Wear-resistant coating produced by electrodeposition and process therefor

Abstract

Disclosed is process for producing a wear-resistant coating on a component. The process comprises providing an electrolyte which contains Co and/or Ni, dispersing first particles comprising hard material particles and/or slip material particles in the electrolyte, dispersing second particles comprising metal alloy particles in which the metal alloy comprises chromium and aluminum in the electrolyte, providing a component to be coated in a bath of the electrolyte which has first and second particles dispersed therein, and electrodepositing a matrix of Co and/or Ni with incorporated first and second particles on the component. A correspondingly produced wear-resistant coating is also disclosed.

Claims

1. A coating, wherein the coating is wear-resistant and comprises an electrodeposited matrix which comprises from 15% by weight to 50% by weight Co, from 15% by weight to 50% by weight Ni, from 10% by weight to 30% by weight Cr, and from 1% by weight to 10% by weight Al, and in which first particles comprising hard material particles and/or slip material particles are incorporated in a proportion of from 5% by volume to 40% by volume.

2. The wear-resistant coating of claim 1, wherein the coating comprises the hard material particles and/or slip material particles in a proportion of from 10% by volume to 30% by volume.

3. The wear-resistant coating of claim 1, wherein the matrix comprises from 20% by weight to 40% by weight Co, from 20% by weight to 40% by weight Ni, from 10% by weight to 25% by weight Cr and from 2% by weight to 8% by weight Al.

4. The wear-resistant coating of claim 1, wherein the first particles have a maximum or average particle size of less than or equal to 10 m.

5. The wear-resistant coating of claim 1, wherein the slip material particles comprise a solid lubricant.

6. The wear-resistant coating of claim 5, wherein the solid lubricant comprises hexagonal boron nitride.

7. The wear-resistant coating of claim 1, wherein the hard material particles comprise oxides.

8. The wear-resistant coating of claim 7, wherein the hard material particles comprise chromium oxide and/or zirconium oxide.

9. The wear-resistant coating of claim 1, wherein the first particles comprise hard material particles and slip material particles.

10. The wear-resistant coating of claim 9, wherein the slip material particles comprise a solid lubricant and the hard material particles comprise oxides.

11. The wear-resistant coating of claim 10, wherein the slip material particles comprise hexagonal boron nitride.

12. The wear-resistant coating of claim 10, wherein the hard material particles comprise chromium oxide and/or zirconium oxide.

13. A coating, wherein the coating is wear-resistant and comprises an electrodeposited matrix which comprises from 15% by weight to 50% by weight Co, from 15% by weight to 50% by weight Ni, from 10% by weight to 30% by weight Cr, and from 1% by weight to 10% by weight Al, and in which first particles comprising A hard material particles and/or slip material particles are incorporated in a proportion of from 5% by volume to 40% by volume and wherein the coating has been obtained by a process which comprises: (a) dispersing the first particles and second particles which comprise metal alloy particles in which the metal alloy comprises chromium and aluminum in an electrolyte which comprises Co and/or Ni; (b) providing a component to be coated in a bath of the electrolyte which has the first and second particles dispersed therein; (c) electrodepositing the matrix with incorporated first and second particles on the component; and (d) subjecting the component with the electrodeposited matrix to a heat treatment.

14. The wear-resistant coating of claim 13, wherein the heat treatment is carried out at a temperature of from 950 C. to 1200 C. for from 2 to 20 h.

15. The wear-resistant coating of claim 13, wherein the heat treatment is carried out in vacuo.

16. The wear-resistant coating of claim 13, wherein the electrolyte comprises NiSO.sub.4 and/or CoSO.sub.4.

17. The wear-resistant coating of claim 13, wherein the electrolyte comprises NaCl and/or H.sub.3BO.sub.3.

18. The wear-resistant coating of claim 13, wherein the first and second particles are each provided in the electrolyte in a proportion of from 50 g/l to 300 g/l.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The accompanying drawings show, in a purely schematic manner, in

(2) FIG. 1 a cross-sectional view of an electrolyte bath dispersed according to the invention;

(3) FIG. 2 a cross-sectional view of an electrolyte bath dispersed according to the invention during the electrodeposition of a layer on a component to be coated;

(4) FIG. 3 a cross section through a component with a layer deposited according to the invention; and in

(5) FIG. 4 a cross section through a component with a wear-resistant coating deposited according to the invention after a heat treatment.

DETAILED DESCRIPTION OF THE INVENTION

(6) The particulars shown herein are by way of example and for purposes of illustrative discussion of the embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the present invention. In this regard, no attempt is made to show details of the present invention in more detail than is necessary for the fundamental understanding of the present invention, the description in combination with the drawings making apparent to those of skill in the art how the several forms of the present invention may be embodied in practice.

(7) FIG. 1 shows an electrolyte 3 in an electrolyte bath, in which first particles 1 and second particles 2 are dispersed.

(8) The electrolyte is a mixture of cobalt sulfate, nickel sulfate, boric acid and sodium chloride, it being possible to use, for example, 240 g/l cobalt sulfate, 240 g/l nickel sulfate, 35 g/l boric acid and 20 g/l sodium chloride. The pH value of the electrolyte is set between 4.5 and 4.7.

(9) The first particles 1, which are dispersed into the electrolyte 3, are hard material particles and/or slip material particles. The hard material particles can be formed by oxides, and in the present preferred exemplary embodiment the hard material particles are formed by chromium oxide or zirconium oxide, which are added to the electrolyte in the form of particles having average particle sizes of 5 m in a quantity of 100 g/l. In addition, the first particles are formed by slip material particles, which are formed by a solid lubricant, for example hexagonal boron nitride. The slip material particles are likewise dispersed in the electrolyte with an average particle size of 5 m in a concentration of 100 g/l.

(10) The second particles 2, which are present in the electrolyte 3, are metal alloy particles containing at least chromium and aluminum, in particular predominantly chromium and aluminum Predominantly in this respect means that the sum total of the proportions of chromium and aluminum forms the largest alloying constituent of the metal alloy particles, in particular makes up more than 50% by weight of the metal alloy of the metal alloy particles.

(11) The second particles 2 can likewise be dispersed into the electrolyte 3 with an average particle size of 5 m in a quantity of 200 g/l.

(12) The electrolyte is brought to a temperature of 30 C. to 70 C. and kept in motion by suitable stirring instruments or the like, so that the dispersed first and second particles 1, 2 are present in a uniform distribution in the electrolyte 3.

(13) FIG. 2 shows the electrolyte bath shown in FIG. 1 during the electrodeposition of a wear-resistant coating according to the invention on a component 4. In this case, the component is connected as cathode to a power supply 6, while an additional anode 5 is arranged in the electrolyte bath.

(14) FIG. 3 shows the component 4 with the deposited layer 7, which comprises an NiCo matrix with incorporated first particles 1 and second particles 2. The current density during the electrodeposition can lie in the range of from 1 to 10 A/dm.sup.2.

(15) The deposited layer 7 is subjected together with the component 4 to a heat treatment, to be precise in a temperature range of 1000 C. to 1150 C. for 5 to 15 hours in vacuo, such that the second particles 2 of a CrAl alloy together with the CoNi matrix of the deposited layer form a CoNiCrAl matrix, in which hard material particles 9a of chromium oxide and/or zirconium oxide and slip material particles 9b of hexagonal boron nitride are present in the CoNiCrAl matrix, in order to form the wear-resistant coating 10 on the component 4.

(16) If, for example, a CrAlY alloy is used for the second particles 2, a CoNiCrAlY matrix 8 of the wear-resistant coating 10 is formed.

(17) In the case of the exemplary embodiment shown in FIGS. 1 to 4, the first particles 1 are provided with a metal shell of nickel and/or cobalt; this dissolves in the matrix 8 during the heat treatment step between FIGS. 3 and 4, and therefore the hard material particles 9a and the slip material particles 9b are present in the wear-resistant coating 10 without a surrounding shell.

(18) While the present invention has been described with reference to exemplary embodiments, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitation. Changes may be made, within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the present invention in its aspects. Although the present invention has been described herein with reference to particular means, materials and embodiments, the present invention is not intended to be limited to the particulars disclosed herein; rather, the present invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims.