Various types of aluminium

[Giammy7]

I would like to learn the difference between stabilized aluminum and normal aluminum, also the dimensions of aluminum for example lamellar, plate etc.

[mx5kevin]

The dimensions of aluminum for example:

https://pyrodata.com/chemicals/Aluminium

I would like to learn the difference between stabilized aluminum and normal aluminum:

Fireworks The Art Science and Technique by Takeo Shimizu page 121 Aluminum

Stabilized aluminum, you have to stabilize it if necessary. 2% H3BO3 are dissolved in small amount of water than with it over coated the aluminum, and dried at room temperature. There are cases when this is just not allowed.

 

There is a type of aluminum powder that is horribly bad to work with. This is the 45µ firefly paint grade Flake aluminum which flutters in air and is extremely bright. It floats into the air, everything get painted from it, seeps through the gaps in the devices. I recommend avoiding this type far away.

When purchasing a given composition, it is very important to pay attention to the grain size of the metal powder it requires. If you put it in a composition that requires it 3-12µ aluminum, using a 40µ aluminum it will not work properly.

In terms of brands, there may be a different brand, but the product does and will know the same thing in compositions. As an example Eckart 5413H Super, Pyro Dark, Super Dark, Indian Black all knows the same Dark (Pyro) Aluminum. You buy a 1-2 micron aluminum for pyrotechnic purposes not better than 3-4 or 4-6 micron, but the price can be double.

Blue Aluminum if you buyght another 30 micron Atomized Aluminum the same product, and knows the same.

It is factory stabilized (against the oxygen in the air, possibly against some moisture in air), and Blue Aluminum are safer marketing gimmick and that's not true, if someone wants to sell this as safer aluminum.

Micron, the lower the number, the finer the powder. Mesh, the higher the number, the finer the powder. 400 mesh most of the particles are around this value, -400 mesh mainly the particles are so fine and it contains even finer particles (this is recommended), +400 mesh mainly the particles are so fine and it contains even more coarser particles not recommended, + and -mesh it is worth looking at the data sheet to see what proportion of other particle sizes it contains. The finer the metal powder, the denser it is, the darker it is. Magnesium and Magnalium 50/50 alloy must be coated in all case, if not NH4ClO4 are used 5% boiled linseed oil dried to them will protect them. Magnesium and Magnalium are much more reactive than aluminum. KClO4 Al 70/30 with 2-12 micron aluminum are similarly strong than with KClO4/Mg 50/50 with -400 mesh (40 micron Magnesium). In the case of magnesium, strong reactions with oxidizers do not require such finesse as in the case of aluminum.

Edited July 17 by mx5kevin

[Zumber]

On 7/16/2024 at 5:43 PM, Giammy7 said:

I would like to learn the difference between stabilized aluminum and normal aluminum, also the dimensions of aluminum for example lamellar, plate etc.

There are three basic types of aluminium.

1- Dark aluminium: it is extremely fine flake aluminium and its darkness is due to presence of carbon during its manufacturing.

Darkness is also due to light effect as light scatter to fine particles and appears dark.

Examples are Indian dark,German dark.

2- Bright aluminium-It is also flake aluminium but flakes are carbon free and its particle size is larger than dark aluminium.

3- Light aluminium-it is usually atomized aluminium. Molten aluminium is sprayed to inert atmosphere and according to that It is categorised as a) spherical b)spheroidal c) granular 

For aluminium mesh size It is not mean that all particals should pass that particular mesh.

For example -325 mesh aluminium means not all particals should pass 325 mesh it does mean that most of particals (more than 50 percent) should pass 325 mesh.

Stability of aluminium-

Aluminium reacts instantly with air to produce Al2O3 (aluminium oxide) and this coating makes aluminium more resistant to corrosion.Aluminium dissolves in alkali liberating H2 gas and forms aluminates ,so in alkaline solution aluminium reacts with nitrate in presence of water to form ammonia and product of this reaction is alkaline. The alkaline product in reaction and heat produced accelerates the attack of aluminium generating ammonia gas and more heat and can results spontaneous ignition. 

At the time of manufacturing aluminium, stearin is added to avoid sticking of aluminium particals together so this coating resists above reaction and make aluminium more stable.

If aluminium is uncoated 1 or 2 percent boric acid neutralize reaction.

[greenlight]

The spherical atomised form of aluminium also has the smallest surface area and least reactivity.  The smoother rounded edges require more energy to ignite.  This form is more suited to flare and illumination compositions.

The flake form has the highest surface area and smallest particle size (if not bright) with high reactivity.  The rough thin edges also take ignition a great deal easier.             This is the form that is preferred for flash compositions due to these reasons.

[Mumbles]

You may want to check out the pinned topic at the top of this section. 

https://www.amateurpyro.com/forums/topic/40-submission-of-new-compositions/