Combustion Behavior of the Inorganic Nitrates‐Based Compositions. Part II: Effect of Al and Al‐Mg Alloy on Burning Rate

Abstract The influence of metallic fuel (aluminum and aluminum‐magnesium alloy) on the burning rate of compositions based on inorganic nitrates (KNO 3 , NaNO 3 , CsNO 3 , Ba(NO 3 ) 2 , Sr(NO 3 ) 2 ) was studied in a wide range of pressure (0.1–18 MPa). Samples have the same binder and differ in basic burning rate and flame temperature. Calculated flame temperature greatly depends on the Al and Al−Mg amount. The effect of metallic fuel on the burning rate of basic samples is complex. It depends not only on the properties of metals but also on the influence of cation nitrate on the burning rate of the basic sample and pressure combustion. Al and Al−Mg alloy have a different effect on the burning rate of the base samples. The efficiency of the metal on the combustion of base compositions is higher for low burning rate samples and samples with an increased oxidizer excess ratio. The lowest positive metal efficiency on the burning rate is observed for the fast‐burning KNO 3 and CsNO 3 ‐based compositions. At low pressure, Al−Mg alloy has a more significant effect than Al on the burning rate of the base samples. A slight increase in the burning rate for fast‐burning basic compositions is observed with the addition of a small amount of Al at atmospheric pressure. With a further rise of Al amount in the composition, the burning rate of the metalized sample becomes lower than the basic sample. With pressure growth, the metal effect on the burning rate increases due to a proportional change in the density of the resulting combustion products. As a result, metal combustion was more complete in the zone affecting the increase of burning rate.