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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.
is an alkaline solution of potassium permanganate; used in organic chemistry as a qualitative test for the presence of unsaturation, such as double bonds; N-Bromosuccinimide: used in radical substitution and electrophilic addition reactions in organic chemistry. Also acts as a mild oxidizer to oxidize benzylic or allylic alcohols.
The free radicals generated by this process engage in secondary reactions. For example, the hydroxyl is a powerful, non-selective oxidant. [6] Oxidation of an organic compound by Fenton's reagent is rapid and exothermic and results in the oxidation of contaminants to primarily carbon dioxide and water.
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 .
An assay (analysis) is never an isolated process, as it must be accompanied with pre- and post-analytic procedures. Both the communication order (the request to perform an assay plus related information) and the handling of the specimen itself (the collecting, documenting, transporting, and processing done before beginning the assay) are pre-analytic steps.
The initial discovery came in 1997 when Cambridge University researchers immersed small samples of certain oxides in baths of molten salt and reduced the oxide with electric current. The cathode uses powdered metal oxide. The anode is made of carbon. The molten salt at 1,000 °C (1,830 °F) is the electrolyte.
High temperature oxidation is generally occurs via the following chemical reaction between oxygen (O 2) and a metal M: [2]. nM + 1/2kO 2 = M n O k. According to Wagner's theory of oxidation, oxidation rate is controlled by partial ionic and electronic conductivities of oxides and their dependence on the chemical potential of the metal or oxygen in the oxide.
[clarification needed] The oxidizer is often oxygen diffusing through the metal bulk from the interface, but it can be also another element (for example sulfur or nitrogen). Internal oxidation is a well-known corrosion mechanism of nickel-based alloys in the temperature range of 500 to 1200 °C. [2] Internal oxidation is distinct from selective ...