The propagation of exothermic reactions in solid systems. Parti. Pre‐ignition reactions

Compressed mixtures of iron and barium peroxide or iron and potassium dichromate are examples of systems capable of undergoing self-propagating incandescent reaction when ignited. It has been found that in both of these systems a non-incandescent reaction, called the pre-ignition reaction, sets in at a measurable rate below the ignition temperature. This reaction has been shown to be a genuine solid-solid reaction. Its kinetics have been investigated, and the part it plays in the propagation of the incandescent reaction is discussed.