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Article

Investigation of Surface Stability and Behavior of Diamalloy 2002 Hard Coatings Under High-Temperature Conditions

by
Yildiz Yarali Ozbek
1,*,
Okan Odabas
2,
Gulfem Binal
3,
Yasin Ozgurluk
4 and
Abdullah Cahit Karaoglanli
3
1
Department of Metallurgical and Materials Engineering, Faculty of Engineering, Sakarya University, 54187 Sakarya, Türkiye
2
Department of Mechanical Engineering, Faculty of Engineering, Architecture and Design, Bartin University, 74110 Bartin, Türkiye
3
Department of Metallurgical and Materials Engineering, Faculty of Engineering, Architecture and Design, Bartin University, 74110 Bartin, Türkiye
4
Program of Medical Services and Techniques, Vocational School of Health Services, Bartin University, 74110 Bartin, Türkiye
*
Author to whom correspondence should be addressed.
Metals 2025, 15(11), 1169; https://doi.org/10.3390/met15111169
Submission received: 3 September 2025 / Revised: 18 October 2025 / Accepted: 19 October 2025 / Published: 23 October 2025
(This article belongs to the Special Issue Metallurgy, Surface Engineering and Corrosion of Metals and Alloys)
Browse Figures
Versions Notes

Abstract

The high-temperature and hot corrosion behavior of Diamalloy 2002 coatings with a WC/Co–NiCrFeBSiC composite structure applied to a 316 L stainless steel surface using the atmospheric plasma spraying (APS) method was investigated. The coatings were held at 900 °C in air for 5, 25, 50, and 100 h and in a molten salt bath of Na2SO4 + V2O5 at 900 °C for 1, 3, and 5 h. SEM, EDS, and XRD analyses revealed that the oxide layer on the surface thickened with increasing temperature and corrosion duration, forming NiO, Cr2O3, and mixed metal oxides. These oxide phases created a protective barrier effect by limiting diffusion between the coating and the substrate. Despite a slight increase in porosity and minor WC dissolution under long-term oxidation conditions, the coatings maintained their structural integrity up to 900 °C, demonstrating significant resistance to high-temperature oxidation and molten salt corrosion. These results demonstrate that Diamalloy 2002 coatings provide an effective surface protection solution in abrasive and oxidizing high-temperature environments.

1. Introduction

Currently, high-temperature-resistant coatings are becoming increasingly important in industrial applications [1]. These coatings are especially preferred to improve the performance and extend the life of equipment utilized in industries like power generation, automotive, aerospace, and metalworking [2]. The benefits of thermal spray coatings include high heat resistance, resistance to oxidation and corrosion, protection against mechanical wear, and improvement of surface microstructural properties [3]. Furthermore, there are different types of these methods (such as plasma spray, flame spray, and HVOF), and each one is chosen according to the requirements of the application area [4,5,6]. Coating systems produced by thermal spray coating methods usually have a multilayer structure consisting of three basic coating layers [7]. These layers are the actual protected substrate layer, the bond coat layer, and the top coat layer [8]. The coating layers are expected to be in good harmony with each other. It is preferred to use cost-effective and readily accessible varieties of stainless steel as substrate material [9]. 316 L stainless steel is a material noted for its superior corrosion resistance and outstanding mechanical characteristics [10]. The low carbon content increases resistance to intergranular corrosion and reduces the risk of cracking and deformation, at the same time providing a reliable performance at high temperatures thanks to its oxidation resistance [11]. As a bond coating layer, NiCrAlY, CoCrAlY, or CoNiCrAlY derivatives with high corrosion and oxidation resistance are generally used [12]. The top coating layer used in coating systems to provide insulation and protection against external factors is one of the most critical components that directly affect the performance of the material [13]. This layer is usually produced using ceramics, metallic alloys, and metal–ceramic composite materials. In the studies conducted to date, there are many negative factors in the preference for ceramic materials in the top coating. The most important of these negative factors is the complexity and cost of the production process of ceramics [14]. The requirement for high-purity raw materials, precise production techniques, and long processing steps increases production costs [15]. However, Diamalloy 2002 alloy (hard phase 50% (88WC-12Co) + matrix phase 50% (66Ni-18Cr7Fe-4B-4Si-1C)), which is preferred as the top coating material, stands out with its superior mechanical strength, high-temperature resistance, and excellent wear properties [16,17]. The use of this material improves the performance of coating systems and provides long-lasting and reliable solutions. Diamalloy 2002 also has excellent adhesion properties [18]. In coatings produced using the HVOF method in particular, microhardness values are reported to be in the range of approximately 850–950 HV, while the corresponding Rockwell hardness values are reported to be in the range of approximately 58–62 HRC. Known for its high resistance to oxidation, wear, and temperature, the Diamalloy 2002 alloy’s hard phase content protects the surface, especially in aerospace applications like engine parts and turbine blades [19,20]. Its nickel-based matrix phase also outperforms conventional coatings in terms of mechanical stability and resistance to thermal shock [21].When applied by thermal spray methods, it bonds strongly to the substrate, minimizing the risk of cracking or peeling and giving the coating system significant properties such as uniform coating thickness and high surface smoothness [22]. In coating systems, coating powders are applied by methods like atmospheric plasma spray (APS), atomic laser deposition (ALD), and cold gas dynamic spray (CGDS) [23,24,25,26]. The APS method preferred in this study can be successfully applied to many coating materials, such as metallic alloys, ceramics, and composite materials [27]. Coatings produced with this method have a homogeneous structure and provide high adhesion properties and high efficiency [28,29]. The main damage mechanisms that coating systems produced with thermal spray coating technology are oxidation and hot corrosion caused by low-quality fuels used [30,31]. High-temperature oxidation degrades the coating system’s thermal barrier qualities and causes oxide layers to grow on the coating material’s surface, making it more difficult to protect the substrate material [32]. Various studies exist in the literature regarding the high-temperature oxidation behavior of Diamalloy coatings. For example, Zhou et al. [33]. subjected Diamalloy 2002 (WC–NiCrFeBSiC) coatings produced by the HVOF method to 100 h of oxidation at 900 °C for 100 h in air and reported that protective Cr2O3 and NiO layers formed on the surface, which increased the oxidation resistance of the coating by limiting oxygen diffusion. Similarly, Kumar et al. [34]. examined Diamalloy 2002 samples coated with the APS method at temperatures of 850–950 °C, demonstrating that mixed metal oxide (NiCr2O4) phases developed under long-term oxidation conditions and that these phases contributed to the coating’s high-temperature stability.
Hot corrosion is usually caused by the reaction of impurities (Na, S, V, K) in low-quality fuels with the coating [35]. In this study, 100% Diamalloy 2002 alloy was coated on 316 L stainless steel by the APS method, and oxidation and hot corrosion tests were carried out at 900 °C and different time periods. Microstructural and phase analyses showed that the Diamalloy 2002 coating system mostly keeps its structure intact when exposed to hot corrosion and oxidation. The results show that this coating system is a reliable material choice for harsh environments that need to be able to withstand high temperatures. It also has a lot of potential for use in many fields, such as aerospace, energy, and industrial surface engineering.

2. Materials and Methods

2.1. Preparation of Substrates and Coatings

Commercial 316 L stainless steel obtained from the Bircelik company (Istanbul, Türkiye) was utilized as a substrate. 316 L steel exhibits high oxidation and corrosion resistance owing to the high concentration of chromium and nickel in its composition. The chemical composition of the steel consists of 16% Cr, 12% Ni, 2% Mo, 1.8% Mn, 0.6% Si, 0.2% Cu, 0.08% C, 0.04% P, 0.05% V, 0.03% S, and 0.005% Ti, and the rest is Fe. With the help of a CNC apparatus, the substrate was machined with dimensions of 25 mm × 25 mm × 4 mm. Following the cutting process, the substrate’s surface was sandblasted to enhance the adhesion of the powders to be coated. The sandblasting process was carried out by sending Al2O3 particles with grit sizes ranging from 50 to 65 pores at an angle of 90° to the surface of the substrate at a pressure of approximately 2–3 mbar. Following the sandblasting process, ultrasonic cleaning was performed using ethyl alcohol (C2H5OH). Diamalloy 2002 (hard phase 50% (88WC-12Co) + matrix phase 50% (66Ni-18Cr-7Fe-4B-4Si-1C)) powder was coated on the prepared substrate surface via the APS technique. Table 1 lists the parameters utilized in the APS method. The particle size of Diamalloy 2002 powder has been determined to be 15–45 µm.

2.2. Investigations on Oxidation and Hot Corrosion

In a high-temperature furnace (Protherm, PLF 130/12, Ankara, Turkey), oxidation and hot corrosion experiments were conducted for 5, 25, 50, and 100 h at 900 °C and 1, 3, and 5 h, respectively. A highly corrosive 55% V2O5 (99.8% purity) + 45% Na2SO4 (99.8% purity) salt mixture was used to examine the damage formation in hot corrosion tests. The mixture of corrosion salts was applied to the surface of the 100% Diamalloy coating at a rate of 2.3 ± 0.2 mg/cm2. After the tests, the deformation and morphological and microstructural alterations that were taking place in the coating system were examined with the help of various characterization methods: X-ray diffractometer XRD (Rigaku Dmax 2200 PC, CuKα radiation, Rigaku, Tokyo, Japan) for crystal/phase analysis, scanning electron microscope-SEM (Zeiss EVO LS10-Germany, Oberkochen, Germany) and energy dispersive spectroscopy-EDS (Oxford Xmax 50, Abingdon, UK) for microstructural analysis, and elemental mapping analysis for monitoring the oxidation behavior and microstructural changes. Schematic diagrams of the coating formation, the oxidation process, and the distribution of hot reactions are demonstrated in Figure 1.

3. Results and Discussion

3.1. Characterization of As-Sprayed Coating System

Figure 2 displays the XRD pattern, elemental mapping analysis, and cross-sectional SEM images of a 100% Diamalloy 2002 coating that was applied using the APS method to a 316 L stainless steel substrate. Diamalloy 2002 alloy is a blend of tungsten carbide, cobalt, and nickel. It is utilized for the preservation of the surfaces from oxidation, corrosion, and wear damage [36]. In the XRD analysis (Figure 2c), peaks belonging to the WC and Co phases and the free-flowing nickel alloy were observed in the 100% Diamalloy 2002 sputter coating, depending on the alloy composition. The structure also contains a W crystalline phase. The W phase is thought to have formed as a result of decarburization of the WC-Co structure by the APS process. When the temperature of WC-Co alloy goes above its eutectic melting point, which is about 1350 °C, the tungsten carbide (WC) phase starts to dissolve into the cobalt (Co) bonded phase. In these high-temperature conditions, the surface areas of WC particles can react with oxygen (O2) in the air, creating intermediates that are not stable thermodynamically. During this process, carbon and oxygen react to make carbon monoxide (CO) gas. This gas can make the microstructure less stable and make the coating’s mechanical properties worse. Additionally, oxidative dissolution and outgassing are considered significant factors contributing to the instability of WC-Co systems at high temperatures. The removal of carbon from the solution allows more WC particles to dissolve. During cooling, W2C and W phases are formed due to the amount of C loss [37]. The amount of decarburization varies depending on the properties of the powder used, the spraying method and parameters, and the amount of oxygen. In the APS method, when the enthalpy of the plasma gas increases, more thermal energy is generated, and this increases the WC decarburization and reaction with the binder phase [38]. When the SEM images (Figure 2a) are evaluated, it is observed that the coating has a dense, heterogeneous structure containing lamellae, small pores, and incompletely melted particles. This type of microstructure is frequently seen in the thermal-sprayed materials [39]. Distinct splats form a layered structure in an average APS coating. This structure, characterized by engaging interfaces and porosity, enhances coating compliance and consequently durability during thermal cycling [40]. The elemental mapping study (Figure 2b) reveals elevated amounts of Ni, Cr, Co, and W in the 100% Diamalloy 2002 coating zone. The uniform distribution of elements in the coating structure determines how the surface behaves. This homogeneity, in particular, makes the coating much more resistant to wear and to environmental factors like oxidation and hot corrosion that happen at high temperatures. This helps the coating stay mechanically stable, which means that the structure will stay strong for a long time. Additionally, an analysis of the chemical composition of the 316 L stainless steel substrate to which the coating was applied indicated a significant iron (Fe) content. This high Fe content is something to think about when it comes to elemental diffusion and microstructural interactions that might happen at the coating–substrate interface.

3.2. Oxidation Effect on Coating Systems

SEM images of a 100% Diamalloy 2002 coating system that was put through an isothermal oxidation test at 900 °C for 5, 25, 50, and 100 h are displayed in Figure 3. The coating maintained its integrity and did not show any indications of spallation despite the oxidation products observed at all exposure times. During the early stage of oxidation, high-temperature sintering inside the coating structure leads to the reduction and closure of pores. Consequently, the coating density escalates. Nonetheless, sintering may induce the emergence of novel damage mechanisms during the later stages of oxidation. It is observed that (JCPDS No: 38-1479 Cr2O3) and (JCPDS No: 10-0340 Cr2NiO4) with a dense structure formed within the coating during oxidation. However, since a continuous Cr2O3 layer is not formed, it does not act as a complete protective diffusion barrier. In addition, porous mixed oxides (JCPDS No: 15-0755 (e.g., NiWO4)) are formed in the coating structure. This porous structure causes rapid oxygen diffusion into the coating and internal oxidation. The cooling phase following the coating process is crucial for maintaining the integrity of the microstructure. During this phase, if the cooling occurs too rapidly or too slowly, thermal stresses may accumulate within the coating. Porous structures can exacerbate these stresses in specific areas, increasing the likelihood of crack formation. Such cracks not only weaken the coating but can also propagate and disrupt the oxide layer, thereby reducing the coating’s protective capabilities. This reduction in effectiveness can significantly impact the coating’s ability to prevent oxidation and corrosion, particularly in high-temperature applications. Therefore, to ensure the long-term performance of the coating, it is essential to optimize the cooling rate after coating and manage porosity effectively [41,42].
Figure 4 shows the XRD pattern and elemental mapping analysis of a 100% Diamalloy 2002 coating system after the oxidation tests. According to the XRD pattern, it was observed that after 5, 25, 50 and 100 h of oxidation at 900 °C, the W and Ni/Co phases in the as-sprayed coating disappeared, while the WC phase preserved its existence. During the oxidation tests, it was determined that Cr2O3, Cr2NiO4, and NiWO4 phases were formed in the coating structure. The adsorption of oxygen by Ni, Cr, and W atoms initiates the oxide formation in the coating (Equations (1)–(3)) [43].
Ni (s) + 0.5 O2 (g) = NiO (s)
Cr (s) + 0.75 O2 (g) = 0.5 Cr2O3 (s)
W (s) + 1.5 O2 (g) = WO3 (s)
Ni and Cr exhibit a high oxidation rate. Ni exhibits significant oxidation resistance at high temperatures. NiO exhibits rapid growth and creates a somewhat porous oxide, so it offers minimal oxidation protection. Cr generates Cr2O3, which similarly exhibits rapid growth. Cr2O3 provides higher oxidation resistance because it has a dense structure. Both Ni and Cr interact and oxidize simultaneously, resulting in the formation of NiO and Cr2O3, besides Cr2NiO4 [44]. Figure 4 illustrates that the coating structure alters as a result of the outward diffusion of coating and substrate elements and the inward diffusion of oxygen. When Cr2O3 particles are surrounded by NiO, a solid-state reaction occurs and spinel is formed according to the reaction given in (Equation (4)) [45]. By decreasing the metal ion diffusion rate, Cr2NiO4 spinel can lower the metal-oxygen ion bonding rate [46]. As a result, the coating may become more resistant to oxidation.
Cr2O3 (s) + NiO(s) → Cr2NiO4 (s)
W present in the coating composition can form WO3 (Equation (3)) as a result of oxidation. WO3 is a compound that is stable at 850 °C and begins to volatilize around 1000 °C [47,48]. NiO can react with WO3 to create NiWO4 (Equation (5)) [49].
NiO (s) + WO3 (s) = NiWO4 (s)
An essential alloying element that improves oxidation resistance in high-temperature applications is chromium (Cr). While preventing the formation of less protective transient oxides like NiO and NiWO4, Cr encourages the surface formation of stable and protective oxide phases like Cr2O3 and Cr2NiO4. A more stable, adherent, and continuous oxide layer can form as a result of limiting oxygen diffusion. Therefore, at high temperatures, the presence of Cr greatly extends the service life and structural integrity of coatings or alloy systems. Through the rapid occurrence of the mixed oxide layer comprising NiWO4, which has low oxidation resistance, W deteriorates oxidation resistance [50,51]. The elemental mapping analysis showed that there were Co signals in parts of the coating where the O signal was strong. This suggests that Co oxides may have formed. However, the XRD pattern from the coated surface did not identify Co oxides.

3.3. Effects of Hot Corrosion on the Coating System

The term “hot corrosion” describes the rapid oxidation of materials at high temperatures brought on by a thin layer of molten salt [52]. When fuel burns, most of the sulfur (S) in it transforms into sulfur dioxide (SO2), and a portion of this gas converts into sulfur trioxide (SO3). When the fuel or combustion air reaches sufficiently high temperatures, sodium chloride (NaCl) reacts with SO3 and water vapor to form sodium sulfate (Na2SO4). Additionally, at elevated temperatures, the vanadium (V) present in the fuel is converted into vanadium pentoxide (V2O5). The reaction between V2O5 and Na2SO4 produces sodium vanadate (NaVO3), which is a corrosive compound that has a low melting point (Equation (6)). This compound can corrode and erode boiler surfaces, potentially reducing the lifespan of the equipment. To enhance the performance and longevity of combustion systems, understanding these mechanisms is essential [53,54].
V2O5 + Na2SO4 → 2(NaVO3) + SO3
Figure 5 shows the SEM images of a 100% Diamalloy 2002 coating system exposed to a hot corrosion test at 900 °C for 1, 3, and 5 h. NaVO3 (melting point 650 °C [55]) melt and corrosion products are observed on the coating surfaces at all time periods. In addition, at 3 and 5 h test times, crack initiation and propagation in the coating are noticed. From these microcracks and pores, it is seen that salt melt infiltrates into the internal structure of the coatings.
Figure 6 shows the XRD pattern and elemental mapping analysis of a 100% Diamalloy 2002 coating system following the hot corrosion tests. According to the XRD pattern, it was observed that after 1, 3, and 5 h of hot corrosion at 900 °C, the W and WC phases in the as-sprayed coating disappeared. During the hot corrosion tests, it was determined that NaVO3, Cr2O3, NiWO4, Co3O4 and CoV2O6 phases were formed in the coating structure. Because NaVO3 acts as an oxygen carrier, the fundamental coating ingredients oxidize rapidly and produce oxide scales like Cr2O3, Co3O4, and NiWO4. In the elemental mapping analysis, the intense Ni, W, and O signals overlapping with each other on the substrate’s surface suggest that a layer of porous NiWO4 compound was formed in this region. Vanadium (V), positioned in periodic table group V-B, possesses five valence electrons that facilitate bonding, enabling it to exhibit multiple oxidation states (+5, +4, +3, and +2). Of them, +5 has the greatest stability, but +2 is readily oxidizable. V has been found in multiple compound types, including VOPO4, VSx, VN, and different MVs. Among these minerals, t-MVs (transition metal vanadates/MxVyOz, M = Fe, Cu, Co, Ni) belong to the AxByOz family. Here, A represents metal elements with low oxidation states, and B represents metal elements with high oxidation states. MVs can inhabit many crystal forms, contingent upon the specific type of metal. In most MVs, V exists in the form of VO43− anions in the 5+ oxidation state, forming octahedral complexes containing six oxygen atoms. The predominant crystal structures of t-MVs comprised MV2O6, M2V2O7, and M3V2O8. In MV2O6, the V-O octahedra share vertices to create a three-dimensional structure, with M (specifically Co for this study) cations situated within the channels [56,57]. In this study, Co in the alloy composition and V2O5 corrosion powder reacted to form the CoV2O6 phase with a relatively low melting temperature. The phase diagram of CoO-V2O5 indicates that CoV2O6 exhibits two polymorphic phases. The α phase (high-temperature) has a brannerite-like monoclinic structure. The γ phase (low temperature) has a triclinic structure. The polymorphic transition and the melting temperatures of CoV2O6 are 662 °C and 740 °C, respectively.
The top surface SEM images and EDS analysis of a 100% Diamalloy 2002 coating system following the hot corrosion tests are given in Figure 7. When SEM images are examined, it is apparent that corrosion products with needle-like, rod-like, and column-like crystalline formations occur on the sample surfaces. Corrosion products are spread over the entire surface. These corrosion products, which have different physical and mechanical properties, reduce the corrosion resistance of the coating system by causing crack initiation and propagation on the coating. The findings of the EDS analysis suggest that chemical phases may be connected to the morphological variations seen on the coating surface. The distinctive morphology of the NiWO4 phase, with local enrichment of Ni and W elements, is believed to be reflected in the needle-like formations found in microstructural investigations. On the other hand, areas where Co and V elements coexist exhibit a concentration of rod-like and columnar structures, indicating a CoV2O6 phase. Additionally, the presence of Na in certain columnar structures raises the possibility that these structures are a part of low-melting, potentially corrosive phases like NaVO3. Important hints for identifying the microstructural signatures of complex oxide phases formed in high-temperature oxidation or hot corrosion environments can be found in these morphological and chemical relationships.

4. Conclusions

This investigation performed the application of a 100% Diamalloy 2002 powder onto 316 L stainless steel via the APS method, followed by isothermal oxidation (5, 25, 50, 100 h) and hot corrosion (1, 3, 5 h) tests at 900 °C. The findings can be encapsulated as follows.
The APS process was successfully applied to 100% Diamalloy 2002 coatings to obtain a coating system with homogeneous distribution and structure. The phase structure of the produced coating includes W, WC and Co phases as well as a self-flowing nickel alloy.
As a consequence of the oxidation test at 900 °C, the coating maintained its integrity and did not show any indications of spallation. Oxidation products were observed at all exposure times. It was observed that the oxidation intensity increased with increasing time and microstructural changes and oxide structures were formed.
During oxidation, thick and strong Cr2O3 and Cr2NiO4 phases were seen to form inside the coating. Furthermore, porous and mixed oxide components, particularly NiWO4, were observed to develop within the coating structure. This significantly affects both the chemical stability and microstructural properties of the coating.
As a consequence of hot corrosion tests, NaVO3 melt and corrosion products (CoV2O6, NiWO4, Co3O4, Cr2O3) were observed on the coating surfaces. In addition, crack initiation and propagation in the coating were noticed. The crack formations that occurred increased the irregularity within the coating structure according to the increasing corrosion severity.
According to high-temperature protection tests, the generated coating system showed overall high resistance to oxidation and hot corrosion damage under a variety of high-temperature conditions and over a range of time periods. The coating system’s exceptional performance makes it a promising material for industrial applications, especially in demanding environments with high temperatures and corrosion.

Author Contributions

Y.Y.O.: Conceptualization, investigation, writing—original draft, validation, visualization; O.O.: methodology, formal analysis, experiments; G.B.: writing—original draft, validation, visualization; Y.O.: Writing, review and editing, investigation, validation; A.C.K.: Conceptualization, validation, discussion, writing—original draft, supervision. All authors have read and agreed to the published version of the manuscript.

Funding

This investigation was financially supported by Sakarya University.

Data Availability Statement

The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding author.

Acknowledgments

The authors also gratefully acknowledge the Bartin University, Metallurgical and Materials Engineering Department for their helpful technical support.

Conflicts of Interest

The authors declare no conflicts of interest.

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Metals 15 01169 g001
Figure 1. Schematic view of damage mechanisms; (a) oxidation damage, (b) hot corrosion damage.
Figure 1. Schematic view of damage mechanisms; (a) oxidation damage, (b) hot corrosion damage.
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Figure 2. As-sprayed analysis of a coating system with 100% Diamalloy content; (a) SEM image, (b) elemental mapping analysis, and (c) XRD pattern.
Figure 2. As-sprayed analysis of a coating system with 100% Diamalloy content; (a) SEM image, (b) elemental mapping analysis, and (c) XRD pattern.
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Figure 3. 100% Diamalloy 2002 coating system cross-sectional SEM images following isothermal oxidation testing at 900 °C for 5, 25, 50, and 100 h.
Figure 3. 100% Diamalloy 2002 coating system cross-sectional SEM images following isothermal oxidation testing at 900 °C for 5, 25, 50, and 100 h.
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Figure 4. 100% Diamalloy 2002 coating system’s (a) elemental mapping analysis, and (b) XRD pattern after isothermal oxidation tests at 900 °C.
Figure 4. 100% Diamalloy 2002 coating system’s (a) elemental mapping analysis, and (b) XRD pattern after isothermal oxidation tests at 900 °C.
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Figure 5. SEM images of 100% Diamalloy 2002 coating system after hot corrosion tests at 900 °C.
Figure 5. SEM images of 100% Diamalloy 2002 coating system after hot corrosion tests at 900 °C.
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Figure 6. 100% Diamalloy 2002 coating system’s (a) elemental mapping analysis, and (b) XRD pattern after 900 °C hot corrosion tests.
Figure 6. 100% Diamalloy 2002 coating system’s (a) elemental mapping analysis, and (b) XRD pattern after 900 °C hot corrosion tests.
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Figure 7. Top surface SEM images and point EDS analyses of 100% Diamalloy 2002 coating system after 900 °C hot corrosion tests.
Figure 7. Top surface SEM images and point EDS analyses of 100% Diamalloy 2002 coating system after 900 °C hot corrosion tests.
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Table 1. Deposition parameters of the APS technique.
Table 1. Deposition parameters of the APS technique.
Current500 A
Voltage65 V
Ar flow55 (L.min−1)
H2 flow8 (L.min−1)
Powder feed rate25 g/min
Stand-off distance200 mm
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MDPI and ACS Style

Ozbek, Y.Y.; Odabas, O.; Binal, G.; Ozgurluk, Y.; Karaoglanli, A.C. Investigation of Surface Stability and Behavior of Diamalloy 2002 Hard Coatings Under High-Temperature Conditions. Metals 2025, 15, 1169. https://doi.org/10.3390/met15111169

AMA Style

Ozbek YY, Odabas O, Binal G, Ozgurluk Y, Karaoglanli AC. Investigation of Surface Stability and Behavior of Diamalloy 2002 Hard Coatings Under High-Temperature Conditions. Metals. 2025; 15(11):1169. https://doi.org/10.3390/met15111169

Chicago/Turabian Style

Ozbek, Yildiz Yarali, Okan Odabas, Gulfem Binal, Yasin Ozgurluk, and Abdullah Cahit Karaoglanli. 2025. "Investigation of Surface Stability and Behavior of Diamalloy 2002 Hard Coatings Under High-Temperature Conditions" Metals 15, no. 11: 1169. https://doi.org/10.3390/met15111169

APA Style

Ozbek, Y. Y., Odabas, O., Binal, G., Ozgurluk, Y., & Karaoglanli, A. C. (2025). Investigation of Surface Stability and Behavior of Diamalloy 2002 Hard Coatings Under High-Temperature Conditions. Metals, 15(11), 1169. https://doi.org/10.3390/met15111169

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