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CN-122003392-A - Powder mixture

CN122003392ACN 122003392 ACN122003392 ACN 122003392ACN-122003392-A

Abstract

The invention relates to a powder suitable for producing a wear-resistant and corrosion-resistant layer, comprising a) a mixture of a first component selected from the group consisting of carbides, carbonitrides, nitrides of Ti and mixtures thereof and a second component selected from the group consisting of carbides, carbonitrides, nitrides of Mo, W, V, nb and mixtures thereof, or b) a solid solution consisting of Ti, a second metal M selected from the group consisting of Mo, W, V, nb and mixtures thereof and a non-metal selected from the group consisting of C, N and mixtures thereof, or c) a mixture of a) and b), wherein the total amount of a) or b) or c) is at least 60 wt%, preferably 70 wt to 99 wt, wherein in a) the weight ratio of the first component to the second component is 70:30 to 98:2, wherein in b) the weight ratio of Ti to the second metal M is 70:30 to 98:2, an organic binder, wherein the content of the metal binder in the powder is at most 15: 15 wt, preferably at most 5: 5 wt.

Inventors

  • Alban Demoli

Assignees

  • 特莱巴赫工业有限公司

Dates

Publication Date
20260508
Application Date
20241009
Priority Date
20231013

Claims (20)

  1. 1. A ceramic powder suitable for use in producing a wear-resistant and corrosion-resistant layer comprising: a) A mixture of a first component selected from the group consisting of carbides, carbonitrides, nitrides of Ti and mixtures thereof and a second component selected from the group consisting of Mo, W, V, nb carbides, carbonitrides, nitrides and mixtures thereof, or B) A solid solution consisting of Ti, a second metal M selected from Mo, W, V, nb and mixtures thereof, and a non-metal selected from C, N and mixtures thereof, or C) a) and b) in a mixture of two or more of the following, Wherein the total amount of a) or b) or c) is at least 60 wt%, preferably 70 wt to 99 wt%, Wherein in a) the weight ratio of the first component to the second component is from 70:30 to 98:2, Wherein in b) the weight ratio of Ti to the second metal M is from 70:30 to 98:2, An organic binder, which is used as a binder, Wherein the content of metal binder in the powder is at most 5 wt%.
  2. 2. Ceramic powder according to claim 1, characterized in that in a) the weight ratio of the first component to the second component is 80:20 to 98:2, preferably 85:15 to 95:5, and in b) the weight ratio of Ti to the second metal M is 80:20 to 98:2, preferably 85:15 to 95:5.
  3. 3. Ceramic powder according to claim 1 or 2, characterized in that the powder is substantially free of metal binder.
  4. 4. Ceramic powder according to any one of the preceding claims, characterized in that the organic binder is selected from the group consisting of polyvinyl alcohol, cellulose-based binders and mixtures thereof.
  5. 5. Ceramic powder according to any one of the preceding claims, characterized in that mixture a) comprises carbides and/or carbonitrides of Ti as the first component and carbides of Mo as the second component.
  6. 6. Ceramic powder according to any of the preceding claims, characterized in that solid solution b) is a carbonitride solid solution of (Ti, mo) (C, N).
  7. 7. Ceramic powder according to any of the preceding claims, characterized in that the ceramic powder is unsintered.
  8. 8. Use of the ceramic powder according to any of the preceding claims in a mixture for producing a wear-resistant and corrosion-resistant layer, wherein the mixture contains stainless steel powder, and wherein the ceramic powder is present in the mixture in an amount of less than 50 wt%.
  9. 9. Use according to claim 8, characterized in that the amount of ceramic powder in the mixture is 5 to 30 wt%, preferably 10 to 25 wt%.
  10. 10. Use according to claim 8 or 9, characterized in that the mixture contains, and most preferably consists essentially of, at least 95 wt%, preferably at least 99wt% of the ceramic powder and the stainless steel powder.
  11. 11. Use according to any one of claims 8 to 10, characterized in that the stainless steel powder is selected from FeCrMn steel, duplex stainless steel, 430 stainless steel according to AISI/SAE stainless steel designation and 316 stainless steel.
  12. 12. Use according to any one of claims 8 to 11, characterized in that the mixture is applied to the surface by cladding, in particular laser cladding.
  13. 13. A wear-resistant and corrosion-resistant layer obtainable by treating a surface with a mixture as defined in any one of claims 8 to 12.
  14. 14. The layer of claim 13, wherein the treatment is laser cladding.
  15. 15. Layer according to claim 13 or 14, wherein the layer has a content of at least 30 vol%, preferably 40 to 60 vol%, of mixture a), or solid solution b) or mixture c).
  16. 16. The layer of any one of claims 13 to 15, wherein the layer is a top coat.
  17. 17. The layer of claim 16, wherein the top coating is a top coating of a brake disc.
  18. 18. A brake disc comprising a layer according to any of claims 13 to 17 as a top coating.
  19. 19. A method of producing the ceramic powder of claims 1 to 7, comprising the steps of: i) Mixing the mixture a), or the solid solution b) or the mixture c) according to claims 1 to 5 with at least one organic binder and optionally a metal binder, Ii) spray-drying the mixture, Iii) Optionally sintering the spray-dried mixture.
  20. 20. The method of claim 19, wherein the organic binder is mixed at a total weight ratio of 0.01 to 10 wt%.

Description

Powder mixture The invention relates to a powder mixture for producing wear-resistant and corrosion-resistant layers, in particular coatings. Background In a tribological system of a brake, the surface of a brake pad is in contact with the surface of a brake disc under application of a mechanical braking force. Interactions between the friction materials cause abrasive wear and, under the influence of ambient humidity and/or corrosive media from the surrounding environment, cause corrosive attack of the brake disc surface, leading to particulate emissions. According to the latest EURO 7 standard (EURO 7), it is expected that new emission standards regulations will bring about emission limits for motor vehicles, requiring a significant reduction of fine particulate emissions since month 7 of 2025. Accordingly, wear resistant friction materials are of particular interest for reducing brake emissions. In order to increase the wear resistance in a brake tribology system, the brake disc is mainly composed of grey cast iron, on which one or more coatings are applied. If more than one coating is applied, the top layer is referred to as a "top coat". Conventional coatings may contain Ni from stainless steel components, which also leads to sensitization in humans (Ni allergy). It is known in the art that wear resistance can be improved by adding carbides such as Cr 3C2, WC or TiC as hard components in the top layer of the coating, embedded in a stainless steel matrix (FeCr matrix). The widespread use of carbide composites as wear resistant materials is due to their unique combination of desirable properties, such as high wear resistance and stiffness, considerable strength, and relatively low production costs. For example, WO 2020/234146 A1 discloses a friction braking element for motor vehicles comprising a plurality of carbide wear layers, the carbides comprising chromium carbide, niobium carbide, titanium carbide, tungsten carbide, molybdenum carbide and vanadium carbide. Another example is disclosed in US 2013/136941 A1, which describes a multifunctional coating for a metal substrate, which coating comprises two layers, one of which comprises particles distributed in a metal or alloy matrix. Particles suitable for use herein may comprise metal carbides, metal nitrides, metal borides, metal silicides, ceramics, cemented carbides or cast carbides. WO 2021/224308 A1 describes a vehicle brake component having a metal substrate surface provided with a coating comprising a hard material, for example tungsten carbide, chromium carbide, titanium carbide, vanadium carbide or silicon carbide. In order to produce a top coating on a metal substrate, alloy raw materials containing carbide forming metals such as Ti, V, cr may also be used. The feedstock is melted in the process and during cooling, the carbide forming metal precipitates with the added carbon or carbon from the steel alloy into finely distributed carbides. For example, the coating may be applied by laser cladding. During laser cladding, a powder or wire feedstock material is melted and consolidated using a laser to coat a substrate. This method is often used to improve the mechanical properties of the material or to increase the corrosion resistance. EP 4 029,966 A1 discloses a method for producing a brake gray cast iron brake disc, wherein a carbide-containing coating is applied to the brake surface by laser cladding. DE 10 2020 203 412 A1 describes a method for producing a protective top layer on brake discs by laser cladding of NbC metal matrix powder or Cr 3C2 metal matrix powder. Furthermore, WO 2021/007409 A1 discloses an iron-based feedstock for various deposition processes (e.g. ultra high speed laser cladding) to form coatings with specific microstructure features and performance characteristics. It has also been found that high carbide content can also reduce the risk of metal pick-up (MPU). MPU is a problematic phenomenon in automotive disc brakes. MPU typically forms metal agglomerates on the brake pad surface. If the brake pads have MPUs, they can cause brake rotor grooving during braking, generate braking noise, and degrade braking performance. MPU is a phenomenon that depends on many factors (e.g., climate, general road conditions, etc.), and thus is not easily quantified. However, it has been shown that a high carbide content not only improves the wear resistance of the brake disc top layer, but also is associated with various problems. One problem is that when larger amounts of carbide are added, the likelihood of cladding the material decreases, as the material becomes very prone to cracking as the carbide content increases. If a crack connects the surface to the substrate, the crack through the coating is fatal to corrosion resistance. The corrosive medium can reach the substrate and corrode the bonding area, causing the substrate to rust, weakening the bond between the substrate and the coating, and eventually causing the coating to delamina