Study On Performance Of Spherical Nano-scaled Ceria Prepared By Detonation Method

Nano-scaled ceria has important application value in the national defense, electronics, aerospace and other fields. In this paper, the performance of spherical nano-scaled ceria synthesized by detonation method was studied. The work of purification and dispersion was researched firstly. The study on the performance of nano-scaled ceria included three aspects: waste water degradation, UV shielding, catalytic action on energetic material about thermal decomposition. The main research contents are as follows:(1) The main impurity are Fe2O3 and Al2O3 among the nano-scaled ceria, the proportion accounts for 3 percent. Orthogonal test was designed to get the best purification parameters of nano-scaled ceria. The parameters are that temperature is 80 ℃, time is 24h, the amounts of distilled water, nitrate and PEG are 0.33mL,6.67mL and 16.67mg each gram of detonation ash. Among them, time and temperature are the important factors to purity.0.12 percent Fe2O3 and 0.17 percent Al2O3 are left over after purifying.(2) Deionized water as the dispersion medium, the effect of six partial sodium phosphate on dispersion is better; Alcohol as the dispersion medium, the effect of polyethylene glycol on dispersion is better. When alcohol as the dispersion medium, the dispersion effect is better without the addition of dispersing agent.(3) When the content of nano-scaled ceria is 3.5g·L-1, the degradation rate and degradation rate constants on methyl orange are maximum, the degradation rate is 83.90 percent. Decreasing the initial pH of solution will promote the degradation activity, the degradation rate and degradation rate constants become larger. Because of the adsorption effect, nano-scaled ceria still has certain degradation effect to methyl orange solution without Ultra Violet light, it reaches adsorption equilibrium after 60 min, the degradation rate is 33.66 percent.(4) Nano-scaled ceria shows a strong ability of ultraviolet(UV) shielding on 190nm-400nm band. The UV absorbance of epoxy resin(EP) film reaches the maximum value with 0.8 percent nano-scaled ceria addition. Compared with no nano-scaled ceria, the service life of EP increases by 62.82 percent, the retention rate of tensile strength increases by 35.25 percent after aging. Conclude from this:nano-scaled ceria has a strong UV shielding effect, it improves the anti ageing capacity to UV of EP.(5) Hexogen and nano-scaled ceria mixed samples synthesized by electrostatic spraying method. RDX is spherical particles and its size is about lum. The mixture of nano-scaled ceria and RDX is uniform, and the reunion phenomenon is inconspicuous.(6) Thermal decomposition of RDX and nano-scaled ceria mixture was studied by Differential Scanning Calorimetry(DSC). The nano-scaled ceria shows good catalysis action on the thermal decomposition of RDX. In the mixed system, the decomposition peak temperature of RDX decreases about 5℃, and the heat release increases 343 J·g-1, the apparent activation energy reduces 16.69 kJ·mol-1.