Diffusion

DIFFUSION

Diffuse your operational issues

To protect high-temperature parts from corrosion and oxidation, we produce a protective barrier by diffusing a metal such as aluminum or chromium into the base metal, which forms a new alloy surface. Typical applications include low- and high-pressure turbine airfoils and marine and industrial gas turbines. 

Diffused Slurry -

Our SermaLoy® slurry-applied aluminide-diffusion coatings are designed to protect gas turbine hot section components and industrial components from hot corrosion. Applied to the component surface and then diffused, these coatings adhere tightly to the part surface. SermaLoy® J coating and its chrome-free version, SermaLoy® J CF, resist both low- and high-temperature hot corrosion and oxidation in marine and industrial gas turbines.

Pack Diffusion -

We provide both pack aluminide and pack chromide services in which parts are placed between layers of powder in a furnace tray or “boat.” The process is referred to as “packed” because the parts are completely covered. The trays are then heated in a furnace until a vapor reaction releases aluminum or chrome to diffuse into the part.

Vapor Phase Diffusion -

Vapor phase diffusion is similar to pack diffusion in that it uses vapor transport. However, the powder source is farther from the parts. This process also allows for vapor to flow into internal passages of such components as turbine blades.

We offer the following vapor phase diffusion processes:

  • Above / beside the pack

  • External chemical vapor deposition (CVD)—These coatings are primarily used to protect the internal surfaces of large, industrial gas turbine components.

  • Simple aluminide structures

  • Platinum aluminide diffusion—The coating choice for many aviation gas turbine hot section airfoils—provides exceptional oxidation protection compared to simple aluminides and is used for many high-pressure (HP) and low-pressure (LP) turbine airfoils where additional environmental protection is needed. Platinum aluminide (PtAl) coatings also provide exceptional Type I and Type II hot corrosion protection and are used in marine and industrial gas turbines to minimize corrosion.