Zirconia Composite Particles Were Prepared, And Its Static Sensitivity And Thermal Properties

Zirconium powder has good combustion and ignition characteristics, while its electrostatic sensitivity is so high that it spontaneous combusts and explodes in the air easily. In this thesis, electrostatic sensitivity of zirconium powder was decreased by two different coating methods.Firstly, nitrocellulose(NC) that the binder of double base propellant was used as coating agent. Zirconium was coated with NC by the method of solvent-nonsolvent. Effects of coating methods and technical process on the morphology and particle size of composite particles were investigated. Composite particles were characterized by FTIR, SEM, EDS and laser particle size analyzer, etc. The results had shown that adopt reverse adding could obtain great saturation composite particle size is small. Particle size of composite particles was decreased with the increasement of NC concentration, thermal difference, stirring speed and with the decreasement of NC solution adding speed. Electrostatic sensitivity of Zr/NC composite particle was lower than that of raw zirconium.Secondly, hydroxyl terminated polybutadiene(HTPB), the binder of composite propellant was used as coating agent. Zirconium powder was coated with HTPB by the method of solvent vaporization. Effects of coating methods and technical process on the morphology and composite particle size were also investigated. Composite particles were characterized by FTIR, SEM, EDS and laser particle size analyzer, etc. The results had shown that coating effect of composite particle by the method of vacuum distillation was better than by the method of stirring vaporization. Composite particle size was homogeneous distribution when coating dosage was 1.0%.Mixed solution of ethyl acetate and anhydrous ethanol was used as the solvent of HTPB. Composite particles were coated uniformly and hard to agglomerate after drying when distillation speed was slow. Minimum ignition energy of Zr/HTPB composite particles was higher than that of raw zirconium powders and Zr/NC composite particles.Finnally, the thermal properties of above two kinds of composite particles were tested by DSC. Zr/HTPB composite particles were added into the composite propellant. The explosive heat of propellant was studied by oxygen bomb calorimeter. The results had shown that decomposition temperatures of zirconium composite particles were higher than that of raw zirconium powders. The combustion performance of propellant that added Zr/HTPB composite particles was improved. Among the designed propellants(zirconium composite particles content is 5%,10% and 15%, respectively), explosive heat of propellant that added 15% Zr/HTPB composite particles was the highest.