What Is Plasma?

What Is Plasma?

Plasma is the fourth state of matter. It has incredible potential, which has also been utilised by our Otinus brand.

A little bit of history

Most of us only learned about the three states of matter at school, and this is because it was not long ago that plasma began to be commonly referred to in this context. The first research was carried out in 1928 by the American physicochemical and Nobel Prize-winning pioneer of research into electrostatic discharges in gases, Irving Langmuir.

Physical characteristics

The states of matter change are influenced crucially by energy. If we deprive a body of energy, it result in the distance between atoms that decreases and the motion of molecules slows down until it stops altogether.

Our theory is confirmed by the following two examples from everyday life:

  • At low temperatures, water freezes because it gives up energy as it cools.
  • Water heated in a vessel evaporates because we provide it with energy.

And so, we distinguish four states of matter:

  1. Solid – Distances between particles are smallest. It is difficult to change the shape of matter and its volume. Particles maintain a fixed position.
  2. Liquid – It is difficult to change volume, and the matter takes the shape of the vessel it is in. The molecules move freely.
  3. Gas – The matter takes on the shape, and volume of the vessel it is in. The distance between molecules is greatest and a high degree of mobility can be observed.
  4. Plasma – Its state of matter resembles a gas in which a significant proportion of the molecules are electrically charged. Depending on the type of plasma, its properties change.

There are three types of plasma according to temperature:

  • Hot plasma (thermal) – with a temperature of more than 1 million K – it is what forms stars.
  • Ring Discharge Plasma – very difficult to study. It is obtained at high electromagnetic field frequencies and low pressures.
  • Cold plasma (non-thermal)- we can observe it on earth e.g. during electromagnetic discharges or in human-made devices called plasmotrons. An example of its use in human activities are our plasma cutters.

How to create a plasma arc?

To produce a plasma arc, we need three things. The first is electrodes between which we want to create an arc. The second is the high voltage with a potential difference of up to 10 kV with a high frequency of 2 MHz. It would seem that an extensive infrastructure is needed to power such a device, but this is not true. A 230 V~ power supply is sufficient to power a system capable of these parameters. The last thing is an inert gas such as argon, nitrogen, or even air, which creates a plasma stream when heated with an electric arc. A device constructed in this way is called a plasmotron, and the plasma particles obtained in it, contain a very high thermal energy density.

Interesting fact

There are also other methods of creating a plasma arc. In the picture, we can see a popular gadget that no science centre can do without. It is a plasma ball (also called a plasma lamp) initially designed by Nikola Tesla.

It produces spectacular electrical discharges in an environment made of a mixture of suitable and highly dilute gases (or very dilute air).

The lamp pedestal contains an internal oscillation circuit that supplies the internal electrode with a high voltage of 10 kV potential and a high frequency of 35 MHz.

The sphere consists of a sealed glass bubble containing a gas and the centrally placed electrode. In a device constructed in this way, ionisation of the gas takes place under the influence of a propagating electric field.

The striking light filaments are plasma. This device shows that it can also be obtained in an electric field. The gadget described has no use whatsoever, apart from its visual and educational effect.

Plasma – let us move on into practice

There are two types of plasma arc created in plasmotrons. One is internal, i.e. obtained between two electrodes. The second arc is created between a torch (electrode) and the workpiece, which must be a good conductor of electric current. This type of arc is used in plasma cutting machines.

As a result, the process is used for machining metals such as steel, aluminium alloys, copper alloys, etc. All in all, the advantage of plasma is that it can be used to cut materials such as stainless steel or tungsten.

The cutting time

The cutting time depends on the thickness of the material to be cut and can be as fast as 10 m/min and the material thickness can be up to 60 mm for low carbon steel. Therefore, in order to obtain a high-quality edge, rotating gases are additionally used to narrow the plasma stream. These are common gases. Thereby, for low carbon steels, oxygen or air is used, and for acid resistant steels nitrogen or a nitrogen/hydrogen/oxygen mixture is.

Handheld plasma cutters vs numerical plotters

There are handheld plasma cutters, which are very similar in appearance to welding machines. They have a wide range of practical applications. Moreover, it is worth remembering that the plasma stream is very precise, and the human hand will not use all of its possibilities. Here, where numerical plasma cutting machines come in, which the modern industry uses extensively. They are very precise and fast.
Additionally, it allows favourable planning of the sheet to be cut. A well-positioned machine will also leave a high-quality edge that will not require additional processing. In short, such a device significantly speeds up working time and improves productivity.

To summarise

Plasma is the fourth state of matter, which is created when a gas is heated to very high temperatures by, for example, an electric arc. The molecules of this gas become electrically charged and have a very high heat density which we can direct.

Have you got interested in plasma?

We invite you to take a look at our sales offer. With our plasma, you will make precise cuts and speed up the production process, where the only limit is imagination.

If you have any questions, please send us an email or leave a comment.

We will respond with pleasure 🙂

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