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List of Chemical Substances
Published in T.S.S. Dikshith, and Safety, 2016
Barium nitrate on contact with combustible materials will ignite. Barium nitrate mixed with aluminum powder, a formula for flash powder is highly explosive. However, barium nitrate is non-corrosive in the presence of glass. It is used in military thermite grenades, in the manufacturing process of barium oxide, the vacuum tube industry, and for green fire in pyrotechnics.
Force-System Resultants and Equilibrium
Published in Richard C. Dorf, The Engineering Handbook, 2018
For joining metals and alloys, welding, brazing, and soldering are the most common methods. Fusion welding consists of melting a part of the metal at the joint interface and allowing the joint to form by flow of the liquid metal, usually with another filler metal. When the same process is assisted by compressive forces applied by clamping the two pieces, the process is called pressure welding. Brazing and soldering use a lower-melting filler metal alloy to join the components. The parent pieces do not undergo melting and the liquid filler acts as the glue that makes the joint. The heat required to cause melting in the welding process classifies the process. Thus, in arc welding, heat is provided by creating an electric arc between electrodes often in the presence of a shielding atmosphere. Gas welding is performed using a gas mixture fuel to create a high-temperature flame that is targeted at the joining interface. The most popular gas-welding device is the oxyacetylene welding torch commonly seen in metalworking shops. Thermite welding is a well-known process for joining large sections in remote locations where gas or electric welding are difficult to perform. The thermite process relies on the exothermic heat generated by the reaction of iron oxide with aluminum. The molten product of the exothermic reaction is brought in contact with the joining interface and causes local melting of the parent pieces, followed by cooling, to form the weld. Electron and laser beam welding are some of the modern methods for joining metals and ceramics. Other methods include electroslag welding, friction welding, and explosive welding, which are made possible by a transient wave generated by detonating an explosive charge.
FeCrNiMnAl high-entropy alloy coating by spray deposition and thermite reaction
Published in Surface Engineering, 2019
Gang Chen, Lihua Zhu, Shucheng Shen, Chengshang Zhou
Spray deposition technology is an effective measure for preparation of rapid solidification alloy ingots [19], and particularly suitable for the preparation of high alloyed alloy ingots with fine microstructures and supersaturated solid solutions [20,21]. On the other hand, thermite reaction is a method to obtain high temperature melts through strong exothermic reaction between aluminium and metal oxides. Its advantages include a simple device and process [22], good adaptability, and high efficiency [23]. This method has been successfully used in smelting of high-melting-point metals and welding of rails [24].