Preparation Of Energetic Combustion Catalyst K₂Pb[Cu(NO₂)₆] And Its Effect On The Performance Of Modified Double-based Propellant

The purpose of this thesis is to explore the optimal preparation process of energetic combustion catalyst K₂Pb[Cu(NO₂)₆]and to explore its influence on the properties of HMX/RDX-CMDB solid propellant.Firstly,a kind of energy-containing combustion catalyst K₂Pb[Cu(NO₂)₆]was prepared by co-precipitation method,and different reaction temperature,reactant concentration,KNO₂addition amount and stirring speed were discussed.The structure,morphology,elemental analysis,purity and particle size of K₂Pb[Cu(NO₂)₆]were characterized by XRD?SEM?EDS?HPLC and laser dry particle size analyzer.The study found that the prepared K₂Pb[Cu(NO₂)₆]sample had a regular morphology and a cubic crystal form.The best preparation process of K₂Pb[Cu(NO₂)₆]:the temperature is 20?,the stirring speed is 200r/min,the ratio of lead nitrate,copper nitrate and potassium nitrite is 1:1:10.The ultrafine K₂Pb[Cu(NO₂)₆]with high yield has an average particle diameter in a range of 10?m to 15?m.Secondly,K₂Pb[Cu(NO₂)₆]sample prepared by the co-precipitation method was ball-milled by mechanical ball milling,and its structure,morphology and particle size were characterized accordingly.The wet milling process was used to prepare the ball-milled product with AP,RDX and HMX into composite particles and the thermal decomposition performance of AP,RDX and HMX was further studied.The research found that the color of K₂Pb[Cu(NO₂)₆]before and after ball milling changed from black to yellow,and the average particle size is reduced to about 5?m.After ball milling,K₂Pb[Cu(NO₂)₆]advances the thermal decomposition peak temperature of RDX and HMX by 34.5°C and 8.1°C respectively,which has better catalytic effect.The pyrolysis products of K₂Pb[Cu(NO₂)₆]are mainly Pb O and Cu O,which can synergistically catalyze the combustion performance of propellants.Finally,K₂Pb[Cu(NO₂)₆]was added to the HMX/RDX-CMDB propellant,and the effects of different loading methods,K₂Pb[Cu(NO₂)₆]and a small amount of three copper salts on the burning rate,pressure index were studied.Its effect on the flame structure,flame suppression performance and chemical stability of the propellant.The target line method,single-magnification color photography method and methyl violet method were used to determine its static burning rate,flame structure and chemical stability.The results show that the internal combustion method of adding K₂Pb[Cu(NO₂)₆]to the propellant has a better burning rate and pressure index than the external method,and adding K₂Pb[Cu(NO₂)₆]can reduce the pressure index of RDX-CMDB propellant by 0.11.Compounding three copper salts with K₂Pb[Cu(NO₂)₆],it was found that the pressure index could be significantly reduced,and K₂Pb[Cu(NO₂)₆]and copper salicylate can reduce the pressure index of the original RDX-CMDB propellant by 0.20.Adding K₂Pb[Cu(NO₂)₆]to the HMX/RDX-CMDB propellant can effectively reduce the flame area,thereby achieving the flame suppression effect.The chemical stability of HMX/RDX-CMDB propellant with K₂Pb[Cu(NO₂)₆]added is within the standard permit range,and it can be used as an energetic combustion catalyst in HMX/RDX-CMDB propellant.