Development of Pyrophoric Foam Materials for Environmentally-Benign Pyrotechnics

Dr. Zhaohua Luan | U.S. Army RDECOM-Army Research, Development and Engineering Center (ARDEC)

WP19-1105

Objective

Pyrophoric foam is a new class of energetic materials discovered at the U.S. Army Combat Capabilities Development Command Armaments Center and has been developed, as a core SERDP program in the past year ( WP19-1105), into a number of aerial decoy flare prototypes demonstrated with satisfactory results in a comparative combat environment [1]. A preliminary sustainability analysis also concluded that the precursor chemicals and the life-cycle end products are both environmental benign [2]. The main focus of this continuing effort will be the development of a novel concept of “flow” or “time-of-flight” bomb calorimetry to capture calibrated aerodynamic data [3], which reflect more of the intrinsic nature of the pyrophoric foam materials when used as aerial decoy flare payloads. Various physiochemical properties, such as the porosity and morphology of the foam materials, as well as iron particle size distribution and formation mechanism, will be closely examined to establish the correlation between formulation, processing parameters, and performance data. Since one particular prototype of the pyrophoric foam materials has been recently selected by the Joint Aircraft Survivability Program (JASP) for testing as a “Next Gen IR Seeker Decoy Design” (funded portion of S-21-11 through USSOCOM PEO-FW) [4], an opportunity exists for assessing the technology gap between the current materials solutions and performance expectation. This combined effort will provide invaluable technical insight to foster a sound technology development plan in future years.

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Technical Approach

This continuing effort will proceed with a limited scope in one-year as three separate but parallel tasks to address a number of technical issues critical to the system-level development.

Task 1. Development of the conceptual “flow” bomb calorimetry. Spontaneous combustion of the pyrophoric foam materials in the air is largely an aerodynamic thermal phenomenon, which is dictated not only by the energetic properties of the foam materials, but, more importantly, by the flow pattern and altitude in the air stream, as the reaction is most likely in a diffusion-controlled mass transport regime. Prior study [1] has indicated that such a dynamic examination of the foam materials in the air stream yields information more relevant to its performance as an aerial decoy flare payload. The deliverable from this task will be an integrated and calibrated “flow” bomb calorimeter to generate aerodynamic data related to materials formulation, processing parameters, and geometric dimensions under varying flow dynamics in the air. Such characterization technique and the information obtained are vital to the further development of both materials and system-level configuration.

Task 2. Characterization of the pyrophoric foam materials. The physiochemical properties of the foam materials have not yet been fully characterized, as the prior effort mainly focused on the scale-up production of the foam materials and demonstration of its viability in an actual pyrotechnic application, as well as an assessment of the environmental impact. To support further materials and system-level development, it is important to characterize the pyrophoric form materials in terms of porosity, morphology, structural integrity, iron nanoparticle size and distribution against formulation and processing parameters. This will lead to a quantitative baseline for a set of materials processing parameters and characteristically defined pyrophoric foam materials.

A combination of characterization techniques do exist in-house at this Army research and development laboratory, and the results will be used to interpret aerodynamic performance data (Task 1 above) and support technology gap analysis (Task 3 below).

Task 3. Technology gap analysis through the comparative flight test. Recent selection of a particular decoy flare prototype with these foam materials by the JASP for testing as a “Next Gen IR Seeker Decoy Design” is encouraging; it provides a great opportunity to assess the technology gap, especially in the area of current and future materials solutions. This analysis will guide the long-term development plan (Section 3.2. below).

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Benefits

Aerial countermeasure is forever an evolving enterprise of technology advancement to deal with new and increasing aerial threats. As a matter of fact, the Army is currently seeking novel or improved materials solutions while addressing the significant environmental concern associated with conventional formulations based on magnesium, Teflon®, and Viton® or Hytemp® as binder. The newly discovered class of pyrophoric foam materials possesses advantageous physiochemical properties and is considered environmentally benign throughout its life-cycle. The decoy flare prototypes with the foam materials have been demonstrated to have great potential to meet those needs with U.S. Government owned technologies. There are also other military applications under consideration, such as ammunition training round markers, etc. The results of this funded effort will be documented in a final report and, most possibly, in a number of U.S. patent applications and peer-reviewed publications in public about the materials and its processing technologies.

1. Luan, Z; Mills, K.; Oyler K.; Moretti, J.; Eck, W. SERDP Project WP19-C4-1105 Report: Development of Pyrophoric Foam Materials for Environmentally-Benign Pyrotechnics; U.S. Army CCDC Armaments Center: Picatinny Arsenal, NJ, 2020.

2. Eck W. S. Toxicology Assessment for SERDP Project WP19-C4-1105: Development of Pyrophoric Materials for Environmentally Benign Pyrotechnics (Toxicology Report No. S.0064909-19); US Army Public Health Center: Aberdeen Proving Ground, MD, 2020.

3. Luan, Z; Motyka, M. U.S. Patent Application (pending submission), 2020.

4. Mills, K. Statement of Work (SOW) for Joint Aircraft Survivability Program (JASP): Next Gen IR Seeker Decoy Design; U.S. Army CCDC Armaments Center: Picatinny Arsenal, NJ, 2020.

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Points of Contact

Principal Investigator

Dr. Zhaohua Luan

U.S. Army RDECOM-Army Research, Development and Engineering Center (ARDEC)

Phone: 973-724-8041

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