Specific features of the oxidation and self-ignition of electroexplosive ultradisperse metal powders in air

The kinetic features of oxidation of ultradisperse powders of aluminum, copper, iron, molybdenum, zinc, and tin, which were obtained by the method of electric explosion of conductors, are studied by the nonisothermal thermogravimetric method. It is shown that the process of oxidation has a multistage character; however, at the initial stage, the products do not form a continuous film and the oxidation of all the metals occurs by a linear law. The temperatures of onset of oxidation with a noticeable rate are determined by the temperatures of desorption of the gas components of ultradisperse powders. The self-ignition temperatures of the powders are determined by the method of differential thermographic analysis. In addition, it is shown that these temperatures depend on the thermophysical properties of a metal and the kinetics of the initial stage of oxidation.