Metal powder for 3D printers and preparation method for metal powder

Abstract

The invention discloses metal powder for a 3D printer. The metal powder for 3D printers is 10-50-micron metal powder made by agglomerating many submicron order metal particles through a granulating process. As the metal powder is combined by submicron order metal particles, the metal powder is low in melting point and high in melting speed, so that the printing speed of the metal 3D printer can be increased and the precision of a printing member can be improved. Meanwhile, the average grain size of the metal powder is equivalent to existing atomized metal powder for 3D printers, and the metal powder has good dispersibility and conveying property, and can be suitable for existing 3D printer equipment.

Claims

1. A preparation method for the metal powder for 3D printer, comprising the specific steps of: (1) firstly preparing the submicron order metal powder through the physical vapor deposition method or the chemical vapor deposition method, wherein the average grain size of the submicron order metal powder is 0.1-3 microns; (2) mixing the submicron order metal powder with the average gain size of 0.1-3 microns obtained in step (1) with a liquid to prepare metal powder slurry, wherein the weight ratio of the submicron order metal powder liquid of the metal powder slurry is (0.25-2.0): 1; (3) adding an organic adhesive which accounts for 0.1-10% by weight of the submicron order metal powder into the metal powder slurry obtained in step (2), and uniformly stirring and mixing the slurry; and (4) preparing the uniformly stirred and mixed slurry in step (3) to the spherical metal powder for 3D printers with the average grain size of 10-50 microns through a centrifugal spray granulator or a pressure spray granulator.

2. The preparation method for the metal powder for 3D printers according to claim 1, wherein the average grain size of the submicron order metal powder in step (1) is 0.5-2 microns.

3. The preparation method for the metal powder for 3D printers according to claim 2, wherein the average grain size of the metal powder for 3D printers in step (4) is 20-30 microns.

4. The preparation method for the metal powder for 3D printers according to claim 1, wherein the metal powder is pure metal powder of titanium, nickel or copper or alloy powder of nickel-based alloy powder, titanium-based alloy powder, aluminium-based alloy powder or iron-base alloy.

5. The preparation method for the metal powder for 3D printers according to claim 1, wherein the liquid in step (1) is water, ethanol, isopropanol or methanol.

6. The preparation method for the metal powder for 3D printers according to claim 1, wherein the organic adhesive in the step (3) is a polyvinyl alcohol adhesive, or an ethyl cellulose adhesive.

7. The preparation method for the metal powder for 3D printers according to claim 1, wherein the rotating speed of the centrifugal spray granulator in step (4) is controlled at 10000-40000 r/m; the pressure of the pressure spray granulator is 6-30 kg/cm.sup.2; other operating parameters of the pressure spray granulator or the centrifugal spray granulator are controlled as follows: the inlet temperature of dry air is 200-350 C. and the outlet temperature is 80-150 C.; the flow of the dry air is 100-300 Nm.sup.3/h; the feeding speed of the metal powder slurry in the pressure spray granulator or the centrifugal spray granulator is 5-20 kg/h.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a scanning electron microscope diagram of the submicron order metal powder.

(2) FIG. 2 is a scanning electron microscope diagram of the metal powder (I) for 3D printers.

(3) FIG. 3 is a scanning electron microscope diagram of the copper-based alloy powder with the average grain size of 1.0 micron.

(4) FIG. 4 is a scanning electron microscope diagram of the copper-based alloy powder with the average grain size of 40 microns.

(5) FIG. 5 is a scanning electron microscope diagram of the titanium-based alloy powder with the average grain size of 0.5 micron.

(6) FIG. 6 is a scanning electron microscope diagram of the titanium-based alloy powder with the average grain size of 45 microns.

(7) FIG. 7 is a scanning electron microscope diagram of the nickel-based alloy powder with the average grain size of 0.25 micron.

(8) FIG. 8 is a scanning electron microscope diagram of the nickel-based alloy powder with the average grain size of 30 microns.

(9) FIG. 9 is a scanning electron microscope diagram of the pure metal nickel powder with the average grain size of 0.5 micron.

(10) FIG. 10 is a scanning electron microscope diagram of the pure metal nickel powder with the average grain size of 40 microns.

(11) FIG. 11 is as scanning electron microscope diagram of the metal powder (II) for 3D printer.

DETAILED DESCRIPTION OF THE EMBODIMENT

(12) The invention is further described in detail through the embodiments, but the invention is not limited to the embodiments.

(13) Equipment associated with the invention, for example the pressure spray granulator or the centrifugal spray granulator etc., are marketed products. The specific working principle is as follows: a feed liquid is input through a pump to spray vaporific liquid drops which then descend in as cocurrent flow with hot air (dry air); powder grains are collected from a discharge port at the bottom of a tower, exhaust gas and fine powder are separated through a cyclone separator, the exhaust gas is extracted through an exhaust fan, the powder is collected through a powder cylinder arranged at the lower end of the cyclone separator, and a second level dedusting device can be further arranged at the outlet of the exhaust fan. The pressure, the flow and the size of spray holes are regulated according to specifications of the product, so that the required spherical particles in a certain proportion in size are obtained.

Embodiment I

(14) A physical vapor deposition method is used: dissolving a copper-based alloy as a raw material in a crucible, wherein gas (hydrogen, argon, nitrogen and etc.) enters from a gas inlet pipe in a plasma transfer arc torch and is transferred into plasma through an external power supply to generate a plasma transfer arc between the crucible and the plasma transfer arc torch (i.e., the lower end of the plasma transfer arc torch generated by the plasma transfer arc torch is connected to a metal liquid level in the crucible); evaporating and vaporizing the metal through the plasma transfer arc torch; passing through a quenching pipeline by metal vapor and adding inert gas or nitrogen at room temperature into the metal vapour at a high speed to reduce the temperature of the metal vapour to be lower than 300 C. to obtain the copper-based alloy powder with the average grain size of 1.0 micron (FIG. 3) (the physical vapor deposition method is a conventional method in the industry, and is not described in detail therein); and then preparing the copper-based alloy powder and ethanol into metal powder slurry with the solid-liquid ratio of 1.5:1. The organic adhesive accounts for 2% by weight of the solid. The metal slurry is prepared into spherical metal powder through the centrifugal spray granulator. The rotating speed of the centrifugal spray granulator is controlled at 12000 r/m, the inlet temperature of dry air of the centrifugal spray granulator is 200 C. and the outlet temperature is 90 C. and the flow of the dry air is 220 Nm.sup.3/h. The feeding speed of the metal powder slurry is 12 kg/h. The dried and granulated metal powder is collected through a cyclone and ultrafine metal powder is collected through a filter bag. The metal powder collected by the cyclone is graded by a vibrating sieve to obtain a metal powder with the average grain size of 40 microns (FIG. 4). The metal powder collected by the filter bag and the metal powder which is screened and removed is recovered to prepare the metal powder slurry.

Embodiment II

(15) The titanium-based alloy powder (FIG. 5) with the average grain size of 0.5 micron produced by the physical vapor deposition method and water are prepared into the metal powder shiny with the solid liquid ratio of 2:1. The organic adhesive (ethyecellulose) accounts for 1.5% by weight of the solid. The metal slurry is prepared into spherical metal powder through the centrifugal spray granulator. The rotating speed of the centrifugal spray granulator is controlled at 12000 r/m, the inlet temperature of dry air of the centrifugal spray granulator is 350 C. and the outlet temperature is 120 C., and the flow of the dry air is 250 Nm.sup.3/h. The feeding speed of the metal powder slurry is 10 kg/h. The dried and granulated metal powder is collected through a cyclone and ultrafine metal powder is collected through a filter bag. The metal powder collected by the cyclone is graded by a vibrating sieve to obtain the metal powder with the average grain size of 45 microns (FIG. 6). The metal powder collected by the filter bag and the metal powder which is screened and removed is recovered to prepare the metal powder slurry.

Embodiment III

(16) The nickel-based alloy powder (FIG. 7) with the average grain size of 0.25 micron produced by the physical vapor deposition method and ethanol are prepared into the metal powder slurry with the solid liquid ratio of 1:1. The organic adhesive (the metallurgical mineral powder pellet adhesive produced by Baoding Jingsu Biotechnology Co., Ltd. with the model number of HY-1) accounts for 1.5% by weight of the solid. The metal slurry is prepared into spherical metal powder through the centrifugal spray granulator. The rotating speed of the centrifugal spray granulator is controlled at 25000 r/m, the inlet temperature of dry air of the centrifugal spray granulator is 200 C. and the outlet temperature is 90 C., and the flow of the dry air is 220 Nm3/h. The feeding speed of the metal powder slurry is 10 kg/h. The dried and granulated metal powder is collected through a cyclone and ultrafine metal powder is collected through a filter bag. The metal powder collected by the cyclone is graded by a vibrating sieve to obtain the metal powder with the average grain size of 30 microns (FIG. 8). The metal powder collected by the filter bag and the metal powder which is screened and removed is recovered to prepare the metal powder slurry.

Embodiment IV

(17) The pure metal nickel powder (FIG. 9) with the average grain size of 0.5 micron produced by the physical vapor deposition method and methanol are prepared into the metal powder slurry with the solid liquid ratio of 1.5:1. The organic adhesive accounts for 1.0% by weight of the solid. The metal slurry is prepared into spherical metal powder through the pressure spray granulator. The pressure of the pressure spray is controlled at 15 kg/cm.sup.2, the inlet temperature of dry air is 250 C. and the outlet temperature is 95 C., and the flow of the dry air is 250 C. The feeding speed of the metal powder slurry is 12 kg/h. The dried and granulated metal powder is collected through as cyclone and ultrafine metal powder is collected through a filter bag. The metal powder collected by the cyclone is graded by a vibrating sieve to obtain the metal powder with the average grain size of 40 microns (FIG. 10). The metal powder collected by the filter bag and the metal powder which is screened and removed is recovered to prepare the metal powder slurry.

(18) It can be known from the drawings that the structure of the metal powder for 3D printers prepared by means of the embodiments is not complete integrated metal powder but is formed by adhering and agglomerating multiple submicron order metal powder, so that the metal powder for 3D printers not only has various advantages of the submicron particles (for example, high degree of sphericity, uniform component and low oxygen content), but also has dispersibility and conveying property of the atomized metal powder.

(19) The metal powder for 3D printers prepared by the embodiments is used for 3D printing. The metal powder for 3D printers is sprayed to as heating mould working platform in a protective room with protective gas to be printed layer by layer through a nozzle of the 3D printers so as to form a 3D printing product; in the spraying process by the nozzle, the metal powder has the advantages that the metal powder is good in dispersibility and is smoothly conveyed; in the process of printing layer by layer, the contact area of the metal powder in each layer at the connected part is fully increased, and the metal powder is firmly adhered.