FeCrNi-steel alloy as a carbide binder

Abstract

This disclosure details a powder comprising, by total weight, the following: iron (Fe) 6.6 wt%–7.9 wt%, carbon (C) 5.2 wt%–5.7 wt%, chromium (Cr) 3.9 wt%–4.5 wt%, nickel (Ni) 2.2 wt%–3.0 wt%, molybdenum (Mo) 0.6 wt%–0.75 wt%, silicon (Si) 0.1 wt%–0.22 wt%, manganese (Mn) 0.07 wt%–0.1 wt%, with the balance being tungsten (W) and unavoidable impurities. This powder, when used in HVOF and / or HVAF processes, provides tungsten carbide embedded in a high-alloy stainless steel binder. Because this binder is cobalt-free, it provides a sustainable and cost-effective alternative to conventional binders for carbide products.

Description

Technical Field

[0001] In the field of powder technology for HVOF and HVAF applications, a series of stainless steel alloys have been proposed as carbide binders, particularly for tungsten carbide.

[0002] background Tungsten / chromium carbide powders are hard materials (hardness ≈ 1000 HV) used for dense coatings. They can be sprayed onto a variety of metal parts and structures using high-velocity oxygen fuel (HVOF) and high-velocity air fuel (HVAF) spraying methods to improve the surface resistance of these parts and structures to severe wear and corrosion. Conventional carbide powders consist of hard WC or Cr3C2 particles in a binder matrix using CoCr powder. Different alloying elements, such as Ni, Fe, Ti, etc., can be added to the matrix to improve mechanical, corrosion, and spraying properties; see, for example, J. García et al. (J. García, V. Collado Ciprés, A. Blomqvist and B. Kaplan, “Cemented carbide microstructures: a review,” International Journal of Refractory Metals and Hard Materials, Vol. 80, pp. 40–68, 2019).

[0003] In recent years, the use of certain elements, particularly Co and Ni, has drawn attention due to their harmful properties to the environment and health, and attempts have been made to replace these elements with less harmful ones in binders, see, for example, M. Walbrühl et al. (M Walbrühl, D. Linder, K. Ågren and A. Borgenstam, “Diffusion modeling incemented carbides: Solubility assessment for Co, Fe and Ni binder systems,” International Journal of Refractory Metals and Hard Materials, Vol. 68, pp. 41-48, 2017).

[0004] It is known that conventional binders can be replaced by high-alloy steel or atomized powder, see, for example, J. García et al. In this paper, the inventors introduce a novel alloy suitable for use as a binder matrix, particularly as a binder for carbides such as tungsten carbide or various chromium carbides, which is a sustainable and cost-effective alternative to conventional carbide products.

[0005] These newly developed alloys are excellent candidates for coating components such as sliding tubes, sliding pistons, shafts, bolts, bushings, flanges, etc., used in aerospace or power generation technologies. The developed alloys can also be used to coat grinding rolls, crusher rolls, and / or calender rolls. Furthermore, because the alloys are co-free, they can also be used in the food industry, for example, in packaging rolls for plastic foil. Brief description of the attached diagram Figure 1 Phase diagram of agglomerated / sintered carbides made of 85% WC particles and 15% binder, calculated using Thermo-Calc.

[0007] Figure 2 Cross-section of agglomerated / sintered carbides made of 85% WC particles and 15% binder.

[0008] Figure 3 Material consumption relative to coverage for different spraying techniques and parameters serves as an indicator of efficiency and productivity.

[0009] Figure 4 Cross-sections of coatings obtained by JP spraying at different magnifications. Scale bar A: 50 μm, Scale bar B: 20 ​​μm.

[0010] Figure 5 Cross-sections of coatings obtained by DJ spraying at different magnifications. Scale bar A: 50 μm, Scale bar B: 20 ​​μm.

[0011] Figure 6 The samples tested by NSS after 1008 hours: A: JP-coated sample and B: DJ-coated sample.

[0012] Figure 7 : The results of the air permeability test of the coated sample.

[0013] Figure 8 Hardness measurement results of samples coated using different techniques and parameters.

[0014] Figure 9 Roughness measurement results of samples sprayed using different techniques and parameters.

[0015] Figure 10 Young's modulus measurement results of samples sprayed using different techniques and parameters.

[0016] Figure 11 The amount of material consumed in the spraying process relative to the abrasion resistance of the sprayed sample.

[0017] Figure 12The SEM images and EDX plots of the elements show the different types of carbides in the Ni-rich FCC matrix.

[0018] Figure 13 Corrosion resistance is measured as the cavitation index relative to the material used in the spraying.

[0019] It should be understood that the embodiments shown in the accompanying drawings are for illustrative purposes and should not be construed as limiting the invention. Unless otherwise indicated, the drawings are intended to be read in conjunction with the specification (e.g., cross-sections, arrangement of parts, scale, extent, etc.) and are considered an integral part of the entire written description of this disclosure.

[0020] Detailed Explanation In the first aspect and embodiments of this document, a ferro-chromium-nickel stainless steel alloy is described in detail, which comprises, by total weight of the alloy, the following: Chromium (Cr): 26.0 wt%-30.0 wt%, Nickel (Ni): 15.0 wt%-18.0 wt%, Molybdenum (Mo): 4.0 wt%-5.0 wt%, Silicon (Si): 1.00 wt% - 1.50 wt%. Manganese (Mn): 0.50 wt%-1.00 wt%, Carbon (C): 0.15 wt% - 0.25 wt%. The balance is iron (Fe) and unavoidable impurities not exceeding 0.3 wt%.

[0021] As detailed in the experimental section below, the stainless steel alloy of the present invention can be used as a sustainable binder for carbides (such as tungsten carbide).

[0022] Generally, the total amount of unavoidable impurities should not exceed 0.3 wt%, but preferably should not exceed 0.2 wt%. Preferably, any individual impurity itself does not exceed 0.1 wt%, and more preferably, any individual impurity itself does not exceed 0.05 wt%. However, the advantage of the alloys of the present invention is that they are not adversely affected by impurities, which allows for the use of a wider range of source materials in the manufacture of the alloys, such as, for example, fine grains from metal processing.

[0023] In embodiments of the iron-chromium-nickel stainless steel alloy, chromium (Cr) is present at at least 26.5 wt%, preferably at least 27.0 wt%, more preferably at least 27.5 wt%, or even more preferably at least 28.0 wt%. In other embodiments, chromium (Cr) is present at up to 29.5 wt%, preferably up to 29.0 wt%, or more preferably up to 28.5 wt%.

[0024] In embodiments of the iron-chromium-nickel stainless steel alloy, chromium (Cr) is present in amounts from 26.5 wt% to 29.5 wt%, preferably from 27.0 wt% to 29.0 wt%, or even more preferably from 27.5 wt% to 28.5 wt%.

[0025] In embodiments of the iron-chromium-nickel stainless steel alloy, nickel (Ni) is present at at least 15.5 wt%, preferably at least 16 wt%, or more preferably at least 16.5 wt%. In other embodiments, nickel (Ni) is present at up to 17.5 wt%, preferably up to 17 wt%, or more preferably up to 16.5 wt%.

[0026] In embodiments of the iron-chromium-nickel stainless steel alloy, nickel (Ni) is present in amounts from 15.5 wt% to 17.5 wt%, preferably from 16.0 wt% to 17.0 wt%, and more preferably from 16.2 wt% to 16.8 wt%.

[0027] In embodiments of the iron-chromium-nickel stainless steel alloy, molybdenum (Mo) is present at at least 4.1 wt%, preferably at least 4.2 wt%, at least 4.25 wt%, more preferably at least 4.3 wt%, even more preferably at least 4.4 wt%, or most preferably at least 4.5 wt%. In other embodiments, molybdenum (Mo) is present at up to 4.9 wt%, preferably up to 4.8 wt%, up to 4.75 wt%, more preferably up to 4.7 wt%, and most preferably up to 4.6 wt% or up to 4.5 wt%.

[0028] In embodiments of the iron-chromium-nickel stainless steel alloy, molybdenum (Mo) is present in amounts ranging from 4.1 wt% to 4.9 wt%, preferably from 4.2 wt% to 4.8 wt%, more preferably from 4.3 wt% to 4.7 wt%, even more preferably from 4.4 wt% to 4.6 wt%, and most preferably from 4.45 wt% to 4.55 wt%.

[0029] In embodiments of the iron-chromium-nickel stainless steel alloy, silicon (Si) is present at at least 1.10 wt%, preferably 1.15 wt%, more preferably at least 1.20 wt%, or most preferably at least 1.25 wt%. In other embodiments, silicon (Si) is present at up to 1.40 wt%, preferably up to 1.35 wt%, more preferably up to 1.30 wt%, or even more preferably up to 1.25 wt%.

[0030] In embodiments of the iron-chromium-nickel stainless steel alloy, silicon (Si) is present in amounts from 1.10 wt% to 1.40 wt%, preferably from 1.15 wt% to 1.35 wt%, more preferably from 1.20 wt% to 1.30 wt%, or most preferably from 1.22 wt% to 1.28 wt%.

[0031] In embodiments of the iron-chromium-nickel stainless steel alloy, manganese (Mn) is present at at least 0.60 wt%, preferably at least 0.65 wt%, more preferably at least 0.70 wt%, or most preferably at least 0.75 wt%. In further embodiments, manganese (Mn) is present at at most 0.90 wt%, preferably at most 0.85 wt%, more preferably at most 0.80 wt%, or most preferably at most 0.75 wt%.

[0032] In embodiments of the iron-chromium-nickel stainless steel alloy, manganese (Mn) is present in amounts from 0.60 wt% to 0.90 wt%, preferably from 0.65 wt% to 0.85 wt%, more preferably from 0.70 wt% to 0.80 wt%, or most preferably from 0.72 wt% to 0.78 wt%.

[0033] In embodiments of the iron-chromium-nickel stainless steel alloy, carbon (C) is present at at least 0.16 wt%, preferably at least 0.17 wt%, more preferably at least 0.18 wt%, even more preferably at least 0.19 wt%, or most preferably at least 0.20 wt%. In other embodiments, carbon (C) is present at at most 0.24 wt%, preferably at most 0.23 wt%, more preferably at most 0.22 wt%, even more preferably at most 0.21 wt%, or most preferably at most 0.20 wt%. Within these carbon concentration ranges, fine particles from other metalworking processes can be advantageously used with the alloys of the present invention without the risk of making the alloys of the present invention brittle.

[0034] In embodiments of the iron-chromium-nickel stainless steel alloy, carbon (C) is present in amounts from 0.16 wt% to 0.24 wt%, preferably from 0.17 wt% to 0.23 wt%, more preferably from 0.18 wt% to 0.22 wt%, or even more preferably from 0.19 wt% to 0.21 wt%.

[0035] Typically, and as for example from Figure 1 As is evident from the phase diagram, the alloys of the present invention are suitable for their intended purpose across all elemental concentration ranges given herein, whether alone or in combination with other elements of the alloy. Therefore, selecting a concentration range oriented towards the center of the widest range implies removing the alloy thus selected from the phase boundaries of the alloy's phase diagram.

[0036] The alloys of the present invention are preferably manufactured by pre-alloying the elements of the alloy, for example, from a premixed composition of the constituent elements (typically a powder mixture). Typically, the pre-alloyed alloys of the present invention are then formulated into powder by, for example, atomizing the pre-alloyed elements (e.g., water atomization), preferably for HVOF and / or HVAF spraying, thereby obtaining pre-alloyed stainless steel powder suitable for other applications and containing the alloys of the present invention. However, if use in, for example, HVOF and / or HVAF spraying is impractical, it is equally possible to form directly from a mixed powder of the constituent elements.

[0037] In an embodiment of pre-alloyed iron-chromium-nickel stainless steel powder, the pre-alloyed iron-chromium-nickel stainless steel powder comprises at least 80 wt% by weight of pre-alloyed iron-chromium-nickel stainless steel powder having a size distribution of 1 μm to 100 μm, preferably 2.5 μm to 75 μm, or even more preferably 5 μm to 50 μm as measured by sieving according to ISO-14232-1-2017-E "Determination of particle distribution by sieving method", and / or preferably comprises at least 85%, at least 90%, or more preferably at least 95% by weight of pre-alloyed iron-chromium-nickel stainless steel powder having a size distribution of 2.5 μm to 100 μm as measured by sieving according to ISO-14232-1-2017-E "Determination of particle distribution by sieving method".

[0038] The advantage of the alloys of the present invention is that, when formulated into powders having a powder size suitable for HVOF and / or HVAF spraying, they can be mixed with carbide powders having a powder size also suitable for HVOF and / or HVAF spraying, and the mixed powders can then be directly sprayed onto a suitable surface to provide a carbide-containing binder alloy on the surface.

[0039] The benefits of the present invention are illustrated below in the context of an agglomerated / sintered carbide product made from 85 wt% WC particles and 15 wt% binder. The binder and carbide are dry-sprayed together and sintered at an isothermal temperature of 1138°C for up to two hours to form the desired tungsten carbide / stainless steel alloy composite. The range of chemical composition elements used to form a suitable tungsten carbide / stainless steel alloy composite is given in Table 1 below.

[0040] Table 1: WC / alloy composites, balance tungsten (W) Therefore, in the embodiments described herein, a powder comprising a pre-alloyed binder powder of an iron-chromium-nickel stainless steel alloy is described in detail, and in the embodiments described above, the powder further comprises a metal carbide powder.

[0041] A key advantage of the alloys of this invention is that they can be formulated as pre-alloyed binder powders and, for example, by internal mixing, added the desired amount of metal carbide powder. This not only broadens the range and composition of metal carbide powders that can be added, making the hard coating independent of the formation chemistry of the constituent powders, but it also allows for lower deposition temperatures, since instead of providing the coating temperature required for metal carbide formation, only the energy needed to melt the pre-alloyed binder powder, rather than the metal carbide, is required.

[0042] The actual concentration and composition of the metal carbide powder in the final pre-alloyed binder powder composition are usually determined by the end user. However, in embodiments of the pre-alloyed binder composition, at least one metal carbide is selected from one or more powders of nickel carbide, chromium carbide, vanadium carbide, tungsten carbide (WC), molybdenum carbide, silicon carbide, manganese carbide, aluminum carbide, titanium carbide, niobium carbide, tantalum carbide, hafnium carbide, or zirconium carbide, preferably selected from one or more powders of nickel carbide, chromium carbide, vanadium carbide, tungsten carbide (WC), molybdenum carbide, silicon carbide, manganese carbide, or aluminum carbide, more preferably selected from one or more powders of nickel carbide, chromium carbide, vanadium carbide, molybdenum carbide, or tungsten carbide (WC), and most preferably tungsten carbide (WC).

[0043] For the commercially desired use of the iron-chromium-nickel stainless steel alloy with tungsten carbide (WC) of the present invention, the inventors have determined that, optimally, tungsten carbide should be present in the Ni-based powder composition of the present invention at a concentration of from 83 wt% to 87 wt%, but preferably about 85 wt%.

[0044] Therefore, in another aspect of the invention, a powder for forming an iron-chromium-nickel stainless steel alloy is described in detail herein, the powder comprising, by total weight, the following: Chromium (Cr): 26.0 wt%-30.0 wt%, Nickel (Ni): 15.0 wt%-18.0 wt%, Molybdenum (Mo): 4.0 wt%-5.0 wt%, Silicon (Si): 1.00 wt% - 1.50 wt%. Manganese (Mn): 0.50 wt%-1.00 wt%, Carbon (C): 0.15 wt% - 0.25 wt%. The balance is iron (Fe) and unavoidable impurities not exceeding 0.3 wt%.

[0045] In its embodiments, chromium (Cr) is present at at least 26.5 wt%, preferably at least 27.0 wt%, or more preferably at least 27.5 wt%; and / or wherein chromium is present at at most 29.5 wt%, preferably at most 29.0 wt%, or more preferably at most 28.5 wt%.

[0046] In its embodiments, nickel (Ni) is present at at least 15.5 wt%, preferably at least 16.0 wt%, or more preferably at least 16.5 wt%; and / or wherein nickel (Ni) is present at at most 17.5 wt%, or preferably at most 17.0 wt%.

[0047] In its embodiments, molybdenum (Mo) is present at at least 4.1 wt%, preferably at least 4.2 wt%, more preferably at least 4.3 wt%, even more preferably at least 4.4 wt%, or most preferably at least 4.5 wt%; and / or wherein molybdenum (Mo) is present at at most 4.9 wt%, preferably at most 4.8 wt%, more preferably at most 4.7 wt%, or most preferably at most 4.6 wt%.

[0048] In its embodiments, silicon (Si) is present at at least 1.10 wt%, preferably at least 1.15 wt%, more preferably at least 1.20 wt%, or most preferably at least 1.25 wt%; and / or wherein silicon (Si) is present at at most 1.40 wt%, preferably at most 1.35 wt%, or more preferably at most 1.30 wt%.

[0049] In its embodiments, manganese (Mn) is present at at least 0.60 wt%, preferably at least 0.65 wt%, more preferably at least 0.70 wt%, or most preferably at least 0.75 wt%; and / or wherein manganese (Mn) is present at at most 0.90 wt%, preferably at most 0.85 wt%, or more preferably at most 0.80 wt%.

[0050] In its embodiments, carbon (C) is present at at least 0.16 wt%, preferably at least 0.17 wt%, more preferably at least 0.18 wt%, even more preferably at least 0.19 wt%, or most preferably at least 0.20 wt%; and / or wherein carbon (C) is present at at most 0.24 wt%, preferably at most 0.23 wt%, more preferably at most 0.22 wt%, or most preferably at most 0.21 wt%.

[0051] In another aspect, this document details an iron-chromium-nickel stainless steel alloy according to any of the above embodiments, which is formed by alloying powder according to any of the above embodiments detailed herein.

[0052] In another aspect, this article details how iron-chromium-nickel stainless steel alloys are pre-alloyed stainless steel powders.

[0053] In an embodiment of pre-alloyed iron-chromium-nickel stainless steel powder, the pre-alloyed stainless steel powder comprises at least 80% by weight of pre-alloyed stainless steel powder having a size distribution of 1 μm to 100 μm, preferably 2.5 μm to 75 μm, or even more preferably 5 μm to 50 μm as measured by sieving according to ISO-14232-1-2017-E "Determination of particle distribution by sieving method", and / or preferably comprises at least 85% by weight, at least 90% by weight, or more preferably at least 95% by weight of pre-alloyed stainless steel powder having a size distribution of 2.5 μm to 100 μm as measured by sieving according to ISO-14232-1-2017-E "Determination of particle distribution by sieving method".

[0054] In another embodiment of the powder comprising pre-alloyed iron-chromium-nickel stainless steel powder of an iron-chromium-nickel stainless steel alloy, the powder further comprises metal carbide powder. In its preferred embodiment, the metal carbide powder is selected from one or more of nickel carbide, chromium carbide, vanadium carbide, tungsten carbide, molybdenum carbide, silicon carbide, manganese carbide, aluminum carbide, titanium carbide, niobium carbide, tantalum carbide, hafnium carbide, or zirconium carbide; preferably selected from one or more of nickel carbide, chromium carbide, vanadium carbide, tungsten carbide, molybdenum carbide, silicon carbide, manganese carbide, or aluminum carbide; more preferably selected from one or more of nickel carbide, chromium carbide, vanadium carbide, tungsten carbide (WC), or molybdenum carbide; or most preferably tungsten carbide (WC).

[0055] In an even more preferred embodiment, the powder comprises pre-alloyed iron-chromium-nickel stainless steel powder, which comprises from 13 wt% to 17 wt% of pre-alloyed iron-chromium-nickel stainless steel powder and from 83 wt% to 87 wt% of tungsten carbide (WC) powder; most preferably 15 wt% of pre-alloyed iron-chromium-nickel stainless steel powder and 85 wt% of tungsten carbide (WC) powder.

[0056] In a preferred embodiment, the powder comprises at least 80 wt% by weight of tungsten carbide (WC) powder contained in a sieve fraction having a size distribution of 1 μm to 100 μm, preferably 2.5 μm to 75 μm, or even more preferably 5 μm to 50 μm as measured by sieving according to ISO-14232-1-2017-E "Determination of particle distribution by sieving method", and / or preferably contains at least 85%, at least 90%, or more preferably at least 95% by weight of tungsten-based powder having a size distribution of 2.5 μm to 100 μm as measured by sieving according to ISO-14232-1-2017-E "Determination of particle distribution by sieving method".

[0057] Surprisingly, the inventors have experimentally determined (see below) that the iron-chromium-nickel stainless steel binder alloy of this disclosure, primarily composed of tungsten metal carbides (and some minor amounts of chromium carbides), can be formed by thermal spraying of the tungsten-based powder composition detailed below. The iron-chromium-nickel stainless steel binder alloy is then deposited from a gas phase containing a large amount of the desired tungsten carbides.

[0058] Therefore, in a second aspect and embodiment thereof, a tungsten-based powder is described in detail herein, which comprises, by total weight of powder, the following: Iron (Fe): 6.6 wt%-7.9 wt%. Carbon (C): 5.2 wt% - 5.7 wt%. Chromium (Cr): 3.9 wt%-4.5 wt%. Nickel (Ni): 2.2 wt% - 3.0 wt%. Molybdenum (Mo): 0.60 wt%-0.75 wt%, Silicon (Si): 0.10 wt% - 0.22 wt%. Manganese (Mn): 0.07 wt%-0.10 wt%, The balance is tungsten (W) and unavoidable impurities not exceeding 0.3 wt%.

[0059] In embodiments of the tungsten-based powder, the carbon (C) content is from 5.25 wt% to 5.7 wt%, from 5.3 wt% to 5.7 wt%, or from 5.5 wt% to 5.7 wt%; preferably from 5.35 wt% to 5.7 wt%, from 5.35 wt% to 5.65 wt%, from 5.4 wt% to 5.65 wt%, or from 5.45 wt% to 5.65 wt%; or more preferably from 5.5 wt% to 5.6 wt%.

[0060] In embodiments of the invention, the tungsten-based powder of the invention is alloyed to form an iron-chromium-nickel stainless steel alloy according to one embodiment of the iron-chromium-nickel stainless steel alloy detailed above, and various metal carbides, but primarily tungsten carbide. The resulting alloy having inclusions (see...) Figure 2 The alloy contains an iron-chromium-nickel stainless steel alloy as a binder and inclusions of formed carbides. Therefore, tungsten-based powder, as detailed above, can be used as a precursor to obtain the iron-chromium-nickel stainless steel alloy of the present invention after alloying.

[0061] In embodiments of the tungsten-based powder, the nickel (Ni) content is from 2.2 wt% to 2.7 wt%. Preferably, the nickel (Ni) content is from 2.3 wt% to 2.6 wt%, or more preferably from 2.4 wt% to 2.5 wt%.

[0062] In embodiments of the tungsten-based powder, the iron (Fe) content is from 6.8 wt% to 7.7 wt%, preferably from 7.0 wt% to 7.5 wt%, or more preferably from 7.2 wt% to 7.4 wt%.

[0063] In embodiments of the tungsten-based powder, the chromium (Cr) content is from 4.0 wt% to 4.4 wt%, preferably from 4.1 wt% to 4.3 wt%.

[0064] Regarding additional alloying elements such as molybdenum (Mo), silicon (Si), and manganese (Mn), these can vary freely within their maximum range. However, their presence remains mandatory, or the iron-chromium-nickel stainless steel alloy of the present invention cannot be formed during the alloying of the tungsten-based powder of the present invention as disclosed above.

[0065] However, in some embodiments, the molybdenum (Mo) content may be at least 0.61 wt%, at least 0.63 wt%, or preferably at least 0.65 wt%; and / or the molybdenum content may be at most 0.74 wt%, at most 0.72 wt%, or preferably at most 0.70 wt%.

[0066] However, in other embodiments, the silicon (Si) content may be at least 0.11 wt%, at least 0.12 wt%, at least 0.13 wt%, or preferably at least 0.14 wt%; and / or the silicon (Si) content may be at most 0.21 wt%, at most 0.20 wt%, 0.19 wt%, or preferably at most 0.18 wt%.

[0067] However, in another embodiment, the manganese (Mn) content is at least 0.075 wt% or at least 0.80 wt%; and / or the manganese (Mn) content is at most 0.095 wt% or at most 0.090 wt%.

[0068] Tungsten-based powders can be obtained using other known methods, such as by atomizing the constituent metal into a composite powder, or by partially or preferably completely alloying the constituent metal from a melt. In the case of using partially alloyed powders or non-pre-alloyed metal powders, alloying occurs during the application of the cermet powder (e.g., spray application).

[0069] In an embodiment of the tungsten-based powder, the tungsten-based powder consists of 13 wt% to 17 wt% of stainless steel pre-alloyed powder according to the first aspect and its embodiments described above, and 83 wt% to 87 wt% of tungsten carbide (WC) powder.

[0070] In an embodiment of the tungsten-based powder, the tungsten-based powder comprises at least 80 wt% by weight of tungsten-based powder having a size distribution of 1 μm to 100 μm, preferably 2.5 μm to 75 μm, or even more preferably 5 μm to 50 μm as measured by sieving according to ISO-14232-1-2017-E "Determination of particle distribution by sieving method", and / or preferably comprises at least 85%, at least 90%, or more preferably at least 95% by weight of tungsten-based powder having a size distribution of 2.5 μm to 100 μm as measured by sieving according to ISO-14232-1-2017-E "Determination of particle distribution by sieving method".

[0071] In its embodiments, the tungsten-based powder comprises at least 90% by weight of tungsten-based powder contained in a sieve fraction having a size distribution from 5 μm to 25 μm as measured by sieving according to ISO-14232-1-2017-E "Determination of Particle Distribution by Sieving Method". In its preferred embodiments, the tungsten-based powder comprises at least 95% by weight, at least 97% by weight, or more preferably at least 99% by weight, or even more preferably at least 99.5% by weight of tungsten-based powder contained in a sieve fraction having a size distribution from 5 μm to 25 μm as measured by sieving according to ISO-14232-1-2017-E "Determination of Particle Distribution by Sieving Method".

[0072] In its embodiments, the tungsten-based powder comprises at least 90% by weight of tungsten-based powder contained in a sieve fraction having a size distribution from 15 μm to 45 μm as measured by sieving according to ISO-14232-1-2017-E "Determination of Particle Distribution by Sieving Method". In its preferred embodiments, the tungsten-based powder comprises at least 95% by weight, at least 97% by weight, or more preferably at least 99% by weight, or even more preferably at least 99.5% by weight of tungsten-based powder contained in a sieve fraction having a size distribution from 5 μm to 25 μm as measured by sieving according to ISO-14232-1-2017-E "Determination of Particle Distribution by Sieving Method".

[0073] In an aspect of the invention, the tungsten-based powder is a cermet powder consisting of 83 wt% to 87 wt% of a powder provided as pre-formed tungsten carbide (WC) powder and 13 wt% to 17 wt% of a powder provided as pre-alloyed stainless steel according to any aspect thereof detailed above.

[0074] In its embodiments, the cermet powder comprises at least 80 wt% by weight of cermet powder having a size distribution of 1 μm to 100 μm, preferably 2.5 μm to 75 μm, or even more preferably 5 μm to 50 μm as measured by sieving according to ISO-14232-1-2017-E "Determination of particle distribution by sieving method", and / or preferably comprises at least 85%, at least 90%, or more preferably at least 95% by weight of cermet powder having a size distribution of 2.5 μm to 100 μm as measured by sieving according to ISO-14232-1-2017-E "Determination of particle distribution by sieving method".

[0075] In aspects of the invention, the use of tungsten-based powder or cermet powder according to any of the embodiments described herein for coating surfaces by thermal spraying is described in detail herein.

[0076] This document further details a metal ceramic formed by thermal spraying from any of the embodiments described herein, preferably a metal ceramic having a composition corresponding to any composition of the tungsten-based powder or metal ceramic powder disclosed herein.

[0077] Therefore, this document details a cermet powder composed of 83 wt% to 87 wt% of a total mass of powder provided as pre-formed tungsten carbide (WC) powder and 13 wt% to 17 wt% of a total mass of powder provided as pre-alloyed stainless steel according to the embodiments detailed herein; preferably composed of 85 wt% of a total mass of powder provided as pre-formed tungsten carbide (WC) powder and 15 wt% of a total mass of powder provided as pre-alloyed stainless steel according to the embodiments detailed herein.

[0078] In its preferred embodiment, the cermet powder comprises at least 80 wt% by weight of cermet powder having a size distribution of 1 μm to 100 μm, preferably 2.5 μm to 75 μm, or even more preferably 5 μm to 50 μm as measured by sieving according to ISO-14232-1-2017-E "Determination of particle distribution by sieving method", and / or preferably comprises at least 85%, at least 90%, or more preferably at least 95% by weight of cermet powder having a size distribution of 2.5 μm to 100 μm as measured by sieving according to ISO-14232-1-2017-E "Determination of particle distribution by sieving method".

[0079] In another aspect, this document details the use of tungsten-based powder according to any of the embodiments described herein for coating surfaces by thermal spraying.

[0080] In another aspect, this document details a composition comprising an iron-chromium-nickel stainless steel alloy and tungsten carbide (WC), said composition being formed by alloying tungsten-based powder according to any of the embodiments detailed herein.

[0081] In the compositions of the preferred group, tungsten carbide (WC) is present as an inclusion in a Ni-rich FCC stainless steel matrix.

[0082] This document further details a shaped object with a coating having a metal ceramic according to any embodiment of the metal ceramic detailed herein.

[0083] This document further details a method for producing a cermet or a shaped article according to any embodiment of the cermet detailed herein, the method comprising the following steps: One or more tungsten-based powders or cermet powders are provided in a form or formulation suitable for thermal spraying, according to the embodiments detailed herein; This powder is used in thermal spraying processes. Obtain metal ceramics or objects.

[0084] experiment The coating properties were tested for different HVOF spraying parameters.

[0085] HVOF thermal spraying systems use different fuels to produce coatings for industrial machinery parts. The resulting coatings are typically hard, thick, and dense. In this work, two different spray guns were used to thermally spray the samples: a diamond spray gun (DJ) and a high-pressure spray gun (JP). The fuel for DJ consists of O2 + H2 + air, while for JP, the fuel is a mixture of oxygen and argon.

[0086] The high-pressure spray gun (JP-5000) is designed for operation with liquid fuel (kerosene) and oxygen. Fuel and oxygen are supplied to the gun, atomized by a coaxial stabilizer, and ignited in the combustion chamber to produce a supersonic flame. Spray powder from the powder feeder is radially supplied to the supersonic flame through two powder ports located directly after the combustion chamber. The jet stream is accelerated to several times the speed of sound through converging / diverging nozzles. The sprayed particles are heated to a molten or semi-molten state and propelled at high speed, impacting the coating surface in a plastic state. Table 2 provides an overview of the spraying parameters used in the experiments of this invention.

[0087] Table 2: Spraying parameters of high-pressure spray gun (JP-5000) The diamond blasting process uses oxygen, fuel gas, and air to generate a high-pressure annular flame, which provides uniform heating to the axially introduced powder coating material. The airflow is accelerated to supersonic speeds through converging / diverging nozzles. The airflow propels powder particles toward the substrate. Individual particles undergo plastic deformation upon impact, firmly bonding the coating to the substrate. Table 3 details the blasting parameters used in the experiments of this invention.

[0088] Table 3: Spraying parameters of diamond spray gun Different spraying parameters, such as powder feeder, nozzle size, and combustion pressure, were tested (see Tables 2 and 3). The parameters were adjusted to achieve a dense coating with optimal deposition efficiency. These parameters are universal and reproducible, applicable in any typical spraying workshop. Individual samples were sprayed with the same parameters for different tests.

[0089] Powder size is determined according to ISO-14232-1-2017-E "Determination of particle distribution by sieving method" and is expressed as 95% of the powder mass falling within the given size exclusion range.

[0090] For each coating parameter, hardness, roughness, air permeability, Young's modulus, and abrasion resistance were measured.

[0091] After spraying, the coated samples were analyzed using an optical microscope to measure the coating thickness and porosity, and were also examined using an electron microscope.

[0092] In further testing, the carbon content of the samples was measured after spraying. As will be discussed further below, carbon content is sensitive to the suitability of the alloys disclosed herein and their use as adhesives as discussed herein.

[0093] Another set of samples was placed in a natural salt spray chamber and evaluated after a specific time period to study corrosion properties. The corrosion resistance of the materials was also evaluated based on permeability and cavitation erosion tests; see [link to relevant documentation]. Figure 13 .

[0094] Finally, SEM / EDX analysis was used to analyze the coated samples to better understand the final product.

[0095] Calculation based on Calphad Figure 1 The phase diagram of the currently developed alloys is shown, calculated using Thermo-Calc software and the steel database TCFE12.

[0096] The composition range marked with a green line in the figure shows the composition range of carbon content in the final carbide, which will result in the cubic carbide existing as a hard phase in the FCC matrix as a binder.

[0097] Although this composition range is wider than the range suggested in Table 1, carbon burnout during thermal spraying should be taken into account.

[0098] If the composition is taken at the lower limit of this range (≈5.2 wt%), the composition will transfer to a phase field containing M6C (called η-carbide), which is a brittle phase with low corrosion resistance, after carbon burn-off.

[0099] For these alloys, the optimal carbon content requires a narrow window to avoid the formation of η-carbides after spraying.

[0100] Figure 1 The arrows in the diagram indicate the optimal range of carbon concentrations, where, when coating is performed at approximately 1200°C, the chemical composition of the coating will remain as desired, even after burn-out.

[0101] Sprayed sample Figure 2A cross-section of (EM) agglomerated / sintered carbides is shown, in which the product examined is composed of 85 wt% WC particles and 15 wt% binder. In this figure, dark cubic WC carbides can be seen within the light-colored sintered binder.

[0102] The sprayed samples were cut and analyzed using a LEICA DM6 M optical microscope to measure the coating thickness and porosity.

[0103] Figure 3 This shows the indices related to deposition efficiency and coating thickness for different spraying methods and parameters. Other products (named Amperit) are also included. ® 618 (WC 15FeCrAl) and 558 (WC 10Co4Cr) are compared with this product.

[0104] Most of the product's tests fell within the high productivity / high efficiency region of the graph (compatible with existing products and, in some cases, superior to existing products), indicating that the product is cost-effective for spraying and can achieve dense coatings.

[0105] Figure 4 and Figure 5 Cross-sections of coatings using JP and DJ technologies are shown respectively. These two technologies enable the production of dense, uniform coatings with a porosity of 0.1%–0.5%, comparable to or better than coatings achievable with existing commercial products.

[0106] The carbon content of all samples was measured using a Leco CS-200 / CS-600 instrument based on nondispersive infrared absorption after combustion in an oxygen stream. The results confirmed that all samples contained more than 5.3 wt% carbon and therefore did not suffer carbon burn-off during spraying.

[0107] Corrosive properties The corrosion properties of the coatings were studied using a Weiss GmbH SC1000 machine according to standard ASTM B117 via natural salt spray (NSS) testing. Samples were placed in a chamber and examined after specific time periods: 168 hours, 336 hours, 504 hours, 672 hours, 840 hours, and 1008 hours. Figure 6 Test specimens for both technologies are shown after 1008 hours, and almost no surface corrosion is visible on them after the study period. Slight corrosion occurred in the installation area, which is expected because salt can diffuse and accumulate there.

[0108] breathability For the coated samples, the air permeability test results (measured using a GPT-03 machine according to standard ISO 4022) are shown below. Figure 7 In this study, the permeability results likely confirm the excellent corrosion resistance, as they indicate that these coatings are very dense and that even under high pressure, gases (and by contrast, liquid salt solutions) cannot easily penetrate and corrode the samples and the base material.

[0109] Mechanical properties The mechanical properties of the coating were measured. Results for hardness, roughness, and Young's modulus are shown in... Figures 8 to 10 middle.

[0110] Hardness is often an important factor when choosing between different categories of carbides. In this work, hardness (HV) was measured using a Struers Dura scanner according to standard ISO 6507,1-4:2018.

[0111] The hardness of tungsten carbides is typically expected to be above 1000 HV. The product of this invention exhibits a general hardness of ≈1200 HV, making it an excellent candidate for its intended applications.

[0112] The roughness of the coated sample was measured using a MarSurf PS10 machine based on standards DIN EN ISO 4287 and ASME B46.1. Figure 9 The results presented indicate that the average value of the product is 2 Ra-4 Ra, which is within the generally accepted range for this property in different carbides (see J. García et al.).

[0113] Young's modulus represents the elastic properties of a material and is related to its hardness. It was measured using an LA-wave V2-1 Fraunhofer IWS instrument. The average value was between 240 GPa and 290 GPa. Figure 10 This is desirable for rigid materials and makes them a good candidate for applications subject to heavy loads.

[0114] According to ASTM G65 ( Figure 11 The abrasion resistance of the coated samples was measured using a built-in machine. The figure shows the volume loss relative to the amount of material consumed by the spraying.

[0115] Figure 11 The results show that all coatings exhibit excellent abrasion resistance, namely, with Amperit. ® Compared to 558, 618 exhibits very low volume loss with moderate powder consumption. This makes the product of this invention significantly advantageous from a cost perspective and a strong candidate for applications where abrasion resistance plays a crucial role.

[0116] SEM analysis The coated samples were analyzed using a Hitachi SU6600 scanning electron microscope. Figure 12 Cross-sections and EDX plots of high-content elements are shown using a voltage of 15 kV. The results are consistent with thermodynamic calculations for different types of carbides in the Ni-rich FCC stainless steel matrix.

[0117] Conclusion Although the invention has been described in detail for illustrative purposes, it should be understood that such details are for that purpose only, and that variations may be made therein by those skilled in the art in practicing the claimed subject matter upon studying the drawings, this disclosure and the appended claims.

[0118] The term "comprising" as used in the claims does not exclude other elements or steps. The indefinite articles "a" or "an" as used in the claims do not exclude more than one. A unit may perform the functions of several means recited in the claims. Reference numerals used in the claims should not be construed as limiting the scope.

Claims

1. An iron-chromium-nickel stainless steel alloy, comprising the following components by total weight: Chromium (Cr): 26.0 wt%-30.0 wt%, Nickel (Ni): 15.0 wt%-18.0 wt%, Molybdenum (Mo): 4.0 wt%-5.0 wt%, Silicon (Si): 1.00 wt% - 1.50 wt%. Manganese (Mn): 0.50 wt%-1.00 wt%, Carbon (C): 0.15 wt% - 0.25 wt%. The balance is iron (Fe) and unavoidable impurities not exceeding 0.3 wt%.

2. The iron-chromium-nickel stainless steel alloy according to claim 1, wherein, Chromium (Cr) is present in an amount of at least 26.5 wt%, preferably at least 27.0 wt%, or more preferably at least 27.5 wt%; and / or wherein chromium is present in an amount of at most 29.5 wt%, preferably at most 29.0 wt%, or more preferably at most 28.5 wt%.

3. The iron-chromium-nickel stainless steel alloy according to claim 1 or claim 2, wherein nickel (Ni) is present in an amount of at least 15.5 wt%, preferably at least 16.0 wt%, or more preferably at least 16.5 wt%; and / or wherein nickel (Ni) is present in an amount of at most 17.5 wt%, or preferably at most 17.0 wt%.

4. The iron-chromium-nickel stainless steel alloy according to any of the preceding claims, wherein molybdenum (Mo) is present in an amount of at least 4.1 wt%, preferably at least 4.2 wt%, more preferably at least 4.3 wt%, even more preferably at least 4.4 wt%, or most preferably at least 4.5 wt%; and / or wherein molybdenum (Mo) is present in an amount of at most 4.9 wt%, preferably at most 4.8 wt%, more preferably at most 4.7 wt%, or most preferably at most 4.6 wt%.

5. The iron-chromium-nickel stainless steel alloy according to any of the preceding claims, wherein silicon (Si) is present in an amount of at least 1.10 wt%, preferably at least 1.15 wt%, more preferably at least 1.20 wt%, or most preferably at least 1.25 wt%; and / or wherein silicon (Si) is present in an amount of at most 1.40 wt%, preferably at most 1.35 wt%, or more preferably at most 1.30 wt%.

6. The iron-chromium-nickel stainless steel alloy according to any of the preceding claims, wherein manganese (Mn) is present in an amount of at least 0.60 wt%, preferably at least 0.65 wt%, more preferably at least 0.70 wt%, or most preferably at least 0.75 wt%; and / or wherein manganese (Mn) is present in an amount of at most 0.90 wt%, preferably at most 0.85 wt%, or more preferably at most 0.80 wt%.

7. The iron-chromium-nickel stainless steel alloy according to any of the preceding claims, wherein carbon (C) is present in an amount of at least 0.16 wt%, preferably at least 0.17 wt%, more preferably at least 0.18 wt%, even more preferably at least 0.19 wt%, or most preferably at least 0.20 wt%; and / or wherein carbon (C) is present in an amount of at most 0.24 wt%, preferably at most 0.23 wt%, more preferably at most 0.22 wt%, or most preferably at most 0.21 wt%.

8. The iron-chromium-nickel stainless steel alloy according to any one of claims 1 to 7, in the form of pre-alloyed stainless steel powder.

9. The pre-alloyed stainless steel powder according to claim 8, wherein the pre-alloyed stainless steel powder comprises at least 80% by weight of the pre-alloyed stainless steel powder having a size distribution of 1 μm to 100 μm, preferably from 2.5 μm to 75 μm, or even more preferably from 5 μm to 50 μm as measured by sieving according to ISO-14232-1-2017-E "Particle distribution determined by sieving method", and / or preferably comprises at least 85% by weight, at least 90% by weight, or more preferably at least 95% by weight of the pre-alloyed stainless steel powder having a size distribution of 2.5 μm to 100 μm as measured by sieving according to ISO-14232-1-2017-E "Particle distribution determined by sieving method".

10. A powder comprising a pre-alloyed powder of an iron-chromium-nickel stainless steel alloy according to any one of claims 1 to 7, as described in claim 8 or claim 9, the powder further comprising a metal carbide powder.

11. A powder comprising the pre-alloyed stainless steel powder according to claim 10, wherein the metal carbide powder is selected from one or more of nickel carbide, chromium carbide, vanadium carbide, tungsten carbide, molybdenum carbide, silicon carbide, manganese carbide, aluminum carbide, titanium carbide, niobium carbide, tantalum carbide, hafnium carbide, or zirconium carbide; preferably selected from one or more of nickel carbide, chromium carbide, vanadium carbide, tungsten carbide, molybdenum carbide, silicon carbide, manganese carbide, or aluminum carbide; more preferably selected from one or more of nickel carbide, chromium carbide, vanadium carbide, tungsten carbide (WC), or molybdenum carbide; or most preferably tungsten carbide (WC).

12. The powder according to any one of claims 10 or 11, wherein the powder comprises pre-alloyed stainless steel powder, wherein the powder comprises from 13 wt% to 17 wt% of the iron-chromium-nickel stainless steel pre-alloyed powder according to claim 8 or 9 and from 83 wt% to 87 wt% of tungsten carbide (WC) powder; preferably 15 wt% of the iron-chromium-nickel stainless steel pre-alloyed powder according to claim 8 or 9 and 85 wt% of tungsten carbide (WC) powder.

13. The powder of claim 12, wherein the powder comprises pre-alloyed stainless steel powder, wherein the powder comprises at least 80 wt% by weight of the tungsten carbide (WC) powder contained in a sieve fraction having a size distribution of 1 μm to 100 μm, preferably from 2.5 μm to 75 μm, or even more preferably from 5 μm to 50 μm as measured by sieving according to ISO-14232-1-2017-E "Particle distribution determined by sieving method", and / or preferably contains at least 85%, at least 90%, or more preferably at least 95% by weight of the tungsten-based powder having a size distribution of 2.5 μm to 100 μm as measured by sieving according to ISO-14232-1-2017-E "Particle distribution determined by sieving method".

14. A powder for forming an iron-chromium-nickel stainless steel alloy, said powder comprising, by total weight: Chromium (Cr): 26.0 wt%-30.0 wt%, Nickel (Ni): 15.0 wt%-18.0 wt%, Molybdenum (Mo): 4.0 wt%-5.0 wt%, Silicon (Si): 1.00 wt% - 1.50 wt%. Manganese (Mn): 0.50 wt%-1.00 wt%, Carbon (C): 0.15 wt% - 0.25 wt%. The balance is iron (Fe) and unavoidable impurities not exceeding 0.3 wt%.

15. The powder for forming an iron-chromium-nickel stainless steel alloy according to claim 14, wherein, Chromium (Cr) is present in an amount of at least 26.5 wt%, preferably at least 27.0 wt%, or more preferably at least 27.5 wt%; and / or wherein chromium is present in an amount of at most 29.5 wt%, preferably at most 29.0 wt%, or more preferably at most 28.5 wt%.

16. The powder for forming an iron-chromium-nickel stainless steel alloy according to claim 14 or claim 15, wherein nickel (Ni) is present in an amount of at least 15.5 wt%, preferably at least 16.0 wt%, or more preferably at least 16.5 wt%; and / or wherein nickel (Ni) is present in an amount of at most 17.5 wt%, or preferably at most 17.0 wt%.

17. The powder for forming an iron-chromium-nickel stainless steel alloy according to any one of claims 14 to 16, wherein molybdenum (Mo) is present in an amount of at least 4.1 wt%, preferably at least 4.2 wt%, more preferably at least 4.3 wt%, even more preferably at least 4.4 wt%, or most preferably at least 4.5 wt%; and / or wherein molybdenum (Mo) is present in an amount of at most 4.9 wt%, preferably at most 4.8 wt%, more preferably at most 4.7 wt%, or most preferably at most 4.6 wt%.

18. The powder for forming an iron-chromium-nickel stainless steel alloy according to any one of claims 14 to 17, wherein silicon (Si) is present at at least 1.10 wt%, preferably at least 1.15 wt%, more preferably at least 1.20 wt%, or most preferably at least 1.25 wt%; and / or wherein silicon (Si) is present at at most 1.40 wt%, preferably at most 1.35 wt%, or more preferably at most 1.30 wt%.

19. The powder for forming an iron-chromium-nickel stainless steel alloy according to any one of claims 14 to 18, wherein manganese (Mn) is present in an amount of at least 0.60 wt%, preferably at least 0.65 wt%, more preferably at least 0.70 wt%, or most preferably at least 0.75 wt%; and / or wherein manganese (Mn) is present in an amount of at most 0.90 wt%, preferably at most 0.85 wt%, or more preferably at most 0.80 wt%.

20. The powder for forming an iron-chromium-nickel stainless steel alloy according to any one of claims 14 to 19, wherein carbon (C) is present in an amount of at least 0.16 wt%, preferably at least 0.17 wt%, more preferably at least 0.18 wt%, even more preferably at least 0.19 wt%, or most preferably at least 0.20 wt%; and / or wherein carbon (C) is present in an amount of at most 0.24 wt%, preferably at most 0.23 wt%, more preferably at most 0.22 wt%, or most preferably at most 0.21 wt%.

21. The iron-chromium-nickel stainless steel alloy according to any one of claims 1 to 7, formed by alloying powder according to any one of claims 14 to 20.

22. The iron-chromium-nickel stainless steel alloy according to claim 21, in the form of pre-alloyed stainless steel powder.

23. The pre-alloyed iron-chromium-nickel stainless steel powder according to claim 21, wherein the pre-alloyed stainless steel powder comprises at least 80% by weight of the pre-alloyed stainless steel powder having a size distribution of 1 μm to 100 μm, preferably from 2.5 μm to 75 μm, or even more preferably from 5 μm to 50 μm as measured by sieving according to ISO-14232-1-2017-E "Particle distribution determined by sieving method", and / or preferably comprises at least 85% by weight, at least 90% by weight, or more preferably at least 95% by weight of the pre-alloyed stainless steel powder having a size distribution of 2.5 μm to 100 μm as measured by sieving according to ISO-14232-1-2017-E "Particle distribution determined by sieving method".

24. A powder comprising a pre-alloyed iron-chromium-nickel stainless steel powder according to claim 22 or claim 23 of any one of claims 1 to 7, said powder further comprising metal carbide powder.

25. A powder comprising the pre-alloyed iron-chromium-nickel stainless steel powder according to claim 24, wherein the metal carbide powder is selected from one or more of nickel carbide, chromium carbide, vanadium carbide, tungsten carbide, molybdenum carbide, silicon carbide, manganese carbide, aluminum carbide, titanium carbide, niobium carbide, tantalum carbide, hafnium carbide, or zirconium carbide; preferably selected from one or more of nickel carbide, chromium carbide, vanadium carbide, tungsten carbide, molybdenum carbide, silicon carbide, manganese carbide, or aluminum carbide; more preferably selected from one or more of nickel carbide, chromium carbide, vanadium carbide, tungsten carbide (WC), or molybdenum carbide; or most preferably tungsten carbide (WC).

26. A powder comprising pre-alloyed iron-chromium-nickel stainless steel powder according to any one of claims 24 or 25, wherein the powder comprises from 13 wt% to 17 wt% of the pre-alloyed iron-chromium-nickel stainless steel powder according to claim 21 or 22 and from 83 wt% to 87 wt% of tungsten carbide (WC) powder; preferably 15 wt% of the pre-alloyed iron-chromium-nickel stainless steel powder according to claim 21 or 22 and 85 wt% of tungsten carbide (WC) powder.

27. The powder of claim 26, wherein the powder comprises at least 80 wt% by weight of the tungsten carbide (WC) powder contained in a sieve fraction having a size distribution of 1 μm to 100 μm, preferably from 2.5 μm to 75 μm, or even more preferably from 5 μm to 50 μm as measured by sieving according to ISO-14232-1-2017-E "Particle distribution determined by sieving method", and / or preferably comprises at least 85%, at least 90%, or more preferably at least 95% by weight of the tungsten carbide powder having a size distribution of 2.5 μm to 100 μm as measured by sieving according to ISO-14232-1-2017-E "Particle distribution determined by sieving method".

28. A tungsten-based powder, comprising the following components by total weight of the powder: Iron (Fe): 6.6 wt%-7.9 wt%. Carbon (C): 5.2 wt% - 5.7 wt%. Chromium (Cr): 3.9 wt%-4.5 wt%. Nickel (Ni): 2.2 wt% - 3.0 wt%. Molybdenum (Mo): 0.60 wt%-0.75 wt%, Silicon (Si): 0.10 wt% - 0.22 wt%. Manganese (Mn): 0.07 wt%-0.10 wt%, The balance is tungsten (W) and unavoidable impurities not exceeding 0.3 wt%.

29. The tungsten-based powder according to claim 28, wherein the carbon (C) content is from 5.3 wt% to 5.7 wt%, preferably from 5.5 wt% to 5.7 wt%.

30. The tungsten-based powder according to any one of claims 28 or 29, wherein the nickel (Ni) content is from 2.2 wt% to 2.7 wt%, preferably from 2.3 wt% to 2.6 wt%, or more preferably from 2.4 wt% to 2.5 wt%.

31. The tungsten-based powder according to any one of claims 28 to 30, wherein the iron (Fe) content is from 6.8 wt% to 7.7 wt%, preferably from 7.0 wt% to 7.5 wt%, or more preferably from 7.2 wt% to 7.4 wt%.

32. The tungsten-based powder according to any one of claims 28 to 31, wherein the chromium (Cr) content is from 4.0 wt% to 4.4 wt%, preferably from 4.1 wt% to 4.3 wt%.

33. The tungsten-based powder according to any one of claims 28 to 32, wherein the content of molybdenum (Mo) is at least 0.61 wt%, at least 0.63 wt%, or preferably at least 0.65 wt%; and / or the content of molybdenum is at most 0.74 wt%, at most 0.72 wt%, or preferably at most 0.70 wt%.

34. The tungsten-based powder according to any one of claims 28 to 33, wherein the silicon (Si) content can be at least 0.11 wt%, at least 0.12 wt%, at least 0.13 wt%, or preferably at least 0.14 wt%; and / or the silicon (Si) content can be at most 0.21 wt%, at most 0.20 wt%, 0.19 wt%, or preferably at most 0.18 wt%.

35. The tungsten-based powder according to any one of claims 28 to 34, wherein the content of manganese (Mn) is at least 0.075 wt% or at least 0.80 wt%; and / or the content of manganese (Mn) is at most 0.095 wt% or at most 0.090 wt%.

36. The tungsten-based powder according to any one of claims 28 to 35, wherein the total mass of the powder is provided as pre-formed tungsten carbide (WC) powder at a rate of 83 wt% to 87 wt%.

37. The tungsten-based powder according to any one of claims 28 to 36, comprising the following: From 13 wt% to 17 wt% of the stainless steel pre-alloyed powder according to claim 8 or claim 9 and from 83 wt% to 87 wt% of tungsten carbide (WC) powder; preferably 15 wt% of the stainless steel pre-alloyed powder according to claim 8 or claim 9 and 85 wt% of tungsten carbide (WC) powder.

38. The tungsten-based powder according to any one of claims 28 to 37, wherein the tungsten-based powder comprises at least 80 wt% by weight of the tungsten-based powder having a size distribution of 1 μm to 100 μm, preferably from 2.5 μm to 75 μm, or even more preferably from 5 μm to 50 μm as measured by sieving according to ISO-14232-1-2017-E "Particle distribution determined by sieving method", and / or preferably comprises at least 85%, at least 90%, or more preferably at least 95% by weight of the tungsten-based powder having a size distribution of 2.5 μm to 100 μm as measured by sieving according to ISO-14232-1-2017-E "Particle distribution determined by sieving method".

39. A cermet powder comprising, by weight, 83 wt% to 87 wt% of a powder provided as pre-formed tungsten carbide (WC) powder and 13 wt% to 17 wt% of a powder provided as pre-alloyed stainless steel according to claim 8 or claim 9; preferably comprising 85 wt% of a powder provided as pre-formed tungsten carbide (WC) powder and 15 wt% of a powder provided as pre-alloyed stainless steel according to claim 8 or claim 9.

40. The cermet powder of claim 36, wherein the cermet powder comprises at least 80 wt% by weight of the cermet powder having a size distribution of 1 μm to 100 μm, preferably from 2.5 μm to 75 μm, or even more preferably from 5 μm to 50 μm as measured by sieving according to ISO-14232-1-2017-E "Particle distribution determined by sieving method", and / or preferably comprises at least 85%, at least 90%, or more preferably at least 95% by weight of the cermet powder having a size distribution of 2.5 μm to 100 μm as measured by sieving according to ISO-14232-1-2017-E "Particle distribution determined by sieving method".

41. A metal ceramic having the composition according to any one of claims 28 to 35.

42. Use of the tungsten-based powder according to any one of claims 28 to 35 for coating a surface by a thermal spraying method.

43. A composition comprising an iron-chromium-nickel stainless steel alloy and tungsten carbide (WC), said composition being formed by alloying tungsten-based powder according to any one of claims 28 to 35.

44. The composition of claim 40, wherein the tungsten carbide (WC) is present as an inclusion in a Ni-rich FCC stainless steel matrix.

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