Distribution of ion-implanted yttrium in Cr sub 2 O sub 3 scale and in the underlying Ni-25 wt % Cr alloy

Conference · Mon Jul 01 04:00:00 EDT 1991

OSTI ID:5207393

Hou, P Y; Brown, I ^[1]; Chia, V ^[2]

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1. Lawrence Berkeley Lab., CA (United States)
2. Evans (Charles) and Associates, Redwood City, CA (United States)

Implantation of yttrium and other reactive metals has been known to show significant effects on the oxidation behavior of Cr{sub 2}O{sub 3}-forming alloys. The oxide growth rate decreases by nearly a factor of ten, and the adhesion of oxide scales to alloys is greatly improved. To better understand the mechanisms by which these elements affect oxidation, it is important to know whether or not they are present in the metal ahead of the oxide layer. In this study, the diffusivity of implanted yttrium in a Ni-25 wt %Cr alloy and its distribution in the oxide scale after different oxidation times have been evaluated using secondary ion mass spectroscopy. It was found that only 17 ppm of yttrium was left in the alloy after just 20 minutes of oxidation at 1000{degrees}C. The implanted Y remained concentrated at the oxide/gas interface as the oxide thickened with time. Within the oxide layer, the Y concentration progressively dropped to zero at the scale/alloy interface. These results are discussed in relation to several important mechanisms proposed for the beneficial effects of reactive element additions on scale adhesion. 17 refs., 5 figs.

• Research Organization: Lawrence Berkeley Lab., CA (United States)
• Sponsoring Organization: EPRI; Electric Power Research Inst., Palo Alto, CA (United States)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5207393
• Report Number(s): LBL-31008; CONF-910707--8; ON: DE92000734
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360105* -- Metals & Alloys-- Corrosion & Erosion
360106 -- Metals & Alloys-- Radiation Effects
656003 -- Condensed Matter Physics-- Interactions between Beams & Condensed Matter-- (1987-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALLOYS
CHALCOGENIDES
CHEMICAL REACTIONS
CHROMIUM ALLOYS
CHROMIUM COMPOUNDS
CHROMIUM OXIDES
DIFFUSION
ELEMENTS
ION IMPLANTATION
METALS
NICKEL ALLOYS
NICKEL BASE ALLOYS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PHYSICAL RADIATION EFFECTS
RADIATION EFFECTS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
YTTRIUM