Next Article in Journal
Comparative Study on Wear Behaviors of Monolayer and Heterogeneous Multilayer Ta Coatings in Atmospheric and SBF Environments
Previous Article in Journal
An Investigation for Minimizing the Wear Loss of Microwave-Assisted Synthesized g-C3N4/MoS2 Nanocomposite Coated Substrate
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Coatings
Volume 13
Issue 1
10.3390/coatings13010119
coatings-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles thumb_up
...
Endorse textsms
...
Comment
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Structure, Mechanical and Thermal Properties of TiSiWN Coatings

by
Wen Hu
1,
Jianwei Du
1,
Zheren Liu
1,
Xu Sun
1 and
Li Chen
1,2,*
1
State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China
2
Zhuzhou Cemented Carbide Cutting Tools Co., Ltd., Zhuzhou 412007, China
*
Author to whom correspondence should be addressed.
Coatings 2023, 13(1), 119; https://doi.org/10.3390/coatings13010119
Submission received: 26 December 2022 / Revised: 5 January 2023 / Accepted: 5 January 2023 / Published: 8 January 2023
(This article belongs to the Section Corrosion, Wear and Erosion)
Browse Figures
Versions Notes

Abstract

:
Elemental alloying has been proven to be a valid approach for improving the performance of coatings and has attracted significant research attention. This study aims to explore the impact of W-addition on the structure, mechanical and thermal properties of arc evaporated TiSiN coatings. Ti0.88Si0.12N coating presents a single-phase structure of fcc-(Ti, Si)N, while Ti0.88Si0.08W0.04N and Ti0.84Si0.09W0.07N coatings show a fcc-(Ti, Si, W)N and bcc-W dual-phase structure. As the W content increases, the surface quality of our coatings is obviously improved on account of the pronounced reduction in growth defects, including macroparticles and holes. Introduction of W slightly increases the hardness from 40.0 ± 0.5 GPa for Ti0.88Si0.12N to 41.6 ± 1.1 GPa for Ti0.88Si0.08W0.04N and 42.0 ± 1.0 GPa for Ti0.84Si0.09W0.07N. All our coatings possess a high thermal stability with their hardness values remaining above 38 GPa even after annealing at 1100 °C. Meanwhile, as a result of the suppressed anatase to rutile TiO2 transformation, alloying with W ameliorates the oxidation resistance of TiSiN coatings. After 750 °C oxidation for 10 h, the W-containing coatings only reveal oxide layers of ~301.5 (Ti0.88Si0.08W0.04N) and 279.2 nm (Ti0.84Si0.09W0.07N), whereas Ti0.88Si0.12N coating has already been entirely oxidized.

1. Introduction

For several decades, researchers have reported many potential materials for protective coatings, including transition metal nitride [1], quasicrystals [2], and refractory high-entropy alloys [3,4], etc. Among them, transition metal nitride coatings have been successfully applied to cutting tools for enhancing their machining performance and service life [5,6]. However, with the advancement of modern cutting technology, there is still a need for further improvements in coating materials regarding mechanical properties and thermal resistance. TiSiN coatings are certainly a promising candidate material for industrial applications, which have been explored widely owing to their high hardness and thermal stability [7,8,9,10,11]. The Si content has a substantial impact on the structure of TiSiN coatings [12,13]. According to the experiment results of Pei et al. [14], a structural evolution of Ti1−xSixN films from (Ti, Si)N solid solution for x ≤ 0.17 to nanocomposite structure with nanocrystalline (nc) TiN encapsulated in amorphous (a) SiNx for x = 0.22 was observed. The excellent mechanical properties of TiSiN coatings can be ascribed to the nanocomposite structure, where the SiNx tissue phase effectively hinders the grain-boundary sliding [15,16,17,18]. Furthermore, numerous reports have confirmed that the hardness of TiSiN coatings can be as high as 37–45 GPa [19,20,21]. Meanwhile, the formation of the SiNx phase also contributes to optimizing the thermal stability, and an almost constant hardness can be observed in nanocomposite TiSiN coatings during annealing up to 1100 °C [22,23]. However, because of their low oxidation resistance, the high-temperature applications of TiSiN coatings still remain limited. After 10 h oxidation at 800 °C, the Ti0.87Si0.13N coating is already completely oxidized [24].
More recently, researches have focused on incorporating a fourth element (e.g., La, V, C, Al, Nb and Ag) into TiSiN coatings to improve their properties [25,26,27,28,29,30,31,32,33]. For instance, adding a small amount (0.4 at.%) of La effectually enhance the hardness, wear resistance, and resistance to plastic deformation, while excessive La-incorporation will cause deterioration in mechanical properties of the coating [25]. V-alloyed TiSiN coatings exhibit excellent tribological properties on account of the emergence of lubricious Magnéli oxides phase (V2O5) at high temperatures, whereas the presence of vanadium ions with lower oxidation state will lead to increased oxidation rate [26,28]. Al-addition within TiSiN coatings can optimize the oxidation properties, based on the smaller oxygen diffusion coefficient of Al2O3 [29]. In addition, the incorporation of C into TiSiN decreases the residual compressive stress significantly, benefiting from the lower defect density during coating growth [30], and alloying with Nb simultaneously elevates the mechanical and corrosion properties of TiSiN on account of the solid solution hardening together with the decreased oxygen vacancy concentration [31].
Besides the already extensively researched alloying elements mentioned above, W, which possesses the highest melting point among metal elements, is also used to ameliorate the properties of nitride coatings. Incorporation of W atoms into MoN coatings provides higher hardness, adhesion strength and corrosion resistance. Yet, with increasing W content, the MoWN coatings undergo a structural transformation from face-centered cubic (fcc) (Mo, W)N single phase to dual-phase containing fcc-(Mo, W)N and softer body-centered cubic (bcc) W phase, which brings about relatively poor mechanical properties [34]. Combined experimental and theoretical investigations of Ti1−xWxNy system demonstrate that alloying with W has the potential to improve toughness and hardness simultaneously [35,36]. Similar toughness-enhancing behaviors have also been reported in other systems such as V1−xWxNy and Zr1−xWxNy [37,38]. Furthermore, some studies have reported a positive impact of W-incorporation on the tribological behavior of coatings, as the formation of self-lubricating phase WO3 reduces the friction coefficient and wear rate [39,40,41]. Li et al. explored the TiAlWN films synthesized by hybrid HiPIMS/DCMS [42,43], revealing that W+ irradiation favors the growth of hard, dense, and low-stress films. In terms of surface quality of arc evaporation technology, alloying with W effectively inhibits the formation of droplets due to the elevated melting point of targets [44]. Meanwhile, it was reported by Szkliniarz et al. [45] that incorporating tungsten into some alloys can also improve their oxidation resistance when exposed to high temperatures.
As mentioned above, W-alloying has been shown to significantly optimize the performance of numerous coating systems, whereas there are few studies about the effect of W-addition on the thermal properties of TiSiN coatings yet. Therefore, the influence of W-incorporation on the structure, mechanical properties, thermal stability and oxidation resistance of TiSiN coatings was researched in this paper.

2. Materials and Methods

2.1. Coating Deposition

TiSiWN coatings with varied W content were fabricated using a commercial cathodic arc evaporation (Oerlikon Balzers, Kila, Balzers, Liechtenstein) from Ti0.85Si0.15, Ti0.82Si0.15W0.03 and Ti0.79Si0.15W0.06 alloyed targets. The cathodic arc is steered by a permanent magnet and electromagnetic coil with a current of 1A. Four cathodes are available for the preparation of the coatings. High-purity nitrogen (99.999%) with a pressure of 3.2 Pa was used as the reactive gas. Before deposition, a base pressure lower than 1.0 × 10−3 Pa and a chamber temperature of 500 °C were achieved. The target current and the substrate bias voltage during the deposition process were fixed at 150 A and −40 V, respectively. Different types of substrates were applied in various characterizations: cemented carbides for morphology and chemical composition investigations; W plates for hardness and elastic modulus measurements; stainless steel sheet (50 × 10 × 0.7 mm3) for residual stresses evaluation; low-alloy steel foils for structure analysis and polycrystalline Al2O3 plates for oxidation test. To obtain excellent adhesion, all substrates were cleaned ultrasonically for 5 min using acetone and ethanol, then etched in argon plasma for approximately 30 min with pressure of 0.3 Pa and substrate bias of −150 V.

2.2. Heat Treatment

The coating powder specimens used for structural analysis were obtained by dissolving the coated low-alloy steel foils with a nitric acid (10 mol%) at 80 °C followed by grounding to powder to eliminate interference from substrate. A differential scanning calorimetry (DSC) instrument (Netzch-STA 409C, Netzsch, Selb, Germany) was utilized for the thermal annealing of coating powders. All specimens were heated to indicated temperatures in Ar (99.9% purity, 20 sccm flow rate) at a rate of 10 K/min, and then cooled to room temperature (RT) at 50 K/min without heat preservation. Additionally, for evaluating the high-temperature mechanical properties, the further annealing experiments were conducted by heating the coated W plates at Ta = 800, 900, 1000, and 1100 °C for 30 min in a vacuum furnace. Simultaneous DSC with thermal gravimetric analysis (TGA) was used to measure the heat flow and mass change of coatings from RT to 1400 °C in ambient air (79% N2 and 21% O2, 20 sccm flow rate). Moreover, to research the phase evolution in the oxidation process, powdered coatings were oxidized to the specified temperatures in ambient air with the same heating and cooling rate used for annealing. Furthermore, the coated polycrystalline Al2O3 substrates were isothermally oxidized for 10 h at 750 °C in a DSC instrument to further analyze the difference in oxidation resistance of each coating.

2.3. Material Characterization

Top-view and cross-sectional scanning electron microscopy (SEM, Zeiss Supre 55, Zeiss, Jena, Germany) were performed under secondary electron mode to determine the thickness and morphology of coatings. The elemental contents of our as-deposited TiSiWN coatings were tested by energy-dispersive X-ray spectroscopy (EDX, Oxford Instrument X-Max, Oxford, UK) system, and the roughness measurements of our coatings were performed with a surface roughness tester (SURFCOM 480A, Tokyo Seimitsu, Tokyo, Japan) at a speed of 0.06 mm/s and a scanning length of 2 mm. In each sample, three areas were measured, and their average Ra and Rz values were calculated. Furthermore, the phase structures of as-deposited, annealed, and oxidized powdered coatings were analyzed by Bruker D8 Advance X-ray diffractometer (XRD, Bruker AXS GmbH, Karlsruhe, Germany) with Cu Kα radiation in powder diffraction mode. To understand the microstructure in detail, transmission electron microscopy (TEM, FEI Titan G2 60-300, FEI, Hillsborough, NC, USA) investigations were conducted. The preparation of cross-sectional TEM specimens was carried out with an FEI Helios NanoLab 600i dual-beam focused ion beam (FIB) system. In addition, a nanoindentation equipped with a Berkovich tip was utilized for measuring the hardness and elastic modulus of coatings onto W plates based on the method of Oliver and Pharr [46]. The indentation depth was kept below 10% of the coating thickness by applying a maximum load of 15 mN. Mean values for each sample were calculated from at least fifteen measurements. Residual stress evaluations were conducted on the coated stainless steel sheet, using the substrate-curvature method [47].

3. Results and Discussion

3.1. Structure and Morphology

For the convenience of description, all coatings are standardized to N/(Ti + Si + W) atomic ratios of 1:1. According to the results of EDX measurements, the chemical compositions of our TiSiWN coatings are Ti0.88Si0.12N, Ti0.88Si0.08W0.04N, and Ti0.84Si0.09W0.07N, corresponding to Ti0.85Si0.15, Ti0.82Si0.15W0.03, and Ti0.79Si0.15W0.06 targets, respectively. As can be seen, there are minor composition differences between the targets and coatings based on the gas scattering, re-sputtering, and different ionization rates during deposition [48]. In addition, Si detected much less for Ti0.88Si0.08W0.04N and Ti0.84Si0.09W0.07N than for Ti0.88Si0.12N by EDX, which can be explained by the enhanced re-sputtering of Si by heavier mass W ions [49]. Figure 1 depicts the XRD diffractograms of as-deposited TiSiWN coatings. Ti0.88Si0.12N coating presents a single-phase face-centered cubic structure. Both Ti0.88Si0.08W0.04N and Ti0.84Si0.09W0.07N coatings show a dual-phase structure composing of fcc-(Ti, Si, W)N and bcc-W (ICDD 00-004-0806), where the bcc-W peaks can be better observed from the fine scanning XRD pattern (inset of Figure 1). In addition, there is a slight intensity enhancement of the bcc-W phase with increasing W concentration. In general, the wider diffraction peaks suggest a lower grain size of coatings. According to the determination of the full width at half maximum (FWHM) for all coatings (Table 1), the Ti0.88Si0.08W0.04N and Ti0.84Si0.09W0.07N coatings display broader diffraction peaks than Ti0.88Si0.12N coating revealing the lower grain size of W-containing coatings. Moreover, no diffraction peaks corresponding to the crystal of titanium silicide or SiNx are detected, indicating that Si either substitutes the lattice sites of Ti within fcc-TiN or exists in amorphous state [14,19].
The surface and cross-sectional morphologies of as-deposited coatings are displayed in Figure 2. Distinct macroparticles (i.e., droplets) and holes can be detected at the surface of Ti0.88Si0.12N coating. These holes are ascribed to the exfoliation of the macroparticles in view of the low adhesive strength between the particles and the coatings [50]. Certain reports have confirmed that the quantity and size of the droplets are primarily affected by the target (cathode) material [51]. In general, target with a high melting point generates fewer and smaller droplets. Alloying TiSi target with W contributes to increasing the melting point of the target material, based on the generation of intermetallic compounds [52]. As shown in Figure 2b,c, the density of the macroparticles and holes significantly decreases with increasing W content. To better prove this behavior, the surface roughness of the coatings was measured, and the results are depicted in Table 1. The Ra values for our Ti0.88Si0.12N, Ti0.88Si0.08W0.04N and Ti0.84Si0.09W0.07N coatings are 0.279, 0.229 and 0.181 μm, and the corresponding Rz values are 3.106, 2.763 and 2.631 μm, respectively. A marked decline in roughness (Ra and Rz values) with increasing W content is observed, associated with the smoother surfaces owing to the decreased growth defects. This is consistent with the above results obtained from surface morphologies. The cross-sections in Figure 2d–f convey that all our coatings present a dense columnar crystal growth and the thickness of Ti0.88Si0.12N, Ti0.88Si0.08W0.04N, and Ti0.84Si0.09W0.07N coatings are ~1.62, 1.51, and 1.48 μm, respectively.
In our previous research [14], the substitution solution of Si for Ti within Ti0.88Si0.12N coating has been affirmed. However, with the introduction of W element, the structural change of coatings is still ambiguous. To further ascertain the microstructure of W-containing coatings, the corresponding cross-sectional TEM analysis of as-deposited Ti0.84Si0.09W0.07N coating was conducted. Figure 3a shows a dense column structure with grains growing along the direction perpendicular to the substrate surface, and the selected area electron diffraction (SAED) pattern (Figure 3b) consisting of polycrystalline diffraction arcs exhibits a typical face-centered cubic structure. Unlike XRD investigation, however, no bcc-W signals could be clearly detected here due to its smaller amount. Further detailed HRTEM analysis in Figure 3c,d verifies the existence of dual-phase structure, where the lattice-plane distance (d) calculated from FFT and IFFT images with ~211 nm and ~0.158 nm corresponds to the (200) planes of fcc-TiN (ICDD 00-038-1420) and (200) planes of bcc-W (ICDD 00-004-0806), respectively. This phenomenon coincides with the above results obtained from XRD analysis (Figure 1). Similar with the Ti0.88Si0.12N W-free coating, the structure of nc-TiN/a-SiNx nanocomposite as reported in Ref. [14] is not observed. Therefore, we conclude that Si atoms exist as a solid solution, while W atoms coexist in the solid solution and bcc-W phase form.

3.2. Mechanical Properties

The hardness, elastic modulus, and corresponding residual stress values of Ti0.88Si0.12N, Ti0.88Si0.08W0.04N, and Ti0.84Si0.09W0.07N coatings are presented in Figure 4. Ti0.88Si0.12N coating reveals a high hardness value of 40.0 ± 0.5 GPa in the as-deposited state. Incorporation of W increases the hardness of Ti0.88Si0.08W0.04N to 41.6 ± 1.1 GPa even though with the formation of soft bcc-W phase. The main reason for this enhancement is the solid solution strengthening and grain refining effect, which offsets the detrimental impact of the bcc-W formation. Nevertheless, further elevating the W content to 7 at.% has a limited increase in hardness (42.0 ± 1.0 GPa) because of the higher proportion of bcc-W phase in Ti0.84Si0.09W0.07N. The elastic modulus and hardness have similar trends, which is firstly increasing from 452.8 ± 12.2 GPa for Ti0.88Si0.12N to 464.9 ± 18.1 GPa for Ti0.88Si0.08W0.04N and then slightly increases to 467.5 ± 13.6 GPa for Ti0.84Si0.09W0.07N. All coatings show high compressive residual stresses, as determined by the substrate-curvature method. W-incorporation induces an increment of residual stress from −9.34 GPa for Ti0.88Si0.12N to −10.49 GPa for Ti0.88Si0.08W0.04N and −12.88 GPa for Ti0.84Si0.09W0.07N.

3.3. Thermal Stability

Figure 5 exhibits the XRD diffractograms of Ti0.88Si0.12N, Ti0.88Si0.08W0.04N, and Ti0.84Si0.09W0.07N coatings before and after annealing in Ar. Detailed structural evolution of Ti0.88Si0.12N coating during annealing has been reported in our previous study [14]. Upon annealing to 1300 °C, Ti0.88Si0.12N coating still maintains its single-phase fcc structure, and only minor changes in the intensity, width, and position of XRD diffraction peaks are observed. Further temperature rises to 1450 °C, the decomposition of Ti0.88Si0.12N coating into fcc-TiN, TiSi2 (ICDD 00-035-0785), and β-Si3N4 (ICDD 00-033-1160) takes place. Ti0.88Si0.08W0.04N and Ti0.84Si0.09W0.07N coatings show a similar thermal decomposition behavior during annealing apart from slightly different diffraction intensities of each phase, see Figure 5b,c. After annealing at 800 and 900 °C, the structure of Ti0.88Si0.08W0.04N and Ti0.84Si0.09W0.07N has no significant changes. Only the peaks slightly shift toward higher 2θ angles, which is associated with the defect elimination and stress release during recovery and recrystallization. Further increasing Ta to 1300 °C, the Ti0.88Si0.08W0.04N and Ti0.84Si0.09W0.07N coatings can still maintain their original structure, while the FWHM of XRD peaks show a continuous drop. The main factors associated with peak width variation are the microstrain relaxation and grain growth during high-temperature annealing. Furthermore, annealing at 1450 °C gives rise to the disappearance of bcc-W phase, and the diffraction signals of Si2W (ICDD 00-011-0195) and W5Si3 (ICDD 00-051-0941) can be detected for all our W-containing coatings.
The above-mentioned structural evolution during annealing will lead to corresponding mechanical properties changes. The hardness variations of Ti0.88Si0.12N, Ti0.88Si0.08W0.04N, and Ti0.84Si0.09W0.07N coatings with annealing temperatures are depicted in Figure 6. In contrary to binary nitrides coating where H decreases typically at high temperatures due to recovery and recrystallization, the hardness of our Ti0.88Si0.12N coating slightly increases to 41.0 ± 1.0 GPa at 800 °C. This phenomenon may stem from denser boundary regions as well as almost constant grain size after annealing [53]. Further temperature increase brings about a continuous hardness decline due to the grain coarsening. Nevertheless, in the temperature range of 800–1000 °C, the hardness of Ti0.88Si0.12N coating can still remain above 40 GPa. After annealing at 1100 °C, the hardness of Ti0.88Si0.12N coating decreases to 38.3 ± 1.0 GPa. For W-containing coatings, they also exhibit good high-temperature hardness retention ability during the whole annealing process. After annealing at 800 and 900 °C, the combined effect of stress relaxation and defect elimination leads to a slight reduction in hardness of W-containing coatings. When Ta increases to 1000 °C, W-containing coatings present a further reduction in hardness by the weakening effect of the bcc-W phase and grain growth, where the hardness values of Ti0.88Si0.08W0.04N and Ti0.84Si0.09W0.07N coatings are 40.0 ± 1.0 GPa and 39.9 ± 1.1 GPa, respectively. Ultimately, with further increased grain size and decomposition of the original phase, the hardness of Ti0.88Si0.08W0.04N and Ti0.84Si0.09W0.07N decreases to 39.1 ± 1.4 GPa and 39.0 ± 0.8 GPa at 1100 °C.

3.4. Oxidation Resistance

Synchronous DSC and TGA analyses were performed under ambient air (from 25 to 1400 °C) to evaluate the oxidation resistance of Ti0.88Si0.12N, Ti0.88Si0.08W0.04N, and Ti0.84Si0.09W0.07N coatings. As seen in Figure 7a, W-containing coatings have a delayed oxidation process, the onset temperature of the exothermic reaction increases from ~759 °C for Ti0.88Si0.12N to ~803 °C for both Ti0.88Si0.08W0.04N and Ti0.84Si0.09W0.07N. Further increasing the temperature above 850 °C aggravates the oxidation reaction and yields a pronounced exothermic peak in the DSC curve. Finally, Ti0.88Si0.08W0.04N and Ti0.84Si0.09W0.07N coatings are completely oxidized at ~1013 and ~1019 °C, respectively, which are higher than Ti0.88Si0.12N (~968 °C). Notably, the endothermic reaction at ~1375 °C may be owing to the sintering behavior of coating powders [54]. Meanwhile, the TGA curves demonstrate a similar change rule with DSC. As presented in Figure 7b, with increasing temperature, the mass of the coatings begins to increase, first slowly and then rapidly until the complete oxidation. Compared to Ti0.88Si0.12N, the Ti0.88Si0.08W0.04N and Ti0.84Si0.09W0.07N coatings present a higher mass gain, which is relevant to the oxidation of heavy element W. To sum up, both onset and final temperatures for oxidation reaction of W-containing coatings are higher than those of Ti0.88Si0.12N, revealing optimized antioxidant properties with the addition of W.
To better explore the oxidation behavior of Ti0.88Si0.12N, Ti0.88Si0.08W0.04N, and Ti0.84Si0.09W0.07N coatings, XRD determinations were performed. As shown in Figure 8a, several inconspicuous anatase (a-) and rutile (r-) TiO2 peaks are detected in Ti0.88Si0.12N coating at 700 °C, indicating the beginning of oxidation as well as the metastable a-TiO2 start to gradually transform to the thermodynamically stable r-TiO2. However, this transformation is usually accompanied by volume contraction, which may result in the generation of cracks, and thus deteriorate the resistance of coatings to oxidation [55,56]. Further temperature increases to 800 and 900 °C, the a-TiO2 and r-TiO2 diffraction peaks show a gradually enhanced intensity. After oxidation at 1000 °C, Ti0.88Si0.12N coating is completely oxidized to form a-TiO2 and r-TiO2. However, no signal of Si-O can be detected by XRD during the whole oxidation process, suggesting that Si atoms exist as solid solution within TiO2 lattice. This can also be evidenced by the shift of a-TiO2 and r-TiO2 peaks toward higher 2θ angles relative to standard ones. Similar to Ti0.88Si0.12N coating, a-TiO2 and r-TiO2 are also formed in Ti0.88Si0.08W0.04N (Figure 8b) and Ti0.84Si0.09W0.07N (Figure 8c) coatings at 700 °C. Increasing Ta to 800 °C, an increased diffraction intensities of a-TiO2 and r-TiO2 can be observed. At 900 °C, there are still diffraction peaks corresponding to initial phase observed and the a-TiO2 and r-TiO2 peak intensity continues to increase. Compared with Ti0.88Si0.12N, W-containing coatings show a higher ratio of diffraction peak intensity for a-TiO2 to r-TiO2, revealing that W-addition retards the phase transformation of TiO2. This could be relevant to the decreased oxygen vacancy caused by the substitution of Ti4+ on the anatase lattice with W6+ of higher valence [55], and this retardation is proportional to the W content in coatings. Further temperature increases to 1000 °C, the initial diffraction peaks are almost invisible, manifesting that W-containing coatings have been totally oxidized to a-TiO2, r-TiO2, and WO3 (ICDD 00-043-1035). Noticeable is that the monoclinic (m-) WO3 only shows weak diffraction signals in Ti0.88Si0.08W0.04N at 1000 °C due to its relatively lower W content.
Figure 9 exhibits the SEM cross-sectional morphologies with EDX line-scan results of Ti0.88Si0.12N, Ti0.88Si0.08W0.04N, and Ti0.84Si0.09W0.07N coatings after a 10 h oxidation test at 750 °C. Ti0.88Si0.12N coating has been fully oxidized, while both Ti0.88Si0.08W0.04N and Ti0.84Si0.09W0.07N coatings still reserve most of the initial nitride layer after oxidation, and the thickness of oxide layers are ~301.5 and 279.2 nm, respectively. Therefore, the Ti0.84Si0.09W0.07N coating reveals the best antioxidant properties among the three coatings, consistent with the DSC results discussed above. This may be ascribed to the inhibited TiO2 phase transformation through alloying with W. Nevertheless, the thermal coefficient mismatch between the coating and Al2O3 substrate can lead to cracking or spalling of the coating [57], which promotes the diffusion of oxygen to the interface between coating and substrate, allowing an oxygen interaction with the coating near the interface, as presented in Figure 9b,c. Further compositional analyses of oxidized TiSiWN coatings were conducted by EDX line-scan. A strong correlation can be found between the elemental distributions and the morphologies of oxidized coatings. During the oxidation process, as a result of either the higher affinity of Ti to O than Si or the outward diffusion of the titanium and the inward diffusion of the oxygen [58,59], a Ti-rich oxide scale will form on the top of all our coatings.

4. Conclusions

In this paper, the structure, mechanical and thermal properties of Ti0.88Si0.12N, Ti0.88Si0.08W0.04N, and Ti0.84Si0.09W0.07N coatings prepared with cathodic arc deposition are systematically studied. The results can be summarized as follows:
  • Ti0.88Si0.12N coating behaves as a single-phase fcc structure, whereas Ti0.88Si0.08W0.04N and Ti0.84Si0.09W0.07N coatings reveal an fcc and bcc dual-phase structure. The hardness of our W-containing coatings with values of 41.6 ± 1.1 GPa (Ti0.88Si0.08W0.04N) and 42.0 ± 1.0 GPa (Ti0.84Si0.09W0.07N) are slightly higher than Ti0.88Si0.12N coating with value of 40.0 ± 0.5 GPa on account of the solid solution strengthening and grain refining effect, which surpasses the weakening effect of softer bcc-W phase;
  • Detailed surface morphologies studies indicate that the amount and the size of the droplets decrease with increasing W content, and thus leads to a smoother surface;
  • XRD analyses of the annealed coatings show a high thermal stability with a dominant fcc structure being stable up to 1300 °C. Meanwhile, the hardness of Ti0.88Si0.12N, Ti0.88Si0.08W0.04N, and Ti0.84Si0.09W0.07N coatings can still maintain 38.3 ± 1.0, 39.1 ± 1.4, and 39.0 ± 0.8 GPa after 30 min of vacuum annealing at 1100 °C, respectively;
  • Introduction of W into TiSiN inhibits the anatase to rutile TiO2 transformation, thereby improving the oxidation resistance. After 750 °C oxidation for 10 h, Ti0.88Si0.12N coating is fully oxidized, while Ti0.88Si0.08W0.04N and Ti0.84Si0.09W0.07N coatings only exhibit oxide scales of ~301.5 and 279.2 nm.

Author Contributions

Formal analysis, data curation, visualization, writing—original draft, W.H.; supervision, J.D.; investigation, Z.L.; writing—review and editing, X.S.; conceptualization, methodology, writing—review and editing, resources, funding acquisition, L.C. All authors have read and agreed to the published version of the manuscript.

Funding

This work is sponsored by a research project (Grant No. 51775560) from the National Natural Science Foundation of China.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Not applicable.

Acknowledgments

L.C. expresses gratitude for support received from State Key Laboratory of Powder Metallurgy of Central South University of China.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Wang, H.W.; Stack, M.M. The slurry erosive wear of physically vapour deposited TiN and CrN coatings under controlled corrosion. Tribol. Lett. 1999, 6, 23–36. [Google Scholar] [CrossRef]
  2. Shadangi, Y.; Shivam, V.; Chattopadhyay, K.; Mukhopadhyay, N.K. Powder Metallurgical Processing of Sn-Reinforced Al-Cu-Fe Quasicrystals: Structure, Microstructure and Toughening Behavior. J. Manuf. Mater. Process. 2022, 6, 60. [Google Scholar] [CrossRef]
  3. Singh, N.; Shadangi, Y.; Goud, G.S.; Pandey, V.K.; Shivam, V.; Mukhopadhyay, N.K. Fabrication of MgAlSiCrFe Low-Density High-Entropy Alloy by Mechanical Alloying and Spark Plasma Sintering. Trans. Indian Inst. Met. 2021, 74, 2203–2219. [Google Scholar] [CrossRef]
  4. Pandey, V.K.; Shadangi, Y.; Shivam, V.; Sarma, B.N.; Mukhopadhyay, N.K. Theoretical and experimental study on phase stability of TiVZrMoW refractory high entropy alloy. Philos. Mag. 2022, 102, 480–503. [Google Scholar] [CrossRef]
  5. Hedenqvist, P.; Olsson, M.; Wallén, P.; Kassman, Å.; Hogmark, S.; Jacobson, S. How TiN coatings improve the performance of high speed steel cutting tools. Surf. Coat. Technol. 1990, 41, 243–256. [Google Scholar] [CrossRef]
  6. Su, Y.L.; Yao, S.H. On the performance and application of CrN coating. Wear 1997, 205, 112–119. [Google Scholar] [CrossRef]
  7. Vepřek, S.; Nesládek, P.; Niederhofer, A.; Glatz, F. Search for superhard materials: Nanocrystalline composites with hardness exceeding 50 GPa. Nanostruct. Mater. 1998, 10, 679–689. [Google Scholar] [CrossRef]
  8. Veprek, S.; Veprek-Heijman, M.G.J.; Karvankova, P.; Prochazka, J. Different approaches to superhard coatings and nanocomposites. Thin Solid Film. 2005, 476, 1–29. [Google Scholar] [CrossRef]
  9. Veprek, S.; Veprek-Heijman, M.J.G. Industrial applications of superhard nanocomposite coatings. Surf. Coat. Technol. 2008, 202, 5063–5073. [Google Scholar] [CrossRef]
  10. Bouzakis, K.D.; Bouzakis, E.; Kombogiannis, S.; Paraskevopoulou, R.; Skordaris, G.; Makrimallakis, S.; Katirtzoglou, G.; Pappa, M.; Gerardis, S.; M’Saoubi, R.; et al. Effect of silicon content on PVD film mechanical properties and cutting performance of coated cemented carbide inserts. Surf. Coat. Technol. 2013, 237, 379–389. [Google Scholar] [CrossRef]
  11. Moritz, Y.; Saringer, C.; Tkadletz, M.; Stark, A.; Schell, N.; Letofsky-Papst, I.; Czettl, C.; Pohler, M.; Schalk, N. Oxidation behavior of arc evaporated TiSiN coatings investigated by in-situ synchrotron X-ray diffraction and HR-STEM. Surf. Coat. Technol. 2020, 404, 126632. [Google Scholar] [CrossRef]
  12. Tian, C.X.; Yang, B.; Wan, Q.; Ding, H.; Hong, M.Q.; Wang, R.Y.; Liu, H.D.; Chen, Y.M.; Yan, S.J.; Ren, F.; et al. Effects of SiH4 flow rate on microstructure and mechanical properties of TiSiN nanocomposite coatings by cathodic arc ion plating. Vacuum 2015, 117, 12–16. [Google Scholar] [CrossRef]
  13. Flink, A.; Beckers, M.; Sjolen, J.; Larsson, T.; Braun, S.; Karlsson, L.; Hultman, L. The location and effects of Si in (Ti1-xSix)Ny thin films. J. Mater. Res. 2009, 24, 2483–2498. [Google Scholar] [CrossRef]
  14. Pei, F.; Xu, Y.X.; Chen, L.; Du, Y.; Zou, H.K. Structure, mechanical properties and thermal stability of Ti1-xSixN coatings. Ceram. Int. 2018, 44, 15503–15508. [Google Scholar] [CrossRef]
  15. Diserens, M.; Patscheider, J.; Lévy, F. Mechanical properties and oxidation resistance of nanocomposite TiN–SiNx physical-vapor-deposited thin films. Surf. Coat. Technol. 1999, 120–121, 158–165. [Google Scholar] [CrossRef]
  16. Vaz, F.; Rebouta, L.; Goudeau, P.; Pacaud, J.; Garem, H.; Rivière, J.P.; Cavaleiro, A.; Alves, E. Characterisation of Ti1−xSixNy nanocomposite films. Surf. Coat. Technol. 2000, 133–134, 307–313. [Google Scholar] [CrossRef]
  17. Greczynski, G.; Bakhit, B.; Hultman, L.; Odén, M. High Si content TiSiN films with superior oxidation resistance. Surf. Coat. Technol. 2020, 398, 126087. [Google Scholar] [CrossRef]
  18. Cheng, Y.H.; Browne, T.; Heckerman, B.; Meletis, E.I. Mechanical and tribological properties of nanocomposite TiSiN coatings. Surf. Coat. Technol. 2010, 204, 2123–2129. [Google Scholar] [CrossRef]
  19. Sperr, M.; Zhang, Z.L.; Ivanov, Y.P.; Mayrhofer, P.H.; Bartosik, M. Correlating elemental distribution with mechanical properties of TiN/SiNx nanocomposite coatings. Scr. Mater. 2019, 170, 20–23. [Google Scholar] [CrossRef]
  20. Nose, M.; Deguchi, Y.; Mae, T.; Honbo, E.; Nagae, T.; Nogi, K. Influence of sputtering conditions on the structure and properties of Ti–Si–N thin films prepared by r.f.-reactive sputtering. Surf. Coat. Technol. 2003, 174–175, 261–265. [Google Scholar] [CrossRef]
  21. Zhu, J.Q.; Johansson-Jöesaar, M.P.; Polcik, P.; Jensen, J.; Greczynski, G.; Hultman, L.; Odén, M. Influence of Ti–Si cathode grain size on the cathodic arc process and resulting Ti–Si–N coatings. Surf. Coat. Technol. 2013, 235, 637–647. [Google Scholar] [CrossRef]
  22. Niederhofer, A.; Bolom, T.; Nesladek, P.; Moto, K.; Eggs, C.; Patil, D.S.; Veprek, S. The role of percolation threshold for the control of the hardness and thermal stability of super- and ultrahard nanocomposites. Surf. Coat. Technol. 2001, 146–147, 183–188. [Google Scholar] [CrossRef]
  23. Männling, H.D.; Patil, D.S.; Moto, K.; Jilek, M.; Veprek, S. Thermal stability of superhard nanocomposite coatings consisting of immiscible nitrides. Surf. Coat. Technol. 2001, 146–147, 263–267. [Google Scholar] [CrossRef]
  24. Wang, H.T.; Xu, Y.X.; Chen, L. Optimization of Cr-Al-N coating by multilayer architecture with TiSiN insertion layer. J. Alloys Comp. 2017, 728, 952–958. [Google Scholar] [CrossRef]
  25. Sahul, M.; Smyrnova, K.; Haršáni, M.; Čaplovič, Ľ.; Pogrebnjak, A.; Sahul, M.; Kusý, M.; Babincová, P.; Vopát, T. Effect of lanthanum addition on the structure evolution and mechanical properties of the nanocomposite Ti-Si-N coatings. Mater. Lett. 2020, 276, 128180. [Google Scholar] [CrossRef]
  26. Fernandes, F.; Oliveira, J.C.; Cavaleiro, A. Self-lubricating TiSi(V)N thin films deposited by deep oscillation magnetron sputtering (DOMS). Surf. Coat. Technol. 2016, 308, 256–263. [Google Scholar] [CrossRef]
  27. Fernandes, F.; Polcar, T.; Cavaleiro, A. Tribological properties of self-lubricating TiSiVN coatings at room temperature. Surf. Coat. Technol. 2015, 267, 8–14. [Google Scholar] [CrossRef]
  28. Fernandes, F.; Loureiro, A.; Polcar, T.; Cavaleiro, A. The effect of increasing V content on the structure, mechanical properties and oxidation resistance of Ti–Si–V–N films deposited by DC reactive magnetron sputtering. Appl. Surf. Sci. 2014, 289, 114–123. [Google Scholar] [CrossRef]
  29. Takahashi, K.; Oka, N.; Yamaguchi, M.; Seino, Y.; Hattori, K.; Nakamura, S.-i.; Sato, Y.; Shigesato, Y. Oxidation Resistance of Ti-Si-N and Ti-Al-Si-N Films Deposited by Reactive Sputtering Using Alloy Targets. Jpn. J. Appl. Phys. 2011, 50, 075802. [Google Scholar] [CrossRef]
  30. Marchin, N.; Ashrafizadeh, F. Effect of carbon addition on tribological performance of TiSiN coatings produced by cathodic arc physical vapour deposition. Surf. Coat. Technol. 2021, 407, 126781. [Google Scholar] [CrossRef]
  31. Xu, J.; Wang, G.d.; Lu, X.; Liu, L.; Munroe, P.; Xie, Z.-H. Mechanical and corrosion-resistant properties of Ti–Nb–Si–N nanocomposite films prepared by a double glow discharge plasma technique. Ceram. Int. 2014, 40, 8621–8630. [Google Scholar] [CrossRef]
  32. Dang, C.; Li, J.; Wang, Y.; Yang, Y.; Wang, Y.; Chen, J. Influence of Ag contents on structure and tribological properties of TiSiN-Ag nanocomposite coatings on Ti–6Al–4V. Appl. Surf. Sci. 2017, 394, 613–624. [Google Scholar] [CrossRef]
  33. Cavaleiro, D.; Carvalho, S.; Cavaleiro, A.; Fernandes, F. TiSiN(Ag) films deposited by HiPIMS working in DOMS mode: Effect of Ag content on structure, mechanical properties and thermal stability. Appl. Surf. Sci. 2019, 478, 426–434. [Google Scholar] [CrossRef]
  34. Yang, J.F.; Yuan, Z.G.; Zhang, G.G.; Wang, X.P.; Fang, Q.F. Manufacture, microstructure and mechanical properties of Mo–W–N nanostructured hard films. Mater. Res. Bull. 2009, 44, 1948–1953. [Google Scholar] [CrossRef]
  35. Buchinger, J.; Koutná, N.; Kirnbauer, A.; Holec, D.; Mayrhofer, P.H. Heavy-element-alloying for toughness enhancement of hard nitrides on the example Ti-W-N. Acta Mater. 2022, 231, 117897. [Google Scholar] [CrossRef]
  36. Sangiovanni, D.G.; Hultman, L.; Chirita, V.; Petrov, I.; Greene, J.E. Effects of phase stability, lattice ordering, and electron density on plastic deformation in cubic TiWN pseudobinary transition-metal nitride alloys. Acta Mater. 2016, 103, 823–835. [Google Scholar] [CrossRef]
  37. Dubey, P.; Srivastava, S.; Chandra, R.; Ramana, C.V. Toughness enhancement in zirconium-tungsten-nitride nanocrystalline hard coatings. AIP Adv. 2016, 6, 075211. [Google Scholar] [CrossRef] [Green Version]
  38. Kindlund, H.; Sangiovanni, D.G.; Lu, J.; Jensen, J.; Chirita, V.; Petrov, I.; Greene, J.E.; Hultman, L. Effect of WN content on toughness enhancement in V1−xWxN/MgO(001) thin films. J. Vac. Sci. Technol. A 2014, 32, 030603. [Google Scholar] [CrossRef]
  39. Gassner, G.; Mayrhofer, P.H.; Kutschej, K.; Mitterer, C.; Kathrein, M. Magnéli phase formation of PVD Mo–N and W–N coatings. Surf. Coat. Technol. 2006, 201, 3335–3341. [Google Scholar] [CrossRef]
  40. Severo, V.; Vilhena, L.; Silva, P.N.; Dias, J.P.; Becker, D.; Wagner, S.; Cavaleiro, A. Tribological behaviour of W–Ti–N coatings in semi-industrial strip-drawing tests. J. Mater. Process. Technol. 2009, 209, 4662–4667. [Google Scholar] [CrossRef]
  41. Tian, B.; Yue, W.; Fu, Z.; Gu, Y.; Wang, C.; Liu, J. Microstructure and tribological properties of W-implanted PVD TiN coatings on 316L stainless steel. Vacuum 2014, 99, 68–75. [Google Scholar] [CrossRef]
  42. Li, X.; Bakhit, B.; Johansson Jõesaar, M.P.; Petrov, I.; Hultman, L.; Greczynski, G. Towards energy-efficient physical vapor deposition: Mapping out the effects of W+ energy and concentration on the densification of TiAlWN thin films grown with no external heating. Surf. Coat. Technol. 2021, 424, 127639. [Google Scholar] [CrossRef]
  43. Li, X.; Bakhit, B.; Joesaar, M.P.J.; Petrov, I.; Hultman, L.; Greczynski, G. Dense, single-phase, hard, and stress-free Ti0.32Al0.63W0.05N films grown by magnetron sputtering with dramatically reduced energy consumption. Sci. Rep. 2022, 12, 2166. [Google Scholar] [CrossRef]
  44. Glatz, S.A.; Bolvardi, H.; Kolozsvári, S.; Koller, C.M.; Riedl, H.; Mayrhofer, P.H. Arc evaporated W-alloyed Ti-Al-N coatings for improved thermal stability, mechanical, and tribological properties. Surf. Coat. Technol. 2017, 332, 275–282. [Google Scholar] [CrossRef]
  45. Szkliniarz, A.; Moskal, G.; Szkliniarz, W.; Swadźba, R. Improvement of oxidation resistance of Ti–47Al–2W–0.5Si alloy modified by aluminizing method. Surf. Coat. Technol. 2015, 277, 270–277. [Google Scholar] [CrossRef]
  46. Oliver, W.C.; Pharr, G.M. An improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiments. J. Mater. Res. 1992, 7, 1564–1583. [Google Scholar] [CrossRef]
  47. Mayrhofer, P.H.; Mitterer, C. High-temperature properties of nanocomposite TiBxNy and TiBxCy coatings. Surf. Coat. Technol. 2000, 133–134, 131–137. [Google Scholar] [CrossRef]
  48. Eriksson, A.O.; Zhu, J.Q.; Ghafoor, N.; Johansson, M.P.; Sjölen, J.; Jensen, J.; Odén, M.; Hultman, L.; Rosén, J. Layer formation by resputtering in Ti–Si–C hard coatings during large scale cathodic arc deposition. Surf. Coat. Technol. 2011, 205, 3923–3930. [Google Scholar] [CrossRef] [Green Version]
  49. Li, X.; Bakhit, B.; Jõesaar, M.P.J.; Hultman, L.; Petrov, I.; Greczynski, G. Toward energy-efficient physical vapor deposition: Routes for replacing substrate heating during magnetron sputter deposition by employing metal ion irradiation. Surf. Coat. Technol. 2021, 415, 127120. [Google Scholar] [CrossRef]
  50. Wan, Q.; Ding, H.; Yousaf, M.I.; Chen, Y.M.; Liu, H.D.; Hu, L.; Yang, B. Corrosion behaviors of TiN and Ti-Si-N (with 2.9at.% and 5.0at.% Si) coatings by electrochemical impedance spectroscopy. Thin Solid Film. 2016, 616, 601–607. [Google Scholar] [CrossRef]
  51. Panjan, P.; Drnovsek, A.; Gselman, P.; Cekada, M.; Panjan, M. Review of Growth Defects in Thin Films Prepared by PVD Techniques. Coatings 2020, 10, 447. [Google Scholar] [CrossRef]
  52. Hollerweger, R.; Zhou, L.; Holec, D.; Koller, C.M.; Rachbauer, R.; Polcik, P.; Mayrhofer, P.H. Controlling microstructure, preferred orientation, and mechanical properties of Cr-Al-N by bombardment and alloying with Ta. J. Appl. Phys. 2016, 119, 065304. [Google Scholar] [CrossRef]
  53. Mayrhofer, P.H.; Mitterer, C.; Wen, J.G.; Petrov, I.; Greene, J.E. Thermally induced self-hardening of nanocrystalline Ti-B-N thin films. J. Appl. Phys. 2006, 100, 044301. [Google Scholar] [CrossRef]
  54. Chen, L.; Paulitsch, J.; Du, Y.; Mayrhofer, P.H. Thermal stability and oxidation resistance of Ti–Al–N coatings. Surf. Coat. Technol. 2012, 206, 2954–2960. [Google Scholar] [CrossRef] [Green Version]
  55. Hanaor, D.A.H.; Sorrell, C.C. Review of the anatase to rutile phase transformation. J. Mater. Sci. 2011, 46, 855–874. [Google Scholar] [CrossRef] [Green Version]
  56. Muscat, J.; Swamy, V.; Harrison, N.M. First-principles calculations of the phase stability of TiO2. Phys. Rev. B 2002, 65, 224112. [Google Scholar] [CrossRef]
  57. Detor, A.J.; Hodge, A.M.; Chason, E.; Wang, Y.; Xu, H.; Conyers, M.; Nikroo, A.; Hamza, A. Stress and microstructure evolution in thick sputtered films. Acta Mater. 2009, 57, 2055–2065. [Google Scholar] [CrossRef]
  58. Kacsich, T.; Nicolet, M.A. Moving species in Ti34Si23N43 oxidation. Thin Solid Film. 1999, 349, 1–3. [Google Scholar] [CrossRef]
  59. Kacsich, T.; Gasser, S.; Tsuji, Y.; Dommann, A.; Nicolet, M.A.; Nicolet, A. Wet oxidation of Ti34Si23B43. J. Appl. Phys. 1999, 85, 1871–1875. [Google Scholar] [CrossRef]
Coatings 13 00119 g001 550
Figure 1. XRD diffractograms of as-deposited Ti0.88Si0.12N, Ti0.88Si0.08W0.04N, and Ti0.84Si0.09W0.07N powdered coatings.
Figure 1. XRD diffractograms of as-deposited Ti0.88Si0.12N, Ti0.88Si0.08W0.04N, and Ti0.84Si0.09W0.07N powdered coatings.
Coatings 13 00119 g001
Coatings 13 00119 g002 550
Figure 2. SEM surface and cross-sectional morphologies of as-deposited (a,d) Ti0.88Si0.12N, (b,e) Ti0.88Si0.08W0.04N, and (c,f) Ti0.84Si0.09W0.07N coatings.
Figure 2. SEM surface and cross-sectional morphologies of as-deposited (a,d) Ti0.88Si0.12N, (b,e) Ti0.88Si0.08W0.04N, and (c,f) Ti0.84Si0.09W0.07N coatings.
Coatings 13 00119 g002
Coatings 13 00119 g003 550
Figure 3. (a) TEM bright-field image, (b) SAED pattern, (c) HRTEM micrograph with FFT pattern, and (d) IFFT pattern of as-deposited Ti0.84Si0.09W0.07N coating.
Figure 3. (a) TEM bright-field image, (b) SAED pattern, (c) HRTEM micrograph with FFT pattern, and (d) IFFT pattern of as-deposited Ti0.84Si0.09W0.07N coating.
Coatings 13 00119 g003
Coatings 13 00119 g004 550
Figure 4. Hardness (H), elastic modulus (E), and residual stresses (σ) of as-deposited Ti0.88Si0.12N, Ti0.88Si0.08W0.04N, and Ti0.84Si0.09W0.07N coatings.
Figure 4. Hardness (H), elastic modulus (E), and residual stresses (σ) of as-deposited Ti0.88Si0.12N, Ti0.88Si0.08W0.04N, and Ti0.84Si0.09W0.07N coatings.
Coatings 13 00119 g004
Coatings 13 00119 g005 550
Figure 5. XRD diffractograms of (a) Ti0.88Si0.12N, (b) Ti0.88Si0.08W0.04N, and (c) Ti0.84Si0.09W0.07N powdered coatings after annealing at indicated temperatures.
Figure 5. XRD diffractograms of (a) Ti0.88Si0.12N, (b) Ti0.88Si0.08W0.04N, and (c) Ti0.84Si0.09W0.07N powdered coatings after annealing at indicated temperatures.
Coatings 13 00119 g005
Coatings 13 00119 g006 550
Figure 6. Hardness of Ti0.88Si0.12N, Ti0.88Si0.08W0.04N, and Ti0.84Si0.09W0.07N coatings as a function of annealing temperature.
Figure 6. Hardness of Ti0.88Si0.12N, Ti0.88Si0.08W0.04N, and Ti0.84Si0.09W0.07N coatings as a function of annealing temperature.
Coatings 13 00119 g006
Coatings 13 00119 g007 550
Figure 7. Synchronous (a) DSC and (b) TGA curves of Ti0.88Si0.12N, Ti0.88Si0.08W0.04N, and Ti0.84Si0.09W0.07N powdered coatings in ambient air.
Figure 7. Synchronous (a) DSC and (b) TGA curves of Ti0.88Si0.12N, Ti0.88Si0.08W0.04N, and Ti0.84Si0.09W0.07N powdered coatings in ambient air.
Coatings 13 00119 g007
Coatings 13 00119 g008 550
Figure 8. XRD diffractograms of (a) Ti0.88Si0.12N, (b) Ti0.88Si0.08W0.04N, and (c) Ti0.84Si0.09W0.07N powdered coatings after oxidation at indicated temperatures.
Figure 8. XRD diffractograms of (a) Ti0.88Si0.12N, (b) Ti0.88Si0.08W0.04N, and (c) Ti0.84Si0.09W0.07N powdered coatings after oxidation at indicated temperatures.
Coatings 13 00119 g008
Coatings 13 00119 g009 550
Figure 9. SEM cross-sectional morphologies and EDX line-scan results of (a) Ti0.88Si0.12N, (b) Ti0.88Si0.08W0.04N, and (c) Ti0.84Si0.09W0.07N coatings after oxidation at 750 °C for 10 h.
Figure 9. SEM cross-sectional morphologies and EDX line-scan results of (a) Ti0.88Si0.12N, (b) Ti0.88Si0.08W0.04N, and (c) Ti0.84Si0.09W0.07N coatings after oxidation at 750 °C for 10 h.
Coatings 13 00119 g009
Table
Table 1. The determination results of FWHM and surface roughness (Ra and Rz) for each coating.
Table 1. The determination results of FWHM and surface roughness (Ra and Rz) for each coating.
CoatingsFWHM, DegRa, μmRz, μm
(111)(200)
Ti0.88Si0.12N0.7820.8760.2793.106
Ti0.88Si0.08W0.04N0.7880.9010.2292.763
Ti0.84Si0.09W0.07N0.9080.9630.1812.631
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Hu, W.; Du, J.; Liu, Z.; Sun, X.; Chen, L. Structure, Mechanical and Thermal Properties of TiSiWN Coatings. Coatings 2023, 13, 119. https://doi.org/10.3390/coatings13010119

AMA Style

Hu W, Du J, Liu Z, Sun X, Chen L. Structure, Mechanical and Thermal Properties of TiSiWN Coatings. Coatings. 2023; 13(1):119. https://doi.org/10.3390/coatings13010119

Chicago/Turabian Style

Hu, Wen, Jianwei Du, Zheren Liu, Xu Sun, and Li Chen. 2023. "Structure, Mechanical and Thermal Properties of TiSiWN Coatings" Coatings 13, no. 1: 119. https://doi.org/10.3390/coatings13010119

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop