Effect of silicon additions on the high temperature oxidation behaviour of Cr–Cr2Ta alloys

On ultra‐high temperature oxidation of Cr–Cr3Si alloys: Effect of germanium

“…Figure compares the parabolic rate constants of alloys studied in this work with a survey summarized by Kofstad on chromia‐forming binary chromium alloys and alumina‐forming alloys . We updated this survey with corresponding data from this work and those reported in recent publications on Cr–W and Cr–Ta alloys by Bhowmik et al and Dogan et al, respectively. To the best of our knowledge, no information is available on the oxidation behavior of Cr alloys at 1350 °C.…”

“…At high temperatures, however, the rapid oxidation of Cr in the initial stage suppresses the influence of the weight loss due to CrO 3 evaporation and results in a parabolic‐like oxidation curve . It has to be noted that, although evaporation of Cr is a well‐known effect in high temperature oxidation of chromium, a term regarding this evaporation step is not considered in the discussion of oxidation kinetics for Cr–W and Cr–Ta alloys .…”

“…However, these advantages are negated by the low ductility at room temperature, embrittlement in air at high temperature by nitrogen contamination, and low oxidation resistance at ultra‐high temperatures (>1000 °C) due to the oxidation of chromia . Researchers have been working on enhancing the mechanical and high temperature performance of Cr‐based alloys by micro–macro alloying with binary–ternary or quaternary elements such as Al, Ag, Si, Mo, Ta, W, Ru, Ce, and Nb . As a result, some of the drawbacks were overcome .…”

Effect of microalloying with silicon on high temperature oxidation resistance of novel refractory high-entropy alloy Ta-Mo-Cr-Ti-Al

“…Minor additions of silicon, which do not lead to the formation of brittle silicides, are, in general, beneficial in terms of the formation of protective oxide layers [12][13][14][15]. The most accepted theories on the Si effect on the oxidation behavior of chromia forming alloys aredepending on the alloy system -(i) the formation of a protective silica scale on the phase boundary substrate/oxide [16,17] and (ii) the promotion of the development of a protective chromia layer, triggered by SiO 2 nucleation sites [18][19][20].…”

“…Bhowmik et al investigated the effect of silicon additions to Cr-Cr 2 Ta-based alloys, which consisted of a eutectic of Cr-based solid solution and the Cr 2 Ta Laves phases with hexagonal C14 and C36 polymorph [12]. There, it was found that silicon additions of up to 7 at.% clearly improve the oxidation characteristics at 1000 °C and 1100 °C.…”