more. The Micro-hardness methods are used to test on metals, ceramics, composites - almost any type of material. Since the test indentation is very small, the Microhardness testing is useful for a variety of applications:
testing very thin materials like foils or measuring the surface of a part, small parts or small areas,
measuring individual microstructures, or measuring the depth of case hardening by sectioning a part
and making a series of indentations to describe a profile of the change in hardness. The Vickers
method is more commonly used. The Knoop method is commonly used when indentations are
closely spaced or testing is close to the edge of a specimen due to the narrow shape of the
indentation. The width of the Knoop indentation can provide more resolution for measurement and the
indentation is also less deep so it is useful for thinner materials.
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