Method and device for producing and coding metal powder

Abstract

The invention relates to a method for coding metal powder. Said method comprises the following steps: providing a melt, forming a melt stream, spraying the melt stream by means of a spraying fluid, and forming metal powder particles from the melt stream. The method is characterized in that, during the spraying of the melt and/or the spraying fluid, a coding component or a coding gas is added in such a way that the use of the coding component in the metal powder can be detected, wherein the gaseous coding component comprises one or more isotopes of at least one gas and the fraction of the at least one isotope is changed in comparison with the naturally occurring fraction of said isotope in the gas and/or wherein the gaseous coding component contains gaseous alloying elements.

Claims

1. A method for producing and coding metal powder, comprising: providing a melt; forming a melt stream; spraying the melt stream by means of a spraying fluid; and forming metal powder particles from the melt stream; wherein, during the spraying of the melt and/or the spraying fluid, a coding component is added in such a way that the use of the coding component in the metal powder can be detected, and wherein the coding component comprises one or more isotopes of at least one gas and the fraction of the at least one isotope is changed in comparison with the naturally occurring fraction of said isotope in the gas.

2. The method of claim 1, wherein information about the coding component and the composition thereof is stored in a database.

3. The method of claim 2, wherein the metal powder is detected by means of a chemical analysis method or by means of a mass spectrometer.

4. The method of claim 2, wherein the metal powder is detected by means of a chemical analysis method or by means of a mass spectrometer and the coding component of the metal powder is verified by comparison with the stored information about the coding component.

5. The method of claim 1, wherein the spraying fluid comprises an inert gas selected from: argon, helium, neon, krypton, xenon and radon; or an active gas selected from the group consisting of O.sub.2, CO.sub.2, H.sub.2, N.sub.2, and mixtures thereof; and the coding component comprises a component selected from oxygen 18 carbon dioxide (C.sup.18O.sub.2), carbon 13 carbon dioxide (.sup.13CO.sub.2), carbon 13 carbon monoxide (.sup.13CO), deuterium (D.sub.2), nitrogen 15 (.sup.15N.sub.2) and oxygen 18 (.sup.18O.sub.2), and mixtures thereof.

6. The method of claim 1, wherein the frequency of the isotopes in comparison with the naturally occurring frequency is increased or reduced by more than 0.5%.

7. The method of claim 1, wherein the coding component contains at least one isotope of an active gas, which reacts with the powder particles of the metal powder in such a way that the at least one isotope of the active gas it remains in the powder particles of the metal powder.

8. The method of claim 1, wherein the coding component comprises one or more isotopes of the spraying fluid, wherein the fraction of one or more isotopes of the spraying fluid in the coding component is changed in comparison with the natural fraction of the one or more isotopes in the spraying fluid, wherein the different isotopes form the coding in the coding component.

9. The method of claim 1, wherein the isotopes are isotopes of the gas, which forms the main component of the spraying fluid.

10. The method of claim 1, wherein the coding component comprises a gaseous alloying element.

11. The method of claim 1, wherein the frequency of the isotopes in comparison with the naturally occurring frequency is increased or reduced by more than 0 1.0%.

12. The method of claim 1, wherein the frequency of the isotopes in comparison with the naturally occurring frequency is increased or reduced by more than 5%.

13. The method of claim 1, wherein the coding component comprises at least one isotope of an inert gas, wherein the isotope becomes included in the metal powder.

14. The method of claim 1, wherein the isotopes are different from the isotopes of the spraying fluid.

Description

(1) The invention will be described in more detail below by means of the figures.

(2) FIG. 1 shows a schematic, laterally cut illustration of a device according to the invention for producing and coding metal powder, and

(3) FIG. 2 shows a schematic, laterally cut illustration of a nozzle apparatus of the device from FIG. 1.

(4) A device according to the invention for coding metal powder by means of a device 1 for producing metal powder by spraying will be described below (FIG. 1).

(5) This device 1 comprises a crucible 2 for providing a metal melt.

(6) The device 1 furthermore comprises a pouring funnel 3, which can be filled with melt by means of the crucible 2. The pouring funnel 3 is provided with a ceramic coating.

(7) An outlet channel 4 of the pouring funnel 3 leads into a nozzle apparatus 4.

(8) The nozzle apparatus 4 centrally comprises a passage opening 5, via which a melt stream, which is formed by the outlet channel 4 of the pouring funnel 3, can pass through.

(9) The passage opening 5 is surrounded by an annular spraying fluid chamber 6 for receiving and distributing a spraying fluid. The spraying fluid chamber 6 leads into an annular gap 7, which is arranged concentrically to the passage opening 5. The annular gap 7 forms a spraying nozzle for creating melt droplets from the melt stream.

(10) In addition, a spraying fluid supply apparatus 8 is provided, by means of which a spraying fluid can be applied to the spraying fluid chamber 6.

(11) The spraying fluid supply apparatus 8 has a spraying fluid storage container 9 for the spraying fluid, wherein the spraying fluid storage container 9 is connected to the spraying fluid chamber 6 via a line section 10.

(12) A coding component supply apparatus 11 is also provided. The coding component supply apparatus 11 comprises a coding component storage container 12. The coding component storage container 12 is connected to the spraying fluid chamber 6 via a line section 13.

(13) A coding gas or a gaseous coding component is stored in the coding component storage container 12.

(14) In the alternative, a mixing chamber (not illustrated) can be provided. The mixing chamber has an inlet for supplying spraying fluid from the spraying fluid storage container 9, and an inlet for supplying coding component from the coding component storage container 12 for the coding component.

(15) The spraying fluid and the coding component or a coding gas can also be provided as premix from a gas storage container (not illustrated), which contains spraying fluid as well as a corresponding fraction of coding component. This gas storage container, which contains the premix, then forms the coding component supply apparatus and is directly connected to the spraying fluid chamber 6, in addition to the storage container for the spraying fluid, or to the mixing chamber.

(16) The passage opening 5 as well as the spraying nozzle 7 of the nozzle apparatus lead into a spraying chamber 8 for spraying the melt droplets in powder particles.

(17) A controller (not illustrated) for controlling the addition of the coding component is also provided. The controller comprise a coding component regulator comprising a closed loop, which regulates the addition. The coding component regulator can comprise a P-regulator, an I-regulator, a D-regulator, and combinations thereof, such as, e.g. a PID-regulator. The coding component regulator captures an actual value of the one or more volume flows in the spraying fluid chamber and/or spraying chamber and/or the mixing chamber by means of a sensor, compares said actual value to a predetermined setpoint value of one or more volume flows, and the predetermined setpoint value is then set via a regulating unit.

(18) A method according to the invention for coding metal powder will be described below.

(19) First of all, a melt of a metal to be sprayed or of an alloy to be sprayed is formed and overheated in the crucible 2.

(20) The overheated melt is subsequently introduced into the pouring funnel 3 and, in the outlet channel 4 thereof, forms a melt stream, which passes perpendicularly through the passage opening 5 of the nozzle apparatus 4.

(21) This melt stream is atomized and coded via the spraying nozzle 7 of the nozzle apparatus 4 in the spraying chamber 14 by means of the spraying medium and the coding component. The resulting droplets solidify in the movement in the spraying chamber 14.

(22) It can furthermore be provided, either in the spraying chamber 14 and/or in downstream gas purification systems (cyclones, filters) to separate the metal powder from the spraying fluid.

(23) In a next step, the metal powder can be analyzed with the help of a detection apparatus, such as for example a mass spectrometer (gas chromatograph) and the coding or the originality, respectively, of the metal powder can thus be verified. An analysis by means of magnetic resonance or also chemical analysis methods are possible.

(24) Due to the coding component, the metal powder obtains a unique isotopic signature.

(25) The coding information is stored in a database.

(26) It is thus possible by means of the method according to the invention to code a metal powder and to subsequently detect this coding.

(27) The coding gas comprises for example the spraying medium and the coding component in such a way that the fraction of nitrogen 15 and nitrogen 14 isotopes in comparison with the natural fraction of nitrogen 15 and nitrogen 14 isotopes or the radio thereof, respectively, is changed. For example in the case of nitrogen, the ratio of .sup.15N (frequency=99.634) to .sup.15N (frequency=0.366) is changed in such a way that the fraction of .sup.15N is increased and the fraction of .sup.14N is reduced (or vice versa).

(28) According to the invention, the used isotopes can be isotopes of the spraying fluid, which means that for example when using nitrogen as spraying fluid, the ratio of nitrogen 15 to nitrogen 14 isotopes is changed. For example, carbon dioxide, which contains carbon 12, carbon 13, and carbon 14 isotopes, can also be provided.

(29) On principle, inert isotopes can be used independently from the material, because the embedding into the micro-porosities is a purely mechanical process.

(30) It is also possible, however, to add other isotopes of another gas, together with a fraction of said other gas, as coding component to the spraying fluid.

(31) According to a further exemplary embodiment of the method according to the invention, a gaseous alloying element is provided in addition or as an alternative as coding component. It can for example be provided hereby to use an inert gas, such as argon, as process gas, which contains a small fraction of between 1 ppm and 10.000 ppm of nitrogen 15 as coding component. Titanium is contained in the metallic starting material. In response to the production of the three-dimensional component, a smaller fraction of the titanium accordingly reacts with the nitrogen 15 and forms titanium nitride 15. In its chemical and physical properties, said titanium nitride 15 cannot be differentiated from titanium nitride 14, and it can thus not be detected by means of chemical analysis methods. It is possible, however, to analyze the component by means of a mass spectrometer. It is then determined thereby that the component had been produced under a nitrogen atmosphere with increased nitrogen 15 fraction.

LIST OF REFERENCE NUMERALS

(32) 1 device 2 crucible 3 pouring funnel 4 nozzle apparatus 5 passage opening 6 spraying fluid chamber 7 spraying nozzle 8 spraying fluid supply apparatus 9 spraying fluid storage container 10 line section 11 coding component supply apparatus 12 coding component storage container 13 line section 14 spraying chamber 15 outlet channel