Optimizing Process Of Porous Silicon Powder By Chemical Etching Method And Its Explosive Performance Evaluation

Energetic material as a special kind of power source plays an important role in national military, and national infrastructure construction. Conventional energetic materials` application has been limited due to their low explosion energy, environmental pollution and other shortcomings. While for the porous silicon energetic material, because of its unique advantages of high energetic explosion characteristic, the explosion products environmental-friendly and good compatibility with the entire silicon-based production technique and other characteristics, receives more and more worldwide attention.The experiment optimized the chemical etching craft using the inorganic silicon powder as main raw material, and meanwhile evaluated the explosion performance of the porous silicon powder energetic material prepared by chemical etching. The influence of the hydrofluoric acid concentration to the physical and chemical performance of the porous silicon energetic material was also analyzed. The conclusions are as follows:â‘ Proposed a porous silicon powder preparation scheme using HF:H₂SO₄:H₂O: NaNO+2 as the etching system through orthogonal experiment optimization of much chemical etching systems; Studied the influence of hydrofluoric acid concentration to the energetic silicon material performance. The empirical formula gained from the experiment as follows: V_HF= 10×( n+ 1)±2V_H2SO4=70 + 5[n(n+1)±1] (n=1,2,3…) .â‘¡Specific surface area determination of the porous silicon powder prepared by chemical etching method indicated that the specific surface area of the porous silicon powder increased with the increasing of HF concentration (in certain HF concentration range). SEM and STM test results of the porous silicon powder prepared at the concentration of 35wt﹪indicated that the porous silicon powder has a coarse and porous surface. The diameter of those pores varied, and has obvious nanomaterial feature with pore diameter and depth of several decade nanometers.â‘¢FT-IR tests showed that there are Si-H, Si-O, the Si-Si bonds exist on the fresh porous silicon powder surface. And tests also observed that the Si-H bond may passive the internal surface combination center, and its existence contributes to the luminous intensity enhancement of the porous silicon, and plays an important role to the luminescence of porous silicon. While the Si-O bond may stabilize the luminescence performance of porous silicon.â‘£Influence of various nitrates on the porous silicon powder explosion performance was tested, and showed that besides lanthanide series nitrates and potassium nitrate can act with porous silicon and form energetic material, and observed for the first time that lithium nitrate can also act with porous silicon and form high energy explosive energetic material.⑤TG - DTA, X-ray diffraction tests of explosion products showed that Si-H bond in the nitrate and porous silicon compound will break when ignited by high energy electric spark, and SiO₂, H₂O and nitrogen oxides formed in the explosion process.â‘¥Porosity of the porous silicon prepared under certain chemical etching concentration was calculated. The calculation indicated that the porous silicon powder with a porosity of more than 46% has explosive ability when the porous silicon formed energetic material.