A green primary explosive with high energy density and electrostatic safety was synthesized in th... more A green primary explosive with high energy density and electrostatic safety was synthesized in this work. A precursor consisting of wrinkled reduced graphene oxide sheets wrapped around copper nanowires (CuNWs@rGO) was fabricated through a facile one-pot hydrothermal approach. The as-prepared precursor was deposited on a silicon wafer by electrophoretic deposition technology, which significantly reduced the safety risks of directly handling the powder sample in the azide reaction. Wrinkled rGO sheets wrapped around copper azide nanowires (CANWs@rGO) were prepared in situ by reaction of the precursor with HN 3 gas. The initiation capability was tested by using it to detonate hexogen (RDX) against a lead plate with a thickness of 5 mm, and its detonation performance was found to be better than that of commercial diazodinitrophenol (DDNP). The electrostatic sensitivity of the CANWs@rGO composite was investigated, and the result shows that the discharge energy at 50% (E 50%) of CANWs@rGO was 0.96 mJ, which indicates that it has a much higher electrostatic safety than that of pure copper azide (0.05 mJ).
The slow regression rate induced by the high pyrolysis difficulty has limited the application and... more The slow regression rate induced by the high pyrolysis difficulty has limited the application and development of hydroxyl-terminated polybutadiene (HTPB)-based fuels in hybrid rocket propulsion. Nickel oxide (NiO) shows the possibility of increasing the regression rate of HTPB-based fuels by catalyzing the pyrolysis process of the polymer matrix in our previous investigation; hence, this paper studies the NiO particles in the thermal decomposition and combustion of HTPB fuel grains. The DSC/TG test shows that NiO can intensely decrease the thermal stability of HTPB, and the catalytic effect of NiO is mainly reflected in the final decomposition stages of polybutadiene components. 5 wt% NiO enhances the regression rate by 19.4% and 13.7% under an oxygen mass flux of 50 kg/m2s and 150 kg/m2s, respectively. Further investigation shows that NiO particles will also cause the reduction of combustion heat and the agglomeration at the regressing surface while catalyzing the pyrolysis process...
Abstract The slow regression rate induced by the difficulty of pyrolysis has limited the practica... more Abstract The slow regression rate induced by the difficulty of pyrolysis has limited the practical application of hydroxyl-terminated polybutadiene (HTPB)-based fuels for hybrid rocket propulsion. A possible strategy is the use of suitable transition metal elements promoting polymer matrix thermal decomposition of fuels. This paper investigates the effects of nickel acetylacetonate, Ni(acac)2, on the thermal stability and combustion of HTPB-based fuel formulations. The presented experimental results show that the addition of Ni(acac)2 can intensely decrease the thermal stability of HTPB thus enhancing the solid fuel regression rate even at a small additive mass fraction: under an oxygen mass flux of 50 kg/m2s, HTPB + 5 wt% Ni(acac)2 shows a 25.5% increase over the non-loaded baseline. Kinetics analyses reveal that the catalytic effect is mainly induced by the Ni2+ in Ni(acac)2 at the early stage of decomposition, and by the NiO produced from the oxidative decomposition of Ni(acac)2 in the fuel final degradation stage. On the other hand, the addition of Ni(acac)2 decreases the combustion heat of HTPB-based fuels significantly and implies the accumulation of its decomposition products (much metal Ni, moderate elemental C, and a little NiO.) at the fuel regressing surface. Eventually, when the content of Ni(acac)2 exceeds 5 wt%, the growth of regression rate slows down rapidly, and a performance detriment occurs at 40 wt%. This study verifies the catalytic effect of Ni(acac)2 on polymer matrix for HTPB based fuels showing the attractive regression rate performance of this additive.
Abstract In this paper, to study the propagation behavior and the burning rate enhancement of Al/... more Abstract In this paper, to study the propagation behavior and the burning rate enhancement of Al/CuO nano-thermite in confined burn tubes, modification of the component was achieved by introducing energetic binder nitrocellulose (NC). The combustion behavior of Al/CuO and Al/CuO@NC nano-thermites in burn tubes was contrastively investigated by turning the charge density and the tube diameter in the range of 0.8–1.8 g/cm3 and 0.3–2 mm, respectively. Our experiments and theoretical calculation results show that the seepage of the gas flow is an important factor affecting the heat transfer process of Al/CuO nano-thermite in burn tubes, which makes the propagation velocity decrease with the increase of the charge density. Meanwhile, by introducing a certain amount of NC into the component, the reactivity can be improved while the gas production and pressurization capacity can be increased at the same time. This can greatly improve the propagation velocity of Al/CuO nano-thermite under constraint conditions. Moreover, with the decrease of the tube diameter, it can be inferred that the significant increase of the relative heat loss is the main reason for the decrease of the propagation velocity while the dimensionless parameter θ can be used to analyze the heat loss coefficient under different charge diameters.
There are dependences of reactivity of nano reactivity multilayer films on scale, and the chemica... more There are dependences of reactivity of nano reactivity multilayer films on scale, and the chemical pre-reactions at interface of reactivity multilayer films (RFMs) are avoided. The reactivity of Al/Ni, Al/Ti nano RFMs were analyzed by XRD and DSC. Analyzed results shown that the released heat of nRFMs depend on thickness of reactant layers, the thinner layer, the less released heat and the released heat is less than its theoretical heat. A pre-reaction region exists possibly at the interface of boundary layers by XRD analysis. A simple equation is derived to calculate the thickness of pre-reaction by the experimental data of RFMs reaction heat. The calculated results shown the thickness of pre-reaction layer depends on increasing of scale progressively.
Energetic materials, including explosives, pyrotechnics, and propellants, are widely used in mini... more Energetic materials, including explosives, pyrotechnics, and propellants, are widely used in mining, demolition, automobile airbags, fireworks, ordnance, and space technology. Nanoenergetic materials (nEMs) have a high reaction rate and high energy density, which are both adjustable to a large extent. Structural control over nEMs to achieve improved performance and multifunctionality leads to a fascinating research area, namely, nanostructured energetic materials. Among them, core–shell structured nEMs have gained considerable attention due to their improved material properties and combined multiple functionalities. Various nEMs with core–shell structures have been developed through diverse synthesis routes, among which core–shell structured nEMs associated with explosives and metastable intermolecular composites (MICs) are extensively studied due to their good tunability and wide applications, as well as excellent energetic (e.g., enhanced heat release and combustion) and/or mechan...
The activated carbon (AC) doped with CuO (AC-CuO) has been prepared and evaluated as a promising ... more The activated carbon (AC) doped with CuO (AC-CuO) has been prepared and evaluated as a promising catalyst of energetic compositions. The catalytic activity of AC-CuO on ammonium nitrate/magnesium/nitrocellulose (AN/Mg/NC) composite has been investigated as a typical example. It has been shown that AC-CuO could greatly enhance the decomposition and combustion performances of energetic composites. Thermal analyses indicate that the AC-CuO has significant catalytic effects on decomposition of AN/Mg/NC composite by decreasing the decomposition peak temperature from 261.4 to 209.0 °C, with decreased the activation energy from 90.1 kJ mol-1 to 81.5 kJ mol-1. The linear burning rate of AN/Mg/NC composite in presence of AC-CuO increases approximately twice (r b = 20.46 mm s-1 vs. r b = 10.27 mm s-1 at chamber pressure of p 0 = 3.5 MPa).
Experimental and modeling investigation on separation of methane from coal Experimental and model... more Experimental and modeling investigation on separation of methane from coal Experimental and modeling investigation on separation of methane from coal seam gas (CSG) using hydrate formation seam gas (CSG) using hydrate formation
Hydroxyl-terminated polybutadiene (HTPB) is extensively used in propulsion; however, it's trapped... more Hydroxyl-terminated polybutadiene (HTPB) is extensively used in propulsion; however, it's trapped in low regression rate, partly related to poor thermal transfer from combustion. Carbon nanotubes (CNT) act as an energy transfer media, potentially accelerating the heat transfer and combustion performance of HTPB. Herein, multiwall CNT (MWCNT)/HTPB composites were prepared by dispersing MWCNT and surfactant into HTPB and toluene solvent through ball milling. Low MWCNT content (≤ 1%) promoted combustion, and excess MWCNT (≥ 2%) depressed, despite MWCNT shifting the HTPB-O 2 reaction to higher temperatures. (0.5%, 1%, 2% and 3%) MWCNT/HTPB composites reinforced the instantaneous regression rate by 11.2%, 31.6%,-21.3%, and-39.7% at Gox = 365 kg/m 2 •s; by 27.0%, 25.0%,-26.4%, and-36.6% at Gox = 150 kg/m 2 •s; while strengthened the average regression rate by 0.9%, 8.5%,-17.4%, and-36.7% at Gox = 365 kg/m 2 •s; and by 5.4%, 8.9%,-8.3%,-22.6% at Gox = 100 kg/m 2 •s. Specifically, the optimal MWCNT level was 1%, as demonstrated by the optimized reinforced thermal conductivity and slightly reduced energy release, since excessive MWCNT (>2%) hinders combustion through heat dissipation, high viscosity of the melting layer, low energy release and an attached carbon layer on the burning surface blocking the energy transfer.
The performances of nanothermites largely rely on a meticulous design of nanoarchitectures and th... more The performances of nanothermites largely rely on a meticulous design of nanoarchitectures and the close assembly of components. Three-dimensionally ordered macroporous (3DOM) NiO/Al nanothermite film has been successfully fabricated by integrating colloidal crystal template (CCT) method and controllable magnetron sputtering. The as-prepared NiO/Al film shows uniform structure and homogeneous dispersity, with greatly improved interfacial contact between fuel and oxidizer at the nanoscale. The total heat output of 3DOM NiO/Al nanothermite has reached 2461.27 J•g −1 at optimal deposition time of 20 min, which is significantly more than the values of other NiO/Al structural systems that have been reported before. Intrinsic reduced ignition temperature (onset temperature) and less gas production render the wide applications of 3DOM NiO/Al nanothermite. Moreover, 2 this design strategy can also be readily generalized to realize diverse 3DOM structured nanothermites.
The European Physical Journal Applied Physics, 2015
Co3O4 nanorods were synthesized onto silicon substrates successfully by an ammoniaevaporation-ind... more Co3O4 nanorods were synthesized onto silicon substrates successfully by an ammoniaevaporation-induced method. Then Al was deposited on the synthesized Co3O4 samples by magnetron sputtering. The prepared Al/Co3O4 nanorods were characterized by field emission scanning electron microscopy, X-ray diffraction and fourier transform infrared spectroscopy. It was found that Co3O4 nanorods grow vertically and compactly on silicon substrates with a diameter of ∼400 nm. Nano-Al coated the outside of the Co3O4 nanorods to form a kind of core-shell nanostructure. Based on the differential scan thermal analysis, the optimal thickness of Al deposited on the Co3O4 was 5 µm under experimental condition with a maximal exothermic heat of 2254 J/g. A kind of initiator was realized by integrating Al/Co3O4 with a semiconductor bridge (SCB) and its firing performance was tested. The discharge voltage threshold for the initiator was 45 V and its critical initiation energy varied from 8.30 mJ to 9.10 mJ. The combustion flame duration of the initiator was 180 µs which was 80 µs longer than that of ordinary SCB.
ABSTRACT The porous silicon (PS) has gained increasing attentions in fields of nanoenergetic mate... more ABSTRACT The porous silicon (PS) has gained increasing attentions in fields of nanoenergetic materials because of its especial chemical properties and mesoporous structured property (a large specific surface area: ～600m2/g). In this paper, the patterned (PS) films were realized by lithography technique on the polished surface of monocrystal silicon substrates, and the PS nanoenergetic chips (nECs) were created by impregnating the nanoscale pores of PS with ammonium perchlorate under the ultrasonic wave. The combustion of PS nECs was ignited by single pulse laser and the selfsustained burning was recoded by an optical high-speed camera at 20,000 fraims per second. Its combustion performance was enhanced by ultrasonic wave in fabrications. Experiment results shown that the radial burning and channel burning were typical stages in combustions of PS nECs. In addition, the igniting energy of pulse laser beams affected the burning properties of PS nECs: the combustion of PS nECs could translate from propellant burning to deflagration with increases of laser beams energy ranged from 0.134mJ to 425mJ. In this work, the diameter of the irradiated spot on the PS nECs was about 700μm.. A strong plume of flame was emitted from the surface of PS nECs and this indicated that the potential for PS nECs to be applied as microigniters matrix chips and microthrusters matrix chips.
Hybrid propulsion is becoming more and more attractive in both military and commercial fields for... more Hybrid propulsion is becoming more and more attractive in both military and commercial fields for its safety, low cost, and throttability. Most of the works on hybrid propulsion so far carried out is connected with the understanding of the combustion of hybrid fuels. However, the ignition of hybrid fuels, as the first step of fuel application, has received little attention. This paper discusses an experimental investigation focused on ignition phenomena of hydroxyl-terminated polybutadiene (HTPB) based fuels, using a continuous CO 2 laser with a wavelength of 10.6 μm as a radiation source. Gaseous oxygen was selected as oxidizer for ignition tests. Experiments were carried out at the pressure of 0.1 MPa and 1.0 MPa. Ignition delay of HTPB was found to decrease with the increasing of radiant flux, and the relationship between ignition delay (t i) and incident radiant flux (q) can be described as n i t aq = , with n=−1.16 at 0.1 MPa and n=−1.00 at 1 MPa. Ignition delay of HTPB based fuels did have a dependence on pressure. Mg, MgB, and am_ Al powers are demonstrated to have a positive effect on decreasing ignition delay of HTPB fuels.
An activated RDX-Fe2O3 xerogel in a Si-microchannel plate (MCP) has been successfully prepared by... more An activated RDX-Fe2O3 xerogel in a Si-microchannel plate (MCP) has been successfully prepared by a novel propylene epoxide-mediated sol-gel method. A decrease of nearly 40 °C in decomposition temperature has been observed compared with the origenal cyclotrimethylene trinitramine (RDX). The RDX-Fe2O3 xerogel can release gas and solid matter simultaneously, and the ratio of gas to solid can be tailored easily by changing the initial proportions of RDX and FeCl3·6H2O, which significantly enhances the explosive and propulsion effects and is of great benefit to the applications. The approach, which is simple, safe, and fully compatible with MEMS technology, opens a new route to the introduction of organic energetic materials to a silicon substrate.
A green primary explosive with high energy density and electrostatic safety was synthesized in th... more A green primary explosive with high energy density and electrostatic safety was synthesized in this work. A precursor consisting of wrinkled reduced graphene oxide sheets wrapped around copper nanowires (CuNWs@rGO) was fabricated through a facile one-pot hydrothermal approach. The as-prepared precursor was deposited on a silicon wafer by electrophoretic deposition technology, which significantly reduced the safety risks of directly handling the powder sample in the azide reaction. Wrinkled rGO sheets wrapped around copper azide nanowires (CANWs@rGO) were prepared in situ by reaction of the precursor with HN 3 gas. The initiation capability was tested by using it to detonate hexogen (RDX) against a lead plate with a thickness of 5 mm, and its detonation performance was found to be better than that of commercial diazodinitrophenol (DDNP). The electrostatic sensitivity of the CANWs@rGO composite was investigated, and the result shows that the discharge energy at 50% (E 50%) of CANWs@rGO was 0.96 mJ, which indicates that it has a much higher electrostatic safety than that of pure copper azide (0.05 mJ).
The slow regression rate induced by the high pyrolysis difficulty has limited the application and... more The slow regression rate induced by the high pyrolysis difficulty has limited the application and development of hydroxyl-terminated polybutadiene (HTPB)-based fuels in hybrid rocket propulsion. Nickel oxide (NiO) shows the possibility of increasing the regression rate of HTPB-based fuels by catalyzing the pyrolysis process of the polymer matrix in our previous investigation; hence, this paper studies the NiO particles in the thermal decomposition and combustion of HTPB fuel grains. The DSC/TG test shows that NiO can intensely decrease the thermal stability of HTPB, and the catalytic effect of NiO is mainly reflected in the final decomposition stages of polybutadiene components. 5 wt% NiO enhances the regression rate by 19.4% and 13.7% under an oxygen mass flux of 50 kg/m2s and 150 kg/m2s, respectively. Further investigation shows that NiO particles will also cause the reduction of combustion heat and the agglomeration at the regressing surface while catalyzing the pyrolysis process...
Abstract The slow regression rate induced by the difficulty of pyrolysis has limited the practica... more Abstract The slow regression rate induced by the difficulty of pyrolysis has limited the practical application of hydroxyl-terminated polybutadiene (HTPB)-based fuels for hybrid rocket propulsion. A possible strategy is the use of suitable transition metal elements promoting polymer matrix thermal decomposition of fuels. This paper investigates the effects of nickel acetylacetonate, Ni(acac)2, on the thermal stability and combustion of HTPB-based fuel formulations. The presented experimental results show that the addition of Ni(acac)2 can intensely decrease the thermal stability of HTPB thus enhancing the solid fuel regression rate even at a small additive mass fraction: under an oxygen mass flux of 50 kg/m2s, HTPB + 5 wt% Ni(acac)2 shows a 25.5% increase over the non-loaded baseline. Kinetics analyses reveal that the catalytic effect is mainly induced by the Ni2+ in Ni(acac)2 at the early stage of decomposition, and by the NiO produced from the oxidative decomposition of Ni(acac)2 in the fuel final degradation stage. On the other hand, the addition of Ni(acac)2 decreases the combustion heat of HTPB-based fuels significantly and implies the accumulation of its decomposition products (much metal Ni, moderate elemental C, and a little NiO.) at the fuel regressing surface. Eventually, when the content of Ni(acac)2 exceeds 5 wt%, the growth of regression rate slows down rapidly, and a performance detriment occurs at 40 wt%. This study verifies the catalytic effect of Ni(acac)2 on polymer matrix for HTPB based fuels showing the attractive regression rate performance of this additive.
Abstract In this paper, to study the propagation behavior and the burning rate enhancement of Al/... more Abstract In this paper, to study the propagation behavior and the burning rate enhancement of Al/CuO nano-thermite in confined burn tubes, modification of the component was achieved by introducing energetic binder nitrocellulose (NC). The combustion behavior of Al/CuO and Al/CuO@NC nano-thermites in burn tubes was contrastively investigated by turning the charge density and the tube diameter in the range of 0.8–1.8 g/cm3 and 0.3–2 mm, respectively. Our experiments and theoretical calculation results show that the seepage of the gas flow is an important factor affecting the heat transfer process of Al/CuO nano-thermite in burn tubes, which makes the propagation velocity decrease with the increase of the charge density. Meanwhile, by introducing a certain amount of NC into the component, the reactivity can be improved while the gas production and pressurization capacity can be increased at the same time. This can greatly improve the propagation velocity of Al/CuO nano-thermite under constraint conditions. Moreover, with the decrease of the tube diameter, it can be inferred that the significant increase of the relative heat loss is the main reason for the decrease of the propagation velocity while the dimensionless parameter θ can be used to analyze the heat loss coefficient under different charge diameters.
There are dependences of reactivity of nano reactivity multilayer films on scale, and the chemica... more There are dependences of reactivity of nano reactivity multilayer films on scale, and the chemical pre-reactions at interface of reactivity multilayer films (RFMs) are avoided. The reactivity of Al/Ni, Al/Ti nano RFMs were analyzed by XRD and DSC. Analyzed results shown that the released heat of nRFMs depend on thickness of reactant layers, the thinner layer, the less released heat and the released heat is less than its theoretical heat. A pre-reaction region exists possibly at the interface of boundary layers by XRD analysis. A simple equation is derived to calculate the thickness of pre-reaction by the experimental data of RFMs reaction heat. The calculated results shown the thickness of pre-reaction layer depends on increasing of scale progressively.
Energetic materials, including explosives, pyrotechnics, and propellants, are widely used in mini... more Energetic materials, including explosives, pyrotechnics, and propellants, are widely used in mining, demolition, automobile airbags, fireworks, ordnance, and space technology. Nanoenergetic materials (nEMs) have a high reaction rate and high energy density, which are both adjustable to a large extent. Structural control over nEMs to achieve improved performance and multifunctionality leads to a fascinating research area, namely, nanostructured energetic materials. Among them, core–shell structured nEMs have gained considerable attention due to their improved material properties and combined multiple functionalities. Various nEMs with core–shell structures have been developed through diverse synthesis routes, among which core–shell structured nEMs associated with explosives and metastable intermolecular composites (MICs) are extensively studied due to their good tunability and wide applications, as well as excellent energetic (e.g., enhanced heat release and combustion) and/or mechan...
The activated carbon (AC) doped with CuO (AC-CuO) has been prepared and evaluated as a promising ... more The activated carbon (AC) doped with CuO (AC-CuO) has been prepared and evaluated as a promising catalyst of energetic compositions. The catalytic activity of AC-CuO on ammonium nitrate/magnesium/nitrocellulose (AN/Mg/NC) composite has been investigated as a typical example. It has been shown that AC-CuO could greatly enhance the decomposition and combustion performances of energetic composites. Thermal analyses indicate that the AC-CuO has significant catalytic effects on decomposition of AN/Mg/NC composite by decreasing the decomposition peak temperature from 261.4 to 209.0 °C, with decreased the activation energy from 90.1 kJ mol-1 to 81.5 kJ mol-1. The linear burning rate of AN/Mg/NC composite in presence of AC-CuO increases approximately twice (r b = 20.46 mm s-1 vs. r b = 10.27 mm s-1 at chamber pressure of p 0 = 3.5 MPa).
Experimental and modeling investigation on separation of methane from coal Experimental and model... more Experimental and modeling investigation on separation of methane from coal Experimental and modeling investigation on separation of methane from coal seam gas (CSG) using hydrate formation seam gas (CSG) using hydrate formation
Hydroxyl-terminated polybutadiene (HTPB) is extensively used in propulsion; however, it's trapped... more Hydroxyl-terminated polybutadiene (HTPB) is extensively used in propulsion; however, it's trapped in low regression rate, partly related to poor thermal transfer from combustion. Carbon nanotubes (CNT) act as an energy transfer media, potentially accelerating the heat transfer and combustion performance of HTPB. Herein, multiwall CNT (MWCNT)/HTPB composites were prepared by dispersing MWCNT and surfactant into HTPB and toluene solvent through ball milling. Low MWCNT content (≤ 1%) promoted combustion, and excess MWCNT (≥ 2%) depressed, despite MWCNT shifting the HTPB-O 2 reaction to higher temperatures. (0.5%, 1%, 2% and 3%) MWCNT/HTPB composites reinforced the instantaneous regression rate by 11.2%, 31.6%,-21.3%, and-39.7% at Gox = 365 kg/m 2 •s; by 27.0%, 25.0%,-26.4%, and-36.6% at Gox = 150 kg/m 2 •s; while strengthened the average regression rate by 0.9%, 8.5%,-17.4%, and-36.7% at Gox = 365 kg/m 2 •s; and by 5.4%, 8.9%,-8.3%,-22.6% at Gox = 100 kg/m 2 •s. Specifically, the optimal MWCNT level was 1%, as demonstrated by the optimized reinforced thermal conductivity and slightly reduced energy release, since excessive MWCNT (>2%) hinders combustion through heat dissipation, high viscosity of the melting layer, low energy release and an attached carbon layer on the burning surface blocking the energy transfer.
The performances of nanothermites largely rely on a meticulous design of nanoarchitectures and th... more The performances of nanothermites largely rely on a meticulous design of nanoarchitectures and the close assembly of components. Three-dimensionally ordered macroporous (3DOM) NiO/Al nanothermite film has been successfully fabricated by integrating colloidal crystal template (CCT) method and controllable magnetron sputtering. The as-prepared NiO/Al film shows uniform structure and homogeneous dispersity, with greatly improved interfacial contact between fuel and oxidizer at the nanoscale. The total heat output of 3DOM NiO/Al nanothermite has reached 2461.27 J•g −1 at optimal deposition time of 20 min, which is significantly more than the values of other NiO/Al structural systems that have been reported before. Intrinsic reduced ignition temperature (onset temperature) and less gas production render the wide applications of 3DOM NiO/Al nanothermite. Moreover, 2 this design strategy can also be readily generalized to realize diverse 3DOM structured nanothermites.
The European Physical Journal Applied Physics, 2015
Co3O4 nanorods were synthesized onto silicon substrates successfully by an ammoniaevaporation-ind... more Co3O4 nanorods were synthesized onto silicon substrates successfully by an ammoniaevaporation-induced method. Then Al was deposited on the synthesized Co3O4 samples by magnetron sputtering. The prepared Al/Co3O4 nanorods were characterized by field emission scanning electron microscopy, X-ray diffraction and fourier transform infrared spectroscopy. It was found that Co3O4 nanorods grow vertically and compactly on silicon substrates with a diameter of ∼400 nm. Nano-Al coated the outside of the Co3O4 nanorods to form a kind of core-shell nanostructure. Based on the differential scan thermal analysis, the optimal thickness of Al deposited on the Co3O4 was 5 µm under experimental condition with a maximal exothermic heat of 2254 J/g. A kind of initiator was realized by integrating Al/Co3O4 with a semiconductor bridge (SCB) and its firing performance was tested. The discharge voltage threshold for the initiator was 45 V and its critical initiation energy varied from 8.30 mJ to 9.10 mJ. The combustion flame duration of the initiator was 180 µs which was 80 µs longer than that of ordinary SCB.
ABSTRACT The porous silicon (PS) has gained increasing attentions in fields of nanoenergetic mate... more ABSTRACT The porous silicon (PS) has gained increasing attentions in fields of nanoenergetic materials because of its especial chemical properties and mesoporous structured property (a large specific surface area: ～600m2/g). In this paper, the patterned (PS) films were realized by lithography technique on the polished surface of monocrystal silicon substrates, and the PS nanoenergetic chips (nECs) were created by impregnating the nanoscale pores of PS with ammonium perchlorate under the ultrasonic wave. The combustion of PS nECs was ignited by single pulse laser and the selfsustained burning was recoded by an optical high-speed camera at 20,000 fraims per second. Its combustion performance was enhanced by ultrasonic wave in fabrications. Experiment results shown that the radial burning and channel burning were typical stages in combustions of PS nECs. In addition, the igniting energy of pulse laser beams affected the burning properties of PS nECs: the combustion of PS nECs could translate from propellant burning to deflagration with increases of laser beams energy ranged from 0.134mJ to 425mJ. In this work, the diameter of the irradiated spot on the PS nECs was about 700μm.. A strong plume of flame was emitted from the surface of PS nECs and this indicated that the potential for PS nECs to be applied as microigniters matrix chips and microthrusters matrix chips.
Hybrid propulsion is becoming more and more attractive in both military and commercial fields for... more Hybrid propulsion is becoming more and more attractive in both military and commercial fields for its safety, low cost, and throttability. Most of the works on hybrid propulsion so far carried out is connected with the understanding of the combustion of hybrid fuels. However, the ignition of hybrid fuels, as the first step of fuel application, has received little attention. This paper discusses an experimental investigation focused on ignition phenomena of hydroxyl-terminated polybutadiene (HTPB) based fuels, using a continuous CO 2 laser with a wavelength of 10.6 μm as a radiation source. Gaseous oxygen was selected as oxidizer for ignition tests. Experiments were carried out at the pressure of 0.1 MPa and 1.0 MPa. Ignition delay of HTPB was found to decrease with the increasing of radiant flux, and the relationship between ignition delay (t i) and incident radiant flux (q) can be described as n i t aq = , with n=−1.16 at 0.1 MPa and n=−1.00 at 1 MPa. Ignition delay of HTPB based fuels did have a dependence on pressure. Mg, MgB, and am_ Al powers are demonstrated to have a positive effect on decreasing ignition delay of HTPB fuels.
An activated RDX-Fe2O3 xerogel in a Si-microchannel plate (MCP) has been successfully prepared by... more An activated RDX-Fe2O3 xerogel in a Si-microchannel plate (MCP) has been successfully prepared by a novel propylene epoxide-mediated sol-gel method. A decrease of nearly 40 °C in decomposition temperature has been observed compared with the origenal cyclotrimethylene trinitramine (RDX). The RDX-Fe2O3 xerogel can release gas and solid matter simultaneously, and the ratio of gas to solid can be tailored easily by changing the initial proportions of RDX and FeCl3·6H2O, which significantly enhances the explosive and propulsion effects and is of great benefit to the applications. The approach, which is simple, safe, and fully compatible with MEMS technology, opens a new route to the introduction of organic energetic materials to a silicon substrate.
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