Study On Electro-explosive Characteristics And Temperature Variation Of Composite SCB

Initiating explosive device plays a key role among the weapon and ammunition systems, in which energetic materaials were used as chermical energy. The higher technology the system is, the more efficient initiating explosive devices it needs. With the development of information weapons, initiating explosive devices need to be more accurate and consistent, anti-static and anti-electromagnetic, so more advanced technology is required in initiating explosive devices. For traditional initiating explosive devices can hardly reach all these requirement, and semiconductor bridge (SCB) igniter as one of the outstanding initiating explosive devices, not only has the advantages of possibility to be combined with digital logic circuit, but also has high reactivity and security, low ignition energy. So it is widely researched. However, the low reliability caused by miniaturization and low ignition energy limits its further application. Compared with general SCB, composite SCB and energetic SCB are expected to increase the ignition capacity with the same energy input, due to existence of metal film or high-energy film. The design, preparation and properties of composite SCB were studied in this paper.A comprehensive review on the research and development of SCB and temperature the measurement of ignition explosive devices was discussed in this paper. By studying the design methods and preparation technology of SCB, composite SCB was manufactured. And then the principle of explosion energy, explosion time and the variation of plasma energy after explosion, were obtained from measuring the variation of voltage and current on three different kinds of composite SCBs, using high-speed Digitizing Storage Oscilloscope (DSO) in capacitance incentive model. Variation of temperature with time under different currents was drawn by measuring the temperature of three composite SCBs in different current incentive models using infrared microscopic thermographer, which provides quantitative support to safety research of SCB. Characteristics of electrical explosion were studied based on the theoretic calculation on enthalpies of SCB, measurement of the explosion time of composite and poly-silicon SCB at the same capacitance but different voltages, and the comparison of energy acting on the plasma. Using heat transfer theory, the temperature changes in composite SCB in capacitance incentive model were simulated. The main conclusions are induced as follows:(1) The explosion time of composite SCB decreases with increase in charge capacitance under different voltages, and shorter explosion time is needed when the voltage is higher at the same capacitance. For the three kinds of composite SCBs measured, type-A has the shortest explosion time, type-B is the second and type-C has the longest explosion time at 30V and 60V.(2) For the explosion energy required in the SCBs, the lowest energy was needed in type-A, the second one was type-B and type-C required the largest amount of energy when the voltage is at 30V and 60V.(3) The energy of composite SCB acting on the plasma at different voltages increases linearly with the charge capacitance raise, and the higher the charge voltage is, the more increase in energy. The energy of the three types of composite SCBs which acts on the plasma, increases linearly with charge capacitance increase, and the three energy-capacitance curves coincide, which shows that energy acting on plasma has no relation with the type of bridge.(4) The maximum temperature of three composite SCBs shows a parabolic line with the current raise, and the increase is related to the electrical resistance of the measured SCB and the length of power cross-section. The larger resistance and the narrower the composite SCB is, the more increase temperature shows.(5) The maximum temperatures of both bridge wires and composite SCB increase as a parabolic line with the current increase, but the range of temperature increase is bigger for bridge wire, which means that a smaller current is required for the same temperature increase for bridge wire. The main reason for a slower temperature increase is that heat can transferred through the metal pad and the base contacting close to composite SCB.(6) Melting ratio and gasification ratio at different time points were obtained using the theory calculation of enthalpy. The variations of current in different stages during the electrical explosion were obtained by comparing the data with that of poly-silicon SCB under similar conditions.(7) The generation of plasma was identified via the analysis of the current changes on composite SCB, especially the current and voltage changes after the explosion. The changing process of current shows that the current is first conducted by the composite bridge area, and then by the plasmas, with the increasing of composite SCB evaporation and ionizing of silicon and metal vapor. Then by calculating the input energy on composite SCB, the progress of current conduction after SCB explosion is verified.(8) The current and voltage changes during the explosion of composite SCB and poly-silicon SCB at the capacitance of 22μin voltage incentive model were analyzed and compared. Combined with the analysis of the difference during the explosion between the two kinds of SCBs from the perspective of energy, the result demonstrates that the reason for the difference is the existence of metal film on composite SCB.(9) According to the law of energy conservation and other heat exchange theory, the temperature-rising model of the semiconductor bridge was established with its voltage and current. By analysis and calculation, the curves of the temperature of SCB along with time were obtained and the sphere of application about the model was researched. It is pointed out that this model could simulate the change of temperature well before SCB bursting. The temperature of two types of semiconductor bridges at bursting under different voltages was compared. It is concluded that composite SCB is more benefical to ignite than polysilicon SCB, because the temperature of composite SCB is higher than SCB's.(10) Based on the data analysis of infrared temperature measurement, steady-state mathematical model of composite SCB was established. Through determining its thermal conductivity and heat capacity, the simplified formula of the composite SCB temperature changes with time was obtained. Then the simulation curve of temperature changes at different current is given by corresponding calculation procedure. Finally compared with the measured data, its fitting effect is very good.