| Emulsion explosive has been accepted by many practitioners and widely used with its excellent explosion performance and adapt to the underwater blasting in complicated environment.But water can absorb a great deal of heat as inert matter in emulsion explosive detonation,and make the explosion power of emulsion explosive be restricted.In order to improve the work ability and safety of emulsion explosive,titanium powder was introduced into emulsion explosive as high energy additive for the first time and compared with aluminum powder.The effects of high energy additive on detonation performance and thermal stability of emulsion explosive were studied comprehensively.The results of the study are as follows:Laboratorial preparation process of emulsion explosive was established base on oxygen balance and other formula design principles,and different kinds of emulsion explosive were obtained by adding titanium powder or aluminum powder with different content and particle sizes respectively.The results show that titanium powder and aluminum powder can improve the explosion performance of emulsion explosive,and the effect of titanium powder is more remarkable than that of aluminum powder by using microstructure observation,detonation velocity test,brisance experiment and theoretical calculation of explosion heat.The effects of different particle sizes and content of aluminum powder and different content of titanium powder on energy output of emulsion explosive were studied by underwater explosion test system.The experimental results show that underwater explosion energy parameters of emulsion explosive with different particle sizes of aluminum powder present the law of increase first and then decrease,which indicates that aluminum powder particle size has an optimal range,not a simple linear relationship with underwater explosion energy.And the effect of aluminum particle size on shock wave energy of underwater explosion is greater.Different content of titanium powder and aluminum powder have a great influence on underwater explosion energy of emulsion explosive,When the content of titanium powder is 10%,the energy of underwater explosion reaches the maximum.In the case of the same content of high energy additive,the performance of titanium powder on explosion energy of emulsion explosive is better than that of aluminum powder.The air explosion experiments of emulsion explosive contain titanium powder,aluminum powder with different content and aluminum powder with different particle sizes were carried out,and pressure-time curves were analyzed and calculated.Under the experimental conditions,the effect of medium grain size aluminum powder(average particle size is 177.2?m)on the peak pressure of shock wave is higher than that of the other two kinds of aluminum powder.With increasing high energy additive(titanium powder and aluminum powder),the peak pressure increases first,but the growth rate of peak pressure is reduced when the content of high energy additive is more than 10%,and the peak pressure of the shock wave of emulsion explosive containing titanium is 5.35%higher than that of emulsion explosive containing aluminum.By scanning electron microscopy and energy dispersive X-ray spectroscopy tests found that the difference in the degree of oxidation of different high energy additives is one of the reasons cause above phenomena.The differential scanning calorimetry combined with DSC and TG was used to analyze emulsion matrix with different particle sizes and content of aluminum powder,and the kinetic parameters such as activation energy were obtained based on DSC and TG curves at different heating rates.The results show that the addition of aluminum powder decreases the peak temperature,while activation energy and thermal stability reduced.What's more,this trend is more obvious with the decrease of aluminum particle size or the increase of aluminum content.Aluminum with different particle sizes have no effect on thermal decomposition mechanism functions of emulsion matrix in the scope of experiments and they are controlled by nucleation and growth mechanism and the mechanism function could be described with Mample principle with n=1.The thermal analysis of emulsion explosive with different content of titanium powder were carried out by using C80 microcalorimeter,and the results show that the activation energy of emulsion explosive decreases with the increase of titanium content.Under the condition that the content of high energy additive is the same,titanium powder,aluminum powder and boron powder all can reduce the thermal stability of emulsion explosive in different degrees,and the degree of decrease are increscent in turn.So titanium powder has the least effect on the thermal sensitivity of emulsion explosive. |
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