Vapor Phase Aluminizing is a surface treatment method widely used in various industries, particularly in the aerospace sector, to deposit aluminium coatings on metallic surfaces. This process uses aluminum vapor at high temperatures to enhance the corrosion resistance of components such as turbine parts.

Applications

  • Engine Components: Used for distributors, turbine blades, compressors, and fuel injectors, as well as other critical engine parts.
  • Maintenance and Repair: Used in maintenance processes to restore worn parts and extend their service life.
  • Performance Enhancement: Parts treated with VPA show significant performance improvements under severe operating conditions.
Batch of helicopter turbine blades in final control after aluminization

Operating Principles

  • Surface Preparation: The metal parts to be treated are first degreased and mechanically cleaned (sandblasting) to remove surface contaminants.
  • Loading into the Furnace: The cleaned parts are loaded into a thermochemical furnace where both atmosphere and pressure are strictly controlled.
  • Heating: The parts are heated to high temperatures (800°C – 1200°C) to facilitate the evaporation and diffusion of aluminum.
  • Aluminizing Reaction: Aluminum vaporizes at high temperatures and diffuses into the metal surface, reacting with the base metal to form a protective aluminum coating. This coating also diffuses into the material, creating a diffusion zone enriched with aluminum.
  • Subsequent Testing and Destructive Controls: To ensure the quality of the treatment, mechanical tests and destructive controls are performed to verify the thickness and uniformity of the coating.
  • Coloration Tests: Our laboratory conducts color tests to evaluate the coating’s quality and homogeneity, ensuring all required specifications are met.

Advantages of the VPA Process

  • Improved Corrosion Resistance: The aluminum coating protects parts against oxidation and corrosion at high temperatures.
  • High-Temperature Resistance: Treated parts can withstand extremely high temperatures and corrosive environments, enhancing their durability and performance. 
  • Adaptability to Complex Shapes: The process is particularly suitable for parts with internal cooling channels, ensuring complete and uniform coverage.
Aluminizing Pack
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Application at Revima Engine Parts

At Revima Engine Parts, the Vapor Phase Aluminizing (VPA) process is NADCAP qualified. We use it to produce new parts or repair high-precision components for major clients such as Pratt & Whitney and Safran.

We primarily treat aerospace parts but also cater to other demanding industrial applications. With five thermochemical furnaces and in-house cement production capabilities, we guarantee optimal performance and extended service life by enhancing parts resistance to corrosion and oxidation. We can also couple the VPA process with platinum electroplating, particularly for parts requiring higher resistance at different stages of their service life.

Our Revima engineering office is also available to assist companies with specific part needs in determining the most effective coating process. We also offer services for the implementation of VPA processes within your operations, providing advice and comprehensive technical support.

Conclusion

The Vapor Phase Aluminizing (VPA) process using thermochemical furnaces is an advanced and effective technique for treating metallic surfaces in the aerospace industry.

It allows the deposition of protective aluminium coatings, significantly enhancing the heat and corrosion resistance of parts. By ensuring uniform coating even on complex geometries and optimal diffusion into the material, VPA is essential for maintaining the highest quality and durability standards required in the aerospace sector, ensuring the reliability and safety of treated components.

Contact us at

soa-customers@revima.com