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Preparation of highly reactive core-shell Al/Co@AP composite and their physical models for the thermal decomposition of AP and the intermetallic reactions under the mutual interaction. [Display omitted] • Core-shell structured Al/Co@AP composite has been prepared. • Al/Co improved the heat release of the thermal decomposition of AP by 52.6%. • AP enhanced the heat release of the intermetallic reaction between Al and Co by 67.7%. • The physical models for the AP thermal decomposition reaction and Al/Co intermetallic reaction have been proposed. In this paper, a group of novel intermetallic metastable composites Al/Co@AP has been designed, and three methods including ultrasonic dispersion, mechanical grinding and spray-drying have been attempted for their preparation. The latter one has demonstrated to be the most appropriate means, by which the core–shell structured Al/Co@AP with desired properties could be successfully obtained. The thermal reactivity of Al/Co/AP composites prepared differently has been investigated and compared by TG/DSC technique. It has been shown that the heat release rate of AP in DSC curve was largely increased in the presence of Al/Co when spray-drying technique was used, which may be attributed to the increased nuclear site by the intimate contact. The initial reaction temperature of AP in Al/Co@AP was decreased by 7.8 °C and the heat releases by the thermal decomposition of AP and the intermetallic reaction between Al and Co were enhanced by 52.6 % and 67.7% in comparison with that of pure AP and Al/Co. The types of major gaseous products of Al/Co@AP are almost identical to that of pure AP, which include HCl, H 2 O, N 2 O and NO 2. However, the concentrations of NO 2 and N 2 O in gaseous products for Al/Co@AP are lower than that observed for pure AP, which may be due to the partial consumption of N element by the reaction of Al with acidic substance (HNO 3) decomposed from AP. In addition, the AP in Al/Co@AP composite decomposes in one-step with the apparent activation energy (E a) of 98.8 kJ·cm−3. The decomposition process of the AP in Al/Co@AP composite follows two-dimensional nucleation and growth model(A2), whereas the pure AP follows different physical models, which are close to three-dimensional nucleation and growth, chain scission and phase boundary-controlled reaction (contracting area) models. The intermetallic reaction between Al and Co in Al/Co@AP is merged into one-step following the A2 physical model. [ABSTRACT FROM AUTHOR]

Owing to the novel insensitive high-energy-density material 2,4,6-triamino-5-nitropyrimidine-1,3-dioxide (ICM-102) has lower sensitivity and higher energy(see in Table S1, Supporting Information), it has great advantages in the application of low-vulnerability propellants. In this paper, the evaluation of ICM-102-containing composite propellants has been carried out, where the decomposition and combustion performances of these propellants have been comprehensively investigated. It has been shown that the main exothermic decomposition peak temperature can be increased from 235 ºC to 350 ºC, when 6 to 10 wt% of ICM-102 was used to replace RDX, but heat release rate was largely increased. Moreover, the burning rate of ICM-102 containing propellants at 3 MPa is in the range of 6.97–7.75 mm• s − 1, depending on its content. The pressure exponent (0.5–3 MPa) is between 0.34–0.44. Compared with the typical propellants with RDX, the burn rate and the flame temperature of ICM-102- containing propellants are higher. In addition, the particle size distributions of condensed combustion products of ICM-102 propellants are narrower and smaller than that of RDX-based one. It also shows that extra products such as aluminum carbide (Al20C) and aluminum oxide nitride (Al5O6N) were produced once ICM-102 was used. [ABSTRACT FROM AUTHOR]

• Composite propellants (CPs) containing insensitive high-energy qy-HMX have been prepared. • The qy-HMX-based CPs has 9.64% higher heat of explosion than HMX-based one. • The burn rate of CPs containing qy-HMX is 4.38 mm·s−1 at 3 MPa, 45.9% lower than that of corresponding HMX-based one. • The average particle size of the CCPs of qy-HMX-based CPs is 71.5% lower than that of HMX-based one. Two types of qy-HMX (insensitive HMX with improved energy density, numbered 1 and 2) have been used and studied as an ingredient of HTPB-based composite propellants (CPs), and the decomposition and combustion performances have been investigated. It has been shown that the main exothermic peak temperature of blank CPs containing 21 wt% of qy-HMX-1 is 258.9 °C, which is 4.7 °C higher than that of HMX-containing one, indicating improved thermostability. The corresponding heat of explosion for blank qy-HMX-2-based CPs was measured to be 5830 J∙g−1, which is 300 J∙g−1 higher than that of HMX-based one. Interestingly, the qy-HMX-2-based CPs has higher energy density than corresponding CL-20-based ones, but it has much lower burn rate under the same pressure, e.g. 4.38 mm∙s−1 at 3 MPa for the former vs. 9.03 mm∙s−1 for the latter. Under the effect of typical conventional catalysts such as nano-CuO and nano-Fe 2 O 3 , the qy-HMX-1-based CPs showed increased heat of explosion and higher burn rate. In addition, the particle sizes of condensed combustion products (CCPs) of CPs containing qy-HMX-2 are much smaller than that of HMX-based one, where the Al 4 C 3 was produced as its unique CCPs ingredient. [ABSTRACT FROM AUTHOR]