The Effects of Alloying Elements Cr, Al, and Si on Oxidation Behaviors of Ni-Based Superalloys

Abstract

Oxidation behaviors of three Ni-based model alloys and pure Ni in the temperature range of 700–1200 °C are investigated to reveal effects of Cr, Al, and Si on the oxidation resistance of Ni-based superalloys. The formation and integrity of consecutive chromia or alumina layers are important for excellent oxidation resistance. The addition of 20 at.% Cr can effectively improve the oxidation resistance of Ni-based alloys by forming a thin chromia film below 1000 °C, while adding 15 at.% Al has a beneficial effect on the oxidation resistance of Ni-based alloys at temperatures above 900 °C. The addition of 2 at.% Si to Ni-Al alloy is insufficient to form a protective SiO2 layer but can accelerate the formation of alumina, which enables Ni-Al alloy to form a consecutive inner alumina layer at a relatively low temperature of 800 °C and further improve the oxidation resistance above 800 °C.

The Preparation and Properties of Ni2Al3 Intermetallic Compound Coating

“…The oxidation kinetics curves of Ni2Al3 coating and 15CrM resistant steel both follow a parabolic law. The relationship between oxidation weight gain ΔG and time t can be obtaine reference as follows [29,30]:…”

“…The oxidation process of metal materials includes initial oxidation, oxygen m adsorption, oxide film formation, and diffusion of metal and oxygen atoms. The K The relationship between oxidation weight gain ∆G and time t can be obtained from reference as follows [29,30]:…”

Oxidation Kinetics of FeCr and FeCrAl Alloys: Influence of Secondary Processes

“…5. Kinetic curves of a similar shape are presented in a number of works for chromium, nickelbased and other alloys or metals [52][53][54][55][56][57][58][59][60][61][62]. However, it should be noted that purely parabolic kinetics are considered here.…”

Oxidation Behavior of Pre-Strained Polycrystalline Ni3Al-Based Superalloy

“…For instance, the outer NiO and inner Al 2 O 3 structures formed during the oxidation process of Ni 3 Al-based superalloys play a crucial role in determining the alloy's antioxidant properties [18]. In addition to applying protective layers to the matrix [19][20][21], the antioxidant properties of the alloys can be enhanced through the processes of heat treatment [8,22,23] and alloying [24,25]. These methods have achieved good results, although it is challenging to achieve further significant improvements in the antioxidant properties of superalloys.…”