Exothermic Welding Powder

Exothermic welding, also known as exothermic bonding, is a welding process for joining two electrical conductors, that employs superheated copper alloy to permanently join the conductors. The process employs an exothermic reaction of a copper thermite composition to heat the copper, and requires no external source of heat or current. The chemical reaction that produces the heat is an aluminothermic reaction between aluminium powder and a mixture of copper oxides (copper(II) oxide and copper(I) oxide), with chemical formula.

3CuO + 2Al --- 3Cu + Al2O3 + Heat
This chemical reaction reaches a temperature of 1,400 ° C (1,670 K). The reactants are usually supplied in the form of powders, with the reaction triggered using a spark from a flint lighter. The activation energy for this reaction is very high however, and initiation requires either the use of a "booster" material such as powdered magnesium metal or a very hot flame source. The aluminium oxide slag that it produces is discarded.