Aluminum carbide is an inorganic binary compound of carbon with aluminum. Its chemical formula is written as Al4C3, it looks like a pale yellow or brown crystal with a complex structural lattice. It is capable of withstanding temperatures up to 1400 ° C at a density of 2.36 g / cm³. Its lattice contains carbon atoms as discrete carbon anions. This compound is obtained by direct reaction of carbon with aluminum in an arc furnace, and a small amount of it is also present in impurities of calcium carbide of industrial origin.
Aluminum carbide : characteristics and application
Electrolytic production of aluminum involves the allocation of this compound as a corrosive product in graphite electrodes. When aluminum carbide reacts with water or dilute acid, methane is formed. In addition, the compound reacts with oxygen and hydrogen, and in the case of interaction with water and sodium hydroxide concentrate, a complex salt is formed, called methane and sodium tetrahydroxoaluminate. Naturally, the compound has specific physical properties, this refers to refractive indices related to the sodium D-line and reaching 20 ° C. At the same time, standard Gibbs energy and standard formation entropy are taken into account; these values reach 196 and 88.95 J / mol / K. Obtaining this compound is possible as an undesirable product in complex chemical reactions.
In particular, in metal matrix compounds based on an aluminum matrix and reinforced with metal carbides such as boron carbide and silicon carbide, aluminum carbide can be generated as an undesirable element. A similar situation is possible in the case of carbon fiber, which, when reacted with an aluminum matrix at temperatures exceeding 500 ° C, also releases the compound in question. During the chemical reaction between cast aluminum and silicon carbide, a layer of aluminum carbide may appear, it will cover silicon carbide particles and reduce the strength of the material.
However, this effect can be reduced by coating the silicon particles with a suitable oxide or by pre-oxidizing them to form a quartz coating. To determine how much tritium is contained in water, the compound is hydrolyzed, resulting in aluminum carbide methane. In this case, the compound is used as a chemical reagent; when reacted with suspended water, a tritium and methane compound is obtained. Aluminum carbide dispersed over the aluminum matrix helps to maintain the density of the material, especially if it is combined with silicon carbide particles.
Composite materials of aluminum carbide can be obtained thanks to mechanical alloys based on aluminum powder and graphite particles. Along with this, the compound is used as an abrasive for cutting high-speed tools, giving them the hardness of topaz. Another area of application of the compound is pyrotechnics, here it allows you to get the effect of a firefly, which is expressed in the excessive appearance of sparks. Note that at different times in pyrotechnics it has always been used with different intensities. In general, this compound is widely used in the chemical industry and manufacturing. This is due to the chemical characteristics of aluminum carbide, providing its unique properties that are not characteristic of other types of compounds of the carbide group.