Surface Coating / Alfa Chemistry

High Hardness Surface Coating


Materials science is a field that is constantly changing. New surface coating options are emerging as materials technology advances and application needs grow. High hardness and sliding wear resistance are ideal features for high-performance applications. Alfa Chemistry can create a high-hardness, sliding-wear-resistant surface coating for use in oil and gas, aerospace, and other industrial applications, considerably improving the coating's performance and longevity.

Why Do You Need A High Hardness Surface Coating?

When two surfaces glide against each other, dry sliding wear occurs. Wear results in the loss of material from the surface, as well as an increase in the rate of corrosion. To withstand wear and avoid failure, high-hardness materials with high wear coefficients are widely employed in aerospace, oil and gas, and other industries.

High Hardness Surface Coating

Aluminum and titanium alloys have outstanding strength-to-weight ratios, but their low wear coefficients limit their use in frictional applications. When a light alloy component is exposed to wear under normal working conditions, it loses material at a faster rate, lowering the component's life. Alfa Chemistry can improve this with a surface coating.

Light alloys with hard coatings can replace more expensive wear-resistant steels or other corrosion-resistant materials due to their good wear resistance. They can also be utilized to reduce contact corrosion, boost electrical or thermal insulation, and improve sliding properties.

Suitable High Hardness Surface Coating Solution

Alfa Chemistry is a sophisticated surface coating solution for light alloys that fundamentally changes the performance characteristics of the light-alloy by applying a plasma electrolytic oxide (PEO) surface coating to the alloy surface. A unique irregular porosity microstructure in the PEO crystalline oxide film coating provides a sliding wear surface for light alloys. Because this porous microstructure provides a superior surface for adherence to other coatings, it allows for the customization of the surface coating by adding secondary or dual coatings.

High Hardness Surface CoatingFig 1. Incorporation of TiN nanoparticles into the composition of PEO coatings can significantly improve the mechanical properties of magnesium alloy surfaces. (Mashtalyar D. V, et al. 2020)

PEO coatings are created by passing an electric current through the electrolyzer's components. The coating qualities can be adjusted by changing the electrolyte composition, voltage, electrical state, and so on, and Alfa Chemistry can leverage this property to provide the customer with the wear resistance required for their design needs.

PEO Process Stages

  • Stage 1

Light alloy parts are oxidized by running a high voltage current through an electrolyte, which is usually a proprietary dilutes aqueous solution free of heavy metals. Alfa Chemistry employs a variety of electrical solutions, depending on the required coating qualities.

  • Stage 2

The high potential generated by the current in the electrolyte causes an increase in the surface temperature of the light-alloy substrate, resulting in a plasma discharge that creates optimal circumstances for the oxide to crystallize mildly and under high pressure. Chemical passivation, low stiffness, and thermal stability are also characteristics of plasma modification.

  • Stage 3

Discharge holes are generated in the coating's outer surface structure as a result of plasma discharge. Alfa Chemistry infuses the outer layer with performance-enhancing reagents that allow the bespoke electrolyte elements to connect to the layer's ceramic composition. Additional coatings can be applied to the plasma-created surface, which adheres firmly to the porous oxide outer layer. Alfa Chemistry can then pick materials to customize the coating qualities to the component's unique application.


  • Mashtalyar D. V, et al. (2020). "Hard Wearproof PEO-Coatings Formed on Mg Alloy Using TiN Nanoparticles." Applied Surface Science. 503: 144062.

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