In-Situ Metal-Gas Reaction Studies

Abstract

Studies of the kinetic and microstructural aspects of the high-temperature interaction of oxygen and hydrogen with single crystalline {100} nickel films were conducted in-situ in a differentially pumped UHV specimen chamber of a transmission electron microscope. To atomically clean the specimen surface before initiating the reaction process, a miniature argon ion gun was developed and installed in the chamber, allowing sputter etching of the specimen surface under simultaneous electron microscope observation while removing surface material at a rate of up to 50 Å/min. The background pressure in the chamber was in the low 10−9 torr range. During the ion etching and metal-gas reaction processes, the total contribution of all background gases – except for tne particular reaction gas – was kept below 2×10−8 torr and recovered to the low 10−9 torr range within several minutes after closing the gas inlet valve.