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This process can be used to grow thick (tens or hundreds of micrometers), largely crystalline, oxide coatings on metals such as aluminium, magnesium [2] and titanium. Because they can present high hardness [ 3 ] and a continuous barrier, these coatings can offer protection against wear , corrosion or heat as well as electrical insulation .
A 19th-century assay laboratory in Tombstone Courthouse State Historic Park, Arizona. A model of a late 19th-century Canadian seal used to certify the quality of assayed gold. A metallurgical assay is a compositional analysis of an ore, metal, or alloy, usually performed in order to test for purity or quality.
Mill scale is a complex oxide that contains around 70% iron with traces of nonferrous metals and alkaline compounds. Reduced iron powder may be obtained by conversion of mill scale into a single highest oxide i.e. hematite (Fe 2 O 3) followed by reduction with hydrogen.
Black oxide or blackening is a conversion coating for ferrous materials, stainless steel, copper and copper based alloys, zinc, powdered metals, and silver solder. [1] It is used to add mild corrosion resistance, for appearance, and to minimize light reflection. [ 2 ]
The most common example of roasting is the oxidation of metal sulfide ores. The metal sulfide is heated in the presence of air to a temperature that allows the oxygen in the air to react with the sulfide to form sulfur dioxide gas and solid metal oxide. The solid product from roasting is often called "calcine".
Other metal oxides can be used, such as chromium oxide, to generate the given metal in its elemental form. For example, a copper thermite reaction using copper oxide and elemental aluminum can be used for creating electric joints in a process called cadwelding, that produces elemental copper (it may react violently): 3 CuO + 2 Al → 3 Cu + Al ...
A process for electrochemical production of titanium through the reduction of titanium oxide in a calcium chloride solution was first described in a 1904 German patent, [1] [2] [3] and in 1954 U.S. patent 2845386A was awarded to Carl Marcus Olson for the production of metals like titanium by reduction of the metal oxide by a molten salt reducing agent in a specific gravity apparatus.
Metallurgy derives from the Ancient Greek μεταλλουργός, metallourgós, "worker in metal", from μέταλλον, métallon, "mine, metal" + ἔργον, érgon, "work" The word was originally an alchemist's term for the extraction of metals from minerals, the ending -urgy signifying a process, especially manufacturing: it was discussed in this sense in the 1797 Encyclopædia ...