Method for cold gas spraying of a layer having a metal microstructure phase and a microstructure phase made of plastic, component having such a layer, and use of said component

Abstract

In a method for cold gas spraying a layer, coating particles are accelerated in a cold spraying nozzle. The particles have a plastic encapsulation. In said manner, the plastic is precipitated onto the substrate together with the metal material, thereby forming in particular layer compositions having good sliding properties, dirt repellent properties, or lubricating properties. The coating can be used as a bearing component of a sliding bearing, as a flow component, in particular as a rotor blade of wind power plants or body components of transportation vehicle, or as trim components of structures.

Claims

1. A process for cold spraying a substrate, comprising: feeding metallic coating particles to a convergent-divergent nozzle device, the metallic coating particles being fed without a plastic encapsulation; supplying a dispersion, comprising a liquid suspension agent and plastic particles dispersed in the liquid suspension agent, to the nozzle device while the metallic coating particles are being fed to the nozzle device, the plastic particles being smaller than the metallic coating particles; accelerating the metallic coating particles with the nozzle device in a cold gas jet, while allowing the plastic particles to accumulate on the coating particles, thereby forming plastic encapsulated coating particles before the metallic coating particles contact the substrate; and depositing the encapsulated coating particles on the substrate to from a layer having a metallic first microstructure phase and a second microstructure phase made of a plastic.

2. The process as claimed in claim 1, wherein the metallic coating particles and the dispersion of plastic particles are fed to a stagnation chamber at an upstream end of the nozzle device.

3. The process as claimed in claim 1, wherein the plastic is a thermoplastic fluoropolymer.

4. The process as claimed in claim 1, wherein the plastic particles are formed from at least one plastic selected from the group consisting of polytetrafluoroethylene (PTFE), perfluoroalkoxy (PFA), fluorinated ethylene propylene (FEP), ethylene-tetrafluoroethylene (ETFE), ethylene chlorotrifluoroethylene (ECTFE) and polyvinylidene fluoride (PVDF).

5. The process as claimed in claim 1, wherein the metallic coating particles have a mean particle diameter of at least 5 m and at most 10 m, measured without plastic encapsulation.

6. The process as claimed in claim 1, wherein the metallic coating particles have a mean particle diameter of at least 7 m and at most 8 m, measured without plastic encapsulation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) These and other objects and advantages of the present invention will become more apparent and more readily appreciated from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings of which:

(2) FIG. 1 shows an exemplary embodiment of the proposed process and also a modified cold spraying nozzle suitable therefor having a stagnation chamber,

(3) FIGS. 2 and 3 show exemplary embodiments of coating particles, as can be used in the process, as cross sections, and

(4) FIGS. 4 and 5 show exemplary embodiments of the component having the layer proposed by the inventors, as partial sections.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(5) Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.

(6) The proposed cold spraying process can be carried out using a cold spraying nozzle 11 as shown in FIG. 1. This has a convergent portion 12 and a divergent portion 13 and a throat 14. Such a nozzle is referred to as a convergent-divergent nozzle. The convergent portion 12 of the cold spraying nozzle 11 is connected to a stagnation chamber 15, into which various feed tubes issue.

(7) A particle feed tube 16 for coating particles 17 issues into the stagnation chamber centrally. Furthermore, a ring of suspension feed tubes 18 is arranged in the stagnation chamber, through which a suspension, including a suspension agent, for example water, and plastic particles, can be introduced into the stagnation chamber in the direction of the arrows 19 indicated. The dispersion mixes with the coating particles 17, such that the plastic particles 20 can be accumulated on the coating particles 17 and thereby form an encapsulation 21 (FIG. 3).

(8) Beforehand, however, the coating particle 17, as can be gathered from FIG. 2, is firstly wetted by the dispersion 22 containing the plastic particles 20. However, the dispersion agent evaporates fairly quickly at the latest after the cold gas jet has eased in the divergent part 13 of the nozzle 11, such that the particles 17 with the encapsulation 21 made of the plastic particles 20 remain. The plastic particles 20 have dimensions in the nanometer range, whereas the metallic fractions of the coating particles 17 have a mean diameter of approximately 8 m.

(9) A component 23 as shown in FIG. 4 includes a substrate 24, on which a layer 25 is deposited. The layer 25 has a first microstructure phase made of metal 26, which is embedded in a second microstructure phase 27 made of plastic. The microstructure phase 27 made of plastic therefore forms a cohesive network in the layer 25.

(10) In the case of the component 23 shown in FIG. 5, the layer 25 has a somewhat different structure. Here, the coating particles form a cohesive matrix, such that the first metallic microstructure phase 26 also provides a cohesive network. This is penetrated by the network of the second microstructure phase 27 made of plastic, such that the two microstructure phases are interlocked, so to speak, or in other words are interwoven with one another.

(11) The invention has been described in detail with particular reference to preferred embodiments thereof and examples, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention covered by the claims which may include the phrase at least one of A, B and C as an alternative expression that means one or more of A, B and C may be used, contrary to the holding in Superguide v. DIRECTV, 69 USPQ2 1865 (Fed. Cir. 2004).