SPONTANEOUS DECOMPOSITION (DEFLAGRATION)
[VDI 2263, Part 1]
Spontaneous decompositions are decomposition reactions that - after local initiation - propagate through entire bulk volumes without the addition of reaction partners (e.g., oxygen).
The velocity of the reaction front is significantly lower than the velocity of sound in the substance concerned.
Spontaneous decompositions often release large amounts of gas, which are combustible in most cases.
Spontaneous decompositions may occur even under inert conditions, i.e., they can not be prevented by inert gas blanketing.
The following substances should be tested for spontaneous decomposition:
those having a decomposition energy > 500-700 kJ/kg and a high activation energy (often autocatalytic)
those showing a reaction with or without flame in the combustibility test under vacuum