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Porous Silicon = Pecrolate + Crystalline Water

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lufer17

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Hello......I left an excerpt from the article and the points that I didn't really understand about it are in bold.

1. I didn't understand about this crystal clear water. I was able to research is that there are actually some crystals in the part of the molecules of the water itself, but I don't Hello......I left an excerpt from the article and the points that I didn't really understand about it are in bold.

1. I didn't understand about this crystal clear water. I was able to research is that there are actually some crystals in the part of the molecules of the water itself, but I don't know exactly how it is really explicit in the same subject of the article.

2. I understood that certain perchlorates have this crystallized and hygroscopic water this can be a disadvantage in the long run, but I did not understand why it is still necessary to have this crystalline water to stabilize the pores of the silicon pores.


Highly explosive nanosilicon-based composite materials -



Due to packaging and long-term stability reasons only solid oxidizers incorporated into the pores of PSi have been explored. The most efficient oxidizers are perchlorates, since they have high oxygen content and are relatively stable in comparison to other oxidizers, e.g. chlorates. Therefore, we have chosen perchlorates as first choice for oxidizer. Unfortunately, most of the perchlorates contain crystal water and are hygroscopic (see Table 2). Non-hygroscopic perchlorates are KClO4 and RbClO4 but they are not solvable in common solvents. We found that perchlorates are much more efficient for explosive interaction than the analogue nitrates. We didn’t find any other oxidizer comparable with perchlorates but, because the energy yield of the reaction is very high, less efficient oxidizers can be sufficient for the possible industrial applications. On one hand, crystal water and hygroscopic nature of perchlorates are certainly disadvantages because they cause problems with long term stability of the samples. On the other hand, according to our experience it seems that at least the crystal water is necessary for stabilizing the salt inside of the pores. For instance, NH4ClO4 is not hygroscopic and contains no crystal water but after evaporation of the solvent it also creeps away of the pores. exactly how it is really explicit in the same subject of the article.

2. I understood that certain perchlorates have this crystallized and hygroscopic water this can be a disadvantage in the long run, but I did not understand why it is still necessary to have this crystalline water to stabilize the pores of the silicon pores.

Highly explosive nanosilicon-based composite materials -

Due to packaging and long-term stability reasons only solid oxidizers incorporated into the pores of PSi have been explored. The most efficient oxidizers are perchlorates, since they have high oxygen content and are relatively stable in comparison to other oxidizers, e.g. chlorates. Therefore, we have chosen perchlorates as first choice for oxidizer. Unfortunately, most of the perchlorates contain crystal water and are hygroscopic (see Table 2). Non-hygroscopic perchlorates are KClO4 and RbClO4 but they are not solvable in common solvents. We found that perchlorates are much more efficient for explosive interaction than the analogue nitrates. We didn’t find any other oxidizer comparable with perchlorates but, because the energy yield of the reaction is very high, less efficient oxidizers can be sufficient for the possible industrial applications. On one hand, crystal water and hygroscopic nature of perchlorates are certainly disadvantages because they cause problems with long term stability of the samples. On the other hand, according to our experience it seems that at least the crystal water is necessary for stabilizing the salt inside of the pores. For instance, NH4ClO4 is not hygroscopic and contains no crystal water but after evaporation of the solvent it also creeps away of the pores.
 

As a youth I was a model rocket enthusiast and fond of chemistry. Certain substances absorb water from the air. The molecule bonds with H20. (Perhaps it's a crystalline structure as the article describes.)

In the case of nitrates and perchlorates used in rocket propellant, having water present reduces its efficiency as an oxidizer. So advice says to heat the chemical before mixing it in propellant, to drive off the water. Thus it becomes more unstable in a manner of speaking.
 

Thank you, I did some more research ..... as I do not know in depth the subject of the process, according to what I understand, the perchlorates have water crystallization, in the oxidation process, it interferes. Failing to find a reason, why can't attack the material.

I know that in the porous silicon manufacturing process, the electrolyte process is used, using 2 or 3 electrodes, a power source, in short a liquid such as hydrofluoric acid is placed where the silicon material becomes porous.

This point I was unable to understand about: Perchlorate is deposited in the porous silicon in the holes, because this crystallization process occurs, if depositing it is not as efficient because of the crystals and the less the crystals the better the result, right? The idea when smaller, the answer will be better, but in any case, there are these crystals, without them there is no ignition / explosion?
I need a better understanding.
 

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