Zinc-free spray powder, copper-containing thermal spray layer, as well as method of manufacturing a copper-containing thermal spray layer

Abstract

The invention relates to a zinc-free spray powder for thermally coating a substrate, in particular for thermally coating a bearing part of a bearing apparatus, which spray powder has the following composition except for unavoidable contaminants: tin=5% to 30% weight percent; aluminum=0.1% to 5% weight percent; iron=at most 1% weight percent, and copper=difference to 100% weight percent. The invention furthermore relates to a layer system applied via thermal spraying, a work piece, particularly a connecting rod, as well as a spray method for manufacturing a spray layer.

Claims

1. A zinc-free thermal spray coating powder consisting essentially of: 15 to 25 wt % tin; 0.1 to 5 wt % aluminum; at most 1 wt % iron; and remainder copper.

2. The powder of claim 1, wherein: tin is 20 wt %.

3. The powder of claim 1, wherein one of: aluminum is 0.5 to 2 wt %; or aluminum is 1 wt %.

4. The powder of claim 1, wherein one of: iron is at most 0.5 wt %; or iron is at most 0.2 wt %.

5. The powder of claim 1, wherein said powder has a particle size of one of: between 5 m and 120 m; or between 10 m and 60 m.

6. A method of making the powder of claim 1, wherein said method comprises: forming said powder via one of: gas atomization; water atomization; sintering; flash drying; or mechanical alloying.

7. A zinc-free layer system comprising: a surface layer consisting essentially of: 15 to 25 wt % tin; 0.1 to 5 wt % aluminum; at most 1 wt % iron; and remainder copper.

8. The layer system of claim 7, wherein the surface layer is one of: a bearing layer; a layer of a bearing part.

9. The layer system of claim 7, wherein: tin is 20 wt %.

10. The layer system of claim 7, wherein: aluminum is 0.5 to 2 wt %; or aluminum is 1 wt %.

11. The layer system of claim 7, wherein one of: iron is at most 0.5 wt %; or iron is at most 0.2 wt %.

12. The layer system of claim 7, wherein the surface layer has a porosity of one of: between 0.5 volume percent and 5 volume percent; or between 1 volume percent and 3 volume percent.

13. The layer system of claim 7, further comprising a top layer one of: comprising tin; or consisting essentially of tin.

14. A workpiece comprising the layer system of claim 7.

15. The workpiece of claim 14, wherein the workpiece is a piston connecting rod.

16. A method of thermal spraying the workpiece of claim 14, comprising: thermal spraying the powder of claim 1 onto the workpiece.

17. The method of claim 16, wherein the thermal spraying comprises one of: atmospheric plasma spraying; vacuum plasma spraying; HVOF spraying; flame spraying; or cold gas spraying.

18. A zinc-free thermal spray coating powder for forming a coating layer, said powder comprising: a particle size between 5 m and 120 m; and a composition consisting essentially of: 15 to 25 wt % tin; 0.1 to 5 wt % aluminum; at most 1 wt % iron; and remainder copper.

Description

(1) For a preferred embodiment of a spray powder in accordance with the invention, the spray powder includes between 15% and 25% weight percent tin, preferable 20% weight percent tin.

(2) In this respect the spray powder can specifically include between 0.5% and 2% weight percent aluminum, preferably 1% weight percent aluminum and/or at most 0.5% weight percent iron, preferably at most 0.2% weight percent iron. In this respect iron can be absent up to marginal unavoidable quantities in a special embodiment.

(3) In practice the size of the particles of the spray powder lies between 5 m and 120 m, preferably between 10 m and 60 m, and depending on the application can also lie between 60 m and 120 m for example.

(4) In this respect, a spray powder in accordance with the invention can be manufactured in a manner known per se, for example, by gas atomization, water atomization, sintering, spray drying, mechanical alloying or manufactured in any other suitable manner.

(5) The invention further relates to a zinc-free layer system applied via thermal spraying. The layer system in this respect includes at least one surface layer, particularly a bearing layer of a bearing part of a bearing apparatus, which bearing layer has the following composition except for unavoidable contaminants: tin=5% to 30% weight percent; aluminum=0.1 percent to 5% weight percent; iron at most 1% weight percent, and copper=difference from 100% weight percent.

(6) The surface layer of a layer system in accordance with the invention can in this respect include between 15% to 25% weight percent tin, preferably 20% weight percent tin, and/or the surface layer can include between 0.5% and 2% weight percent aluminum, preferably 1% weight percent aluminum, and/or the surface layer includes at most 0.5% weight percent iron, preferably at most 0.2% weight percent iron. In special cases, iron can also be completely absent except for unavoidable contaminants. Incidentally, for example, unavoidable quantities of various oxides or unavoidable remnants of process gases, such a noble gases, nitrogen and so forth can also be present in a layer system in accordance with the invention which, for example, can result via the thermal spray process, with the surface layer, having e.g. a porosity of from 0.5% to 5% volume percent, particularly between 1% and 3%.

(7) In an embodiment important in practice a layer system in accordance with the invention can additionally include an outer top layer including tin which can preferably be provided directly on the zinc-free surface layer made of the sprayed powder in accordance with the invention, wherein, in a particularly important embodiment, the outer top layer only contains tin except for unavoidable contaminants. The outer top layer in this respect can in special cases be a running-in layer having a function known per se, which at least partially changes or alternatively wears out during the running-in process known in the art, in which, for example, the counter running-partners of a bearing are geometrically ideally tuned to one another or alternatively run in.

(8) The invention finally also relates to a work piece, in particular to a connecting rod for a reciprocating piston internal combustion engine with a layer system as described in detail above, as well as to a spray method for the manufacture of a layer system in accordance with the invention on a work piece on use of a spray powder of the invention, in particular to manufacture a surface layer on a bearing part of a bearing, wherein the spray method is a thermal spray method, in particular an atmospheric plasma spray method, a vacuum plasma spray method, a HVOF-process, a flame spray method or a cold glass spray method.