Liquid nitriding

Liquid Nitriding. As in gas nitriding, the process is carried out below the austenite region, and hardening is associated with the formation of hard nitrides in the ferrite. Liquid cyanide salts are used with others to provide the source of nitrogen. 

Liquid nitriding, case hardening by, 16 210 Liquid nitrogen, 8 42 13 457-458... 

Inorganic amides contain the ion NH2". They are formed by the action of ammonia on metals or by the ammonolysis of nitrides. The heavy metal amides are prepared by meta-thetical reactions in liquid ammonia, e.g. 

The technical problem in die high teiiiperamre application of Si3N4 is that unlike the pure material, which can be prepared in small quantities by CVD for example, die commercial material is made by sintering the nitride with additives, such as MgO. The presence of the additive increases the rate of oxidation, when compared with the pure material, by an order of magnitude, probably due to the formation of liquid magnesia-silica solutions, which provide short-circuits for oxygen diffusion. These solutions are also known to reduce the mechanical strength at these temperatures. 

The measures of solid state reactivity to be described include experiments on solid-gas, solid-liquid, and solid-solid chemical reaction, solid-solid structural transitions, and hot pressing-sintering in the solid state. These conditions are achieved in catalytic activity measurements of rutile and zinc oxide, in studies of the dissolution of silicon nitride and rutile, the reaction of lead oxide and zirconia to form lead zirconate, the monoclinic to tetragonal transformation in zirconia, the theta-to-alpha transformation in alumina, and the hot pressing of aluminum nitride and aluminum oxide. 

Tellurium nitride was first obtained by the reaction of TeBt4 with liquid ammonia more than 100 years ago. The empirical formula TeN was assigned to this yellow, highly insoluble and explosive substance. However, subsequent analytical data indicated the composition is Tc3N4 which, in contrast to 5.6a and 5.6b, would involve tetravalent tellurium. This conclusion is supported by the recent preparation and structural determination of Te6N8(TeCl4)4 from tellurium tetrachloride and tris(trimethylsilyl)amine (Eq. 5.5). The TceNs molecule (5.12), which is a dimer of Tc3N4, forms a rhombic dodecahedron in which the... 

The heavier alkaline earth metals Ca, Sr, Ba (and Ra) react even more readily with non-metals, and again the direct formation of nitrides M3N2 is notable. Other products are similar though the hydrides are more stable (p. 65) and the carbides less stable than for Be and Mg. There is also a tendency, previously noted for the alkali metals (p. 84), to form peroxides MO2 of increasing stability in addition to the normal oxides MO. Calcium, Sr and Ba dissolve in liquid NH3 to give deep blue-black solutions from which lustrous, coppery, ammoniates M(NH3)g can be recovered on evaporation these ammoniates gradually decompose to the corresponding amides, especially in the presence of catalysts ... 

Metal nitrides have also been prepared by adding KNH2 to liquid-ammonia solutions of the appropriate metal salts in order to precipitate the nitride, e.g. CU3N, Hg3N2, AIN, TI3N and BiN. 

Bad-kasten, m. (electrolytic) cell, -nitrieren, n. Metal.) fused-salt nitriding, -patentieren, n. Wire) patenting with cooling in a lead or salt bath, -spannung, /. bath tension, cell voltage, -Spiegel, m, bath level, bath surface, -zementieren, n. Metal.) bath cementation, liquid carburizing,... 

RT-ILs are also selected as lubricant additives. Usage of ionic liquids as boundary lubricant additives for water has resulted in dramatically reduced running-in periods for silicon nitride materials [70]. When ILs were mixed into a neat mineral oil, the mixture has proven to produce lower wear on aluminum flat than either the oil or the ionic liquid alone [72], which indicates that a small amount of ILs in the mineral oil may function as an anti-wear additive. 

Molybdenum disulhde (M0S2), graphite, hexagonal boron nitride, and boric acid are examples of lamella materials commonly applied as solid lubricants. The self-lubricating nature of the materials results from the lamella crystalline structure that can shear easily to provide low friction. Some of these materials used to be added to oils and greases in powder forms to enhance their lubricity. Attention has been shifted in recent years to the production and use of nanosize particles of M0S2, WS2, and graphite to be dispersed in liquid lubricants, which yields substantial decreases in friction and wear. 

Soft, silver white metal that melts in the hand (29.8 °C) and remains liquid up to 2204 °C (difference 2174 °C, suitable for special thermometers). Gallium is quite widespread, but always in small amounts in admixtures. Its "career" took off with the advent of semiconductors. Ga arsenide and Ga phosphide, which are preferential to silicon in some applications, have extensive uses in microchips, diodes, lasers, and microwaves. The element is found in every mobile phone and computer. Ga nitride (GaN) is used in UV LEDs (ultraviolet light-emitting diodes). In this manner, a curiosity was transformed into a high-tech speciality. 

Interaction with liquid ammonia at — 15°C forms tellurium nitride ( ), which explodes at 200°C. 

A mixture of magnesium powder and liquid nitrogen reacts very violently when lit with a fuse, forming magnesium nitride. 

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