Advanced Chemical Vapor Aluminizing Technology: Co-Deposition Process and Doped Aluminized Coatings

Abstract

Chemical Vapor Aluminizing (CVA) is used for more than 20 years to protect blades and vanes in the hot section of aero- and land based turbines against oxidation and hot corrosion [1]. Modern CVA is an advanced process capable of controlled alloying the coating with additional elements using metal chlorides and tight control of the coating composition. CVA processes offer a number of advantages over conventional pack and above-the-pack cementation. This paper deals with the industrial CVA technology to produce multi-component coatings using different metal chloride generating devices. Specific examples illustrate the influence of the coating parameters and base materials on the NiAl-based coatings microstructure and composition. Advanced co-deposition CVA processes with addition of different metal elements to the aluminide coatings are presented. Modified coating properties and structures of multiple metal coatings with elements like Al, Cr, Si, Co, Y and others will be discussed.