What is plasma electrolytic oxidation?

Plasma Electrolytic oxidation (PEO) is one of several processes that stretch the surface of the metal object with a protective ceramic layer. Materials that can be treated in this way include metals such as aluminum and magnesium, and the ceramic coating is usually oxide. The process has a similarity to anodization, but uses significantly higher electrical potentials, which can cause plasma discharge. This tends to create very high temperatures and pressures along the surface of the workpiece, which can result in somewhat stronger ceramic coatings than traditional anodization. The protective layer created by plasma electrolytic oxidation can provide benefits such as corrosion and wear resistance. Each of the Peo techniques works on the same basic principle, which is that certain metals can be triggered if you want to create a protective oxide coating under the correct conditions. Many metals will naturally form an oxide layer in the presence of oxygen, but it is not usually too strong. To increase the thickness of the oxide coating must be afterUsed anodization and other techniques.

At the most basic level, plasma electrolytic oxidation has a similarity to traditional anodization. The metal workpiece is reduced to the electrolyte bath and connected to the electricity source. In most cases, the metal workpiece will act as one electrode, while the VAT containing electrolyte is the other. Electricity is applied to electrodes that cause hydrogen and oxygen release from the electrolytic solution. Once the oxygen is released, it reacts with the metal and forms a layer of oxide.

Traditional anodization uses approximately 15 to 20 volts to grow an oxide layer on a metal workpiece, a wtertness of electrolytic oxidation techniques in plasma uses pulses of 200 or more volts. This high voltage is able to overcome the dielectric power of oxide, leading to the plasma reactions on which this technique depends. These plasma reactions can create temperatures of about 30,000 ° F (about 16,000 ° C),This is necessary for the formation of thick oxide layers that are able to shape the PEO processes.

oxide coatings that can be created through the electrolytic oxidation process in plasma may be more than several hundred micrometers (0.0078 inches) in thickness. Anodization can also be used to create oxide layers up to about 150 micrometers (0.0069 inches) thick, although this process requires a strong acid solution, unlike diluted basic electrolyte, usually used for plasma electrolytic oxidation. The PEO coating properties can also be changed by adding different chemicals to the electrolyte or by changing the timing of the voltage pulses.