JPH0426178B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a rotating anode for an X-ray tube and a method for manufacturing the same, and particularly to a rotating anode for a high-load X-ray tube and a method for manufacturing the same. [Prior Art] In general, a rotating anode for an X-ray tube (hereinafter referred to as a target) has the characteristics of being able to withstand high loads,
Moreover, it is required to have a high melting point. Therefore,
Conventionally, Re-W/Mo laminate materials have been used as targets for X-ray tubes. Furthermore, in order to use the target as a high-load target with improved target characteristics, a method has been adopted in which the target itself is made larger (larger diameter, thicker plate) to increase the heat storage capacity of the target. However, while increasing the size of a metal target can increase its heat capacity, it also increases the mass of the target itself, which causes various inconveniences to the rotating mechanism during high-speed rotation. In addition, there was a problem that the time required to reach a steady rotational speed was increased. Therefore, in recent years, graphite, which has a large heat capacity and is lightweight, has been used as a heat storage material.
- A high-load target with a structure in which W/Mo is combined with a heat storage material bonded to the Mo side of the laminated material by brazing is being researched. Conventional brazing fillers generally used for bonding graphite and high-melting point metals include Ti-Cu-Ni, Ti-Cu
-Si, Ti-78Ag-22Cu, Fe-36~45Ni-Ti,
35Au−35Ni−30Mo, or Mo−Co, Zr−
Ti etc. were used. [Problems to be Solved by the Invention] However, the conventional targets for high-load X-ray tubes using brazing filler metals made of the above-mentioned components cannot be used at high temperatures during the brazing process or in the high vacuum in which they are actually used. (1200℃), the temperature near the boundary between the heat storage material and the brazing material, that is, the brazing area, is 1000℃
At high temperatures of 1,200°C, metal carbides from the brazing filler metal components are formed at the boundary between the graphite and the brazing filler metal. In other words, metal carbides are not only hard and brittle in general, but also change in volume during formation, which causes separation between the Re-W/Mo laminate material and the heat storage material, reducing heat resistance and impact resistance. let me,
There was a problem in that the target had almost no resistance and was not suitable for practical use. SUMMARY OF THE INVENTION In view of the above drawbacks, an object of the present invention is to provide a rotating anode for a high-load X-ray tube that does not generate metal carbides, and a method for manufacturing the same. [Means for Solving the Problems] According to the present invention, a bonding material formed by bonding a W or W alloy layer to a Mo or Mo alloy layer, a heat storage material containing craftite, and one of the bonding materials A brazing material made of 5 to 30% by weight Ru-Pd is interposed between the Mo or Mo alloy layer and the heat storage material, and the bonding material and the heat storage material are joined via the brazing material. A rotating anode for an X-ray tube is obtained. Furthermore, according to the present invention, a bonding material formed by bonding a W or W alloy layer to a Mo or Mo alloy layer, and a heat storage material containing kraftite.
A preparation process of preparing a brazing material consisting of 30% by weight Ru-Pd, and a brazing material consisting of 30% by weight of Ru-Pd, and
a brazing step in which the brazing material is interposed between the Mo alloy layer and the heat storage material, heating is performed in a vacuum while applying a load, and the brazing material is melted and then cooled. A method for producing a characteristic rotating anode for an X-ray tube is obtained. Specifically, the present invention provides W or a W alloy (Re-W,
ThO ₂ -W, Ru-W, ZrO ₂ -W, etc.) and Mo or
Mo alloy (Hf−Mo, ZrO ₂ −Mo, A ₁₂ O ₃ −Mo,
Ru-Pd is used as a brazing material when a heat storage material containing graphite is brazed to the Mo side of a bonding material made of (CO--Mo, etc.). This is because the brazing filler metal does not generate carbides that can cause peeling, and the melted brazing filler metal dissolves well in graphite, forming a so-called mixed layer, so it exhibits good bonding strength. This is because it has very good wettability with the Mo side, allowing uniform brazing. Moreover, the getter effect of absorbing gas components (especially hydrogen gas) by the brazing material absorbs trace gas components inside the X-ray tube, working to create a higher vacuum, resulting in In addition, an X-ray tube with excellent voltage resistance is formed. In addition, the chemical composition of the brazing filler metal consisting of Ru and Pd is 5 to 30% by weight of Ru with the balance being Pd, and most preferably Ru with the balance being 20% by weight. This is because a brazing filler metal with a chemical composition in which Ru exceeds 30% by weight and the remainder is Pd will cause breakage in the graphite portion in a heat cycle test.
The reason for setting the balance Pd to 20% by weight is that pure palladium brazing filler metals and brazing filler metals with a chemical composition in which Ru exceeds 30% by weight and the balance Pd has a weak high-temperature transverse rupture strength at the joint. [Example] An example of the present invention will be described with reference to the drawings. First, the rotating anode (target) for an X-ray tube shown in Fig. 1 consists of a hollow conical Mo layer 1 with a trapezoidal cross section.
and the 5% Re-W alloy layer 2 laminated on the inclined surface formed by the generatrix of this Mo layer 1.
A bonded material 3 with a thickness of 8 mm at the center and Ru on the bottom surface of the Mo layer 1 of this bonded material 3.
−Outer diameter joined via brazing filler metal 4 made of Pd
It is composed of a heat storage material 5 made of high-purity, high-density graphite with a length of 120 mm and a thickness of 15 mm. Next, the manufacturing method will be explained. First, in the preparation process, a hollow cone-shaped Mo layer with a trapezoidal cross section and a 5% Re-W alloy layer 2 were laminated together and formed into the above-mentioned product shape with an outer diameter of 125 mm.
Laminated material 3 with center thickness 8mm and outer diameter 120
Thermal storage material 5 made of high-purity, high-density graphite with a thickness of 15 mm and 35 g of powdered or foil Ru
- Prepare a brazing filler metal 4 made of Pd. A frame 6 is attached to the outer periphery of the Mo layer 1 of the bonding material 3 to prevent the heat storage material 5 from shifting during brazing. Next, in the brazing process, 35 g (0.3 to 0.4 g/cm ² ) of brazing material 4 is sandwiched between the bottom surface of the Mo layer 1 of this bonding material 3 and the heat storage material 5, and the amount is 10 ^-5 Torr or less. Place it in a vacuum furnace maintained at a high vacuum. In a vacuum furnace, while applying a load of 300 to 500 g/ ^cm2 , heat to a temperature above the melting point of the brazing material of 1550 to 1750°C to melt the brazing material to form the brazing material 4, and hold for 5 to 30 minutes. do. Thereafter, it is cooled to room temperature while maintaining a high vacuum. At this time, the thickness of the brazing material layer is 0.1 to 0.2 mm, and the protruding brazing material is removed by cutting or the like to form a finished product. Of these targets, when the boundary between the heat storage material 5 and the brazing material 4, that is, the brazed part, was analyzed by X-ray diffraction, no formation of metal carbides that could cause peeling etc. was observed. Ta. In addition, in order to evaluate the bonding strength of the brazed portion, a transverse rupture strength test was conducted in which a concentrated load was applied to the bonded portion between the laminate material 3 and the heat storage material 5, that is, the brazing material 4. The method will be explained with reference to FIGS. 2 and 3. FIG. 2 shows a test piece for a high-temperature bending test according to an example of the present invention, and FIG. 3 shows a high-temperature testing machine.
First, from the laminated material of molybdenum and graphite, the length is 30 mm, the width (w) is 5 mm, and the joint part 9 of molybdenum 7 and graphite 8 is the center.
Second to fifth test pieces 10,1 with a thickness (t) of 1 mm
I got 0... Next, as shown in Fig. 3, each test piece 10, 10, . . .
1 and 12 were set as supporting ends. In this state, the load (L) concentrated on the brazed part 9 is applied to the hard bar 1.
Added via 3. Rigid bar 1 placed on the support end
The horizontal distance (span d) of 1 and 12 is 20 mm, and the transverse rupture force (F) can be adjusted by adjusting the load (L) in stages.
It is possible to measure up to 1/10Kg/ ^mm2 . The above test piece was placed in a furnace with a vacuum level of 10 ^-5 Torr or less.
Heating at 1200℃ for 10 minutes, test pieces 10, 10,...
..., measure the minimum load at break (Lmin) and calculate the transverse rupture force (F)
was calculated using the following formula. Table 1 shows the results.
Shown below. F=2/3×Lmin×d/w×t ₂ where w is the width of the test piece 5 mm, t is the thickness of the test piece 1 mm, d is the span 20 mm, and Lmin is the minimum load at breakage. Next, a heat cycle test will be described. In hydrogen, tungsten plate electrically heated body 15
A brazed test piece having the same shape as the above bending test piece was placed on top of the test piece, and the presence or absence of breakage of the brazed portion 9 was confirmed by repeatedly turning on and cutting off the current under the following conditions. Heating temperature: 1100 to 1300°C, heating time: 30 seconds, heating time: 30 seconds, cycle: 10 times The results are shown in Table 1. In addition, the first and sixth comparative example test pieces, which were made under the same conditions, are also described.

[Table] Here, the mark ○ in the heat cycle test column indicates no breakage. From Table 1, it can be seen that those using a brazing filler metal with a chemical composition of 5 to 20% by weight of Ru and the balance Pd have a higher high-temperature transverse rupture strength (F) than conventional targets that have almost no transverse rupture strength.
Moreover, there was no breakage in the heat cycle test. On the other hand, as a result of the bending test at room temperature, all of the test pieces 10 using the brazing filler metal with the chemical composition shown in Table 1 had
It was confirmed that the bond did not break at the brazed portion 9, was blocked by the graphite base material 8, and had a bonding strength greater than that of the base material 8. [Effects of the Invention] As explained above, according to the present invention, metal carbides that cause peeling are not generated, and the metal carbide dissolves well in graphite and exhibits good bonding strength.
On the other hand, it has very good wettability with the Mo side and enables uniform brazing, so the bonding strength is excellent not only at room temperature but also at high temperatures. A rotating anode for wire tubes is obtained. Furthermore, according to the present invention, it has a Getter effect that absorbs gas components (particularly hydrogen gas),
A rotating anode for an X-ray tube with excellent voltage resistance that absorbs trace gas components inside the X-ray tube and acts to create a higher vacuum can be obtained.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a rotating anode for an X-ray tube according to an embodiment of the present invention, FIG. 2 is a view showing a high temperature bending test piece used to confirm the effects of the present invention, and FIG. FIG. 3 is a diagram showing a high temperature bending tester for testing the test piece shown in FIG. 2. FIG. 4 is a diagram for explaining a heat cycle test of the test piece shown in FIG. In the figure, 1 is a Mo layer, 2 is a Re-W alloy layer, 3 is a bonding material, 4 is a brazing material, 5 is a heat storage material, 6 is a frame,
9 is a brazed joint, and 10 is a test piece.

Claims (1)

[Claims] 1. A lamination material formed by laminating a W or W alloy layer on a Mo or Mo alloy layer, a heat storage material containing graphite, and a brazing material consisting of 5 to 30% by weight Ru-Pd. X-rays, characterized in that the brazing material is interposed between the Mo or Mo alloy layer of the laminated material and the heat storage material to bond the laminated material and the heat storage material. Rotating anode for pipes. 2. A preparation step of preparing a bonding material formed by bonding a W or W alloy layer to a Mo or Mo alloy layer, a heat storage material containing graphite, and a brazing material consisting of 5 to 30% by weight Ru-Pd; In a vacuum, the brazing material is interposed between the Mo or Mo alloy layer of the laminated material and the heat storage material,
A method for manufacturing a rotating anode for an X-ray tube, comprising a brazing step of heating while applying a load, melting the brazing material, and then cooling.