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In order to clarify the relationship between elemental compilation, phase compilation and intrinsic characteristics of Al-based alloy fuels, the influence laws on physicochemical characteristics and combustion properties when Iowa bowling point metals, tow meriting point mete! and high meriting point mete! are used as al toying cements were summarized respectively, when the differences in ignition and Combusiion mechanisms of different aluminum-based alloy leis wet analyzed. Aluminum-tow boiling point metal afro(Al-MB), labium meriting point metal alloy(Al-MM) and aluminum-high meting point metal alloy(Al-MM) have particulate ignition and Combusiion mechanism, and thus possess the menace of physicochemical properties and Combusiion characteristics. Dicing the Combusiion process of labium-based alloy fuels, thee ate various principles font improving Combusiion efficiency such as interposition of Al-MB, exothermic alloying/oxidation channels in Al-MM, and expo-thermic erasable phase in AI-Mm . Research poetess of the research on he application of Al-based alloy leis in sod to-paeans was summarized in terms of energy enhancement and burning ate regulation. it is pointed out that the energy perform-lance of sod propellants can be improved through the increase of theoretical specific impulse, Combusiion efficiency, density and the decease of two-phase low kiosks. The effect of the Al-based alloy leis on the burning ate of sod propellants can be adjusted by the component of oxidize and bidet. The key point is to determine the relationship font preparation-structures-characteristics, solve he contradiction between he safety and activity, and improve the mechanism of Combusiion carnalities and energy td ease in reaction, which ate coca font the deign, application and performance control font Al-based alloy as leis font propellants. 75 References were attached. [ABSTRACT FROM AUTHOR]

in order to investigate the influence of N-butyl-N-nitratoethylnitramine (Bu-NENA) on the energy and combustion properties of NC based propellants, energy properties was theoretically calculated by Russian Real software. The propellant samples were prepared by the method of absorption-extrusion technique. The density, detonation heat, specific volume, ignition delay time, burning rate were tested and the pressure exponent were calculated. The mechanism of the influence of Bu-NENA on the combustion performance of the propellant was analyzed by combustion waves, flame photographs and morphology of flameout surface. The results showed that the replacement of NG by Bu-NENA in NC based propellant reduces energy but increases gas production. The burning rate of propellants can be significantly reduced, with the decrease of more than 75% for 2 MPa and the decrease of more than 64% for 20MPa. The pressure exponent was increased. Some catalysts used for NC/NG based propellants may fail in NC/Bu-NENA based system. The propellant ignition delay time is increased. The burning rate of the propellant is greatly reduced because of the volatilization of Bu-NENA dufing combustion and the decrease of thermal feedback caused by the decrease of combustion temperature. [ABSTRACT FROM AUTHOR]

The influence of nano-copper (n-Cu), nano-nickel (n-Ni) and carbon nanotubes on the combustion performance of RDX-CMDB propellants was investigated. The mechanism of n-Ni on the combustion performance was also discussed by analysis of flame morphology and thermal decomposition performance. The results reveal that n-Ni with mass ratio of 0. 6% would reduce the pressure exponent of RDX-CMDB propellant from 0.29 to 0.11 in the pressure range of 6 -- 16MPa. By contrast, the effect was not obvious for the 0.2% n-Cu, which even causes the decrease of burning rate at 2 MPa and 8-16 MPa. For the 0. 8% CNTs with conventional Pb-Cu-C as catalyst, the burning rate of RDX-CMDB propellant increases from 17.12 to 22.12mm/s at 10MPa. Furthermore, The thermal decomposition and flame morphology imply that n-Ni improves the decomposition heat, enhances the burning surface temperature and thermal feedback, which is contributed to the thermal decomposition rate. [ABSTRACT FROM AUTHOR]

In this work, the preparation and combustion catalysis effects of Cu2O−PbO/GO and CuO−Bi2O3/GO nanocomposites were systematically investigated. It was shown that the burning rate of the DB propellants can be significantly enhanced by both the nanocomposite catalysts, with reduced pressure exponent. In particular, the Cu2O−PbO/GO induced a burn rate enhancement for DB propellant in pressure range of 2–14 MPa, with the maximum catalytic efficiency of 3.87 at 2 MPa. More interestingly, it resulted in "mesa" burning of DB propellant in the pressure range of 12–20 MPa (n=‐0.05). The CuO−Bi2O3/GO have the same effect with a burning rate increasing from 2.15 to 8.57 mm s−1 at 2 MPa. Similarly, for the RDX‐CMDB propellant, the GO‐based composites of Cu2O−PbO/GO and CuO−Bi2O3/GO showed evident catalytic activities. Plateau combustion was achieved in their presence, which is of great importance for practical applications. The catalysis effects of the two composites are closely related to the high dispersion of metal oxide particles and GO with excellent thermal conductivity. [ABSTRACT FROM AUTHOR]

The RDX, HMX, and AP are currently the most widely used energetic ingredients in composite solid propellants, since the newly developed energetic compounds are still unable to replace them due to various bottleneck technical problems. In order to improve their combustion efficiency and performance, a common alternative way is to utilize novel nano-sized energetic additives. There are a great many nanomaterials that have been developed in the past decades, which include nanometal particles, metal oxides, metal salts, metallic composites, organometallic compounds, energetic nanocatalysts, and carbon nanomaterials. These additives could increase both the decomposition and the burning rate as well as enhance the combustion efficiency of the corresponding solid propellants by changing the thermal conductivity, energy barrier of thermolysis, heat of reaction, and gas-phase reaction mechanisms of the main ingredients such as RDX, HMX, and AP. This review paper discusses and summarizes the effects of abovementioned nano additives on decomposition kinetics, reaction models, decomposition mechanisms and burning rates, pressure exponents, combustion wave structures, and flame propagation of RDX-, HMX-, and AP-based energetic compositions. The catalytic mechanisms associated with different types of nanomaterials are explained and clarified. Owing to their extremely large specific surface areas, nano-sized energetic additives have significant catalytic effects in both condensed and gas phases during decomposition and subsequent combustion via activation of the reactants and acceleration of their transition state formations. The flame structures of AP-based composite propellants under the effect of some nanoadditives are presented showing the enhanced burning characteristics and stabilized combustion process. [ABSTRACT FROM AUTHOR]

The high-pressure thermal properties and their correlation with burning rates of the composite modified double base (CMDB) propellants containing 3,6-bis (1H-1,2,3,4-tetrazol-5-yl-amino)-1,2,4,5-tetrazine (BTATz), a substitute of hexogen (RDX), were investigated using the high-pressure differential scanning calorimetry (PDSC). The results show that there is a main exothermal decomposition process with the heating of each propellant. High pressure can restrain the volatilization of NG, accelerate the main decomposition reaction, and make the reaction occur easily. High pressure can change the main decomposition reaction mechanism function and kinetics, and the control process obeys the rule of Avrami-Erofeev equation at high pressure and chemical reaction at normal pressure. However, the mechanism function can not be changed by the ballistic modifier. The correlation between PDSC characteristic values and burning rates was carried out and found that u and $$ \left( {p \, \Updelta H_{\text{d}} { / }\Updelta T} \right)^{ 1 / 2} $$ keep a good linear relation, k keeps a similar changing trend with u, and it can be used to study the effect of the ballistic modifier or the other component on the burning rates. [ABSTRACT FROM AUTHOR]

Abstract: The composite modified double base (CMDB) propellants (nos. RB0601 and RB0602) containing 3,6-bis (1H-1,2,3,4-tetrazol-5-yl-amino)-1,2,4,5-tetrazine (BTATz) without and with the ballistic modifier were prepared and their thermal behaviors, nonisothermal decomposition reaction kinetics, thermal safety and burning rates were investigated. The results show that there are three mass-loss stages in TG curve and two exothermic peaks in DSC curve for the BTATz-CMDB propellant. The first two mass-loss stages occur in succession and the temperature ranges are near apart, and the decomposition peaks of the two stages overlap each other, inducing only one visible exothermic peak appear in DSC curve during 350–550K. The reaction mechanisms of the main exothermal decomposition processes of RB0601 and RB0602 are all classified as chemical reaction, the mechanism functions are f(α)=(1− α)2, and the kinetic equations are and . The thermal safety evaluation on the BTATz-CMDB propellants was obtained. With the substitution of 26% RDX by BTATz and with the help of the ballistic modifier in the CMDB propellant formulation, the burning rate can be improved by 89.0% at 8MPa and 47.1% at 22MPa, the pressure exponent can be reduced to 0.353 at 14–20MPa. [Copyright &y& Elsevier]

Abstract: A bismuth 3-nitro-1,2,4-triazol-5-one (Bi-NTO) complex was prepared and characterized, and its effects on the thermal behaviors, non-isothermal decomposition reaction kinetics, and burning rates of the double-base (DB) propellant containing the mixed ester of triethyleneglycol dinitrate (TEGDN) and nitroglycerin (NG) with Bi-NTO complex as a ballistic modifier were investigated by thermogravimetry and derivative thermogravimetry (TG–DTG), and differential scanning calorimetry (DSC). The results show that Bi-NTO complex can increase the decomposition heat by 140Jg−1, and it can change the decomposition reaction mechanism function, the kinetic parameters and kinetic equation of the propellant under 0.1MPa. Combustion experiment shows that Bi-NTO complex can increase the burning rate and reduce the pressure exponent of the NG/TEGDN/NC propellant effectively, with the increase of the catalysis efficiency by 40%. [Copyright &y& Elsevier]

The effects of different ballistic modifiers (Cr2O3·CuO, ammonium oxalate, and carbon fiber) on the thermal decomposition behavior of RDX/AP/HTPB propellant are studied using pressure DSC. The burning rates of the four propellants are determined by using a Crawford bomb. The results show that in the presence of Cr2O3·CuO or carbon fiber, the peak temperatures of the decomposition of RDX and AP decrease. The enthalpy of decomposition and the burning rates and the number of the exothermic decomposition peak of two kind of RDX/AP/HTPB propellant containing Cr2O3·CuO and carbon fiber increase. When ammonium oxalate is added into the RDX/AP/HTPB system, the peak temperature of decomposition of RDX shifts upwards, and the enthalpy of decomposition of RDX/AP/HTPB propellant decreases, and the burning rate reduces. These facts indicate that the relationship between the effect of the ballistic modifiers on the burning rate and that on the thermal behavior of RDX/AP/HTPB propellant is close. [Copyright &y& Elsevier]