Interfacial reactions between nickel--chromium alloys and aluminum

Journal Article · Wed Apr 15 04:00:00 EDT 1992 · Journal of Applied Physics; (United States)

DOI:https://doi.org/10.1063/1.350887· OSTI ID:7203303

Tan, Z; Heald, S M ^[1]

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1. Brookhaven National Laboratory, Upton, New York 11973 (United States)

We have studied the interface structure and reactions of Ni--Cr alloy and Al thin film bilayers using glancing-angle x-ray reflectivity and extended x-ray-absorption fine structure techniques. The Al/Ni--Cr bilayers were prepared by evaporation in ultrahigh vacuum with a clean interface (Clean) or an interface exposed to 600 Langmuir oxygen (O-exposed). No interfacial reaction is observed at room temperature in either the Clean or the O-exposed samples. Upon annealing for 10 minutes, initial reaction occurs at about 250 {degree}C in the Clean sample and 310 {degree}C in the O-exposed sample. The oxygen impurity at the interface retards the initial reaction and also modifies the diffusion behavior. In both Clean and O-exposed systems, the reaction starts between Ni and Al forming NiAl{sub 3}. The reaction results in a Cr-rich region near the interface which transforms to the bcc structure. Only at higher temperatures do Cr and Al react to form CrAl{sub 7}. The role of various diffusion channels and oxygen impurity at the interface in relationship to the reaction pattern will be discussed.

• DOE Contract Number: AS05-80ER10742
• OSTI ID: 7203303
• Journal Information: Journal of Applied Physics; (United States), Journal Name: Journal of Applied Physics; (United States) Vol. 71:8; ISSN 0021-8979; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
ALLOYS
ALUMINIUM
CHEMICAL REACTIONS
CHROMIUM ALLOYS
DEPOSITION
ELEMENTS
FILMS
INTERFACES
METALS
NICKEL ALLOYS
NONMETALS
OXYGEN
STRUCTURAL CHEMICAL ANALYSIS
SURFACE COATING
THIN FILMS
VACUUM COATING