High-temperature stability of nichrome in reactive environments

Nichrome, the commercially available nickel-chromium alloy, was employed in the, hot-wire chemical vapor deposition (HWCVD) of Teflonlike thin films. The stability and reactivity of this material under HWCVD conditions was studied using measurements of deposition rates, electrical resistance, and x-ray photoelectron spectroscopy (XPS). It was found that under HWCVD conditions, the performance of Nichrome 80 declined for approximately 5 h before stabilizing. The stabilized ribbons could then be used for another 5 h before the ribbons experienced mechanical failure. The transient behavior was attributed to preferential oxidation of chromium and subsequent segregation of nickel. Substantial differences were observed in the behavior of the Nichrome 60 and 80 alloys, which. was attributed to differences in the phase stability of these two materials. (C) 2003 American Vacuum Society.