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Physical properties. Osmium, remelted pellet. Osmium is a hard, brittle, blue-gray metal, and the densest stable element —about twice as dense as lead. The density of osmium is slightly greater than that of iridium; the two are so similar (22.587 versus 22.562 g/cm 3 at 20 °C) that each was at one time considered to be the densest element.
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t. e. Heavy metals are metallic elements with relatively high densities, atomic weights, or atomic numbers. The criteria used, and whether metalloids are included, vary depending on the author and context and has been argued should not be used. [2][3] A heavy metal may be defined on the basis of density, atomic number or chemical behaviour.
In its raw form, tungsten is a hard steel-grey metal that is often brittle and hard to work. Purified, monocrystalline tungsten retains its hardness (which exceeds that of many steels), and becomes malleable enough that it can be worked easily. [18] It is worked by forging, drawing, or extruding but it is more commonly formed by sintering.
Superhard material. A superhard material is a material with a hardness value exceeding 40 gigapascals (GPa) when measured by the Vickers hardness test. [1][2][3][4] They are virtually incompressible solids with high electron density and high bond covalency. As a result of their unique properties, these materials are of great interest in many ...
The hardness of osmium is moderately high at 4 GPa. Because of its hardness, brittleness, low vapor pressure (the lowest of the platinum-group metals), and very high melting point (the fourth highest of all elements, after carbon, tungsten, and rhenium), solid osmium is difficult to machine, form, or work.
The ignition is easier and the arc burns more stably than without the addition of thorium. For powder metallurgy applications, binders have to be used for the sintering process. For the production of the tungsten heavy alloy, binder mixtures of nickel and iron or nickel and copper are widely used. The tungsten content of the alloy is normally ...
Osmium (76 Os) has seven naturally occurring isotopes, five of which are stable: 187 Os, 188 Os, 189 Os, 190 Os, and (most abundant) 192 Os. The other natural isotopes, 184 Os, and 186 Os, have extremely long half-life (1.12×10 13 years and 2×10 15 years, respectively) and for practical purposes can be considered to be stable as well. 187 Os ...