Thermal Stability of Ru–Al Multilayered Thin Films on Inconel 617

Abstract

Ru-riched and equiatomic Ru-Al multilayered thin films were fabricated on Si and Inconel 617 substrates. These thin films exhibited a multilayered structure that is caused by stacking cyclical gradient concentration through cosputtering. X-ray diffraction analysis indicated that the as-deposited Ru-Al multilayers comprised Ru and RuAl phases. Oxidation that is caused by annealing atmospheres and elements diffused from substrates was investigated. The results indicated that the inward diffusion of O at 600 • C in a 1% O 2-99% Ar atmosphere was restricted by the formation of an amorphous Al-oxide sublayer, and inward diffusion of O at 800 • C in air was limited by the formation of a crystalline Al 2 O 3 scale. Additionally, the outward diffusion of elements from Inconel 617 penetrated the unoxidized parts of the 800 • C-annealed Ru-Al multilayers.

Highly Durable Pt–Ru-Doped Ce0.9Zr0.1O2 as an Effective Dual Catalyst for Low-Temperature Simultaneous Propane and Carbon Monoxide Oxidation

“…Therefore, the presence of Ru in the aged catalyst is confirmed. The Ru content decreases upon aging as suggested by SEM–EDX, possibly due to some of the Ru being oxidized to volatile species such as RuO 4 during the high-temperature thermal treatment, − and is subsequently evaporated off the catalyst.…”

Oxidation Behavior of Ta–Al Multilayer Coatings

“…The annealed Ta0.61Al0.39 and Ta0.81Al0.19 coatings maintained multilayered structures ( Figure 3); however, the two outermost stacking periods extended their widths. The thicknesses of the Ti interlayers increased after annealing which was attributed to the interdiffusion of the Ti interlayer and Si substrate [24]. The cross-sectional TEM image (Figure 4a) of the Ta0.61Al0.39 coating annealed at 600 °C for 30 min exhibited a remaining multilayer structure.…”

“…The multilayer structure with O-saturated Al 2 O 3 oxide sublayers benefited to inhibit further oxidation. Moreover, the Ru-Al multilayer films subjected to an ambient atmosphere at 800 • C exhibited a limited oxidation depth [24]. Considering the merits of oxidation resistance and cost reduction, the feasibility of Ta-Al to replace the Ru-Al multilayer coatings in high-temperature applications was evaluated.…”

“…A cubic α-Ta (110) reflection (ICDD 00-004-0788) became clear for the Ta 0.61 Al 0.39 coating that had been annealed at 600 • C, whereas one extra broadened reflection, which was attributed to surface oxidation, was observed for the Ta 0.81 Al 0.19 coating that had been annealed at 600 • C. The annealed Ta 0.61 Al 0.39 and Ta 0.81 Al 0.19 coatings maintained multilayered structures (Figure 3); however, the two outermost stacking periods extended their widths. The thicknesses of the Ti interlayers increased after annealing which was attributed to the interdiffusion of the Ti interlayer and Si substrate[24].Coatings 2019, 9, 810 4 of 10…”

Enhancing the Crystallization and Properties of the SrRuO3 Electrode Film Grown by Atomic-Layer-Deposited SrO and Pulsed-Chemical Vapor-Deposited RuO2 through Al Substitution

“…Toward this end, previous research on the annealing of the RuAl alloy film under the oxygen-containing environment drew attention. , It showed that annealing under the O 2 atmosphere of the alloy film grew the Al 2 O 3 scale layer at the surface, and Ru, separated from Al, formed a Ru-rich RuO x layer under the Al 2 O 3 layer. Moreover, although the Ru-rich layer was oxidized to RuO 2 as the annealing proceeded, it was oxidized considerably slower than pure Ru.…”