This work aims to uncover the ignition behavior and explosion characteristics of disilane. An electrically controlled four-way switching valve was used to switch the parallel disilane and nitrogen flows so that disilane can be released without acceleration to the vent stub. By using mass flow controllers, the flow rate of disilane was controlled accurately to determine the critical exit velocity of pure and dilute disilane for different vent diameters. With the aid of boundary layer theory, the ignition of pure disilane always occurs in a mixture fraction of 0.61, which is called the most reactive mixture fraction. With careful control of the disilane feeding process to prevent premature ignition, premixed disilane/air mixture was successfully prepared in 20-L sphere apparatus for determination of lower flammability limit (LFL). The premixed disilane/air mixture was ignited by an electric spark with an energy of 10 J. LFL of disilane in air was determined to be 0.50 ± 0.02 vol.%. Maximum pressure rise and deflagration index of varied disilane concentrations were also characterized. Interestingly, disilane reacts spontaneously with a very lean oxygen-nitrogen mixture of 0.1 vol.%. The results in this work will be useful for risk management of disilane.
Keywords: Disilane, autoignition, jet release, lower flammability limit.