超细硼粉的氟化锂包覆

Surface Coating of Superfine Boron Particles With Lithium Fluoride

以L iOH、HF为主要原料,采用中和沉淀法对超细硼粉进行了表面包覆。研究了L iOH的浓度对包覆效果的影响。透射电镜、X-光电子能谱、酸度计、黏度计用于包覆效果分析。结果表明,硼粉颗粒表面包覆了均匀且致密的L iF薄膜,薄膜厚度25 nm。酸度及黏度测试结果表明,经L iF包覆后硼粉悬浊液体系的pH值明显增大,并有效地降低了HTPB体系的黏度。含包覆硼推进剂的点火延迟时间及燃烧残渣分析表明,含包覆硼粉的推进剂点火延迟时间明显缩短,由70.475 s减为23.585 s;包覆后推进剂中硼的燃烧效率明显提高,推进剂燃烧残渣中硼与B2O3的摩尔比由包覆前的37.5∶1变为包覆后的3.1∶1。

The surface of superfine boron powder was coated with lithium fluoride prepared by reacting LiOH with HF by the neutral precipitation method. The effect of the concentration of LiOH solution on the coating effectiveness of superfine boron particles was studied. Transmission Electron Microscope, rotary viscometer and X-ray photoelectron spectroscopy were used to analyze the coating effectiveness of boron particles coated with LiF. The results show that the film on the boron particles is well distributed and compact and the thickness of film is about 25 nm. The analysis results obtained by acidity-instrument and rotary viscometer show that coating of LiF can enhance the value of PH of the solution with boron and effectively reduce the viscosity of HTPB system. The analysis of ignition delay time and combustion residues shows the ignition delay time of B/MA/AP/HTPB propellant obviously reduced after coated by LiF from 70. 475 s to 23. 585 s. The burning efficiency of B in propellant was obviously improved after coated by LiF, and the amount of substance proportion between B and B2O3 decreases from 37.5 ： 1 to 3.1 ： 1.