Toward understanding the reaction between silicon carbide and iridium in a broad temperature range

Abstract

The reaction between iridium and SiC in the 1000°C-1900°C temperature range was studied in details. The rate of this reaction was found to depend not only on temperature, but also on the grain sizes of the initial reagents, oxygen impurities in SiC, as well as the Ir: SiC ratio. The use of fine-grained initial reagents accelerates the reaction, whereas oxygen impurities in SiC powders slow it down. For the Ir: SiC ratio = 1:1, the IrSi silicide phase became dominant at 1400°C and remained the main phase at temperatures up to 1900°C. For the 3:1 ratio, Ir 2 Si was the main phase at 1900°C. It was suggested that stabilization of this phase is due to the quenching effect. No Si-rich silicide phases were detected in the 1000°C-1900°C temperature range. The coefficients of thermal expansion of silicide phases were determined by high-temperature X-ray diffraction analysis. K E Y W O R D Siridium, silicide, silicon carbide, thermal expansion GOLOSOV et aL.

High‐temperature solid‐state reaction between zirconium carbide and iridium: New insights into the phase formation

“…An approach involving displacement of the interlayer between the carbon surface and iridium was proposed overcome this limitation 15 . It was suggested that the refractory carbides of group IV–V metals can be appropriate compounds for these purposes 16–19 . Indeed, refractory carbides react with iridium metal at temperatures above 1200°C to form MIr 3 intermetallics, which are thermodynamically and chemically stable and can act as coating materials for operation under extreme conditions 20–22 .…”

“…15 It was suggested that the refractory carbides of group IV-V metals can be appropriate compounds for these purposes. [16][17][18][19] Indeed, refractory carbides react with iridium metal at temperatures above 1200 • C to form MIr 3 intermetallics, which are thermodynamically and chemically stable and can act as coating materials for opera-tion under extreme conditions. [20][21][22] Zirconium-containing refractory compounds are of special interest because they have an obvious advantage over hafnium-or tantalum analogs in terms of density.…”