Indian Defence Review

Nanotechnology “could completely change the face of weaponry,”
– Andy Oppenheimer, Jane’s Information Group[1]

 On 11 September 2007, Russians tested Father of All Bombs (FOAB), an Aviation Thermo baric Bomb of Increased Power (ATBIP). It was said to be the most powerful conventional bomb in the world, with a 7-Ton explosive mixture resulting in a devastating effect equivalent to 44 tons of TNT[2]. It was hinted that the FOAB contained a liquid fuel, such as ethylene oxide, mixed with energetic nano-aluminium powder, which was dispersed by a high explosive booster. Some reports speculated that the liquid fuel was purified using nano-filters. What caught the imagination of defence experts was the fact that the Russian FOAB had less fuel than the similar US device Mother of All Bombs (MOAB), the GBU-43/B Massive Ordnance Air Blast bomb, but was four times more powerful. It was also probably the first time that the nonprofessional learned of the lethal uses of nanotechnology. Not much information is available through open sources about the developments involving nanotechnology in explosives, much of it has to be gleaned from research papers and patents (for e.g. Patents like US6955732 – Advanced thermo baric explosive compositions and WO2013119191A1 – Composition for a fuel and air explosion).

Since 2004, ‘Combat Safe Insensitive Munitions’ concept has shifted the focus of safety from a pure materials approach to making marine explosives insensitive to a platform based approach based upon mechanics to increase insensitivity[3]. US Navy has been at the forefront of R&D into new energetic materials since a long time and it is opined that nanotechnology enabled energetic materials would form the backbone of the future defense systems. Timely induction of nano enabled energetic systems with controlled energy release is the focus of current research at institutes like the U.S. Naval Academy, Naval Surface Warfare Center, and the University of Maryland.

In simple terms, Nanoenergetic materials (nEMs) perform better than conventional materials because of much larger surface area, which increases speed of reaction and larger energy release in much shorter time. Addition of Superthermites[4] (nano-aluminium based) have shown instantaneous increase in explosive power of existing compositions[5]. Further, use of nano-sized materials in explosives has significantly increased safety and insensitivity by as much as over 30% without affecting reactivity. It is predicted that nEMs would provide the same explosive power at mass up to two orders of magnitude less than the current explosive systems[6].

In rocket, propellants nEMs have shown similar capabilities at Los Almos National Laboratories with nitrogen-energized nEMs[7]. In addition, incorporation of more than one burning rate in rocket propellants has given rise to novel design options by creating grains with continuously varying properties along the length as well as across the radius of the grain in Functionally Graded Materials (FGM).

While nanosizing of high explosives leads to increasing their explosive power[8] and decreasing their sensitivity to external forces[9], it also decreases their thermal stability. The shelf life of such explosives could therefore stand reduced, however, some patents reveal that this issue has also been resolved technically (e.g. patent US20120227613 Thermal enhanced blast warhead). In India the work on explosives and propellants is being undertaken at HEMRL, a DRDO laboratory, and it is understood that the research in nEMs is progressing satisfactorily.

Projections

Nanotechnology is permeating in all fields of design & manufacturing of weapons and ammunitions. It is bringing unprecedented precision in weapon systems, robustness in triggering mechanisms and opening new frontiers in propellant and pyrotechnic functioning. In addition to explosive and propellants, nanomaterials have ushered in innovative improvements in many characteristics of ammunition such as guidance, penetration capacity, embedded sensors for monitoring condition, embedded antennae for guidance and so on.

It can be envisaged that nEMs would replace the conventional explosives in the next decade. This would provide existing conventional weapons with explosive powers higher in magnitude by a factor of two and enhance the safety to external stimulation by at least 30%. In simple terms, a missile warhead having an explosive content of 200 kg of TNT equivalent would have an explosive power of 20,000 kg of TNT equivalent when substituted with nEMs material of same weight of 200 kg!

This advancement could displace Tactical nukes from the battlefield.

What can also be foreseen is the mushrooming of new classes of extremely precise and lethal small/micro weapon systems, which could be scaled down by at least second order of magnitude from the current systems- thus creating space for the likely paradigm shift from bigger & larger to the smaller & numerous holdings of weapons. This in turn would herald the era of Swarm Warfare. 

Courtesy: http://www.claws.in/1571/nanoenergetic-materials-nems-in-conventional-ammunition-sanatan-kulshrestha.html