CN104772473B - A kind of preparation method of 3D printing fine grained sized spherical titanium powder - Google Patents

Abstract

The preparation method of a kind of 3D printing fine grained sized spherical titanium powder, belongs to metal dust preparing technical field.Using high pure metal titanium bulk is raw material, in an inert atmosphere arc evaporation, is filled with hydrogen simultaneously, titantium hydride nanometer powder is synthesized by gas phase；Then titantium hydride nanometer powder is carried out agglomeration granulation, obtain the micron order titanium hydride powders of higher density；Finally micron order titanium hydride powders after pelletize is carried out heat treatment, by degumming, dehydrogenation and densification consolidation, it is thus achieved that granularity, sphericity and mobility meet 3D and print the pure titanium powder granule required.This method is strong to the sphericity of titanium powder granule and the controllability of particle diameter distribution；Technique is simple, low cost；By firstly generating the new way of sludge proof titantium hydride nano-powder particles, stably there is the Titanium of greatly activity, the oxygen content in the titanium powder granule finally prepared can be controlled.

Description

A preparation method of fine particle spherical titanium powder for 3D printing

technical field

The invention relates to a method for preparing fine particle spherical titanium powder for 3D printing, belonging to the technical field of metal powder preparation.

Background technique

3D printing technology is especially suitable for the development of high value-added complex structural products, personalized customization and verification of design and R&D before mass production. Compared with the current international advanced level, my country still has a big gap in the research and development of forming materials required for 3D printing. At present, the material design and preparation process mainly follow the foreign progress. In terms of forming material products for 3D printing, the fine-grained spherical titanium and titanium alloy powder needed in China are almost completely dependent on imports. The lack of high-quality forming materials for 3D printing is one of the bottleneck factors restricting the promotion and application of 3D printing technology in my country.

For fine-grain titanium metal powder for 3D printing, the process has high requirements on powder materials, such as particle size range of 20-50 microns, high sphericity, low oxygen content, etc. The existing titanium powder preparation technologies mainly include: electrochemical method, mechanical ball milling method, atomization method, reduction method, etc. At present, the morphology of titanium or titanium alloy powder prepared by these methods is difficult to control, and the particle size is coarse and the distribution range is wide. Among them, due to the low air velocity of the gas atomization method, the yield of the prepared metal or alloy powder with a particle size below 50 μm is usually only about 30%; the cost of electrochemical and reduction methods is high, and the solvents and reducing agents used are mostly Highly toxic and easy to introduce impurities such as halogens and sulfur; the ball milling method can only be used for brittle materials, usually with high oxygen content and unable to control the shape of powder particles. Therefore, there is an urgent need for a method for preparing metal or alloy powders for 3D printing with low cost, high purity, and controllable particle size.

In view of the background of the above field, in order to solve the limitations of the prior art, the present invention provides a method for preparing fine particle spherical titanium powder suitable for 3D printing technology.

Contents of the invention

The process flow and principle of the preparation method provided by the present invention are as follows: using high-purity metal titanium blocks as raw materials, arc evaporation in an inert gas environment, and filling hydrogen at the same time, and synthesizing titanium hydride nanopowder through gas phase reaction; The powder is agglomerated and granulated to obtain a higher density micron-sized titanium hydride powder; finally, the granulated micron-sized titanium hydride powder is heat-treated to obtain particle size, sphericity and fluidity through degumming, dehydrogenation and densification and consolidation Pure titanium powder particles that meet the requirements of 3D printing. Compared with other process methods, this method has strong controllability to the sphericity and particle size distribution of metal particles; the process is simple and the cost is low; through the new way of first generating oxidation-resistant titanium hydride nanopowder, it is stable and has great activity The metal titanium can effectively control the oxygen content in the final prepared metal powder particles.

A preparation method of fine particle spherical titanium powder suitable for 3D printing requirements provided by the present invention is characterized in that it comprises the following steps:

(1) Using high-purity titanium block as the anode, in an inert gas argon or helium environment, a high-intensity arc is formed by discharge, the arc starting current is 100-250A, the arc voltage is 10-30V, and then hydrogen is introduced , the volume ratio of hydrogen to inert gas is 1:(1~3), titanium hydride (TiH ₂ ) is generated through gas phase reaction, and solid titanium hydride nanoparticles are formed after condensation;

(2) preparing polyvinyl alcohol, polyethylene glycol, deionized water and the titanium hydride nanoparticles prepared in step (1) into a suspension slurry, and after agglomeration and granulation, spherical titanium hydride particles of 20 to 50 μm are obtained;

(3) Carry out heat treatment on the granulated spherical titanium hydride particles prepared in step (2) by using an argon-protected tube furnace. The heat treatment temperature in the first stage is 230-280° C., and the holding time is 60-120 minutes; the heat treatment in the second stage The temperature is 700-750°C, and the holding time is 120-180min; the third stage heat treatment temperature is 900-950°C, and the holding time is 60-90min, and finally cooled to room temperature with the furnace to obtain high density, high fluidity, low Micron-sized spherical titanium powder with fine particles of oxygen content.

The technical features and advantages of the present invention mainly include: (1) During the arcing and evaporation process of the titanium block, hydrogen gas is charged, and the hydrogen gas reacts rapidly with the metal gas at high temperature to produce pure titanium hydride, and the arcing current is used to , voltage and the regulation of the ratio of hydrogen and inert gas can adjust the yield and particle size of titanium hydride, so that the average particle size can be controlled within the range of 30-80nm; (2) using titanium hydride powder with good stability as the initial material, Using methods such as centrifugal spraying to granulate can effectively control the introduction of impurities such as oxygen during the granulation process, and at the same time obtain good sphericity and high micron-scale particle density; (3) The heat treatment process after granulation has great impact on the final obtained Metal powders that meet the requirements of 3D printing are very important. In the present invention, a three-stage heat treatment method is adopted. The effect of the first stage heat treatment is to volatilize the organic binder added in the granulation process; the effect of the second stage heat treatment is to completely decompose titanium hydride to obtain metal titanium; the third stage heat treatment The role of titanium powder is to form a solid-phase bond between titanium powder particles, which not only ensures sufficient inter-particle bonding strength and density, but also does not cause rapid coarsening of particles (or internal microstructure) or overall sintering. The present invention can prepare high-quality fine-particle spherical titanium metal powder with excellent sphericity, high fluidity and average particle size and particle size distribution meeting the requirements of 3D printing by adjusting and controlling the combination of parameters in each process step. In particular, through the new way of first generating oxidation-resistant titanium hydride nanopowder particles, the metal titanium with great activity can be stabilized, the oxygen content in the final titanium powder particles can be effectively controlled, and the whole preparation route is simple and easy Compared with the existing preparation methods of other pure titanium micron powders, the cost is greatly reduced.

Description of drawings

Fig. 1 is the phase detection spectrum of the nano-titanium hydride powder prepared in Example 1 of the present invention.

The microscopic morphology, crystal structure and particle size distribution of the nano-titanium hydride powder prepared in Fig. 2 Example 2 of the present invention; wherein a is the high-magnification transmission electron microscope topography figure of the nano-titanium hydride powder, and b is the selected area of the nano-titanium hydride powder particle Electron diffraction pattern, c is the statistical result of particle size distribution of nano titanium hydride powder particles.

Fig. 3 is a phase detection spectrum of the titanium powder prepared in Example 1 of the present invention.

Figure 4 is the microscopic morphology and particle size distribution of titanium powder particles prepared in Example 2 of the present invention; where a is the scanning electron microscope topography of titanium powder, b is the high-magnification topography of a single titanium particle, and c is titanium powder Particle size distribution statistical results.

Table 1 Test results of sphericity, fluidity and density of titanium metal powder particles prepared in Example 1 and Example 2 of the present invention.

detailed description

The present invention will be further described below in conjunction with the examples, but the present invention is not limited to the following examples.

Example 1. Using the raw material high-purity titanium block (purity 99.99wt%) as the anode, in an inert gas argon environment, a high-intensity arc is formed by discharge, the arcing current is 100A, the arc voltage is 10V, and then hydrogen is introduced , the ratio of hydrogen to inert gas is 1:1, titanium hydride (TiH ₂ ) is generated through gas phase reaction, and solid titanium hydride nanoparticles are formed after condensation, as shown in Figure 1; polyvinyl alcohol, polyethylene glycol and deionized water are mixed with hydrogenated Titanium nanoparticles were formulated into suspension liquid slurry, and then agglomerated and granulated by centrifugal atomization drying method to obtain spherical titanium hydride particles of 20 μm; the granulated titanium hydride powder was heat-treated in an argon-protected tube furnace. The heat treatment temperature in the first stage is 230°C, and the holding time is 120 minutes; the heat treatment temperature in the second stage is 700°C, and the holding time is 180 minutes; the heat treatment temperature in the third stage is 900°C, and the holding time is 90 minutes. Micron-sized spherical titanium powder with fine particles, high fluidity and low oxygen content. The phase detection spectrum of the prepared titanium powder is shown in Figure 3, and the measurement results of sphericity, bulk density, fluidity and oxygen content are shown in Table 1.

Example 2. Using the raw material high-purity titanium block (purity 99.99wt%) as the anode, in an inert gas helium environment, a high-intensity arc is formed by discharge, the arc starting current is 250A, the arc voltage is 30V, and then hydrogen is introduced , the ratio of hydrogen to inert gas is 1:3, titanium hydride (TiH ₂ ) is generated through gas phase reaction, and solid titanium hydride nanoparticles are formed after condensation, and its microscopic appearance and particle size distribution are shown in Figure 2; polyvinyl alcohol, Polyethylene glycol, deionized water and titanium hydride nanoparticles are prepared into a suspension liquid slurry, and the centrifugal atomization drying method is used for agglomeration and granulation to obtain spherical titanium hydride particles of 50 μm; argon-protected tube furnace is used for granulation The final titanium hydride powder is subjected to heat treatment. The heat treatment temperature of the first stage is 280°C and the holding time is 90min; the heat treatment temperature of the second stage is 750°C and the holding time is 120min; the heat treatment temperature of the third stage is 950°C and the holding time is 60min After cooling down to room temperature with the furnace, a micron-sized spherical titanium powder with high density, high fluidity and low oxygen content is obtained. The micromorphology and particle size distribution of the prepared titanium powder are shown in Figure 4, and the measurement results of sphericity, bulk density, fluidity and oxygen content are shown in Table 1.

Table 1 The physical parameters of the titanium powder prepared by Example 1 and Example 2 of the present invention

Claims (1)

1. being applicable to the preparation method that 3D prints the fine grained sized spherical titanium powder of demand, it is special Levy and be, comprise the following steps:

(1) using high purity titanium bulk as anode, under noble gas argon or helium environment, Forming high intensity electric arc by discharge process, striking current is 100～250A, and arc voltage is 10～30V, then pass to hydrogen, hydrogen is 1:(1～3 with the volume ratio of noble gas), Titantium hydride (TiH is generated by gas phase reaction₂), form solid-state titantium hydride nano-particle after condensation；

(2) hydrogenation prepared by polyvinyl alcohol, Polyethylene Glycol and deionized water and step (1) Titanium nano-particle is configured to suspension slip, carries out agglomeration granulation, it is thus achieved that the ball of 20～50 μm Shape titanium hydride particles；

(3) spherical hydrogenation after the pelletize that step (2) is prepared by the tube furnace of employing argon shield Titanium granule carries out heat treatment, and first stage heat treatment temperature is 230～280 DEG C, and temperature retention time is 60～120min；Second stage heat treatment temperature is 700～750 DEG C, and temperature retention time is 120～180min；Phase III heat treatment temperature is 900～950 DEG C, and temperature retention time is 60～90min, finally cool to room temperature with the furnace, obtain having high compactness, high fluidity, low The fine grained micron-size spherical titanium powder of oxygen content；

Utilize the regulation and control of step (1) striking current, voltage and hydrogen and inert gas ratio, adjust The productivity of whole nanometer titanium hydride powders granule and particle size, make mean diameter at 30～80nm models In enclosing.