Composite B·Mg powders prepared by mechanical milling

Document Type

Conference Proceeding

Publication Date

1-1-2016

Abstract

Enhancement of boron combustion, including shorter ignition delays and higher burn rates is expected as a result of augmenting boron with magnesium. In this work, preparation of composite B-Mg reactive materials with 40 wt% magnesium by mechanical milling is explored. Acetonitrile was used to pre-wash boron to remove surface boron oxide, preventing its reaction with magnesium during milling. Milling with acetonitrile as a process control agent (PCA) was found to be impractical as causing formation of organic compounds, making the powders difficult to ignite. The most attractive materials were prepared using boron preliminarily washed in acetonitrile and milled with magnesium using stearic acid as PCA. Thermo-gravimetric measurements showed two oxidation stages. X-ray diffraction analysis of partially reacted samples showed that selective oxidation of magnesium occurred at lower temperatures and was followed by oxidation of boron. The onset temperature of magnesium oxidation was reduced for materials prepared using longer milling times. Performance of the prepared composite powders was assessed using their ignition by an electrically heated filament, by electrostatic discharge (ESD), and in constant volume explosion tests. Ignition temperature was reduced approaching that of pure magnesium. Faster initiation was observed for powders prepared using washed boron.

Identifier

84971529990 (Scopus)

Publication Title

2016 Spring Technical Meeting of the Eastern States Section of the Combustion Institute Essci 2016

Fund Ref

Defense Threat Reduction Agency

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