KR100811099B1 - Hot isostatic pressing joining method between be and cu alloy by formation of the diffusion layers between coated interlayers - Google Patents

Abstract

An HIP(Hot Isostatic Pressing) joining method between Be and Cu alloy by formation of the diffusion layers between coated interlayers is provided to be availably used for manufacturing of a fusion reactor first protective wall with a reliable performance by enhancing a joining strength between the Be and Cu alloy. An HIP joining method between Be and Cu alloy by formation of the diffusion layers between coated interlayers includes the steps of: pre-treating a Be surface; forming a diffusion inhibition layer(1), a joining promoting layer(3), and a diffusion layer(2) on the pre-treated Be surface; pre-treating a Cu alloy surface; and HIP joining the Be with the diffusion layer and the pre-treated Cu alloy.

Description

Hot isostatic pressing joining method between Be and Cu alloy by formation of the diffusion layers between coated interlayers}

1 is a view showing a bonding method of beryllium and a copper alloy according to an embodiment of the present invention,

2 is a view showing a bonding method of beryllium and a copper alloy according to another embodiment of the present invention,

3 is a view showing a bonding method of beryllium and a copper alloy according to another embodiment of the present invention.

(The numbers in parentheses in the drawing indicate the process sequence of the conjugate of beryllium and copper alloy.)

The present invention relates to a high temperature isotropic pressure (HIP) bonding method for improving the bonding strength of beryllium and copper alloy by forming a diffusion layer between the coated intermediate layer.

The primary barrier of the fusion reactor has a structure in which the plasma facing material is bonded to the heat removal layer and must maintain excellent performance even in a high neutron flux and heat flux environment. In the fusion reactor primary barrier, materials that must perform different functions must be fabricated into the final part through bonding. Therefore, the joining technique of dissimilar materials is considered as the core technology for manufacturing the primary barrier.

In general, in the manufacture of the primary barrier for nuclear fusion, beryllium (Be) is mainly used as the plasma facing material, and copper (Cu) alloy is used as the heat removal layer material. Hot isostatic pressing (HIP) bonding, a kind of diffusion bonding, is considered as a promising method to realize sufficient mechanical integrity under high neutron and high stress conditions expected in the operation of nuclear fusion reactors. Compared with other commercial joining methods, HIP has been reported to be useful for joining complex shapes with less dimensional change of workpiece before and after joining.

However, it is of utmost importance to improve the bonding strength of high temperature isotropically pressurized joints for the manufacture of primary barriers that have reliable performance under fusion reactor operating conditions.

To this end, various studies have been conducted to improve the bonding strength of high temperature isostatic pressing.

US Patent No. 6,176,418, European Patent Publication No. 0901869 A1 and Japanese Patent Application Laid-open No. Hei 10-216960 disclose a method for joining stainless steel / copper alloy / beryllium in one process. A process of inserting an intermediate layer made of (Ti), molybdenum (Mo) and niobium (Nb) is disclosed.

In addition, U.S. Patent No. 6,164,524 and Japanese Patent Laid-Open No. 11-285895 disclose that titanium and chromium may be formed by physical vapor deposition (PVD) or thermal spraying on the surface of beryllium in bonding beryllium and a copper alloy. Forming a diffusion inhibition layer made of (Cr), molybdenum, or silicon (Si), and forming a copper or nickel (Ni) layer on the surface of the diffusion suppression layer, A method of joining the beryllium and a copper alloy using a bonding promoter layer as a bonding surface is disclosed.

Further, US Patent No. 6,824,888, EP 1297925 A2, and Japanese Patent Publication No. 2003-112269 disclose that when bonding beryllium and a copper alloy, titanium, as a diffusion suppressing layer between the beryllium and the copper alloy, Forming a chromium, molybdenum and silicon layer and forming a copper layer on the surface of the diffusion suppressing layer, and then forming a diffusion promoting layer of aluminum (Al), zirconium (Zr) and copper on the high temperature isotropic pressure bonding Is starting.

In addition, U.S. Patent No. 6,286,750, EP 1043111 A2, and JP 2001-225176A disclose that when bonding beryllium and a copper alloy, titanium and vanadium are used as diffusion suppression layers on the surface of the copper alloy. Coated with a layer of (V), niobium, chromium, molybdenum or silicon, and in the bonding of the coated copper alloy with beryllium, an intermediate composed of an aluminum (Al) -magnesium (Mg) alloy is placed between copper and beryllium A method for high temperature isostatic pressing is disclosed so that the copper and beryllium are diffusion bonded through an insert body.

However, in order to manufacture a primary barrier having reliable performance under operating conditions of a fusion reactor, it is constantly required to develop a joining method for improving the bonding strength of high temperature isostatic pressure bonding.

Therefore, while the present inventors are studying a bonding method for improving the high temperature isotropic pressure bonding strength between beryllium and copper alloy, by forming a diffusion layer between the coated intermediate layer to improve the bonding strength between the beryllium and copper alloy between It was confirmed that the high temperature isotropic pressure bonding strength is improved and completed the present invention.

An object of the present invention is to provide a high temperature isotropic pressure bonding method for improving the bonding strength of beryllium and copper alloy by forming a diffusion layer between the coated intermediate layer.

In order to achieve the above object, the present invention

Pretreatment of the beryllium surface (step 1);

Forming a diffusion suppression layer, a bonding promoter layer, and a diffusion layer on the surface of the beryllium pretreated in step 1 (step 2);

Pretreating the surface of the copper alloy (step 3); And

Beryllium to improve the bonding strength of the beryllium and copper alloy by forming a diffusion layer between the beryllium formed in the diffusion layer of step 2 and the coated intermediate layer comprising the step of HIP bonding the copper alloy pretreated in step 3 (step 4) It provides a HIP bonding method of the copper alloy with.

In the present specification, the "intermediate layer" includes a diffusion inhibitory layer or a bonding promoter layer formed between the beryllium and the copper alloy.

Hereinafter, the present invention will be described in detail.

First step is to pretreat the beryllium surface.

In the bonding method according to the present invention, the pretreatment preferably polishes the bonding portion of the beryllium to a mirror surface, and then performs pickling and drying after pickling and ultrasonic cleaning, followed by ion sputtering.

In this case, dilute nitric acid may be used as the acid used in the pickling, and a solvent used in the ultrasonic cleaning may be a mixed solvent of ethanol and acetone.

The ion sputtering removes the oxide film of beryllium oxide (BeO) formed in the air on the surface of the beryllium to form a series of good intermediate layers later, and is preferably performed in a vacuum of 10 ⁻⁶ torr or less using the PVD method. At this time, it is preferable to use argon (Ar) or the like as the ion used for the ion sputtering.

The ion sputtering may be performed after increasing the temperature of the beryllium tile to 200 ~ 300 ℃ as needed. This is to remove the organic matter and gas that may exist on the beryllium surface to increase the adhesion of the intermediate layer later.

Next, step 2 is a step of forming a diffusion suppression layer, a bonding promoter layer and a diffusion layer on the surface of the beryllium pretreated in step 1.

The purpose of forming the diffusion suppression layer is to suppress the formation of brittle intermetallic compounds at the interface due to the interdiffusion of beryllium and copper when the beryllium and copper alloy are directly bonded.

In the bonding method according to the present invention, the diffusion suppression layer is preferably formed using a PVD method or a thermal spraying method under a vacuum of 10 ⁻⁶ torr or less.

The diffusion suppression layer may be made of titanium, chromium or zirconium, wherein the thickness of the diffusion suppression layer is preferably 0.1 to 100 ㎛. If the thickness of the diffusion suppression layer is less than 0.1 µm, there is no effect of diffusion suppression, and if the thickness exceeds 100 µm, it is economically undesirable.

The bonding promotion layer is formed to promote bonding between the diffusion suppression layer and the copper alloy and to receive thermal stress generated during HIP bonding and thereby prevent breakage. It is preferable to use a pure copper layer as the bonding promoter layer, and the thickness of the bonding promoter layer is preferably 0.1 to 100 µm. If the thickness of the bonding promotion layer is less than 0.1 ㎛ there is no effect of bonding promotion, if it exceeds 100 ㎛ it is economically undesirable.

The bonding promotion layer may also be carried out using a PVD method or a spraying method in a vacuum of 10 ⁻⁶ torr or less as in step 2.

The diffusion layer may be formed by performing a subsequent heat treatment to improve the bonding between the layers formed by the beryllium base material and the coating to increase the bonding strength during HIP bonding with the copper alloy. The subsequent heat treatment time is not limited, and for example, may be performed once after the diffusion suppression layer is formed, or once after the diffusion suppression layer and the bonding promoter layer are formed, or after the diffusion suppression layer is formed. The first step may be performed and the second step may be performed after the bonding promoter layer is formed.

At this time, the temperature of the subsequent heat treatment is preferably 400 ~ 950 ℃, the thickness of the diffusion layer between the beryllium base material and the diffusion suppression layer or the diffusion suppression layer and the bonding promoter layer through the subsequent heat treatment is preferably 0.05 ~ 5 ㎛. Do. If the subsequent heat treatment temperature is less than 400 ° C, a diffusion layer having a desired thickness may not be obtained. If the subsequent heat treatment temperature exceeds 950 ° C, the thickness of the diffusion layer may be excessively grown to decrease the bonding strength.

Next, step 3 is a step of pretreating the surface of the copper alloy.

The copper alloy used may include a CuCrZr alloy, a dispersion-strengthened Cu (DS-Cu) alloy, pure copper, and the like. The copper alloy is ground finely before joining, and then dried after ultrasonic cleaning. .

Next, step 4 is HIP bonding beryllium having the diffusion layer of step 2 and the copper alloy pretreated in step 3.

Specifically, first, a canning of contacting the beryllium and the pretreated copper alloy and enclosing it with a stainless steel plate is carried out, followed by heating to about 450 ° C. to sufficiently extract the air to a vacuum of 10 ^-5 torr or less, and leak helium. The integrity of the weld is verified using the test method and then sealed by pinching. The sealed sample is moved to the HIP bonding equipment.

HIP bonding is carried out in a high-purity Ar gas atmosphere, it is preferable that the HIP bonding temperature is 400 ~ 650 ℃, HIP bonding pressure is 10 ~ 200 MPa. If the HIP bonding temperature is less than 400 ℃ bond strength is lowered, if it exceeds 650 ℃ copper strength may be lowered. In addition, when the HIP bonding pressure is less than 10 MPa, there is a problem such as deterioration of the bonding performance, and when it exceeds 200 MPa, it may cause a safety problem in the HIP bonding equipment configuration.

Had this same as shown in the same way a conjugate Figs bond, these are the by performing a subsequent heat treatment after coating a diffusion inhibiting layer and the bonding promotion layer on the beryllium surface to form a diffusion layer between the coating layer beryllium Improved bonding strength between the copper alloy and the copper alloy can be usefully used in the manufacture of the primary barrier fusion reactor having a reliable performance.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are illustrative of the present invention, and the content of the present invention is not limited by the examples.

< Example  1>

After performing mechanical polishing and chemical pickling on the surface of the beryllium tile (S-65C), charged into a PVD apparatus to remove the oxide film formed on the surface by high-purity (more than 99.999%) argon ion sputtering. Thereafter, titanium was formed on the surface of the beryllium surface by the PVD apparatus as a diffusion inhibiting layer to a thickness of 10 μm, and then a subsequent heat treatment was performed at 800 ° C. to improve adhesion between the coating layers. Thereafter, copper was formed to a thickness of 10 μm on the coated and subsequent heat treated beryllium tiles by PVD method, and then the beryllium and copper alloy were HIP bonded at a temperature of 580 ° C. and a pressure of 150 MPa for 2 hours. .

< Example  2>

The method of Example 1 was repeated except that chromium was formed to a thickness of 1 μm instead of titanium as a diffusion suppression layer on the beryllium surface.

< Example  3>

The same method as in Example 1 was performed except that zirconium was formed to a thickness of 10 μm instead of titanium as a diffusion suppression layer on the surface of the beryllium.

< Example  4>

After the formation of the adhesion promoter layer on the surface of the beryllium, it was carried out in the same manner as in Example 1 except that the secondary subsequent heat treatment was performed at 800 ℃.

< Example  5>

After the formation of the bonding promoter layer on the surface of the beryllium, it was carried out in the same manner as in Example 2 except that the secondary subsequent heat treatment was performed at 800 ℃.

< Example  6>

After the formation of the bonding promoter layer on the surface of the beryllium, it was carried out in the same manner as in Example 3 except that the secondary subsequent heat treatment was performed at 800 ℃.

< Example  7>

Instead of performing the subsequent heat treatment after forming the diffusion suppression layer on the surface of the beryllium was carried out in the same manner as in Example 1 except that the subsequent heat treatment was performed at 800 ℃ after the bonding promoter layer was formed.

< Example  8>

Instead of performing the subsequent heat treatment after forming the diffusion suppression layer on the surface of the beryllium was carried out in the same manner as in Example 2 except that the subsequent heat treatment was performed at 800 ℃ after the bonding promoter layer was formed.

< Example  9>

Instead of performing the subsequent heat treatment after forming the diffusion suppression layer on the surface of the beryllium was carried out in the same manner as in Example 3 except that the subsequent heat treatment was performed at 800 ℃ after the bonding promoter layer was formed.

< Comparative example  1>

The same process as in Example 1 was conducted except that the subsequent heat treatment was not performed on the beryllium.

< Comparative example  2>

The same process as in Example 2 was conducted except that the subsequent heat treatment was not performed on the beryllium.

< Comparative example  3>

The same process as in Example 3 was conducted except that the subsequent heat treatment was not performed on the beryllium.

< Comparative example  4>

The beryllium was HIP bonded to the copper alloy without performing diffusion suppression layer formation, bonding promotion layer formation and subsequent heat treatment.

Experimental Example

In order to evaluate the bonding strength of the HIP bonded body produced in the above Examples or Comparative Examples, the bending test piece of four points about the bonded interface of the HIP bonded body prepared in the above Examples or Comparative Examples according to the JIS R 1624 (1995) procedure Was taken to measure the bending strength, and the results are shown in Table 1.

division Diffusion Inhibition Layer (Thickness (㎛)) 1st follow-up heat treatment (℃) Bonding Promotion Layer (Thickness (㎛)) 2nd follow-up heat treatment (℃) Bending strength (MPa) Example 1 Ti (10) 800 Cu (10) - 220 Example 2 Cr (1) 800 Cu (10) - 195 Example 3 Zr (10) 800 Cu (10) - 180 Example 4 Ti (10) 800 Cu (10) 800 210 Example 5 Cr (1) 800 Cu (10) 800 180 Example 6 Zr (10) 800 Cu (10) 800 160 Example 7 Ti (10) - Cu (10) 800 225 Example 8 Cr (1) - Cu (10) 800 200 Example 9 Zr (10) - Cu (10) 800 195 Comparative Example 1 Ti (10) - Cu (10) - 120 Comparative Example 2 Cr (1) - Cu (10) - 100 Comparative Example 3 Zr (10) - Cu (10) - 90 Comparative Example 4 - - - - 10

As shown in Table 1, the bending strength was 90 to 120 MPa when the subsequent heat treatment was not performed after the coating (Comparative Examples 1 to 4), but about 1.8 times improved to 160 to 220 MPa when the subsequent heat treatment was performed. Confirmed. In addition, when HIP bonding the copper alloy without coating the diffusion inhibitor layer and the bonding promotion layer on the surface of the beryllium, the bending strength is shown as 10 MPa, it can be seen that the bonding strength is low, the bonding is difficult.

Therefore, the bonding method according to the present invention improves the bonding strength between the beryllium and the copper alloy by forming a diffusion layer between the coating layer by coating the diffusion inhibitor layer and the bonding promotion layer on the surface of the beryllium and then performing a subsequent heat treatment. Nuclear fusion reactors with good performance can be useful in the construction of primary barriers.

As described above, in the bonding method according to the present invention, after coating the diffusion inhibiting layer and the bonding promotion layer on the surface of beryllium, a subsequent heat treatment is performed to form a diffusion layer between the coating layers to bond strength between the beryllium and the copper alloy. It can be usefully used in the manufacture of primary fusion barriers with improved fusion and reliable performance.

Claims (12)

Pretreatment of the beryllium surface (step 1); Forming a diffusion suppression layer, a bonding promoter layer, and a diffusion layer on the surface of the beryllium pretreated in step 1 (step 2); Pretreating the surface of the copper alloy (step 3); And Beryllium to improve the bonding strength of the beryllium and copper alloy by forming a diffusion layer between the beryllium formed in the diffusion layer of step 2 and the coated intermediate layer comprising the step of HIP bonding the copper alloy pretreated in step 3 (step 4) HIP joining method of copper and copper alloy. The method according to claim 1, wherein the pretreatment of step 1 is performed by polishing the junction of the beryllium with a mirror surface, followed by pickling and ultrasonic washing, drying and ion sputtering. HIP bonding method of beryllium and copper alloy to improve the bonding strength of beryllium and copper alloy. The method of claim 1, wherein the diffusion suppression layer or the adhesion promoter layer of step 2 is formed using a physical vacuum deposition method or a thermal spraying method to form a bonding strength of beryllium and copper alloy by forming a diffusion layer between the coated intermediate layer. HIP bonding method of beryllium and copper alloy to improve. 2. The bonding strength of beryllium and copper alloy is improved by forming a diffusion layer between the coated intermediate layers according to claim 1, wherein the diffusion suppression layer of step 2 is one selected from the group consisting of titanium, chromium and zirconium. HIP bonding method of beryllium and copper alloy. The HIP bonding method of claim 1, wherein the bonding promoter layer of step 2 is a pure copper layer to improve the bonding strength of beryllium and copper alloy by forming a diffusion layer between the coated intermediate layers. The method of claim 1, wherein the thickness of the diffusion suppression layer or the bonding promotion layer of the step 2 is 0.1 to 100 ㎛ beryllium to improve the bonding strength of the beryllium and copper alloy by forming a diffusion layer between the coated intermediate layer and HIP bonding method of copper alloy. The method of claim 1, wherein the diffusion layer of step 2 is formed by subsequent heat treatment to improve the bonding strength of beryllium and copper alloys by forming a diffusion layer between the coated intermediate layers. The method of claim 7, wherein the subsequent heat treatment is performed once after the diffusion suppression layer is formed, or once after the diffusion suppression layer and the bonding promoter layer are formed, or after the formation of the diffusion suppression layer. HIP bonding method of the beryllium and copper alloy to improve the bonding strength of the beryllium and copper alloy by forming a diffusion layer between the coated intermediate layer, characterized in that the secondary layer is formed after the promotion layer. The method of claim 7, wherein the temperature of the subsequent heat treatment is 400 ~ 950 ℃ HIP bonding method of beryllium and copper alloy to improve the bonding strength of beryllium and copper alloy by forming a diffusion layer between the coated intermediate layer. The method of claim 1, wherein the thickness of the diffusion layer of step 2 is 0.05 ~ 5 ㎛ HIP bonding method of beryllium and copper alloy to improve the bonding strength of beryllium and copper alloy by forming a diffusion layer between the coated intermediate layer . The method of claim 1, wherein the pretreatment of the surface of the copper alloy of step 3 is performed by grinding the surface of the joint portion of the copper alloy, and drying after ultrasonic cleaning of the beryllium and copper alloy by forming a diffusion layer between the coated intermediate layer HIP bonding method of beryllium and copper alloy to improve the bonding strength. The bonding strength of the beryllium and copper alloy by forming a diffusion layer between the coated intermediate layer, characterized in that the bonding temperature in the HIP bonding step 4 is 400 ~ 650 ℃, the bonding pressure is 10 ~ 200 MPa HIP bonding method of beryllium and copper alloy to improve the.

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