Process for producing intermetallic wear-resistant layer for titanium materials

Abstract

Disclosed is a process for producing a wear-resistant layer, in particular on components of gas turbines or aero engines. The process comprises providing a component with a titanium material on at least part of a surface on which the wear-resistant layer is to be produced, applying a solder formed from a cobalt base material to the titanium material, soldering the solder to the titanium material by applying heat and producing at least one diffusion zone between solder and titanium material which comprises intermetallic phases.

Claims

1. A process for producing a wear-resistant layer on a component, wherein the process comprises: providing a component which comprises a titanium material on at least part of a surface of the component on which the wear-resistant layer is to be produced, contacting the titanium material with a solder in the form of a paste or semifinished product formed from a cobalt base material, soldering the solder to the titanium material by applying heat to thereby produce one or more diffusion zones between solder and titanium material, which one or more diffusion zones comprise one or more intermetallic phases and form the wear-resistant layer, the soldering being carried out at a temperature of from about 1100 C. to about 1200 C.

2. The process of claim 1, wherein the component is a component of a gas turbine or of an aero engine.

3. The process of claim 1, wherein the process further comprises removing excess solder present on top of the one or more diffusion zones, whereby the wear-resistant layer is present on the surface of the correspondingly treated component.

4. The process of claim 1, wherein the solder comprises hard phase particles.

5. The process of claim 4, wherein the hard phase particles comprise ceramic and/or intermetallic phases.

6. The process of claim 1, wherein the solder is employed in the form of a paste.

7. The process of claim 1, wherein the solder is employed in the form of a semifinished product.

8. The process of claim 7, wherein the semifinished product is a solder tape.

9. The process of claim 1, wherein in addition to cobalt the solder comprises one or more elements selected from chromium, molybdenum, iron, nickel, tungsten, tantalum, titanium, zirconium, and silicon.

10. The process of claim 1, wherein the titanium material comprises titanium as main constituent and one or more elements selected from molybdenum, niobium, aluminum, boron, silicon.

11. The process of claim 1, wherein soldering is carried out at a temperature of from about 1100 C. to about 1200 C. with a holding time of from about 2 min to about 10 min and/or under protective gas or vacuum.

12. The process of claim 1, wherein soldering is carried out at a temperature of from about 1150 C. to about 1200 C.

13. The process of claim 1, wherein at least one of the one or more diffusion zones comprises one or more intermetallic phases based on one or more of the binary systems Co-Ti, CoAl, TiB, and MoSi.

14. The process of claim 1, wherein the cobalt based solder is formed from an alloy which comprises from 6.5% to 7.5% by weight tungsten, from 3% to 4% by weight tantalum, from 22.5% to 24.35% by weight chromium, from 0.55% to 0.65% by weight carbon, from 9% to 11% by weight nickel as well as titanium and zirconium, remainder cobalt.

15. The process of claim 1, wherein the wear-resistant layer comprises at least two diffusion zones, one diffusion zone comprising about 11% by weight chromium, about 4% by weight nickel, about 13% by weight molybdenum, about 2% by weight silicon, about 13% by weight titanium, about 8% by weight aluminum and about 1% by weight niobium, remainder cobalt, and another diffusion zone comprising about 21% by weight chromium, about 12% by weight molybdenum, about 1% by weight silicon, about 12% by weight titanium, about 6% by weight aluminum and about 1% by weight niobium, remainder cobalt.

16. A process for producing a wear-resistant layer on a component, wherein the process comprises: providing a component which comprises a titanium material on at least part of a surface of the component on which the wear-resistant layer is to be produced, contacting the titanium material with a solder in the form of a paste or semifinished product formed from a cobalt base alloy which comprises from 6.5% to 7.5% by weight tungsten, from 3% to 4% by weight tantalum, from 22.5% to 24.35% by weight chromium, from 0.55% to 0.65% by weight carbon, from 9% to 11% by weight nickel as well as titanium and zirconium, remainder cobalt, soldering the solder to the titanium material by applying heat to thereby produce one or more diffusion zones between solder and titanium material, which one or more diffusion zones comprise one or more intermetallic phases and form the wear-resistant layer.

17. The process of claim 16, wherein the wear-resistant layer comprises at least two diffusion zones, one diffusion zone comprising about 11% by weight chromium, about 4% by weight nickel, about 13% by weight molybdenum, about 2% by weight silicon, about 13% by weight titanium, about 8% by weight aluminum and about 1% by weight niobium, remainder cobalt, and another diffusion zone comprising about 21% by weight chromium, about 12% by weight molybdenum, about 1% by weight silicon, about 12% by weight titanium, about 6% by weight aluminum and about 1% by weight niobium, remainder cobalt.

18. The process of claim 16, wherein soldering is carried out at a temperature of from about 1150 C. to about 1200 C.

19. A process for producing a wear-resistant layer on a component, wherein the process comprises: providing a component which comprises a titanium material on at least part of a surface of the component on which the wear-resistant layer is to be produced, contacting the titanium material with a solder in the form of a paste or semifinished product formed from a cobalt base material, soldering the solder to the titanium material by applying heat to thereby produce at least two diffusion zones between solder and titanium material, one diffusion zone comprising about 11% by weight chromium, about 4% by weight nickel, about 13% by weight molybdenum, about 2% by weight silicon, about 13% by weight titanium, about 8% by weight aluminum and about 1% by weight niobium, remainder cobalt, and another diffusion zone comprising about 21% by weight chromium, about 12% by weight molybdenum, about 1% by weight silicon, about 12% by weight titanium, about 6% by weight aluminum and about 1% by weight niobium, remainder cobalt, which at least two diffusion zones comprise one or more intermetallic phases and form the wear-resistant layer.

20. The process of claim 19, wherein soldering is carried out at a temperature of from about 1150 C. to about 1200 C.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In a purely schematic illustration, the appended drawings show, in

(2) FIG. 1 a partial cross section through a component surface to be coated with an applied solder paste;

(3) FIG. 2 a partial sectional view through the component surface shown in FIG. 1 after the soldering process has been carried out; and in

(4) FIG. 3 a partial sectional view through the component surface shown in FIGS. 1 and 2 after removal of the excess solder material, with a two-layer wear-resistant layer.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

(5) 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.

(6) FIG. 1 shows a section through part of a surface of a component 1, in which a solder paste 2 has been applied to the surface. The component surface of the component 1 is formed from a titanium material, for example a TiAl alloy, which can comprise titanium and aluminum virtually with identical proportions as main constituents and also further alloying constituents such as niobium and molybdenum. The solder paste 2 is formed from a mixture of a cobalt base solder and hard phase particles, for example in the form of a hard material alloy. By way of example, the cobalt base solder can be formed by the alloy MAR-M-509 (trademark of Martin Marietta), which comprises 6.5% to 7.5% by weight tungsten, 3% to 4% by weight tantalum, 22.5% to 24.35% by weight chromium, 0.55% to 0.65% by weight carbon, 9% to 11% by weight nickel and also titanium and zirconium, remainder cobalt. The hard material alloy Tribaloy T-800 (trademark of Deloro Stellite Holdings Corporation) can be mixed in powder form into said cobalt alloy.

(7) The component 1 with the solder paste 2 can be annealed under vacuum at a temperature of between about 1150 C. and about 1200 C. and with a holding duration of about 5 minutes and then rapidly cooled, so that the heat treatment gives rise to a soldering process in which the solder paste 2 is joined fixedly to the component 1 by diffusion processes. Corresponding diffusion of constituents from the component 1 into the solder paste 2 can form, as shown in FIG. 2, a diffusion zone 3, whereas diffusion of constituents of the solder paste 2 into the component 1 forms a diffusion zone 4, the diffusion zones having different chemical compositions. Thus, for example, the diffusion zone 3 may comprise about 11% by weight chromium, about 4% by weight nickel, about 13% by weight molybdenum, about 2% by weight silicon, about 13% by weight titanium, about 8% by weight aluminum and about 1% by weight niobium, remainder cobalt, whereas the diffusion zone 4 may comprise about 21% by weight chromium, about 12% by weight molybdenum, about 1% by weight silicon, about 12% by weight titanium, about 6% by weight aluminum and about 1% by weight niobium, remainder cobalt. In addition, a bonding zone which extends further into the base material of the component 1 and has small proportions of cobalt and chromium can form (not shown).

(8) Intermetallic phases, in particular intermetallic CoTi phases, CoAl phases, TiB phases and MoSi phases, are formed in the diffusion zones. These intermetallic phases, together with the incorporated hard material particles, have a high hardness and strength, and therefore the diffusion zones are resistant to abrasion and to wear.

(9) Accordingly, the wear-resistant layer is finished by removing the solder paste 2 which has remained, so that the diffusion zones 3, 4 come to lie on the surface of the correspondingly treated component 1 (see FIG. 3).

(10) Instead of a solder paste comprising a mixture of a cobalt base solder and hard phase particles, it is also possible to provide merely a cobalt base solder without the additional incorporation of hard phase particles, since a sufficient strength and hardness and therefore wear resistance are already achieved by the intermetallic phases which form during the soldering process.

(11) Instead of a solder paste, the solder can also be applied in a different form, for example in the form of a solder tape, i.e. a semifinished product made of the soldering material, which can additionally comprise a suitable binder to achieve the dimensional stability.

(12) Instead of subjecting the component to be provided with the wear-resistant layer to a complete heat treatment during the soldering process, local heating in the region of the surface of the component or in the region of the applied solder may also be adequate. By way of example, the soldering process could be carried out inductively, so as not to subject the base material of the component to thermal loading.

(13) Instead of the two diffusion zones described in the exemplary embodiment, it is also possible for merely a single homogeneous diffusion zone to be formed.

(14) The formation of the diffusion zones on the one hand forms hard intermetallic phases which therefore increase the wear resistance and on the other hand gives rise to an intimate bond of the wear-resistant layer as a result of the interdiffusion of solder and base material of the component. Correspondingly, a good adhesive strength of the wear-resistant layer is therefore provided.

(15) 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.