Thermal spraying material, a thermally sprayed coating, a thermal spraying method and also a thermally coated workpiece

Abstract

The invention relates to a thermal spraying material (5) for the coating of a surface of a workpiece by means of a thermal spraying method, wherein the spraying material (5) contains zinc. The invention further relates to a thermal spraying method and to a thermally sprayed coating sprayed with the material (5).

Claims

1. A thermal spray coating as applied on a surface, wherein the thermal spray coating is of the kind ZnX, with Zn being in the range of 70% by weight to less than 100% by weight of the coating, and X consists of two or more members selected from the group consisting of Sn, Mg, Ca, Fe, Ni, Co, Cu, Mo, Ti, Cr, Zr, Y, La, Ce, Sc, Pr, Dy, C, O, N, and compounds and combinations thereof, wherein a first one of the selected members is Sn in the amount of 1% to 4% by weight of the coating, wherein a second one of the selected members consists of at least one of an oxidic component or a ceramic component, and wherein the at least one of the oxidic component or the ceramic component comprises at least one of MgO or carbide and further comprises a nitride.

2. The thermal spray coating of claim 1, wherein the second one of the selected members consists of a ceramic component.

3. A thermal spray coating as applied on a surface, wherein the thermal spray coating is of the kind ZnX, with Zn being in the range of 70% by weight to less than 100% by weight of the coating, and X consists of two or more members selected from the group consisting of Sn, Mg, Ca, Fe, Ni, Co, Cu, Mo, Ti, Cr, Zr, Y, La, Ce, Sc, Pr, Dy, C, O, N, and compounds and combinations thereof, wherein a first one of the selected members consists of Sn in the amount of 1% to 4% by weight, wherein a second one of the selected members consists of a compound of the type M.sub.aO.sub.bN.sub.c, and wherein M is selected from the group consisting of Sn, Mg, Ca, Fe, Ni, Co, Cu, Mo, Ti, Cr, Zr, Y, La, Ce, Sc, Pr, Dy, and C, and a, b, and c are positive integers.

4. The thermal spray coating of claim 3, wherein M.sub.aO.sub.bN.sub.c is a thermodynamically stable compound.

5. The thermal spray coating of claim 4, wherein M consists of Zr, Cr, Ti, or combinations or compounds thereof.

6. A thermal spray coating as applied on a surface, wherein the thermal spray coating is of the kind ZnX, with Zn being in the range of 70% by weight to less than 100% by weight of the coating, and X consists of: Sn in the amount of 1% to 4% by weight of the coating, and at least one member selected from the group consisting of Fe, Co, Cu, Mo, Ti, Zr, Y, La, Ce, Sc, Pr, Dy, C, O, N, and compounds and combinations thereof.

7. A thermal spray coating as applied on a surface, wherein the thermal spray coating comprises: Zn being in the range of 70% by weight to less than 100% by weight; and a component that consists of two or more members selected from the group consisting of Sn, Mg, Ca, Fe, Ni, Co, Cu, Mo, Ti, Cr, Zr, Y, La, Ce, Sc, Pr, Dy, C, O, N, and compounds and combinations thereof, wherein a first one of the selected members is Sn in the amount of 1% to 4% by weight of the coating, wherein a second one of the selected members is at least one of: MgO and a nitride; or carbide and a nitride.

8. A thermal spray coating as applied on a surface, wherein the thermal spray coating comprises: Zn being in the range of 70% by weight to less than 100% by weight of the coating, and a component that consists of: Sn in the amount of 1% to 4% by weight of the coating, and at least one member selected from the group consisting of Fe, Co, Cu, Mo, Ti, Zr, Y, La, Ce, Sc, Pr, Dy, C, O, N, and compounds and combinations thereof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) An important effect of a special embodiment of a method in accordance with the invention will be explained more closely in the following with the help of the drawings, which show:

(2) FIG. 1 is an under-expanded/over-expanded pressure diagram; and

(3) FIG. 2 shows the effect of the under-expanded condition on the flow of particles in the coating beam.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(4) A diagram is illustrated in FIG. 1 in which pressure values are recorded on the ordinate, such as for example could arise during plasma spraying at the outlet 4 of a nozzle 3 of a spray gun 2, and, on the abscissa, gas pressures such as, for example, could be set in a process chamber during the coating of a substrate. In this connection, the separating line 1 separates the diagram into two-part regions, which are characterized with under-expanded and over-expanded. In the under-expanded region, the pressure at the outlet 4 of the nozzle 3 is higher than the gas pressure in the process chamber. On the other hand, in the over-expanded part region, the gas pressure in the process chamber is higher than the pressure at the outlet 4 of the nozzle 3.

(5) In carrying out of a method in accordance with the invention the pressure parameters are preferably selected so that coating takes place in the under-expanded region.

(6) FIG. 2 shows in a schematic manner how the selection of the pressure parameters in the under-expanded region affects the movement of a spraying material 5 in a coating beam 6.

(7) In FIG. 2 a section of a plasma spray gun 2 is schematically illustrated from which a coating beam 6 discharges from a nozzle 3. The coating beam 6 is ultrasonic so that shock waves form in the coating beam 6. The formation of the shock waves is illustrated symbolically by the wavelike outline of the coating beam 6. On the right-hand side in FIG. 2 there is a not-illustrated substrate, which is coated by the coating beam 6.

(8) In the example of FIG. 2 a gas pressure of the gas atmosphere in the process chamber is selected, which is smaller than the pressure at the outlet 4 of the spray gun 2. This selection of the pressure parameters corresponds to the part region under-expanded in the diagram of FIG. 1. The selection of these parameters is, as has already been mentioned, particularly advantageous when the spray material 5 contains a material which vaporizes easily, in other words has a high vaporizing pressure.

(9) The coating beam 6 of FIG. 2 spreads ultrasonically, so that shock-like waves or conditions form which represent a barrier for the material 5 located in the coating beam 6, so that this essentially cannot leave the coating beam 6. This means that the coating beam 6 has a similar effect to a light conductor for light, as a more or less totally reflecting barrier, so that the vaporized material is caught in the coating beam and, for example, follows the path 7 in the direction towards the substrate to be coated. For this reason it is possible to also coat materials with high vapor pressure, such as for example with Zn, using a method in accordance with the present invention.

(10) In this connection it goes without saying that the invention is not limited to the described embodiments and, in particular, the embodiments in accordance with the invention described within the context of this application can, of course, also be combined in any suitable manner.