Pack cementation aluminide coatings on superalloys: codeposition of Cr and reactive elements
- Ohio State Univ., Columbus (United States)
A single-step chloride-activated pack cementation process has been developed for growing a Cr/RE(Y, Zr)-modified or a RE(Y, Zr, Hf)-doped aluminide diffusion coating on commercial Ni-base superalloys. The coatings consisted of an outward-grown hypostoichiometric [beta]-NiAl layer with a substantial enrichment in Cr and a low reactive element content. The Cr was both dissolved in the [beta]-NiAl matrix and precipitated as [alpha]-Cr second-phase particles. Aluminide coatings grown outwards in a pack permitting powder contact with the substrate were embedded with Al[sub 2]O[sub 3] and reactive element (RE) oxide pack particles. Physical separation of the substrates from the powder mixture eliminated powder entrapment but reduced the growth rate and the amount of Cr enrichment in the coating. Isolation of the substrate from the pack introduced partial rate control by gaseous diffusion.
- OSTI ID:
- 6541299
- Journal Information:
- Journal of the Electrochemical Society; (United States), Vol. 140:4; ISSN 0013-4651
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ALUMINIUM COMPOUNDS
DEPOSITION
CHROMIUM COMPOUNDS
HAFNIUM COMPOUNDS
HEAT RESISTING ALLOYS
DIFFUSION COATINGS
NICKEL BASE ALLOYS
YTTRIUM COMPOUNDS
ZIRCONIUM COMPOUNDS
CORROSION RESISTANCE
DOPED MATERIALS
GAS TURBINES
INTERMETALLIC COMPOUNDS
NICKEL COMPOUNDS
THERMAL STRESSES
ALLOYS
COATINGS
EQUIPMENT
HEAT RESISTANT MATERIALS
MACHINERY
MATERIALS
NICKEL ALLOYS
REFRACTORY METAL COMPOUNDS
STRESSES
TRANSITION ELEMENT COMPOUNDS
TURBINES
TURBOMACHINERY
360601* - Other Materials- Preparation & Manufacture