Nickel-18% chromium binary alloy and alloy 600 (77% Ni, 16% Cr, 8% Fe) have been oxidized at 600 °C for periods of several minutes under 02 pressures of < 10–6to 10 -4Torr 02. The polycrystalline surfaces were pretreated by ion bombardment with 5 kV hydrogen ions. The oxide structure developed thereafter is found to be strongly influenced by grain orientation. One major grain orientation produced a chromium-rich surface oxide, while a second orientation gave rise to a surface oxide with a high nickel concentration. On some grain surfaces, a repetitive pattern of nodule oxide growth was observed with a structural pattern which is peculiar to a specific grain orientation. On surfaces remote from H+ bombarded areas, initial surface oxide composition is more governed by local stresses which develop along scratches. It is argued that alloy surface pretreatment with H+ anneals local mechanical stresses and allows substrate crystallographic orientation effects to become important.
|Number of pages||9|
|Journal||Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films|
|Publication status||Published - Jul 1986|
ASJC Scopus subject areas
- Condensed Matter Physics
- Surfaces and Interfaces
- Surfaces, Coatings and Films