Nanocomposite thermite powders with improved flowability prepared by mechanical milling

Document Type

Article

Publication Date

3-1-2018

Abstract

Nanocomposite thermite powders can be used in reactive parts and components. Manufacturing these components requires tailoring powder particle size distributions, particle shapes, and powder flowability. Specifically, an improved flowability is desired to use such powders as feedstock in additive manufacturing. Arrested reactive milling (ARM) offers a versatile and practical approach for preparing nanocomposite thermites with fully dense particles, which will retain their structures and mixedness between reactive components while being stored, handled, and processed. However, ARM products usually have broad particle size distributions, rock-like particle shapes, and poor flowability. Here, ARM is modified to include a low-energy milling step to tune the shapes and flowability of the prepared powders. Experiments are performed with aluminum-rich Al·Fe2O3 thermites. After the initial nanocomposite thermite is prepared in a planetary mill, it is additionally milled at a reduced rotation rate, replacing milling balls with smaller glass beads, and adding different liquid process control agents. Powders with modified particle shapes and size distributions are obtained, which have substantially improved flowability compared to the initial material. The reactivity of the initial and modified powders is evaluated using their ignition on a heated wire, by electro-static discharge, by thermal analysis (DSC) and in constant volume explosion tests. The reactivity of the modified powders is not diminished; instead, an improved reactivity is observed for selected samples.

Identifier

85040165079 (Scopus)

Publication Title

Powder Technology

External Full Text Location

https://doi.org/10.1016/j.powtec.2017.12.082

e-ISSN

1873328X

ISSN

00325910

First Page

368

Last Page

380

Volume

327

Grant

DE-AC52-07NA27344

Fund Ref

Lawrence Livermore National Laboratory

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