Nav: Home

Safe fog

November 10, 2016

Safety combined with power and effectiveness is one of the most important targets in the development of pyrotechnic obscurants. In the journal Angewandte Chemie, German and Polish scientists introduced phosphorus nitride as a safe but very powerful alternative to the well-known red phosphorus formulations, which have been used in military and civilian applications for decades.

Obscurants fulfill a prominet role in military applications. An obscurant smoke is an aerosol cloud suddenly brought into the line of sight between an observer and a target. The most prominent source for pyrotechnic obscurants is still powdery red phosphorus, although it suffers from quite unsafe handling and a relatively sluggish burning with the possible release of toxic phosphine. Ernst-Christian Koch at Lutradyn-Energetic Materials Science & Technology and Stanislaw Cudzilo at the Military University of Technology in Warszawa (Poland) have now proposed phosphorus(V) nitride as a safe and effective replacement for red phosphorus.

At ambient temperature, phosphorus(V) nitride, P(3)N(5) is a crystalline powder. Its performance was examined in typical pyrolant formulations, that is, mixed with an oxidant such as potassium nitrate. Upon ignition, which means under excessive heat and air, the phosphorus sublimes and undergoes combustion into its oxide, which serves as the actual aerosol-generating machine by taking up large amounts of water from atmospheric air. The resulting smog of phosphoric acid and water microdroplets will then conceal whatever should be taken out of sight.

The scientists reported three main advantages of phosphorus(V) nitride over red phosphorus. Firstly, the nitride burned fast. "The burn rates are two orders of magnitude greater then those obtained with state-of-the-art red phosphorous / potassium nitrate based pyrolants," said the authors. Secondly, it does not hydrolyze to highly toxic and flammable phosphine. Thirdly, and most importantly, it is resistant to friction. "Phosphorus(V) nitride is safe to handle with a range of oxidizers including chlorates, perchlorates, and nitrates," said the authors. Thus, differently from red phosphorus, there should be no need to add vast amounts of protective fillers like graphite to the formulation.

Notably, phosphorus(V) nitride as a commercial compound has no large-scale application yet. With these revelations on its possible use as a highly effective obscurant, this situation might be about to change.
-end-
About the Author

Dr. Koch is founder of Lutradyn - Energetic Materials Science & Technology Consulting company in Kaiserslautern (Germany) and is a specialist in energetic materials. Dr. Cudzilois is a Professor of Chemistry and Dean of the Faculty of Advanced Technologies and Chemistry at the Military University of Technology, Warsaw (Poland). His main specialty is the chemistry and technology of energetic materials.

mailto:e-c.koch@lutradyn.com

Wiley

Related Phosphorus Articles:

Graphene heterostructures with black phosphorus, arsenic enable new infrared detectors
MIPT scientists and their colleagues from Japan and the U.S.
Recovering phosphorus from corn ethanol production can help reduce groundwater pollution
Dried distiller's grains with solubles (DDGS), a co-product from corn ethanol processing, is commonly used as feed for cattle, swine and poultry.
Chemists have managed to stabilize the 'capricious' phosphorus
An international team of Russian, Swedish and Ukrainian scientists has identified an effective strategy to improve the stability of two-dimensional black phosphorus, which is a promising material for use in optoelectronics.
Life could have emerged from lakes with high phosphorus
Life as we know it requires phosphorus, and lots of it.
Reassessing strategies to reduce phosphorus levels in the Detroit river watershed
In an effort to control the cyanobacteria blooms and dead zones that plague Lake Erie each summer, fueled by excess nutrients, the United States and Canada in 2016 called for a 40% reduction in the amount of phosphorus entering the lake's western and central basins, including the Detroit River's contribution.
Reduce, reuse, recycle: The future of phosphorus
Societies celebrate the discovery of this important element in 1669.
Lack of reporting on phosphorus supply chain dangerous for global food security
A new study from Stockholm University and University of Iceland shows that while Phosphorus is a key element to global food security, its supply chain is a black box.
Hydrogenation of white phosphorus leads way to safer chemical technology
White phosphorus is well-known for being a highly toxic compound with suffocating scent.
Rice cultivation: Balance of phosphorus and nitrogen determines growth and yield
Cluster of Excellence on Plant Sciences CEPLAS at the University of Cologne cooperates with partners from Beijing to develop new basic knowledge on nutrient signalling pathways in rice plants.
Ammonia by phosphorus catalysis
More than 100 years after the introduction of the Haber-Bosch process, scientists continue to search for alternative ammonia production routes that are less energy demanding.
More Phosphorus News and Phosphorus Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Meditations on Loneliness
Original broadcast date: April 24, 2020. We're a social species now living in isolation. But loneliness was a problem well before this era of social distancing. This hour, TED speakers explore how we can live and make peace with loneliness. Guests on the show include author and illustrator Jonny Sun, psychologist Susan Pinker, architect Grace Kim, and writer Suleika Jaouad.
Now Playing: Science for the People

#565 The Great Wide Indoors
We're all spending a bit more time indoors this summer than we probably figured. But did you ever stop to think about why the places we live and work as designed the way they are? And how they could be designed better? We're talking with Emily Anthes about her new book "The Great Indoors: The Surprising Science of how Buildings Shape our Behavior, Health and Happiness".
Now Playing: Radiolab

The Third. A TED Talk.
Jad gives a TED talk about his life as a journalist and how Radiolab has evolved over the years. Here's how TED described it:How do you end a story? Host of Radiolab Jad Abumrad tells how his search for an answer led him home to the mountains of Tennessee, where he met an unexpected teacher: Dolly Parton.Jad Nicholas Abumrad is a Lebanese-American radio host, composer and producer. He is the founder of the syndicated public radio program Radiolab, which is broadcast on over 600 radio stations nationwide and is downloaded more than 120 million times a year as a podcast. He also created More Perfect, a podcast that tells the stories behind the Supreme Court's most famous decisions. And most recently, Dolly Parton's America, a nine-episode podcast exploring the life and times of the iconic country music star. Abumrad has received three Peabody Awards and was named a MacArthur Fellow in 2011.