FILLER FOR VACUUM BRAZING OF TU1 OXYGEN-FREE COPPER AND APPLICATION THEREOF

Abstract

A filler for vacuum brazing of TU1 oxygen-free copper is an Au—Cu—Ni filler including the following elemental compositions in a specified proportion: 69% to 90% of Au, 9% to 30% of Cu, and 1% to 5% of Ni. The filler has a melting temperature of 900° C. to 910° C. The filler for vacuum brazing of TU1 oxygen-free copper can be used for brazing X-ray tube anodes, thereby realizing effective vacuum brazing.

Claims

1. A filler for vacuum brazing of TU1 oxygen-free copper, wherein the filler is an Au—Cu—Ni filler comprising the following elemental compositions in a first specified proportion: 69% to 90% of Au, 9% to 30% of Cu, and 1% to 5% of Ni.

2. The filler according to claim 1, wherein the filler comprises the following elemental compositions in a second specified proportion: 74% to 81% of Au, 15% to 22% of Cu, and 3.5% to 4.5% of Ni.

3. The filler according to claim 2, wherein the filler comprises the following elemental compositions in a third specified proportion: 77% to 80% of Au, 16% to 19% of Cu, and 3.8% to 4.1% of Ni.

4. The filler according to claim 3, wherein the filler comprises the following elemental compositions in a fourth specified proportion: 78.25% of Au, 17.78% of Cu, and 3.97% of Ni.

5. The filler according to claim 1, wherein the filler has a melting temperature of 900° C. to 910° C.

6. A method of brazing an X-ray tube anode, comprising: using the filler according to claim 1.

7. The filler according to claim 2, wherein the filler has a melting temperature of 900° C. to 910° C.

8. The filler according to claim 3, wherein the filler has a melting temperature of 900° C. to 910° C.

9. The filler according to claim 4, wherein the filler has a melting temperature of 900° C. to 910° C.

10. The method according to claim 6, wherein the filler comprises the following elemental compositions in a second specified proportion: 74% to 81% of Au, 15% to 22% of Cu, and 3.5% to 4.5% of Ni.

11. The method according to claim 10, wherein the filler comprises the following elemental compositions in a third specified proportion: 77% to 80% of Au, 16% to 19% of Cu, and 3.8% to 4.1% of Ni.

12. The method according to claim 11, wherein the filler comprises the following elemental compositions in a fourth specified proportion: 78.25% of Au, 17.78% of Cu, and 3.97% of Ni.

13. The method according to claim 6, wherein the filler has a melting temperature of 900° C. to 910° C.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG. 1 is a schematic diagram of a brazed joint, where 1 represents a brazed joint and 2 represents a tungsten target surface;

[0028] FIG. 2 is a picture showing the macroscopic surface morphology of the brazed joint;

[0029] FIG. 3 is a partially enlarged picture showing the macroscopic surface morphology of the brazed joint;

[0030] FIG. 4 is an EDS spectrum of the filler of the present invention; and

[0031] FIG. 5 is an image of a plane scanning area showing the microscopic morphology of the brazed joint.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] The technical solutions in the embodiments of the present invention are clearly and completely described below with reference to the drawings in the embodiments of the present invention. Apparently, the described embodiments are merely a part rather than all of the embodiments of the present invention. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

Embodiment 1

[0033] A filler for vacuum brazing of TU1 oxygen-free copper is an Au—Cu—Ni filler including the following elemental compositions in a specified proportion: 69% to 90% of Au, 9% to 30% of Cu, and 1% to 5% of Ni.

Embodiment 2

[0034] A filler for vacuum brazing of TU1 oxygen-free copper is an Au—Cu—Ni filler including the following elemental compositions in a specified proportion: 74% of Au, 22% of Cu, and 4% of Ni.

Embodiment 3

[0035] A filler for vacuum brazing of TU1 oxygen-free copper is an Au—Cu—Ni filler including the following elemental compositions in a specified proportion: 81% of Au, 15% of Cu, and 4% of Ni.

Embodiment 4

[0036] A filler for vacuum brazing of TU1 oxygen-free copper is an Au—Cu—Ni filler including the following elemental compositions in a specified proportion: 78% of Au, 18% of Cu, and 4% of Ni.

Embodiment 5

[0037] A filler for vacuum brazing of TU1 oxygen-free copper is an Au—Cu—Ni filler including the following elemental compositions in a specified proportion: 77% of Au, 19% of Cu, and 4% of Ni.

Embodiment 6

[0038] A filler for vacuum brazing of TU1 oxygen-free copper is an Au—Cu—Ni filler including the following elemental compositions in a specified proportion: 78.2% of Au, 18% of Cu, and 3.8% of Ni.

Embodiment 7

[0039] A filler for vacuum brazing of TU1 oxygen-free copper is an Au—Cu—Ni filler including the following elemental compositions in a specified proportion: 79% of Au, 16.9% of Cu, and 4.1% of Ni.

Embodiment 8

[0040] A filler for vacuum brazing of TU1 oxygen-free copper is an Au—Cu—Ni filler including the following elemental compositions in a specified proportion: 77.5% of Au, 18.6% of Cu, and 3.9% of Ni.

[0041] It is found from the comparison of the fillers in Embodiments 2 to 8 with a filler in the prior art that:

[0042] 1. Compared with the Au-based filler of the present invention, commonly used Ag-based fillers (such as pure silver, AgCu.sub.28, and AgCu.sub.50) have lower wettability and reliability. In the electro-vacuum industry, any defects such as brazing pores are fatal. Therefore, the Au-based filler in the embodiments is superior as having strong corrosion resistance, low vapor pressure, and excellent fluidity and wettability.

[0043] 2. Commonly used Cu-based fillers (such as CuGe.sub.12 and CuGe.sub.10-11, and CuGeNi.sub.12-0.25) are cheap, but have wettability far worse than that of Au-based fillers and lead to a higher vapor pressure than Au-based fillers in a vacuum environment. Moreover, during the brazing process of oxygen-free copper, an excessively high proportion of Cu will affect the brazing effect of oxygen-free copper.

[0044] 3. The filler with 80% of Au and 20% of Cu is obtained from preliminary experiments, also showing a certain effect of brazing oxygen-free copper. However, the filler is not added with Ni, and thus has slightly lower wettability, fluidity, and strength than the filler composed of Au, Cu and Ni, which is not conducive to the stability of the brazed joint in a long-term X-ray environment.

[0045] 4. An excessively high proportion of Ni in the filler (such as 75% of Au, 15% of Cu, and 10% of Ni) will affect the optimal ratio of Au to Cu previously obtained, and will negatively affect the wettability of the filler.

Embodiment 9

[0046] A filler for vacuum brazing of TU1 oxygen-free copper is an Au—Cu—Ni filler including the following elemental compositions in a specified proportion: 78.25% of Au, 17.78% of Cu, and 3.97% of Ni. The filler has a melting temperature of 900° C. to 910° C.

[0047] The EDS spectrum and the plane scanning area of the filler are shown in FIG. 4 and FIG. 5, respectively. The elemental compositions of the filler in the plane area can be measured by EDS to verify the specific elemental compositions and proportions of different elements in the filler. The image of the plane scanning area shows the microscopic morphology of the brazed joint, so that the elemental compositions in this area can be measured.

[0048] The above results are consistent with the estimated proportion (about 80% of Au/about 20% of Cu +a certain proportion of Ni) designed and verified in the practical research and development, which proves that the filler of the present invention is effective and reliable for the brazing of oxygen-free copper. Moreover, compared with Embodiments 2 to 8, the addition of Ni in a proportion of 3.97% can achieve the optimal connection strength for the brazed joint.

TABLE-US-00002 Embodiment Connection strength of brazed joint (MPa) 2 172 3 174 4 189 5 185 6 194 7 190 8 188 9 198

[0049] In addition, it is found through experiments that the Au—Ni filler has a connection strength of 124 MPa to 168 MPa. In comparison with the data in the above table, it can be known that the filler of the present invention also has higher connection strength than the Au—Ni filler.

[0050] Although the embodiments of the present invention have been illustrated and described, it should be understood that those of ordinary skill in the art may make various changes, modifications, replacements and variations to the above embodiments without departing from the principle and spirit of the present invention, and the scope of the present invention is limited by the appended claims and legal equivalents thereof.