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Due to the surface acidic impurities, amorphous boron powder has poor compatibility with hydroxyl-terminated polybutadiene. For increasing boron amount in propellant, boron powder need modification treatment. Boron powder’s particle size is also an important factor affecting the process performance of the fuel-rich propellant. Boron combustion is slow and the ramjet fills fuel efficiency and is low. To consider from the agglomerate of combustion process, diameter of the boron particles should be as small as possible. Thus it can ensure the afterburning efficiency. The diameter should less than 1µm. The only way to solve this problem is to increase the particle size of boron powder particles. It means amorphous boron powder with reunion modified can get boron in appropriate particle size. It will effectively improve the process performance of the boron-rich fuel propellant. Amorphous boron powder by the reunion of the modification, you can greatly increase the amount of boron in the propellant, thus improving the propellant energy, but also in the B content in the same conditions, the reunion of boron can improve the propellant formulation ultrafine oxidant content, and ultimately improve the propellant burning rate. The study also found that boron particles reunion modified to improve the boron-rich fuel propellant combustion performance tests on amorphous boron powder were the reunion modified investigated the impact of different factors on the reunion of the boron particles, in order to find the preparation of the optimum parameters of the reunion boron. Dry in the reunion process, in order to ensure that the reunion of boron particles density and the desired surface shape need to be rolling compaction. Rolling compaction process, the uncured plasticity reunion boron particles in the scroll of the role of the pressure strength to keep the compression compacting plastic deformation, so the pressure on the strength of the greater, the higher the degree of compaction. Suffered in this process, the pressing force generated by the rotor of centrifugal force to control, the greater the speed, the greater the clamping force suffered more dense particles from the reunion of the density of boron particles, the higher . The density of the boron powder bulk density and true density of two types of two density measurement methods are essentially similar. The true density of the particles reflects the porosity of the particles, using the pycnometer method compared to the density around the boron particles reunion. Boron powder in the reunion process, in order to make the boron particles can bond the particles have a certain degree of humidity, but humidity is too large, pre-reunion of a single particle in the centrifuge process will occur between the adhesive, not a single The pre-reunion of the boron particles. Pre-reunion of boron particles in a certain pressure by squeezing to produce plastic deformation, the final completion of the adhesive curing process, the plastic deformation of the longer, RCC dense process more fully, the particles in the rolling process, the more tend to spherical, the better the sphericity will be. Particle surface is more smooth than the surface area of the smaller particles in the slurry to move the resistance movement, thus the propellant slurry composed of smooth surface particles have a greater packing density and smaller viscosity. Moreover, under the action of the reunion process of the formation of aggregate, the solvent in the capillary suction between the particles, the particle surface evaporation, dissolved in a solvent of the adhesive in reunion particles deposited with the volatile solvent, the particles solidified to form reunion particles. In this process, the process temperature is the most important factor affecting boron agglomerated particles. This experiment investigated the surface roughness of reunion boron in different temperatures. After reunion modified of amorphous boron powder by metal powder supplier, boron powder’s particle size increases and the surface morphology is greatly improved. It is substantially lower than the surface area, which is very beneficial to improve the technological properties of the boron-rich fuel propellant. The propellant slurry can improve the content of the pure boron, ultrafine AP and solid components. In the reunion process, the use of styrene solvent, a lower temperature and longer curing time is good for preparation of reunion boron particles with a high spherical and smooth surface. The reunion process needs further improvement in order to increase the density of reunion boron. Source:http://www.mhcmp.com
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