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Author: Subject: Reactive Liners
MineMan
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[*] posted on 7-5-2018 at 13:43
Reactive Liners


I have questions on reactive shape charge liners that I think will turn into a good discussion. Some use Ni, Ti, Hf, Al, and Ta. Others use a combination of PTFE and metal powders.

Is there another fluorine containing molecule that has more fluorine per mass than PTFE and is available (or somewhat available) or is denser than PTFE's 2.0sg??

The paper I found uses around 77 percent PTFE and 23 Percent Al for a reactive liner. The drawback is the density is so low that penetration is sacrificed. I was thinking if the Al was replaced by Ti.

Are heats of formation from fluorine oxidation and different metals easily found? The goal being to achieve the highest density jet, and highest energy of oxidation of the liner material per gram.

Its a bonus if the products can further react with crushed SiO2 from sand or rock....

If I find some answers to my own questions I will update... but my goal is the theoretical maximum damage of igneous (SiO2) based rock; and reactive liners react once they have penetrated into the rock...

[Edited on 8-5-2018 by MineMan]
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[*] posted on 7-5-2018 at 17:27


I like reading the stuff from you energetics fellows, but know very little my self. That being said: Is this in addition to a copper cone, or by itself, doing more of a thermal lance type thing? Sorry I have nothing to add as far as your questions.



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[*] posted on 9-5-2018 at 23:39


Huh, really thought this would have become a popular discussion. Anyway, from an experimentation stand point the challenge is that PTFE seems to need pressing and sintering to create a cone, quite the challenge. Perhaps the mixture can be held between two thin plastic cones.

Another difficult part is the sizing of the PTFE and Al... if it is too fine, it can react before penetration. The only values I have found so far are 28um PTFE and 8um spherical Al... definitely not standard sizes for these materials, as most PTFE powder seems to be 1.6um. Perhaps larger Al can be used to compensate for the smaller oxidizer size. Maybe these powdered mixtures can be mixed and cast with epoxy. The results from these charges are too amazing to pass up, the jet, including kinetic energy has a TNT equivalence of 7.7! So, 100 grams of this high energy jet could be equivalent to 770grams of TNT... buried inside the target!! Truly a shining star for demolition work!

I see Hf, Ta, and Zr as too exotic, not to mention dangerous to test. Al, Ni, And Ti seem like the best metallic fuels for this from my perspective, maybe Zinc also... and Si being a possibility, but most likely inferior to Al.

My other thought is a cone made from tungsten and graphite, which on impact should form tungsten carbide... a fantastically dense and hard material! of course at 7km/s materials act hydro-dynamically and hardness does not matter... but the density of the tungsten should keep the jet well below that speed, the other advantage is the enormous vapor temperature of tungsten carbide, upon impact it should not vaporize, as much....
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[*] posted on 10-5-2018 at 03:07


Look into alloying processes that are exothermic, perhaps?

https://www.sigmaaldrich.com/technical-documents/articles/ma...

Nickel-Aluminum layered cone? Reasonably dense, adds a few more joules...

They don't show Nickel-Iron here, but that releases energy too, probably not self sustaing though.. The original Pyrenol underwater cutting torch thermite formula used both Ni and Fe oxides for this reason.

20180510_084643.png - 327kB

(Edit)

Looks like someone working for Haliburton had a similar idea to OP- Not trying for behind armor effect, intending to use the additional energy to modify the behavior of perf guns and the initial flow of fluids back into the fired perf gun down hole carrier.

They actually trialed depleted Uranium as an SC liner? Of course they did... Wouldn't you? As long as the DU particles don't end up in MY back yard? This patent shows up in a bunch of sites, blogs, etc. by anti fracking people because of the inclusion of Uranium in the examples.

Attachment: Fracking perforator .pdf (123kB)
This file has been downloaded 43 times

Quote:


[0013] In one embodiment, the shaped charge component
may be formed from or may contain a reactive material such
as a pyrophoric material, a combustible material, a Mixed
Rare Earth (MRE) alloy or the like including, but not limited
to, zinc, aluminum, bismuth, tin, calcium, cerium, cesium,
hafnium, iridium, lead, lithium, palladium, potassium,
sodium, magnesium, titanium, zirconium, cobalt, chromium,
iron, nickel, tantalum, depleted uranium, mischmetal or the
like or combination, alloys, carbides or hydrides of these
materials. In certain embodiments, the shaped charge component
may be formed from the above mentioned materials in
various powdered metal blends. These powdered metals may
also be mixed with oxidizers to form exothermic pyrotechnic
compositions, such as thermites. The oxidizers may include,
but are not limited to, boron(III) oxide, silicon(IV) oxide,
chromium(III) oxide, manganese(IV) oxide, iron(III) oxide,
iron(II, III) oxide, copper(II) oxide, lead(II, III, IV) oxide and
the like. The thermites may also contain fluorine compounds
as additives, such as Teflon. The thermites may include nanothermites
in which the reacting constituents are nanoparticles.

...

[0032] The secondary pressure generators may be formed
as all or a part of a charge case such as charge case 128
including as a coating on the charge case, a liner such as liner
130 or the explosive within a shaped charge such as shaped
charge 126. Preferably, the secondary pressure generators are
formed from a reactive material such as a pyrophoric materials,
a combustible material, a Mixed Rare Earth (MRE)
alloy or the like including, but not limited to, zinc, aluminum,
bismuth, tin, calcium, cerium, cesium, hafnium, iridium,
lead, lithium, palladium, potassium, sodium, magnesium,
titanium, zirconium, cobalt, chromium, iron, nickel, tantalum,
depleted uranium, mischmetal or the like or combination,
alloys, carbides or hydrides of these materials. In certain
embodiments, the secondary pressure generators may be
formed from the above mentioned materials in various powdered
metal blends. These powdered metals may also be
mixed with oxidizers to form exothermic pyrotechnic compositions,
such as thermites. The oxidizers may include, but
are not limited to, boron(III) oxide, silicon(IV) oxide, chromium(
III) oxide, manganese(IV) oxide, iron(III) oxide, iron
(II, III) oxide, copper(II) oxide, lead(II, III, IV) oxide and the
like. The thermites may also contain fluorine compounds as
additives, such as Teflon. The thermites may include nanothermites
in which the reacting constituents are nanoparticles.
The reaction generated by the secondary pressure generators
may manifest itself through a thermal effect, a
pressure effect or both. In either case, the reaction causes an
increase in the pressure within perforating gun 100, the near
well bore region or both which counteracts the forces created
by the dynamic underbalance condition in the well bore




[Edited on 5-10-2018 by Bert]




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[*] posted on 10-5-2018 at 19:21


Ok great tip on the alloying energy, now i know the term to search for.

That patent casts a REALLY wide net... but the thing is another patent could be filed if an easier manufacturing method was obtained... hence if there is a fluorine thermoplastic, the metal powder could be added in and the cone could be injection molded, perhaps!

I doubt they really intent to only use a one to two of those metals and oxidizers, pretty crappy that the patent office allows this, it should only if they provide test data for ALL of the materials they use... why not just say basically any metal or transition metal on the periodic table.

I think the best combination would be a Ti, Zr, or Hf hydride with PTFE... that would be unbelievable! As it would produce hydrogen gas.. and that hydrogen gas could further react into HF...

Perf guns are out of my relm :P, at least for now :). No doubt this technology would be good for demolition of buildings and bridges to
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[*] posted on 10-5-2018 at 21:15


MineMan, could you provide the sources (publications) for this? How is TNT equivalence of 7.7 measured? PTFE/Al has energy of 10 MJ/kg. This is 2.5 TNT eq. Even pure Al has 30 MJ/kg, still not 7.7. Not to mention that TNT is capable of fuel-air effects if confinement is presented.


-------------
"The paper I found uses around 77 percent PTFE and 23 Percent Al for a reactive liner. The drawback is the density is so low that penetration is sacrificed. I was thinking if the Al was replaced by Ti. he only values I have found so far are 28um PTFE and 8um spherical Al... definitely not standard sizes for these materials, as most PTFE powder seems to be 1.6um. Perhaps larger Al can be used to compensate for the smaller oxidizer size. Maybe these powdered mixtures can be mixed and cast with epoxy. The results from these charges are too amazing to pass up, the jet, including kinetic energy has a TNT equivalence of 7.7!"




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[*] posted on 13-5-2018 at 14:48



The paper is: Demolition Mechanism and Behavior of Shaped Chargewith Reactive Liner, Jianguang Xiao et al., 2016


Hi Red, I suppose I better respond to my own thread if I want discussions ;)!

Your right, Al only gives around 30MJ/Kg when it oxidizes, but when if fluronates it does give off more energy, the value I don't know... maybe one of our resident chemists can answer?

This would be excluding TNT's FAEs, equivalent TNT comparisons always do. For this one, it seems that they are calculating the equivalence based on the blasted radius of the rock target, (runway in this case)... so not pure energy or MJ to MJ of course. Here are a few quotes from the paper to further explain.

"As listed in Table 2, the TNT equivalence factor for reactive
materials calculated by Equation (5) is 3.41, 7.77, and
5.51, respectively. However, theoretical energy contained in
Al/PTFE (26.5/73.5wt-%) is just 14151 J/g
(about four
times of TNT)."

"The relatively larger value estimated in this
paper could be caused by neglecting the kinetic energy
contained in the shaped charge jet, which also does much
damage to these targets. When the average velocity of
a 1 kg jet varies from 2000 to 6000 m/s
, the kinetic energy
could reach 0.6–5.4 times TNT equivalence. The total of kinetic
and chemical energy tends to be consistent with theoretical
calculation results."




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[*] posted on 14-5-2018 at 22:47


Seems interesting, I've seen for the first time TNT eq to be calculated based on the blasted radius of rock target...

Calculating those energies is easy, anyway, they already did it: 14151 J/g. Don't have time to check if it is correct now. From experimental data I recall it is about 10 MJ/kg, so values are close.




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