What Does Aluminizing Mean?

Aluminizing is a high-temperature chemical vapor deposition (CVD) process whereby aluminum vapors diffuse into the surface of the base metal, forming new metallurgical aluminide alloys. Interdiffusion between the depositing aluminum and the substrate alloy results in the formation of the intermetallic coating, primarily NiAl, CoAl, FeAl or TiAl depending on the alloy base, but containing to a degree, most of the elements present in the base alloy, either in solution or as dispersed phases.

The aluminizing process protects the base material from corrosion at elevated temperatures. Aluminizing is used extensively by industry to protect steel components from heat oxidation and corrosion at extreme temperatures ensuring long-term protection.


Aluminizing is not an inexpensive process, however when protection of process components that see high-temperature and corrosive environments is performed, the extended life of those components and the downtime associated with replacement is considered, the return on investment is realized. Aluminum diffusion alloying inhibits corrosion by protecting the surface of steels, stainless steels and nickel alloys operating in severe high-temperature environments where corrosion is also contributing to the ultimate failure of the component.  It is very effective in combating the effects of sulfidation, oxidation, and carburization.

Aluminized alloys are used to increase the processed material’s resistance to:

  • Sulfidation – steel protection from H2S, SO2 and SO3 attack
  • Oxidation – stable aluminum oxide film formed
  • Carburization – prevents carbon diffusion into base metal
  • Hydrogen permeation – diffusion rates of H2 into steel reduced
  • Metal Dusting

Aluminizing is particularly effective for protecting mild, low alloy and high carbon steels. It is very effective at protecting generator chimneys, ducts, generator mufflers and boiler chimneys against heat and corrosion at high temperatures. Aluminized components used in marine and acidic environments perform extremely well. The aluminized products are particularly resistant to attacks by sulfurous gases which make them very popular in petrochemical processing equipment and gas plants.

Applications using the Aluminizing Process:

  • Oil & Gas Tubes and Pipes
  • Industrial Furnace Components
  • Catalyst Trays
  • Solar Power Plant components where molten salt corrosion is prevalent
  • Hydrogen Generation – Steam reformer tubes and other components experiencing metal dusting
  • Steam Methane Reforming (SMR)
  • Methanol Production
  • Gas Desulfurising Processes
  • Furnace Burners

At Ferralloy, Inc. our team can customize the proper surface treatment technology to your specific requirements. Call or email us today to learn more about how we can help with your Aluminizing requirements.

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