Structure and Properties of High-Entropy Nitride Coatings

Abstract

The interest in nitride coatings based on high-entropy alloys (HEAs) has increased rapidly in the last decade. According to a number of papers, such high-entropy nitride (HEN) coatings have a single-phase structure and properties that significantly exceed those of simpler nitride systems. These properties include high hardness, wear resistance, oxidation resistance and thermal stability. It is believed that these distinctive properties are due to the high entropy of mixing, which increases with an increase in the number of elements in the composition. However, comparison with various binary and ternary systems shows that better properties are not typical of each HEA-based coating, and the effect of the number of elements competes with other factors that can make even more pronounced contributions to the structure and properties of the coating. Because of fragmentation of data on the structure and properties of high-entropy coatings, a unified concept of alloying is needed. This review compares the methods for obtaining HEN coatings, describes their structural features and analyzes the main properties, such as hardness, wear resistance and oxidation resistance, in order to establish an understanding of the influence of the number of elements and their role in the composition of coatings.

Microstructure, Mechanical Properties, Wear and Erosion Performance of a Novel High Entropy Nitride (AlCrTiMoV)N Coating Produced by Cathodic Arc Evaporation

“…The voids/pores can provide an initiation site for further damage and contribute to a higher erosion rate [39,40]. In comparison to some of the studies on HEN coatings discussed above, the (AlCrTiMoV)N coatings investigated in this study showed comparable results [8][9][10][11][12][13][14][15][16][17]. Th B1 FCC structure is consistent with the findings presented in this study.…”

“…The coating contains spherical metallic droplets, which lower the bulk hardness and are believed to detrimentally influence the coating perfor mance. The wear rate of (AlCrTiMoV)N was measured to be 1.35 × 10 −15 m 3 /(m*N), in othe words half the wear rate of the TiN coating, showing a better wear resistance than TiN Sand particle erosion tests showed an increase in the erosion rate with increasing impinge ment angles: erosion rates of 26 μg/g at 30° to 62 μg/g at 90°, higher than that measured In comparison to some of the studies on HEN coatings discussed above, the (AlCr-TiMoV)N coatings investigated in this study showed comparable results [8][9][10][11][12][13][14][15][16][17]. The B1 FCC structure is consistent with the findings presented in this study.…”

“…These studies have also reported high wear resistance [9], scratch resistance [10] and thermal phase stability [11]. While a significant majority of HEN coatings are produced by magnetron sputtering [8][9][10][11][12][13], a limited number of studies have investigated the use of cathodic arc evaporation to deposit HEN coatings, including those on (TiZrNbAlYCr)N [14], (TiZrHfVNbTa)N [15], (TiZrA-lYNb)N [16] and (MoNbTaVW)N [17]. Compared to magnetron sputtering which has a lower ion flux and ion energy, in CAE the high current density of the arc discharge produces a plasma with high ion flux and ion energy, which improves the coatings' structure and properties [18].…”

Influence of Plasma Treatment Parameters on the Structural-Phase Composition, Hardness, Moisture-Resistance, and Raman-Enhancement Properties of Nitrogen-Containing Titanium Dioxide

“…Thus, the increase in the microhardness of the films can be associated with the minimum number of dislocation sources in the grains and the predominant effect of the grain-boundary deformation mechanism through the determining role of grain boundaries. The inclusions of the nitrogen-containing phases are mainly concentrated at the grain boundaries, which themselves have a high microhardness [ 38 ]. An additional factor may be internal compressive stresses associated with a feature of plasma treatment: a high velocity of the oxidation front from the surface to the depth of the coating.…”

High‐Throughput Exploration of Structural and Electrochemical Properties of the High‐Entropy Nitride System (Ti–Co–Mo–Ta–W)N

“…However, the stability of nitrides against oxidation, especially under OER conditions, has to be taken into consideration. [28][29][30] Thin-film materials libraries [31] in the form of continuous composition spreads were fabricated by reactive cosputter deposition on 4-inch-diameter thermally oxidized Si substrates. Using materials libraries is advantageous: in one step many different compositions are fabricated and their properties can be screened using so-called high-throughput characterization methods.…”