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The European Council (informally EUCO) is a collegiate body ( directorial system) that defines the overall political direction and priorities of the European Union. The European Council is part of the executive of the European Union (EU), beside the European Commission. It is composed of the heads of state or of government of the EU member ...
Material properties of diamond. Burns above 700 °C in air. Diamond is the allotrope of carbon in which the carbon atoms are arranged in the specific type of cubic lattice called diamond cubic. It is a crystal that is transparent to opaque and which is generally isotropic (no or very weak birefringence ).
Rockwell scale. The Rockwell scale is a hardness scale based on indentation hardness of a material. The Rockwell test measures the depth of penetration of an indenter under a large load (major load) compared to the penetration made by a preload (minor load). [1] There are different scales, denoted by a single letter, that use different loads or ...
Diamond is the hardest known material to date, with a Vickers hardness in the range of 70–150 GPa. Diamond demonstrates both high thermal conductivity and electrically insulating properties, and much attention has been put into finding practical applications of this material. However, diamond has several limitations for mass industrial ...
Graphite, named by Abraham Gottlob Werner in 1789, from the Greek γράφειν ( graphein, "to draw/write", for its use in pencils) is one of the most common allotropes of carbon. Unlike diamond, graphite is an electrical conductor. Thus, it can be used in, for instance, electrical arc lamp electrodes.
Diamond-like carbon ( DLC) is a class of amorphous carbon material that displays some of the typical properties of diamond. DLC is usually applied as coatings to other materials that could benefit from such properties. [1] DLC exists in seven different forms. [2] All seven contain significant amounts of sp 3 hybridized carbon atoms.
Knoop hardness test. The Knoop hardness test / kəˈnuːp / is a microhardness test – a test for mechanical hardness used particularly for very brittle materials or thin sheets, where only a small indentation may be made for testing purposes. A pyramidal diamond point is pressed into the polished surface of the test material with a known ...
Indentation hardness tests are used in mechanical engineering to determine the hardness of a material to deformation. Several such tests exist, wherein the examined material is indented until an impression is formed; these tests can be performed on a macroscopic or microscopic scale. When testing metals, indentation hardness correlates roughly ...