Structural and electronic properties of chromium carbides and Fe-substituted chromium carbides

Abstract

Chromium carbides are coated over base metal (Fe) to increase wear and corrosion resistance. The electronic structure and bonding properties for chromium carbide bulk phases (Cr 3 C 2 , Cr 7 C 3 and Cr 23 C 6 ) and Fe-substituted chromium carbides is investigated using Density Functional Theory (DFT). The bonding in these carbides has been interpreted in the form of partial density of states, electron density distribution and Mulliken population method. Cr 3 C 2 exhibits the strongest covalent character while Cr 7 C 3 displays the highest metallicity. Cr 3 C 2 showed the highest stability among the chromium carbide phases. In the Fe-substituted chromium carbides (Cr 2 FeC 2 ), the site preference of Fe in Cr 3 C 2 system has been reported. In Fe-substituted chromium carbides also show both of metallic and covalent character and Cr 2 Fe3C 2 is found to be the most stable Fe-substituted chromium carbide system.

The influence of Fe variations on the phase stability of CrMnFexCoNi alloys following long-duration exposures at intermediate temperatures

“…Based on the evidence of Cenrichment in the elemental partitioning maps, the dark-contrast precipitates are thought to be a Cr-carbide phase. Three stable Cr-carbide phases have been reported in the literature: Cr23C6 which is fcc, and Cr7C3 and Cr3C2 which both have orthorhombic symmetry [47]. Among them, the Cr23C6 phase is most common and has previously been identified in alloys of this system, due to the intentional [48][49][50][51][52][53][54] and unintentional [11,12,26,27] incorporation of C. Moreover, the composition of the Cr carbide phase closely matched those of the Cr23C6 phase reported in the literature [12,26,27].…”

A Carbon‐Stabilized Austenitic Steel with Lower Hydrogen Embrittlement Susceptibility

“…APT analysis hence confirms that ≈1.9 wt% of C could be dissolved in the austenite matrix by the solution heat treatment. Cr 7 C 3 is a stable carbide [ 31 ] where W is not expected to be present. We hence detect a higher W content of 0.9 wt% in the austenite matrix from APT analysis compared to the bulk W content obtained from OES which was 0.62 wt%.…”

Microstructure and Wear Resistance of Plasma Surface Layers Based of Alloy Mixture CuSn10/CrxCy

“…It is known that chromium carbides are widely used in many industries due to their low cost, flexibility, and popularity. The low melting point helps to reduce the heat consumption during the melting process, and the proximity of the temperature coefficient of linear expansion is comparable to that of steels, leads to a decrease in stresses in the transition layer when coating a steel base [15][16]. Therefore, when approaching the creation of a coating of the Fe-Cr-C-Cu-Sn system, the combination of tinbronze and chromium carbide (CrxCy) during plasma heating of their preliminary coating layer can lead to high uniformity due to their high solubility at high temperatures with little attention to substrate dilution.…”