KR20170073390A

KR20170073390A - Manufacturing method of tantalum coating layers, sputtering targer material and niobium coating layers

Info

Publication number: KR20170073390A
Application number: KR1020150182266A
Authority: KR
Inventors: 이기안; 김형준; 지대훈
Original assignee: 안동대학교 산학협력단
Priority date: 2015-12-18
Filing date: 2015-12-18
Publication date: 2017-06-28

Abstract

A method for forming a tantalum coating layer, a method for forming a sputtering target using tantalum, and a method for forming a niobium coating layer are disclosed. The method for forming a tantalum coating layer according to the present invention includes: preparing a tantalum powder for preparing a tantalum powder; And a first tantalum laminating step of laminating the powder prepared in the tantalum powder preparing step to an aluminum (Al) base material at a speed of 300 to 1300 kPa using a Kinetic Spray Process, In the first tantalum laminating step, the feed gas of the powder is helium (He), the temperature of the feed gas is 550 to 650 ° C, the pressure is 2 to 4 MPa, the temperature of the powder is 450 to 650 ° C and the feed rate ) Is 2.5 to 3.5 kg / h, the nozzle moving speed is 90 to 110 mm / sec, and the jetting distance is 25 to 35 mm. According to the present invention, it is possible to provide a method for forming a tantalum coating layer which can form a tantalum coating layer having low porosity and excellent density and hardness, and can form a tantalum coating layer having excellent purity by heat treatment.

Description

TECHNICAL FIELD [0001] The present invention relates to a method of forming a tantalum coating layer, a method of forming a tantalum sputtering target, and a method of forming a niobium coating layer.

The present invention relates to a tantalum coating layer forming method, a sputtering target reformation method using tantalum and a niobium coating layer forming method, and more particularly, to a tantalum coating layer forming method using a kinetic spray process, a sputtering target using tantalum A reforming method and a method of forming a niobium coating layer.

Tantalum (Ta, tantalum) is a rare-earth metal of Group 5A having a high melting point of 2996 ° C and a high density of 16.6 g / cm 3, and has advantages of high temperature strength, corrosion resistance, low resistance temperature coefficient and high thermal conductivity. Due to the characteristics of tantalum, it is becoming more and more applicable as a component in many fields such as electronic products industry, machinery industry, chemical industry, aerospace industry, and military industry.

However, because of its high melting point and high oxygen affinity, it is difficult to manufacture and process parts using tantalum materials, which requires precise control processes and high costs.

Accordingly, a thermal spray coating process has been attracting attention as a means for overcoming limitations unique to a material in the manufacturing process of a tantalum material. Among them, kinetic spraying, a new molding process, accelerates a powder material having a particle size of 1 ~ 50 ㎛ at a supersonic jet velocity to collide with a base material, thereby forming a dense coating layer in a solid state by plastic deformation of the powder material .

Since this process is performed at a low temperature, it can overcome disadvantages such as phase change and deterioration of properties due to oxidation during production, and is particularly useful for forming a coating layer having high density and high purity.

In addition, the kinetic spray process utilizes the solid state without melting the initial powder, which is a suitable process for a metal material having a high melting point such as tantalum and therefore difficult to be melted.

Accordingly, researches for obtaining a tantalum-coated material having excellent properties by utilizing a kinetic spray process have been actively pursued and progressed.

However, there is still a limit to the production of a high density tantalum coating layer.

On the other hand, sputtering target materials are generally produced as a raw material for a sputtering process by a manufacturing method using a casting and rolling process, a manufacturing method using a powder, a manufacturing method using a sintering, a hot isostatic pressing (HIP) .

Such a sputtering target material is used by a sputtering process to a minimum of 30 to 40% and a maximum of 70%, and then treated with a waste target material.

Accordingly, there is a growing interest in a technique for recycling a waste target material to an expensive sputtering target material.

In recent years, the technology has been developed to recycle and target the waste target using a pure Ru target material, to produce a high-purity Ru powder using a plasma process, and then to produce a Ru sputtering target material. However, in this case, there are many steps such as waste target cleaning, backing plate separation, waste target material melting, powder production, sintering, molding, re-bonding to backing plate, .

Therefore, there is a demand for a method for manufacturing a sputtering target material more easily.

Niobium (Nb, Niobium) is a refractory metal with high melting point of 2468 ℃. It has very good heat resistance, belongs to the lightest metal among the refractory metals, has a high superconducting critical temperature characteristic of 9.46K and has a low transition temperature of minus 120 ℃ And thus can be sufficiently molded at room temperature.

In order to obtain niobium in bulk form, niobium is produced from niobium ores by hydrofluoric acid dissolution, solvent extraction, and thermal reduction. Finally, niobium with a purity of 99.9% is produced through vacuum casting in an electron beam furnace. However, post-treatment is indispensable because many problems such as microstructure non-uniformity, internal bonding, property deterioration, etc. of the manufactured material may occur.

(0001) T. V. Steenkiste and D. W. Gorkiewicz: J. Thermal Spray Techn., 13, 265 (2004). (0002) H. Koivuluoto, J. Nakki and P. Vuoristo, J. Thermal Spray Techn., 18, 75 (2009). (0003) M. Honkanen and P. Vuoristo, Surface & Coatings Technology., 204, 2353 (2010).

The present invention relates to a method for forming a tantalum coating layer by forming a tantalum coating layer using a kinetic spray process and improving density and properties by post-heat treatment of main process conditions (feed gas, powder shape, etc.) .

It is another object of the present invention to provide a method of forming a sputtering target by a tantalum sputtering process through a kinetic spray process and a sputtering target remediation method excellent in porosity, hardness and grain size.

It is another object of the present invention to provide a method for forming a niobium coating layer in which a niobium coating layer is formed using a kinetic spraying process and density and characteristics are improved through post-heat treatment of main process conditions (feed gas, powder shape, etc.) will be.

The object is achieved by a tantalum powder preparation method for preparing a tantalum powder; And a first tantalum laminating step of laminating the powder prepared in the tantalum powder preparing step on an aluminum (Al) base material at a speed of 300 to 1300 kPa using a kinetic spray process, wherein the kinetic spraying process (He), the temperature of the feed gas is 550 to 650 ° C, the pressure is 2 to 4 MPa, and the temperature of the powder is 450 to 650 ° C And the feed rate is 2.5 to 3.5 kg / h, the nozzle moving speed is 90 to 110 mm / sec, and the spraying distance is 25 to 35 mm.

The method of forming a tantalum coating layer according to the present invention may further include a first heat treatment step of performing heat treatment at 800 to 1100 ° C in an argon (Ar) atmosphere (99.9% purity) after the first tantalum laminating step.

Meanwhile, the method of forming a tantalum coating layer according to the present invention may further include a second heat treatment step of performing a heat treatment at 800 to 1100 ° C in a vacuum atmosphere after the first tantalum depositing step.

Further, in the first tantalum laminating step using the kinetic spray process, the temperature of the feed gas is 600 캜, the pressure is 3 MPa, the temperature of the powder is 500 캜, the feed rate is 3 kg / h, The nozzle moving speed is 100 mm / sec, and the jetting distance is 30 mm.

The above object can also be achieved by a tantalum powder preparation method for preparing a tantalum powder; And a second tantalum laminating step of laminating the powder prepared in the tantalum powder preparing step on a copper (Cu) base material at a speed of 300 to 1300 kPa using a Kinetic Spray Process, wherein the kinetic spraying process (N ₂ ), the temperature of the feed gas is 700 to 800 ° C., the pressure is 30 to 35 bar, the temperature of the powder is 650 to 850 ° C. , The nozzle moving speed is 40 to 60 mm / sec, and the jetting distance is 25 to 35 mm.

In the method of forming a sputtering target according to the present invention, after the second tantalum laminating step, the substrate is subjected to a HIP (Hot Isostatic Pressing) process at 1000 to 1200 ° C in an atmosphere of argon (Ar, 99.9% And a second heap processing step of performing a second heap processing.

Meanwhile, the method for forming a sputtering target according to the present invention may further include a third heat treatment step of performing a heat treatment in a vacuum atmosphere at a temperature of 900 to 1100 ° C (preferably 1000 to 1100 ° C) after the second tantalum deposition step .

Also, in the second tantalum laminating step using the kinetic spraying process, the temperature of the feed gas is 750 ° C, the pressure is 30 bar, the temperature of the powder is 650 ° C, the nozzle moving speed is 50 mm / sec, 30 mm.

The above object can also be achieved by a niobium powder preparation method for preparing a niobium powder; And a niobium laminating step of laminating the powder prepared in the niobium powder preparing step to a blast-treated copper (Cu) base material at a speed of 300 to 1300 kPa using a kinetic spray process, Wherein the feed gas of the powder is nitrogen (N ₂ ), the temperature of the feed gas is from 750 to 800 ° C., the pressure is from 30 to 35 bar, the temperature of the powder is from 650 to 800 ° C., 800 ° C, the nozzle moving speed is 15 to 55 mm / sec, and the jetting distance is 25 to 60 mm.

The method for forming a niobium coating layer according to the present invention may further include a fourth heat treatment step of performing heat treatment at 800 to 1100 ° C in an argon (Ar, 99.9% purity) gas atmosphere after the niobium layering step.

Meanwhile, the method of forming a niobium coating layer according to the present invention may further include a fifth heat treatment step of performing a heat treatment at 800 to 1100 ° C in a vacuum atmosphere after the niobium layering step.

The method for forming a niobium coating layer according to the present invention may further include a step of forming a second niobium layer on the surface of the first niobium layer by a hot isostatic pressing (HIP) process at 1000 to 1200 ° C in an argon (Ar, 99.9% And a heap processing step.

According to the present invention, it is possible to provide a method for forming a tantalum coating layer which can form a tantalum coating layer having low porosity and excellent density and hardness, and can form a tantalum coating layer having excellent purity by heat treatment.

According to the present invention, it is possible to form a very thick and pure tantalum layer without peeling from the base material, thereby forming an excellent sputtering target material, and forming a tantalum sputtering target material having high density and excellent hardness.

According to the present invention, a niobium coating layer having low porosity, excellent density and hardness, minimizing crack formation and impurity content can be formed, and a niobium coating layer capable of forming a niobium coating layer with excellent purity by heat treatment Method.

1 is a flowchart showing a method of forming a tantalum coating layer according to an embodiment of the present invention,
FIG. 2 is a flowchart showing a method for forming a sputtering target according to an embodiment of the present invention. FIG.
3 is a flowchart showing a method of forming a niobium coating layer according to an embodiment of the present invention,
FIG. 4 is a schematic view illustrating a kinetic spray device according to the present invention,
FIG. 5 (a) is a photograph showing the shape of the initial tantalum powder in the method of forming a tantalum coating layer according to the present invention, FIG. 5 (b)
6 is a photograph showing a tantalum coating layer which has been subjected to the first tantalum laminating step in the method of forming a tantalum coating layer according to the present invention,
7 is a photograph showing the interface between the inside of the tantalum coating layer and the base material using an optical microscope in the method of forming a tantalum coating layer according to the present invention,
FIG. 8 is a result of XRD analysis to examine the phase change of a pure tantalum coating layer which has undergone the initial tantalum powder and the first tantalum laminating step in the method of forming a tantalum coating layer according to the present invention,
9 is a result of EPMA analysis of a tantalum coating layer produced through a first tantalum laminating step in the method of forming a tantalum coating layer according to the present invention,
10 is a cross-sectional photograph of a tantalum coating layer produced by a kinetic spraying process in the method of forming a tantalum coating layer according to the present invention after etching and performing a first heat treatment step and a second heat treatment step,
11 is a graph showing hardness and porosity measured values of a tantalum-coated material according to respective temperatures in a first heat treatment step and a second heat treatment step in the method of forming a tantalum coating layer according to the present invention,
FIG. 12 is a view showing an XRD phase analysis result after the first heat treatment step or the second heat treatment step, and FIG.
13 is a graph showing the results of EPMA analysis after the first heat treatment step or the second heat treatment step in the method of forming a tantalum coating layer according to the present invention,
FIG. 14 is a photograph of the shape of the initial tantalum powder observed in the method of forming a sputtering target according to the present invention,
15 is a photograph of a tantalum coating layer which has undergone a second tantalum deposition step in the sputtering target reformation method according to the present invention,
16 is a result of observing the interface between the inside of the tantalum coating layer and the base material using an optical microscope in the sputtering target reformation method according to the present invention,
FIG. 17 is a result of XRD analysis to examine the phase change of the tantalum coating layer which has been subjected to the tantalum powder and the second tantalum laminating step in the method of forming a sputtering target according to the present invention,
18 is a result of observing the microstructure in the case where the first heap treatment step and the third heat treatment step are performed in the sputtering target reformation method according to the present invention,
19 is a graph showing the results of analysis of porosity and hardness in the case where the third heat treatment step is performed in the sputtering target reformation method according to the present invention,
FIG. 20 shows the result of observing the microstructure after etching the material when the third heat treatment step is performed in the sputtering target reformation method according to the present invention,
21 is a graph showing hardness values in the case where the first heap processing step and the third heat treatment step are performed in the sputtering target reformation method according to the present invention,
22 is a result of XRD analysis in the case where the first heap processing step and the third heat processing step are performed in the sputtering target reformation method according to the present invention,
23 is a result of grain size measurement through EBSD (Electron Back Scattered Diffraction)
24 is a result of grain size measurement through EBSD,
25 is a photograph showing the shape of the initial niobium powder in the method of forming a niobium coating layer according to the present invention,
FIG. 26 is a cross-sectional photograph of a niobium coating layer having been subjected to the niobium lamination step in the method of forming a niobium coating layer according to the present invention,
FIG. 27 is a graph showing the XRD analysis results and the EPMA mapping analysis results for examining the phase change of the niobium coating layer after the niobium lamination step in the niobium coating layer forming method according to the present invention,
28 is a schematic view showing an optical microscope (OM) in a state where the fourth heat treatment step (FIG. 28 (a)) and the fifth heat treatment step (FIG. 28 (b)) are carried out after the niobium lamination step in the niobium coating layer forming method according to the present invention, The results are shown in Fig.
29 is a schematic view showing a scanning electron microscope (SEM) in a state where the fourth heat treatment step (FIG. 29 (a)) and the fifth heat treatment step (FIG. 29 (b) The results are shown in Fig.
FIG. 30 is a graph showing porosity and hardness of the niobium-coated layer according to the present invention in a state where the fourth heat treatment step and the fifth heat treatment step are carried out after the niobium layering step, respectively,
31 is a graph showing the XRD analysis results in the niobium coating layer forming method according to the present invention,
32 is a graph showing the results of EPMA analysis in which the fourth and fifth heat treatment steps are performed after the niobium lamination step in the niobium coating layer forming method according to the present invention,
FIG. 33 is a photograph showing a cross section of a base material on which a niobium coating layer having a niobium lamination step is formed in the method of forming a niobium coating layer according to the present invention,
Fig. 34 is a graph showing the results of measurement of a specimen using an optical microscope (OM) in a state after the niobium lamination step (Fig. 34 (a)) and the second heap processing step (Fig. 34 Observation results,
FIG. 35 is a graph showing the XRD analysis results of the niobium layer-forming step and the second heap processing step in the niobium coating layer forming method according to the present invention,
36 shows the results of EPMA analysis in the niobium layer forming step (FIG. 36 (a)) and the second heap processing step (FIG. 36 (b)) in the niobium coating layer forming method according to the present invention,
37 is a sectional view of a niobium coating layer forming method according to the present invention using SEM in a state after the niobium lamination step (Fig. 37 (a)) and the second heap processing step (Fig. 37 (b)
38 is a result of grain size measurement through EBSD in the niobium coating layer forming method according to the present invention (FIG. 38 (a)) and the second heap processing step (FIG. 38 (b)
FIG. 39 shows the results of measurement of porosity and strength of a specimen after the niobium lamination step, the fourth heat treatment step and the second heap processing step in the niobium coating layer forming method according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, the well-known functions or constructions are not described in order to simplify the gist of the present invention.

The method for forming a tantalum coating layer according to the present invention includes a tantalum powder preparing step (S110) and a first tantalum laminating step (S120). The method of forming a tantalum coating layer may further include a first heat treatment step (S131) or a second heat treatment step (S132).

In the tantalum powder preparation step (S110), tantalum powder is prepared. In the present invention, pure tantalum powder produced by atomization may be used. 5 (a) is a photograph of the shape of the initial tantalum powder, and the powder has irregular spherical shape. 5 (b) shows the particle size distribution of the initial tantalum powder used. Here, the particle size of the powder is 6 to 47 μm and the average particle size is 24 μm.

In the first tantalum laminating step (S120), a pure tantalum coating layer can be prepared using a known kinetic spray process. Specifically, for the kinetic spraying process, a device of the type shown in FIG. 4 (a kinetic spray device ) Can be used.

The kinetic spray apparatus used in the kinetic spray process includes a gas supply line 10, a powder supply unit 20, a gas heating unit 30 and a nozzle 40. The kinetic gas and the powder sprayed from the nozzle 40 And is stacked on the surface of the base material 50.

Each feed gas is supplied through the gas supply line 10. In the present invention, helium (He), nitrogen (N ₂ ) and / or air can be used as the feed gas. The gas supply line 10 is connected to the nozzle after the powder supply part 20 and the gas are branched to the heating part 30.

The powder supply part 20 supplies and heats each powder (tantalum powder or niobium powder) and is connected to the gas supply line 10 so that the powder inside the powder supply part 20 is supplied through the gas supply line 10 Into the nozzle together with the feed gas.

The gas heating portion 30 heats the gas supplied through the gas supply line 10 and allows the heated feed gas to flow toward the nozzle.

In the first tantalum laminating step S120 according to the present invention, a kinetic spraying process is used. At this time, the tantalum powder feed is helium (He) and the temperature of the feed gas (the temperature of the feed gas heated by the heating part The temperature of the tantalum powder (the temperature of the tantalum powder heated by the powder feed) is 450 to 650 ° C. and the feed rate is 2.5 to 3.5 kg / h, the nozzle moving speed (moving speed in the direction parallel to the surface of the base material) is 90 to 110 mm / sec, and the jetting distance (distance between the nozzle and the base material) is 25 to 35 mm.

More preferably, in the first tantalum laminating step (S120), the temperature of the feed gas is 600 占 폚, the pressure is 3 MPa, the temperature of the powder is 500 占 폚, the feed rate is 3 kg / h, Is 100 mm / sec, and the spraying distance is 30 mm.

Preferred process conditions in the first tantalum laminating step (S120) are shown in Table 1 below.

Tantalum coating Carrier gas He gas Gas temperature (℃) 600 Powder temperature (℃) 500 Powder feed rate (Kg.h) 3 Pressure (Mpa) 3 Gun traveling speed (mm / sec) 100 Spray distance (mm) 30

In the first tantalum laminating step (S120), aluminum (Al) is used as a base material, and pure aluminum is used without blasting.

In the present invention, a test piece (a base material having a tantalum coating layer formed thereon) is cut in a cross-section direction and cold-mounted to observe the microstructure. The surface of the test piece is polished to a level of 1 탆, (OM) and Scanning Electron Microscope (SEM).

For the porosity measurement, the specimens were micro-polished using SiC abrasive paper and diamond paste, then photographed at 200 × magnification and analyzed with Image-pro analysis equipment. The porosity was obtained by averaging the results of 100 measurements.

Phase analysis was performed using an X-ray diffractometer (XRD Ultima IV) to observe the phase change of the powder and the coating layer before and after the first tantalum laminating step (S120). Also, a Vickers hardness tester was used to measure the hardness of the powder and coating layer used. The hardness was measured 12 times using a rolling time of 10 seconds under a load of 100 g. In the present invention, an average value excluding the maximum value and the minimum value was used.

The microstructure observation, the porosity measurement method, the phase change observation and the hardness measurement method described above are equally applied to a specimen manufactured according to a sputtering target reformation method and a niobium coating layer formation method to be described later.

The first heat treatment step (S131) is performed after the first tantalum deposition step (S120) and is performed by heat treatment at 800 to 1100 占 폚 in an argon (Ar, 99.9% purity) gas atmosphere.

The second heat treatment step (S132) is also performed after the first tantalum laminating step (S120), and is performed by heat treatment at 800 to 1100 ° C in a vacuum atmosphere.

In the experiment for the present invention, the specimen was observed while the temperature of the heat treatment in the first heat treatment step (S131) and the second heat treatment step (S132) was raised to 800, 900 and 1000 ° C., / min, furnace cooling after the isothermal heat treatment at the target temperature for 1 hour.

Further, the first tantalum passed through the laminating step (S120) the specimen, the first heat treatment step (S131) to the specimen and the rough 10㎖ HNO to a second heat treatment step (S132) of a specimen subjected to microstructure observation 10㎖ ₃ + HF + 20 ㎖ Glycerin solution, and observed using optical microscope and SEM.

Phase analysis using XRD was performed to investigate the phases generated further after the first heat treatment step (S131) and the second heat treatment step (S132). Also, EPMA (Electron Probe Micro Analyzer) was used for the distribution and relative quantitative analysis of the material after the first tantalum coating layer, the first heat treatment step (S131) and the second heat treatment step (S132).

6 is a photograph showing an initial tantalum powder and a tantalum coating layer which has been subjected to the first tantalum laminating step (S120) under the process conditions shown in Table 1. Specifically, FIG. 6 (a) is a photograph of the surface of the macro layer of the coating layer, and FIG. 6 (b) is a photograph of the cross section of the uncoated coating layer.

As shown in FIG. 6, in the case of the manufactured tantalum coating layer, no peeling occurred between the coating layer and the base material, and the thickness was 1.73 mm. Accordingly, according to the process conditions according to the present invention, It is possible to manufacture a relatively thick tantalum coating layer.

7 shows the results of observing the interface between the inside of the tantalum coating layer and the base material by using an optical microscope. First, the tantalum coating layer prepared from the results of the unetched test pieces (FIGS. 7 (a) and 7 (b) It can be seen that it has a very dense structure. Also in the interface region with the base material (Fig. 7 (b)), it was possible to confirm a structure in which the base material and the coating layer are well layered, in which pores are hardly observed.

As a result of the observation of the etched samples (Fig. 7 (c) and (d)), it was observed that the tantalum particles deposited in the coating layer tended to elongate in a direction perpendicular to the lamination direction, unlike the spherical shape of the initial powder. This is due to the plastic deformation that occurs when the metal powder is deposited at high speed and it can be seen that the particles deposited near the interface are more deformed and elongated than the particles deposited inside the coating layer, It is because another powder is layered and particles near the interface are further deformed by the peening effect.

On the other hand, it can be observed that some spherical tantalum particles are embedded intact in the base material near the interface.

In the method of forming a tantalum coating layer of the present invention, the porosity of the tantalum coating layer produced through the first tantalum laminating step (S120) was measured to be 0.04%. This porosity value is remarkably low as compared with the values (3% or more) presented in the tantalum coating layer (tantalum coating layer prepared by the conventional kinetic spraying process) reported so far, and the porosity value is low by the tantalum coating layer forming method The tantalum coating layer shows a very good density.

Also, the hardness of the tantalum coating layer prepared after the first tantalum laminating step (S120) was measured to be 550 Hv, which is 2.4 times higher than the hardness value (228 Hv) of the initial tantalum powder. The increase in hardness of the coating layer compared to the initial tantalum powder is due to the work hardening caused by the plastic deformation caused when the tantalum powder particles are deposited at high speed in the kinetic spraying process in the first tantalum laminating step (S120).

Fig. 8 shows the results of XRD analysis to examine the phase change of the pure tantalum coating layer after the initial tantalum powder and the first tantalum laminating step (S120). The initial tantalum powder was composed of a single-phase α-tantalum phase, and the α-tantalum peaks identical to those of the powder were also observed in the coating layer.

9 is an EPMA analysis result (Ta, O element) of the tantalum coating layer produced through the first tantalum laminating step (S120). As can be seen from FIG. 9, the XRD analysis (FIG. 8) shows that the phase containing oxygen, which was not detected, is finely distributed between the particles of the coating layer and the particles. This is because in the kinetic spray process, the powder particles are accelerated by the feed gas and local oxidation occurs at the particle surface during transport to the base material.

FIG. 10 is a cross-sectional photograph of the tantalum coating layer prepared by the kinetic spraying process after the first heat treatment step (S131) and the second heat treatment step (S132) are performed and then etched. Regardless of the annealing atmosphere, as the annealing temperature increases, the boundary regions between the particles and the particles, which seemed to be clearly visible in the coating layer, gradually become blurred. Also, defects that were observed unevenly at the grain boundary gradually disappear with increasing heat treatment temperature, and the coating layer structure becomes more dense. The tendency of the grain boundary to disappear and disappear was more easily confirmed in the second heat treatment step (S132) (vacuum atmosphere) than in the first heat treatment step (S131) (argon atmosphere).

The hardness and porosity measurement values of the tantalum-coated material according to the respective temperatures in the first heat treatment step (S131) and the second heat treatment step (S132) are shown in FIG.

In the first heat treatment step (S131) (argon atmosphere), the porosity decreased from 0.04% to 0.025% as the heat treatment temperature increased. In the case of the heat treatment step (vacuum atmosphere), as the heat treatment temperature was increased, the porosity was also decreased from 0.04% to 0.025%.

On the other hand, in the case of the first heat treatment step (S131) (argon atmosphere), the hardness value of the tantalum coating layer exhibiting a value of 550 Hv before the first heat treatment step (S131) or the second heat treatment step (S132) And 530 Hv, 511 Hv, and 495 Hv, respectively, after heat treatment at 1000 ℃. In the second heat treatment step (S132) (vacuum atmosphere), the hardness decreased to 540 Hv, 532 Hv, and 530 Hv under the same heat treatment conditions. That is, regardless of the annealing atmosphere, the hardness value was continuously decreased as the annealing temperature was increased, and the decrease was larger in the first annealing step (S131) (argon atmosphere).

FIG. 12 shows the XRD phase analysis results after the first heat treatment step (S131) or the second heat treatment step (S132). Regardless of the heat treatment atmosphere of vacuum or argon gas, the initial powder and coating layer had the same α-Tantalum phase at all heat treatment temperatures.

FIG. 13 shows the results of the EPMA analysis conducted to confirm the presence of fine oxide between particles that can be generated in the coating layer after the first heat treatment step (S131) or the second heat treatment step (S132).

Comparing FIG. 13 with the EPMA results of the initial coating layer (FIG. 9), it can be seen that the distribution of oxygen gathered at the grain interface is still finer regardless of the annealing atmosphere (argon gas, vacuum) It can be confirmed that it is maintained.

However, in the first heat treatment step (S131) (argon gas atmosphere), the oxygen distribution between the powder particles and the particles increased remarkably in the heat treatment at 1000 ° C. In contrast, in the case of the second heat treatment step (S132) (vacuum atmosphere), it is noteworthy that a minute oxygen distribution is maintained even when the heat treatment temperature is increased to 1000 deg. In addition, several tens of EPMA points were quantitatively analyzed under the same conditions under the same conditions (1000 ℃ heat treatment conditions), and the average values were obtained to compare the oxygen content of the atmosphere heat treatment coating layer. As a result, the oxygen content of the coating layer was 0.47 wt.% And the coating layer after the second heat treatment step (S132) (vacuum atmosphere) was 0.58 wt.% (As a result of as-sprayed (before the first heat treatment step (S131) or the second heat treatment step .%, And the coating layer after the first heat treatment step (S131) (argon atmosphere) was measured to be 0.68 wt.%.

As a result, in both the first heat treatment step (S131) and the second heat treatment step (S132), the oxygen content is slightly increased as the heat treatment temperature is increased, but the heat treatment in the second heat treatment step (S132) S131) (argon gas atmosphere) than that of the heat treatment of the sintering atmosphere (S131) (argon gas atmosphere).

The sputtering target reformation method according to the present invention includes a tantalum powder preparation step (S210) and a second tantalum deposition step (S220). Also, the sputtering target reformation method may further include a first heap processing step (S231) or a third heat treatment step (S232).

In preparing the tantalum powder (S210), a tantalum powder having a purity of 99.95% may be used. Fig. 14 is a photograph of the shape of the initial tantalum powder. The powder had a particle size of 9 to 37 mu m and an average particle size of 19 mu m.

In the second tantalum deposition step (S220), a tantalum coating layer is prepared using a kinetic spray process, and the apparatus used for the kinetic spray process is the same as the apparatus (kinetic spray apparatus) shown in Fig. 1 Lt; / RTI >

As such, the second tantalum laminating step (S220) in accordance with the present invention the kinetic spray process is used, at this time, the feeding gas of the tantalum powder is nitrogen (N _2), and feeding the gas temperature (gas fed gas is heated by yeolbu (Temperature of the tantalum powder heated by the powder feed portion) is 650 to 850 ° C, the nozzle moving speed is 40 to 60 mm / sec, and the temperature of the tantalum powder (Distance between the nozzle and the base material) may be 25 to 35 mm.

More preferably, in the second tantalum laminating step S220, the temperature of the feed gas is 750 DEG C, the pressure is 30 bar, the temperature of the powder is 650 DEG C, the moving speed of the nozzle is 50 mm / sec and the jetting distance is 30 mm Lt; / RTI >

Preferred process conditions in the second tantalum laminating step (S220) are shown in Table 2 below.

Thick Ta materials Carrier gas N ₂ gas Main temperature (℃) 750 Powder heater temperature (℃) 850 Powder line temperature (℃) 650 Pressure (bar) 30 Gun traveling speed (mm / sec) 50 step / number of cycles / cycle 1/20/13 Spray distance (mm) 30

And copper (Cu) was used as the base material in the second tantalum laminating step (S220).

The first heap processing step S231 is performed after the second tantalum deposition step S220 and is performed by performing a HIP (Hot Isostatic Pressing) process at 1000 to 1200 ° C in an argon (Ar, 99.9% purity) gas atmosphere.

The third heat treatment step S232 is performed after the second tantalum lamination step S220 and is performed by heat treatment at 1000 to 1100 ° C in a vacuum atmosphere.

FIG. 15 is a photograph showing a tantalum coating layer having undergone the second tantalum laminating step (S220) under the process conditions shown in Table 2. FIG.

In the case of the prepared tantalum coating layer, no peeling occurred between the coating layer and the base material, and the thickness was about 7 mm. Accordingly, according to the process conditions according to the present invention, the second tantalum deposition step (S220) It can be confirmed that the coating layer can be produced, and that it can be used as a sputtering target material.

FIG. 16 shows the result of observing the interface between the inside of the tantalum coating layer and the base material by using an optical microscope. As a result of the interface observation with the base material, it can be confirmed that no peeling is observed and the fine tantalum is bonded.

From the results of the pre-etching sample (Fig. 16 (b)), a very dense microstructure with almost no pores can be seen, and the porosity was measured to be 0.12%.

16 (c)). It can be seen that the powder was plastic-deformed in the vertical direction of spraying, and the powder was subjected to plastic deformation, and the hardness increased from 130 Hv to 351 Hv in the hardness of the coating layer.

The results of XRD analysis of the tantalum coating layer through the tantalum powder and the second tantalum lamination step (S220) are shown in FIG. As a result of XRD analysis, it was confirmed that an α-Ta phase like the initial powder was detected, which is a result of showing no phase change or oxide formation by manufacturing the material at room temperature according to the kinetic spray process.

18 is a result of observing the microstructure when the first heap processing step (S231) and the third heat treatment step (S232) are performed in the sputtering target reformation method according to the present invention. Particularly, In step S231, the substrate was processed at 1145 DEG C for 4 hours. In the third heat treatment step (S232), the substrate was processed at 1100 DEG C for 1 hour.

As shown in Fig. 18, in the case where the third heat treatment step S232 (FIG. 18 (a)) and the first heap treatment step S231 (FIG. 18 (b) As a result of observing the microstructure after etching (right image of each of them), the case where the first heap processing step (S231) is performed is more dense than the case where the third heat treatment step (S232) &Lt; / RTI >

19 is a graph showing the results of analyzing the porosity and hardness of the sputtering target according to the present invention after the third heat treatment step (S232).

As a result of measurement of porosity, the porosity decreased from 0.11 to 0.12 to 0.067 to 0.068, and the hardness also decreased from 327.7 to 311.4 to 289.9 to 291.2. The difference in porosity and hardness was found to decrease with heat treatment, and the decrease in porosity and hardness was attributed to recovery, recrystallization, and grain growth.

FIG. 20 is a result of observing the microstructure after etching of the material when the third thermal processing step (S232) is performed in the sputtering target reformation method according to the present invention.

As a result of the microstructure observation after the third heat treatment step (S232), it can be seen that the intergranular interface is blurred than the initial material, and this tendency can be seen more clearly at 1100 ° C than in the case of the heat treatment temperature of 900 ° C , It can be seen that the porosity decreases as the particles are dense as the interface diffuses.

FIG. 21 is a graph showing hardness values in the case where the first heap processing step (S231) and the third heat treatment step (S232) are performed in the sputtering target reformation method according to the present invention.

In the third heat treatment step S232, the hardness is slightly decreased, and when the first heap processing step S231 is performed, the hardness is increased. If the hardness is increased through the first heap processing step S231, It can be understood that heat and pressure work together to change the texture of the specimen.

22 shows XRD analysis results in the case where the first heap processing step (S231) and the third heat treatment step (S232) are performed in the sputtering target reformation method according to the present invention.

When the third heat treatment step (S232) was performed, the same α-Ta phase as the initial powder was detected, and no new phase formation other than the α-Ta phase was observed even after the first heap treatment step (S231).

23 shows the result of grain size measurement through EBSD (Electron Back Scattered Diffraction), in which (a) shows the result after the second tantalum laminating step (before heap treatment or heat treatment) in the sputtering target reformation method according to the present invention (b) is a result of the third heat treatment step (S232) at 900 ° C for one hour, and (c) is a result of the third heat treatment step (S232) at 1,100 ° C for one hour.

The grain size of the initial tantalum was measured by EBSD as 0.32 ~ 0.37 ㎛ and the interface part was subjected to more severe plastic deformation due to the peening effect.

As a result of measuring the grain size of tantalum material through EBSD in the third heat treatment step (S232) at 900 ° C for 1 hour, it was confirmed to be 2.1 ~ 4.6 ㎛ and partial recrystallization and grain growth were observed.

When the third heat treatment step (S232) was performed at 1100 ° C for 1 hour, the grain size of the tantalum material was measured through the EBSD and found to be 4.5 to 4.6 탆. Recrystallization and grain growth were observed as a whole, It can be seen that the grain sizes of the center and the surface are uniformly set to about 4.5 탆.

FIG. 24 shows the result of grain size measurement through EBSD. FIG. 24 (a) shows the result of the third heat treatment step (S232) at 1100.degree. C. for 1 hour in the sputtering target reformation method according to the present invention, And the first heap processing step (S231) at 1145 占 폚 for 4 hours.

The crystal grain size is about 4.5 mu m when the third heat treatment step S232 is performed, and the crystal grain size is about 4.2 mu m when the first heap processing step S231 is performed. In the first heap processing step S231, HIP It can be understood that the crystal grain size is relatively small.

As described above, according to the sputtering target reformation method of the present invention, it can be seen that a material having a very high density can be formed with a porosity of 0.11 to 0.12% and a hardness of 341.4 to 327.8 Hv, It can be seen that the porosity of the sputtering target material (S231) and the third heat treatment step (S232) is significantly reduced and the grain size is uniformly uniform throughout. The purity of the initial powder is substantially maintained, Can be produced.

The method for forming a niobium coating layer according to the present invention includes a niobium powder preparing step (S310) and a niobium laminating step (S320). In addition, the niobium coating layer forming method may further include a fourth heat treatment step (S331), a fifth heat treatment step (S332), or a second heap treatment step (S333).

In the preparation of the niobium powder (S310), niobium powder is prepared and massive niobium powder having a purity of 129.7% can be used. Fig. 25 is a photograph of the shape of the initial niobium powder. The powder had a particle size of 8 to 60 mu m and an average particle size of 23.8 mu m.

In the niobium lamination step (S320), a niobium coating layer is prepared using a kinetic spray process, and the apparatus used in the kinetic spraying process may be the same as the apparatus (kinetic spray apparatus) shown in FIG. 1 have.

Thus, the niobium laminating step (S320) in accordance with the present invention the kinetic spray process is used, at this time, the feeding gas of the niobium powder is nitrogen (N _2), and the feeding temperature (temperature of the gas to the fed gas heated by the yeolbu of gas The temperature of the niobium powder (the temperature of the niobium powder heated by the powder feed part) is 650 to 800 ° C., the moving speed of the nozzle is 15 to 55 mm / sec, The distance (distance between the nozzle and the base material) can be 25 to 35 mm.

When the fourth heat treatment step (S331) or the fifth heat treatment step (S332) is carried out subsequently in the niobium coating layer forming method according to the present invention, the temperature of the feed gas is 790 DEG C and the pressure is 30 bar, The temperature of the powder is 675 DEG C, the nozzle moving speed is 20 mm / sec, and the jetting distance is 60 mm.

Preferred process conditions in this niobium lamination step (S320) are shown in Table 3 below.

Nb coating Carrier gas N ₂ gas Main temperature (℃) 790 Powder line temperature (℃) 675 Powder feed rate (rpm) 6 Pressure (bar) 30 Gun traveling speed (mm / sec) 20 Spray distance (mm) 60

Alternatively, in the niobium laminating step (S320), if the second heap processing step (S333) is followed in the niobium coating layer forming method according to the present invention, the temperature of the feed gas is 800 ° C, the pressure is 30 bar, 800 ° C, the nozzle moving speed is 50 mm / sec, and the jetting distance is 30 mm.

Preferred process conditions in this niobium lamination step (S320) are shown in Table 4 below.

Nb coating Carrier gas N ₂ gas Main temperature (℃) 800 Powder temperature (℃) 800 Powder feed rate (rpm) 5 Pressure (bar) 30 Gun traveling speed (mm / sec) 50 Spray distance (mm) 30

In the niobium lamination step (S320), blast-treated copper (Cu) was used as the base material.

The fourth heat treatment step (S331) is performed after the niobium layering step (S320). The fourth heat treatment step (S331) is performed after heat treatment at 800 to 1100 ° C in an argon (Ar, 99.9% purity) gas atmosphere.

The fifth heat treatment step (S332) is also performed after the niobium layering step (S320) and is performed by heat treatment at 800 to 1100 ° C in a vacuum atmosphere.

The second heap processing step (S333) is performed after the niobium deposition step (S320), and may be performed by performing a HIP (Hot Isostatic Pressing) process at 1000 to 1200 ° C in an argon (Ar, 99.9% , And each inspection and analysis described below is based on the result of hot compression molding (HIP) at 1145 캜 and 103 MPa.

26 is a photograph showing a cross section of a niobium coating layer subjected to a niobium lamination step (S320) under the process conditions shown in Table 3. [

In the case of the niobium coating layer, it was confirmed that no peeling between the coating layer and the base material occurred and a thick coating layer of about 1.08 mm was formed. As a result of ICP analysis, it was confirmed that the purity was 99.6% and the oxygen content was 0.23% It was confirmed that the purity of the post-powder was almost maintained.

As a result of observing the cross section of the niobium-coated layer, it was found that the niobium-coated layer had a hardness of 214 Hv and a porosity of 2.94% Respectively.

The XRD analysis results and the EPMA mapping analysis results are shown in FIG. 27 in order to examine the phase change of the niobium coating layer subjected to the niobium lamination step (S320) according to the process conditions shown in Table 3. As a result of the XRD component analysis, it was confirmed that only the pure Nb single phase, which is the same as the initial powder, was not generated and EPMA mapping showed that the main elements were homogeneously and finely distributed.

FIG. 28 is a graph showing the relationship between the niobium layering step (S320) and the fourth heat treatment step (S331) (FIG. 28 (a)) and the fifth heat treatment step (S332) (OM) in the state of the test specimen.

As shown in FIG. 28, it can be seen that as the annealing temperature is increased, the particle interface becomes dense due to diffusion, and the pores at the particle interface gradually decrease, and it is confirmed that recrystallization occurs at 1100 ° C have.

FIG. 29 is a graph showing the relationship between the niobium lamination step S320 and the fourth heat treatment step S331 (FIG. 29 (a)) and the fifth heat treatment step S332 (FIG. 29 (b) (Scanning Electron Microscope, Tescan).

As shown in FIG. 29, it can be seen that recrystallization occurred at 1000 ° C., and grain growth was observed at 1100 ° C., and recovery, recrystallization, and grain growth were observed as the heat treatment temperature was increased.

30 is a graph showing the degree of porosity and hardness of the niobium lamination step (S320), the fourth heat treatment step (S331) and the fifth heat treatment step (S332), respectively, under the process conditions shown in Table 3, Is a graph showing the results of XRD analysis.

As shown in FIG. 30, it can be seen that the porosity decreases to 0.8% as the atmospheric heat treatment temperature is increased, and the hardness tends to decrease as the heat treatment temperature increases. As a result, Recrystallization, and grain growth.

As shown in FIG. 31, it can be seen that the pure Nb single phase like the initial coating layer appears even after the atmosphere heat treatment, and it is possible to maintain the phase of the initial powder as it is after the heat treatment.

32 is a graph showing the results of the EPMA analysis in the state where the niobium lamination step (S320), the fourth heat treatment step (S331) and the fifth heat treatment step (S332) are respectively performed under the process conditions shown in Table 3, and the fourth heat treatment step It can be seen that the oxygen distribution is uniformly maintained even in the case where the heat treatment temperature is increased in both of the S331 (argon gas atmosphere) and the fifth heat treatment step (S332) (vacuum atmosphere).

As described above, in the niobium coating layer forming method according to the present invention, the niobium layering step (S320) and the fourth heat treatment step (S331), or the niobium layering step (S320) and the fifth heat treatment step (S332) It can be confirmed that the boundary is dense, the porosity is decreased, recrystallization and crystal grain growth occur, and it is possible to form a niobium coating layer of excellent quality.

FIG. 33 is a photograph showing a cross-section of a base material on which a niobium coating layer having undergone the niobium lamination step (S320) is formed according to the process conditions shown in Table 4. FIG.

As shown in FIG. 33, microstructure of the coating layer was found to be well bonded without peeling to the base material. In the internal microstructure, pores were observed at some powder particle interfaces (porosity: 0.18%). . As a result of observation of microstructure after the etching (Fig. 33 (c)), the powder was found to undergo plastic deformation in the vertical direction of spraying, and the hardness of the coating layer was found to be 221Hv. As a result of plastic deformation of the powder, Value (38Hv).

34 shows the optical microscope OM in the state (FIG. 34 (b)) after the niobium lamination step (S320) (FIG. 34 (a)) and the second heap processing step (S333) And the pores after the second heap processing step (S333) are remarkably reduced.

FIG. 35 is a graph showing the XRD analysis result of the state after the niobium laminating step (S320) and the second heap processing step (S333) according to the process conditions shown in Table 4. In the second heap processing step (S333) Respectively.

36 shows the results of EPMA analysis in the state (FIG. 36 (b)) after the niobium lamination step (S320) (FIG. 36 (a)) and the second heap processing step (S333) It can be seen that no oxide formation appears before and after the second heap processing step (S333).

37 shows the results of scanning electron microscope (SEM) scanning in a state (FIG. 37 (b)) after the niobium lamination step (S320) (FIG. 37 (a)) and the second heap processing step (step S333) (S333). By the second heap processing step (S333), the pores of the particle interface are separated from the powder particle interface It can be seen that the liver binding increases.

38 is a graph showing the results of electron backscattered diffraction (EBSD) in the state (FIG. 38 (b)) after the niobium lamination step (S320) (FIG. 38 (a)) and the second heap processing step (step S333) ), And the average grain size increased after the second heap processing step (S333), and the bond between the interface of the powder particles disappears due to the high temperature and high pressure, and thus, the powder is densified .

FIG. 39 shows the results of measuring the porosity and strength of a sample after the niobium lamination step (S320), the fourth heat treatment step (S331), and the second heap processing step (S333) in the niobium coating layer forming method according to the present invention will be.

As a result of the measurement of the porosity, it was found that it decreased to 0.13% after the fourth heat treatment step (S331), to 0.08% after the second heap treatment step (S333) S331), it increases to 253 Hv in the second heap processing step (S333).

As described above, by further performing the second heap processing step (S333) in the niobium coating layer forming method according to the present invention, it is possible to form a coating material having a small amount of cracks, a small amount of impurities, And it is possible to provide a densification plan of the niobium material.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It is obvious to those who have. Accordingly, it should be understood that such modifications or alterations should not be understood individually from the technical spirit and viewpoint of the present invention, and that modified embodiments fall within the scope of the claims of the present invention.

S110: Tantalum powder preparing step S120: First tantalum laminating step
S131: First heat treatment step S132: Second heat treatment step
S210: Tantalum powder preparing step S220: Second tantalum laminating step
S231: First heap processing step S232: Third heat treatment step
S310: niobium powder preparation step S320: niobium lamination step
S331: fourth heat treatment step S332: fifth heat treatment step
S333: Second heap processing step
10: gas supply line 20: powder supply part
30: gas heating part 40: nozzle
50: base metal

Claims

A tantalum powder preparation step of preparing a tantalum powder; And
And a first tantalum laminating step of laminating the powder prepared in the tantalum powder preparing step on an aluminum (Al) base material by accelerating the powder to 300 to 1300 kPa using a kinetic spray process,
In the first tantalum deposition step using the kinetic spray process,
Wherein the feed gas of the powder is helium (He), the temperature of the feed gas is 550 to 650 ° C, the pressure is 2 to 4 MPa, the temperature of the powder is 450 to 650 ° C, 3.5 kg / h, the nozzle moving speed is 90 to 110 mm / sec, and the jetting distance is 25 to 35 mm.

The method according to claim 1,
Further comprising a first heat treatment step of performing heat treatment at 800 to 1100 占 폚 in an argon (Ar, 99.9% purity) gas atmosphere after the first tantalum laminating step.

The method according to claim 1,
Further comprising a second heat treatment step after the first tantalum deposition step of performing heat treatment at 800 to 1100 占 폚 in a vacuum atmosphere.

The method according to claim 2 or 3,
In the first tantalum deposition step using the kinetic spray process,
The temperature of the feed gas is 600 캜, the pressure is 3 MPa, the temperature of the powder is 500 캜, the feed rate is 3 kg / h, the nozzle moving speed is 100 mm / sec, Wherein the tantalum coating layer is formed on the substrate.

A tantalum powder preparation step of preparing a tantalum powder; And
And a second tantalum laminating step of laminating the powder prepared in the tantalum powder preparing step on a copper (Cu) base material by accelerating the powder to 300 to 1300 kPa using a Kinetic Spray Process,
In the second tantalum laminating step using the kinetic spray process,
Wherein the feed gas of the powder is nitrogen (N ₂ ), the temperature of the feed gas is 700 to 800 ° C., the pressure is 30 to 35 bar, the temperature of the powder is 650 to 850 ° C., / sec, and the spraying distance is 25 to 35 mm.

6. The method of claim 5,
(HIP, Hot Isostatic Pressing) method at 1000 to 1200 ° C in an argon (Ar, 99.9% purity) gas or vacuum atmosphere after the second tantalum laminating step By weight based on the total weight of the sputtering target.

6. The method of claim 5,
Further comprising a third heat treatment step after the second tantalum deposition step of performing heat treatment at 900 to 1100 占 폚 in a vacuum atmosphere.

8. The method according to claim 6 or 7,
In the second tantalum laminating step using the kinetic spray process,
Wherein the temperature of the feed gas is 750 DEG C, the pressure is 30 bar, the temperature of the powder is 650 DEG C, the moving speed of the nozzle is 50 mm / sec, and the spraying distance is 30 mm.

A niobium powder preparation step of preparing a niobium powder; And
And a niobium laminating step of laminating the powder prepared in the niobium powder preparing step to a blast-treated copper (Cu) base material by accelerating to 300 to 1300 kPa using a kinetic spray process,
In the niobium laminating step using the kinetic spray process,
Wherein the feed gas of the powder is nitrogen (N ₂ ), the temperature of the feed gas is 750-800 ° C, the pressure is 30-35 bar, the temperature of the powder is 650-800 ° C, the nozzle moving speed is 15-55 mm / sec, and the spraying distance is 25 to 60 mm.

10. The method of claim 9,
Further comprising a fourth heat treatment step of performing heat treatment at 800 to 1100 占 폚 in an argon (Ar, 99.9% purity) gas atmosphere after the niobium layering step.

10. The method of claim 9,
And a fifth heat treatment step of performing heat treatment at 800 to 1100 ° C in a vacuum atmosphere after the niobium layering step.

10. The method of claim 9,
(HIP, Hot Isostatic Pressing) method at 1000-1200 占 폚 in an argon (Ar, 99.9% purity) gas or a vacuum atmosphere after the niobium laminating step A method for forming a niobium coating layer.