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  2. Hardness - Wikipedia

    en.wikipedia.org/wiki/Hardness

    When testing coatings, scratch hardness refers to the force necessary to cut through the film to the substrate. The most common test is Mohs scale, which is used in mineralogy. One tool to make this measurement is the sclerometer. Another tool used to make these tests is the pocket hardness tester. This tool consists of a scale arm with ...

  3. Hardnesses of the elements (data page) - Wikipedia

    en.wikipedia.org/wiki/Hardnesses_of_the_elements...

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  4. Brinell hardness test - Wikipedia

    en.wikipedia.org/wiki/Brinell_hardness_test

    If Meyer's index is greater than 2.2, then the ratio increases. [1] The Brinell hardness is designated by the most commonly used test standards (ASTM E10-14 [2] and ISO 6506–1:2005) as HBW (H from hardness, B from brinell and W from the material of the indenter, tungsten (wolfram) carbide). In former standards HB or HBS were used to refer to ...

  5. Vickers hardness test - Wikipedia

    en.wikipedia.org/wiki/Vickers_hardness_test

    The unit of hardness given by the test is known as the Vickers Pyramid Number (HV) or Diamond Pyramid Hardness (DPH). The hardness number can be converted into units of pascals, but should not be confused with pressure, which uses the same units. The hardness number is determined by the load over the surface area of the indentation and not the ...

  6. Indentation hardness - Wikipedia

    en.wikipedia.org/wiki/Indentation_hardness

    As such, hardness can only offer a comparative idea of the material's resistance to plastic deformation since different hardness techniques have different scales. The equation based definition of hardness is the pressure applied over the contact area between the indenter and the material being tested. As a result hardness values are typically ...

  7. Glossary of chemistry terms - Wikipedia

    en.wikipedia.org/wiki/Glossary_of_chemistry_terms

    2. In chemical engineering, any method used on an industrial scale (especially in manufacturing) to change the composition of one or more chemicals or materials. chemical reaction The change of one or more substances into one or more different substances. chemical species. Also simply called a chemical.

  8. Hard water - Wikipedia

    en.wikipedia.org/wiki/Hard_water

    The total water hardness is the sum of the molar concentrations of Ca 2+ and Mg 2+, in mol/L or mmol/L units. Although water hardness usually measures only the total concentrations of calcium and magnesium (the two most prevalent divalent metal ions), iron , aluminium , and manganese are also present at elevated levels in some locations.

  9. Intensive and extensive properties - Wikipedia

    en.wikipedia.org/wiki/Intensive_and_extensive...

    The ratio of two extensive properties of the same object or system is an intensive property. For example, the ratio of an object's mass and volume, which are two extensive properties, is density, which is an intensive property. [10] More generally properties can be combined to give new properties, which may be called derived or composite ...