Preparation Of Micro-nano Nitrogen/oxygen-enriched Combustion Catalysts By Ultrasonic Spray Drying And Research On Their Performance

Ammonium perchlorate(AP)is one of the most important oxidant in solid propellant.It has a significant effect on the combustion of solid propellant.Micro nanocatalysts can effectively increase the thermal decomposition of AP to improve the burning rate of the solid propellant.Here,the nitrogen-rich,oxygen-rich and carbon-rich organic metal salts,2,4-dihydroxybenzates {(2,4-DHB)nM,M=Co,Cu,Fe,Ni,Pb},3,5-dinitrobenzates {(3,5-DNB)nM,M=Co,Cu,Fe,Ni,Pb} and composites of 3,5-dinitrobenzates {(3,5-DNB)M·M?,(M=Co,Cu,Fe,Ni)},are selected as the combustion catalysts and prepared into micro-nano spherical particles by using spray drying methods.The morphology,microstructure,element distribution,particle size distribution(PSD)and composition of the products are carefully tested by infrared spectrometer(IR),scanning electron microscope(SEM),element energy spectrum(EDS),transmission electron microscope(TEM),high-resolution transmission electron microscopy(HRTEM)and elements distribution(Mapping)and laser particle size analyzer(LDPSA).The relationships between concentration of precursor solution(PC)and particle mean size(D50)of the products are determined,the optimum conditions are obtained by investigating influences of ultrasonic spray drying conditions on morphology and particle size distribution(PSD)of the products.The catalytic effects of the micro-nano particles of(2,4-DHB)nM,(3,5-DNB)nM and(3,5-DNB)M·M? on the thermal decomposition of AP are studied by DSC technique,and compared with that of the classical nano combustion catalysts.The main achievements are as followings:(1)The micro-nano particles of(2,4-DHB)nM,(3,5-DNB)nM and(3,5-DNB)M·M? with solid and core-shell spherical structure by self-assembly,are successfully obtained by new developped ultrasonic spray drying method.(2)The correlation between the precursor concentration(PC)and the D50 of the products particles is fitted well with power function.When PC < 0.5 g/100 ml,D50 is easily affected by PC;when PC > 1 g/100 ml,the D90 is largely influenced by PC.The experiment results show that the ultrasonic spray drying method can manufacture products with controllabl size and distribution.(3)The composites micro-nano particles of(3,5-DNB)Co Cu,(3,5-DNB)Co Ni,(3,5-DNB)Fe Co and(3,5-DNB)Fe Cu are successfully prepaered by ultrasonic spray drying method.The element intensity of the(3,5-DNB)M·M? micro-nano particles can be adjusted easily by component ratio of the precursor solution.(4)The optimum ultronoice spray drying processes of(3,5-DNB)nM and(3,5-DNB)M·M? micro-nano spherical particles: PC 0.5 g/100 ml,the carrier gas 0.02 MPa,the drying temperature 100 ?.The optimum ultronoice spray drying process of the(2,4 DHB)nM micro-nano spherical particles: PC 0.1 g/100 ml,carrier gas 0.025 MPa ~ 0.03 MPa,the drying temperature 130? ~ 150 ?.(5)The results of the thermal decomposition of AP mixed with(2,4-DHB)nM show that the thermal decomposition of AP in presence of(2,4-DHB)2Pb is delayed to 408 ?,while(2,4-DHB)2Co,(2,4-DHB)2Cu,(2,4-DHB)3Fe,(2,4-DHB)2Ni can accelerate the the thermal decomposition.(2,4-DHB)2Cu has the best catalysis effect,which can effectively low HTD(419 ?)temperature of AP down to 332.1 ?,ADH increase from 319 J/g up to 2022 J/g.(6)The results of the thermal decomposition of AP in presence of(3,5-DNB)nM show that(3,5-DNB)2Pb lead the AP thermal decomposition move forward to 410.01 ?,(3,5-DNB)2Co,(3,5-DNB)2Cu,(3,5-DNB)3Fe and(3,5-DNB)2Ni effectively decrease the exothermal decomposition peak temperature down dramatically.(3,5-DNB)2Cu possesses the best catalysis,which can make LTD(318 ?)and HTD(419 ?)of AP down to 298.9 ? and 327.5 ?,ADH increase up to 942 J/g.(7)The results of the thermal decomposition of AP in presence of(3,5-DNB)M·M? show that(3,5-DNB)Fe Co,(3,5-DNB)Fe Cu,(3,5-DNB)Co Cu and(3,5-DNB)Co Ni composite micro-nano spherical particles have various effective catalysis on AP thermal decomposition obviously,which have synergetic catalysis compared with(3,5-DNB)nM.(3,5-DNB)Co Cu has the best catalysis of which can low the LTD and HTD temperature down to 271.3 ? and 311.8 ?,ADH increase up to 383.3 J/g.