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Because the density is so similar to that of gold (tungsten is only 0.36% less dense), and its price of the order of one-thousandth, tungsten can also be used in counterfeiting of gold bars, such as by plating a tungsten bar with gold, [99] [100] [101] which has been observed since the 1980s, [102] or taking an existing gold bar, drilling holes ...
Reactivity series. In chemistry, a reactivity series (or reactivity series of elements) is an empirical, calculated, and structurally analytical progression [1] of a series of metals, arranged by their "reactivity" from highest to lowest. [2][3][4] It is used to summarize information about the reactions of metals with acids and water, single ...
Tungsten carbide (chemical formula: WC) is a chemical compound (specifically, a carbide) containing equal parts of tungsten and carbon atoms. In its most basic form, tungsten carbide is a fine gray powder, but it can be pressed and formed into shapes through sintering [7] for use in industrial machinery, cutting tools, chisels, abrasives, armor-piercing shells and jewelry.
Refractory metals. Refractory metals are a class of metals that are extraordinarily resistant to heat and wear. The expression is mostly used in the context of materials science, metallurgy and engineering. The definition of which elements belong to this group differs. The most common definition includes five elements: two of the fifth period ...
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.
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 industrial areas ...
Tungsten is one of the oldest elements used for alloying steel. It forms a very hard carbide and iron tungstite. High tungsten content in the alloy, however, tends to cause brittleness and makes it subject to fracturing rather than bending. [1] The SAE designation for all tungsten steels consist of four numbers beginning with the number 7, in ...
The surface strain of the thin layer places the harder metal under compression, so that when the entire composite is sintered the rupture strength increases markedly. With this method, strengths on the order of 2.8 GPa versus 550 MPa have been observed for, respectively, coated (25% cobalt) and uncoated tungsten carbides. [12]