High-Temperature Gas Turbine Blade Coatings with LSR™

Repaired RB211 Blades

Why Gas Turbine Hot Section Components Need Advanced Coatings

Gas turbine hot section components traditionally rely on plain or modified diffused aluminide and MCrAlY overlay coatings for enhanced surface oxidation or hot corrosion protection. These coatings are industry standard, and the processes involved often demand specialized facilities and intricate logistics, leading to extended manufacturing and repair cycles. Liburdi Engineering responded with the LSR process to reduce cycle time and delivery. LSR is an environmentally friendly, adaptable coatings process applied by brushing, dipping, or spraying components and letting them cure by air drying for one hour before further processing or handling them.

How the LSR™ Gas Turbine Coating Process Reduces Cycle Time

The LSR process uses a slurry mixture of powdered metals, organic binders, and solvents containing only metallic alloying elements and hydrocarbons. The slurry is hexavalent chrome-free, and once applied and cured, it forms a green coating layer of metal powder embedded in a polymer matrix. Curing at ambient temperature produces a robust coating with excellent control over thickness and uniformity.

One notable advantage of LSR is its ability to incorporate coating operations within manufacturing or repair cells, reducing overall cycle time. The process eliminates the need for specialized facilities and complex logistics, streamlining the coating process for enhanced efficiency.

Available Aluminide Coating Options with LSR™

Liburdi's LSR process accommodates various aluminide coatings with different compositions and microstructures. We can provide plain aluminide coatings, silicon-modified aluminide coatings, platinum-modified aluminide coatings and others. These coatings exhibit microstructures, chemistries, and oxidation behaviour comparable to conventional coatings, ensuring excellent oxidation resistance and durability.

Nickel aluminide formed on IN738 alloy by diffusion of an LSR aluminum slury at 1080°C.
Figure 1: Nickel aluminide coating formed on IN738 alloy using LSR™ diffusion process

Environmentally Friendly Gas Turbine Coatings

LSR coatings are environmentally friendly. We carefully formulate our unique slurry mixtures to exclude chlorine, fluorine, sulphur, phosphorus, or potassium contaminants and are hexavalent chromium-free, making LSRa sustainable practice. The process minimizes hazardous waste concerns associated with traditional coating methods, making LSR an environmentally conscious option.

Proven Performance Through Testing and Turbine Service Experience

‍LSR™ coatings have successfully undergone multiple laboratory cyclic oxidation tests to assess their performance. The results reveal a consistent cyclic oxidation behaviour comparable to reference coatings in both LSR™ aluminide and silicon-modified aluminide coatings. But we have more to offer than just lab tests. With extensive operational experience spanning several years and OEM acceptances such as Magellan, Liburdi's operational experience proves our coatings' suitability for demanding turbine environments.

Pt/Si-aluminide produced by a platinum-bearing LSR slurry diffused at 1080°C.
Figure 2: Pt/Si aluminide gas turbine coating produced using platinum-bearing LSR™ slurry
Comparative cyclic oxidation behaviour of LSR coatings and reference coatings as characterized by remnant beta phase left after 650 cycles at 1120°C.
Figure 3: Cyclic oxidation comparison of LSR™ coatings vs reference turbine coatings

Why LSR™ Is a Smarter Choice for Turbine Component Coatings

LSR coatings are an efficient, environmentally friendly, reliable and sustainable alternative to timely conventional coating processes. Our performance in demanding turbine environments exceeds expectations time and time again. Bottom line: Liburdi offers quality coatings and saves you time and money. Why go anywhere else?

Are you interested in learning more about LSR™ or other Gas Turbine Services and Component Repairs Liburdi offers? ‍

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