Silicon explosive

S.K.Lazarouk, A.V.Dolbik, V.E.Borisenko, Photogallery of lightning ball formed by porous silicon explosion and combustion processes, www.nano-center.org (2005). 

The energy yield of porous silicon explosive devices was measured using a calorimetric bomb test, resulting in a value of 7.3 kJ/g with calcium perchlorate as oxidizer (Clement et al. 2005). Differential scanning calorimetry techniques were also used to measure the energy output for sodium perchlorate at almost 9 kJ/g (Plummer et al. 2008). The extent of the NaC104 reaction was observed with bomb calorimetry in N2 and O2 atmospheres. Without the supplementary O2 environment, the heat of reaction was measured to be 9.9 1.8 kJ/g, but with supplementary O2, the reaction yielded 27.3 3.2 kJ/g and approached the theoretical value of 33.0 kJ/g for complete Si oxidation (Becker et al. 2010). 

The temperature of the flame and the amount of gas generated during the nano-explosion were also experimentally investigated (Mason et al. 2009). The nominal maximum flame temperature for most porous silicon oxidizer systems is about 3,000 K, with the oxidant sulfur an exception where the flame temperature is only 1,600 K. The maximum gas production of the porous silicon explosives ranged from 650 cm /g of reactant for sulfur to 4,800 cm /g of reactant for NaC104. 

Silicon hydride (Silane) (SiH4) Explosive Rapid... 

Group 3 Nitrate/metal compositions without sulphur Compositions with <35-65% chlorate Compositions with black powder Lead oxide/silicon with >60% lead oxides Perchlorate/metal Burn fast Large firework shells Fuse protected signal flares Pressed report cartridges in primary packagings Quickmatches in transport packagings Waterfalls Silver wheels Volcanoes Black powder delays Burn very violently with single-item explosions... 

When this reaction has occuiTcd accidentally sufficient hydrogen chloride has been liberated to explosively burst the vessel. The purest form of hydrogen chloride is made by the action of water on silicon tetrachloride ... 

These alloys have corrosion resistance similar to that of copper, with mechanical properties equivalent to mild steel. Because silicon bronzes do not generate sparks under shocks, they can be used in the fabrication of explosion-proof equipment. Compared to tin bronzes, the tinless bronzes have a higher shrinkage (1.7-2.5% against 1.3-1.5% of tin bronzes) and less fluid-flow, which is an important consideration in designing. 

To retard corrosion and to facilitate future maintenance (e.g., allow the non-destructive removal of threaded Junction box covers), all threaded connections should be lubricated with an antiseize compound which will not dry out in the environment. If lubricant is applied to the threaded (or flanged) portion of covers of explosion-proof enclosures, the lubricant must have been tested and approved as suitable for flame path use. It is cautioned that some lubricants contain silicone, which will poison most catalytic gas detector sensors and should not be used near gas detectors. 

W.B. Steward, A Fractographlc Investigation of Explosively Fragmented Silicon-Manganese Steels By Scanning Electron Microscopy , FA-M72-1M (1972) 50) J.W S. Hearle,... 

Explosive Properties. It undergoes an expl reaction with H2, but concn and temp limits of the expin were not reproducible in Pyrex or stainless steel reactors, probably due to the presence or absence of Initiating radicals on the walls. The results became more reproducible after the walls were coated with silicone oil. Addn of tetrafluorohydrazine to H2/difluoramine or H2/N trifluoride mixts caused immediate explns (Ref 9). It also can expld on contact with reducing agents or from high press produced by shock wave or blast (Ref 11)... 

In the study by Hetsroni et al. (2006b) the test module was made from a squareshaped silicon substrate 15 x 15 mm, 530 pm thick, and utilized a Pyrex cover, 500 pm thick, which served as both an insulator and a transparent cover through which flow in the micro-channels could be observed. The Pyrex cover was anod-ically bonded to the silicon chip, in order to seal the channels. In the silicon substrate parallel micro-channels were etched, the cross-section of each channel was an isosceles triangle. The main parameters that affect the explosive boiling oscillations (EBO) in an individual channel of the heat sink such as hydraulic diameter, mass flux, and heat flux were studied. During EBO the pressure drop oscillations were always accompanied by wall temperature oscillations. The period of these oscillations was very short and the oscillation amplitude increased with an increase in heat input. This type of oscillation was found to occur at low vapor quality. 

This oxidant reacts with many compounds. In organic chemistry it is an agent which entirely oxidises substances enabling one to measure them. In microbombs , the contact causes a small explosion. Thus silicon compounds are converted into silica, which can then be measured by gravimetry. When opening the bomb , overpressures can cause comosive substances (especially peroxide in excess) to be thrown up and cause harm. 

Chlorine has caused numerous accidents with metals. Beryllium becomes incandescent if it is heated in the presence of chlorine. Sodium, aluminium, aluminium/titanium alloy, magnesium (especially if water traces are present) combust in contact with chlorine, if they are in the form of powder. There was an explosion reported with molten aluminium and liquid chlorine. The same is true for boron (when it is heated to 400°C), active carbon and silicon. With white phosphorus there is a detonation even at -34°C (liquid chlorine). 

Lead oxide reacts violently with numerous metals such as sodium powder (immediate ignition), aluminium (thermite reaction, which is often explosive), zirconium (detonation), titanium, some metalloids, boron (incandescence by heating), boron-silicon or boron-aluminium mixtures (detonation in the last two cases). Finally, silicon gives rise to a violent reaction unless it is combined with aluminium (violent detonation). It also catalyses the explosive decomposition of hydrogen peroxide. 

Boron reacts explosively when ground with silver fluoride silicon reacts violently. Titanium... 

As it reacts explosively in bulk, the amount of silicone grease used on joints must be minimal. 

Interaction of the lithium derivative with a range of chloro- and fluoro-derivatives of arsenic, boron, phosphorus, silicon and sulfur during warming to 25°C tended to be violently exothermic in absence of solvent. Thionyl chloride reacted with explosion. See Hexafluoroisopropylideneamine Butyllithium See other jv-metal derivatives... 

Paritosh, D. R. et al Chem. Abs., 1994, 121, 35869j U.S. Pat. Appl. 42,229 Paritosh, D. R. etal., Phosphorus, Sulfur, Silicon Relat. Elem., 1994, 90(1-4), 175 This and several other compounds with fewer nitro groups and partial replacement of the spiro rings by halogen are patented as explosives. 

The finely powdered silicide is a significant dust explosion hazard [1]. The lower explosion limit for a calcium-silicon dust cloud of mean particle size 9.7 pm was measured as 79 g/m3, in good agreement with a calculated value [2], Other dust cloud parameters are presented and related to predictions [3],... 

MRH Aluminium 10.71/33, iron 4.35/50, magnesium 10.88/40, manganese 5.06/50, sodium 5.56/55, phosphorus 7.32/25, sulfur 4.27/20 Mixtures of the chlorate with ammonium salts, powdered metals, phosphorus, silicon, sulfur or sulfides are readily ignited and potentially explosive [1], Residues of ammonium thiosulfate in a bulk road tanker contaminated the consignment of dry sodium chlorate subsequently loaded, and exothermic reaction occurred with gas evolution during several hours. Laboratory tests showed that such a mixture could be made to decompose explosively. A reaction mechanism is suggested. 

Silicone process oils mixed with liquid chlorine confined in a stainless steel bomb reacted explosively on heating polydimethysiloxane at 88-118°C, and poly-methyltrilluoropropylsiloxane at 68-114°C. Previously, leakage of a silicone pump oil into a liquid chlorine feed system had caused rupture of a stainless steel ball valve under a pressure singe of about 2 kbar. 

A highly explosive liquid [1]. Early attempts failed to isolate it but prepared numerous other explosive compounds. Reaction of dichlorine hexoxide with silicon tetrachloride or tetrabromide gave an explosive solid, apparently a perchlorato oligosiloxane. Silver perchlorate and silicon tetrahalides in ether gave explosive volatile organics, perhaps ethyl perchlorate. Replacing ether by acetonitrile as solvent, a solid (di)acetonitrile adduct of the tetraperchlorate precipitated, described as exceptionally explosive even in the smallest quantities [2],... 

Boron (finely divided forms) reacts violently with cone, acid and may attain incandescence. The vapour of phosphorus, heated in nitric acid in presence of air, may ignite. Boron phosphide ignites with the cone, acid [1], Silicon crystallised from its eutectic with aluminium reacts violently with cone, acid [2], arsenic may react violently with the fuming acid, and finely divided carbon similarly with cone, acid [3], Use of cone, acid to clean a stainless steel hose contaminated with phosphorus led to an explosion [4],... 

A mineral was being leached by heating with 7 M nitric acid in a PTFE-lined bomb heated by immersion in a silicone oil bath, and at 195°C a violent explosion occurred. This was attributed to prior leakage of oil into the pressure vessel, which had been immersed in the oil at 120°C, then allowed to cool, before being heated to the higher temperature. Appropriate precautions are recommended. 

Spontaneous explosions have been observed [1] with this dangerously explosive material, especially when pure. A sample at 0°C exploded during removal of traces of benzene under high vacuum [2], A residue containing the tetraazide, silicon chloride triazide and probably silicon dichloride diazide, exploded on standing for 2 or 3 days, possibly owing to hydrazoic acid produced by hydrolysis. 

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