A kind of short process making method of micro-sized spherical titanium powder
Technical field
The invention belongs to the powder preparation technical field, a kind of short process making method of micro-sized spherical titanium powder particularly is provided.
Technical background
Titanium or titanium alloy has premium properties such as density is low, specific strength is high, corrosion resistance is good, hear resistance is high, no magnetic, good welding performance, can be widely used in fields such as Aero-Space, automobile, bioengineering, wrist-watch, sports goods, environmental protection.But at present aspect complex-shaped, the even structure of preparation, high performance titanium or titanium alloy near-net-shape product, use maximum powder injection formings and gel injection mold and be molded over having relatively high expectations to powder on the technology, it requires the titanium valve granularity tiny, even, regular shape, good fluidity, and oxygen content is low, and common titanium valve is difficult to satisfy its requirement.Though the titanium valve shape for aerosolization method preparation be spherical, good fluidity, oxygen content are low, and size distribution is inhomogeneous, and the production cost height, so a kind of method for preparing micro-sized spherical titanium powder is provided is very important.
Prepare the method for tiny spherical metal titanium powder at present, productivity ratio is lower, and cost is higher.The radio frequency plasma method be prepare that component is even, defective is few, the titanium valve or the titanium alloy powder of good fluidity, good sphericity, have both lower production cost again, higher productivity ratio is that a kind of skill is preferably stated approach.Plasma has the big characteristic of high temperature, Gao Han, high activity and thermograde, does thermal source aspect the spheroidising of micron sub-micron and some nano-powder material with plasma, has bigger technical advantage.The radio frequency plasma technology and equipment makes it to be applied even more extensively in the dusty material technical field than microwave and DC arc plasma heat source owing to it does not introduce any impurity, operation is continual and steady, material processed speed is fast, production capacity is high and equipment manufacturing cost is moderate.Has higher using value in preparation of high performance structures material or functional material and manufacture field.The principle that metal dust is handled in the nodularization of radio frequency (RF) plasma is: with carrier gas metal dust is sent in the high-temperature plasma under protective atmosphere; powder particle heat absorption rapidly makes its surface (or whole) fusion; and under surface tension effects the polycondensation glomeration; powder enters cooling chamber after by the plasma high-temperature region; owing to shock chilling function sphere is fixed up, thereby obtains spherical powder.The plasma melting spheronization techniques is considered to obtain the effective means of densification, regular spherical particle.Powder sphericity height, good fluidity, epigranular, the impurity content of the preparation of radio frequency (RF) plasma melting and spheroidizing technology are low.
With the titantium hydride is raw material, and the principle of using above-mentioned radio frequency (RF) plasma nodularization processing metal dust prepares the method for micro-sized spherical titanium powder, yet there are no report.
Summary of the invention
The objective of the invention is to solve the problems such as oxidation in fine titanium valve nodularization and the nodularization process, the preparation method of the micro-sized spherical titanium powder that technologies such as a kind of injection moulding that is used for powder metallurgy, gel casting technology use is provided, this method energy savings, reduces and pollute, enhance productivity, reduce production costs.
Purpose of the present invention realizes in the following manner, and a kind of short process making method of micro-sized spherical titanium powder is with titantium hydride (TiH
2) powder is raw material, directly handles dehydrogenation, fragmentation, melting and spheroidizing by the nodularization of radio frequency (RF) plasma and prepares sized spherical titanium powder, realizes the short flow preparation of sized spherical titanium powder.
A kind of short process making method of micro-sized spherical titanium powder may further comprise the steps:
(1) chooses titantium hydride (TiH
2) powder is raw material, is that protection gas is full of the entire reaction device with the argon gas, avoids the oxidation in the spheroidizing of powder process.
(2) set up the radio frequency plasma of stable operation, its main technologic parameters is: power 30~80KW, argon gas working air current amount 20~35slpm, argon shield throughput 150~300slpm, the negative pressure 200~280mm of system mercury column.
(3) with argon gas for carrying gas with titantium hydride (TiH
2) powder sends into the plasma high-temperature region, it carries throughput 4~7slpm, and powder feeding rate is 25~80g/min.
(4) titantium hydride (TiH
2) powder absorbs heat in the high temperature radio frequency plasma and decomposes rapidly dehydrogenation, simultaneously in certain embodiments owing to absorb heat rapidly and discharge a large amount of hydrogen and make the particle cracking, brokenly generate fine titanium valve, titanium valve heat absorption melting and spheroidizing and quenching are solidified into spherical powder; Cyclonic separation is collected micro-sized spherical titanium powder.
The particle mean size of described hydride powder powder stock is 50~250 μ m, and the granularity of the micro-sized spherical titanium powder of preparing is 10~50 μ m.
Described titanium hydride powders injects from the radio frequency plasma central upper, makes the titanium hydride powders heating fully, prevents electrode fouling.
The invention has the advantages that:
(1) adopting titanium hydride powders is raw material, has reduced the dehydrogenation operation of hydrogenation-dehydrogenation technological process, and shortened process is enhanced productivity, and energy savings reduces production costs.
(2) adopting than the coarsegrain titanium hydride powders is raw material, solves the powder reunion that exists in the attritive powder course of conveying and carries problems such as discontinuous.
(3) adopting radio frequency plasma is thermal source, and argon gas is a plasma work gas, reduces the problem of oxidation of titanium valve in the nodularization process, and powder can inject from the plasma central upper simultaneously, and volume is big, heats fully electrodeless pollution.
(4) Zhi Bei micro-sized spherical titanium powder granularity is tiny, even, and good fluidity, sphericity height, oxygen content are low.
Description of drawings
Fig. 1 is the schematic diagram of the short flow preparation micro-sized spherical titanium powder of the present invention;
Fig. 2 is the titantium hydride (TiH that the present invention uses
2) former powder sem photograph;
Fig. 3 is the sem photograph of the micro-sized spherical titanium powder for preparing of the present invention.
The specific embodiment
A kind of short process making method of micro-sized spherical titanium powder, this method is carried out according to the following steps:
At first choose titantium hydride (TiH
2) powder is raw material, is that protection gas is full of the entire reaction device with the argon gas, avoids the oxidation in the spheroidizing of powder process.
The employing titanium hydride powders is a raw material, has reduced the dehydrogenation operation of hydrogenation-dehydrogenation technological process, shortened process, and energy savings reduces production costs.Titantium hydride (TiH
2) belonging to a kind of metal mold hydride, itself can be used as hydrogen storage material, utilizes its fragility and the dehydrogenation behavior under vacuum high-temperature, can prepare the high-purity fine titanium valve with it.
TiH
2620~720 ℃ following decomposition reaction takes place under the condition that anaerobic, nitrogen exist:
TiH
2=Ti+H
2↑
Import needed argon gas working air current amount 20~35slpm to radio frequency plasma, keep the power of 30~80KW, input argon shield throughput 150~300slpm, the negative pressure 200~280mm of system mercury column is set up the radio frequency plasma of stable operation.
With argon gas for carrying gas with titantium hydride (TiH
2) powder sends into the plasma high-temperature region, it carries throughput 4~7slpm, and powder feeding rate is 25~80g/min.Titanium hydride powders also can inject from the radio frequency plasma central upper, makes the titanium hydride powders heating fully, prevents electrode fouling.Employing is a raw material than the coarsegrain titanium hydride powders, solves the powder reunion that exists in the attritive powder course of conveying and carries problems such as discontinuous.
Under protective atmosphere, with carrier gas with titantium hydride (TiH
2) powder sends in the high-temperature plasma, utilizes hydrogenation-dehydrogenation (HDH) technology to combine titantium hydride (TiH with the radio frequency plasma melting and spheroidizing technology
2) powder absorbs heat in high-temperature plasma and decompose rapidly dehydrogenation, in certain embodiments, make particle cracking, the fine titanium valve of broken generation simultaneously owing to absorbing heat rapidly and discharging a large amount of hydrogen, titanium valve heat absorption melting and spheroidizing and under surface tension effects the polycondensation glomeration, powder enters cooling chamber after by the plasma high-temperature region, owing to shock chilling function sphere is fixed up, thereby obtains spherical powder.Fig. 1 is the schematic diagram of the short flow preparation micro-sized spherical titanium powder of the present invention, as shown in the figure: the bulky grain titanium hydride powders is transported in the radio frequency plasma, decompose dehydrogenation owing to absorbing heat rapidly, the powder cracking, be broken for fine titanium valve, titanium valve is forming sized spherical titanium powder through heat absorption fusion behind the radio frequency plasma.
Fig. 2 provides the sem photograph of the former powder of titantium hydride, as shown in the figure, the former powder out-of-shape of titantium hydride, powder particle has polygon corner angle, and most of particle is about 100~250 μ m.Fig. 3 provides the sem photograph of the micro-sized spherical titanium powder of the present invention's preparation, as shown in the figure, the sized spherical titanium powder nodularization rate height of preparation, good sphericity, and epigranular is tiny, and most of powder size is about 10~25 μ m.
Preparation method of the present invention directly finishes the dehydrogenation of hydride powder and one step of spheroidising process by plasma treatment, realizes short flow preparation micro-sized spherical titanium powder.
Example 1
The preparation average grain diameter is the micro-sized spherical titanium powder of 15 μ m.
With particle mean size is the titantium hydride (TiH of 100 μ m
2) powder is raw material, the radio frequency of stable operation (RF) plasma power is 50KW, and argon gas working air current amount is 30slpm, and the flow of argon shield gas is 150slpm, and system's negative pressure is the 200mm mercury column.The argon gas that with the flow is 4slpm is sent into titanium hydride powders in the high-temperature plasma, and carrying powder speed is 40g/min, and spheroidising is after cyclonic separation can receive that average grain diameter is the micro-sized spherical titanium powder of 15 μ m.
Example 2
The preparation average grain diameter is the micro-sized spherical titanium powder of 20 μ m.
With particle mean size is the titantium hydride (TiH of 150 μ m
2) powder is raw material, the radio frequency of stable operation (RF) plasma power is 60KW, and argon gas working air current amount is 40slpm, and the flow of argon shield gas is 200slpm, and system's negative pressure is the 230mm mercury column.The argon gas that with the flow is 4.5slpm is sent into titanium hydride powders in the high-temperature plasma, and carrying powder speed is 50g/min, and spheroidising is after cyclonic separation can receive that average grain diameter is the micro-sized spherical titanium powder of 20 μ m.
Embodiment 3
The preparation average grain diameter is the micro-sized spherical titanium powder of 10 μ m.
With particle mean size is the titantium hydride (TiH of 50 μ m
2) powder is raw material, the radio frequency of stable operation (RF) plasma power is 45KW, and argon gas working air current amount is 30slpm, and the flow of argon shield gas is 200slpm, and system's negative pressure is the 200mm mercury column.The argon gas that with the flow is 4slpm is sent into titanium hydride powders in the high-temperature plasma, and carrying powder speed is 30g/min, and spheroidising is after cyclonic separation can receive that average grain diameter is the micro-sized spherical titanium powder of 10 μ m.
Embodiment 4
The preparation average grain diameter is the micro-sized spherical titanium powder of 40 μ m.
With particle mean size is the titantium hydride (TiH of 250 μ m
2) powder is raw material, the radio frequency of stable operation (RF) plasma power is 65KW, and argon gas working air current amount is 40slpm, and the flow of argon shield gas is 280slpm, and system's negative pressure is the 260mm mercury column.The argon gas that with the flow is 6slpm is sent into titanium hydride powders in the high-temperature plasma, and carrying powder speed is 60g/min, and spheroidising is after cyclonic separation can receive that average grain diameter is the micro-sized spherical titanium powder of 40 μ m.