JPH01195643A - Laminating material and rotary anode for x-ray tube - Google Patents

Abstract

PURPOSE:To obtain a laminating material with small warping deformation on an inclined portion at a high temperature in a large structure by forming a three-layer laminated structure. CONSTITUTION:A substrate 1 has a disk and an inclined portion 1a extended from the peripheral section of this disk and is provided with a truncated cone shape with a uniform thickness as a whole. A through hole 2 is provided at the center of the substrate 1, the material of the substrate 1 is formed with Mo or Mo alloy, for example, a thin film layer 7 made of Re-W alloy containing 5% of Re is laminated on the inclined portion 5 of the outer face 3 inclined by about 10 deg. against the flat face of the substrate 1. A thin film layer 8 made of W or W alloy is laminated on the inclined portion 6 of the inner face 4 of the substrate 1, a three-layer structure is formed with the substrate 1 and the thin film layers 7 and 8. The warping deformation of the inclined portion is eliminated by the three-layer structure of this laminating material, thereby no displacement of the focal point of X-rays occurs.

Description

Detailed Description of the Invention [Industrial Field of Application J] The present invention relates to a laminated material of high-melting point metals, particularly a laminated material f4 having a three-layer laminated structure, and a rotating anode for an X-ray tube for high loads. It is related to.

[Prior art] Generally, a rotating anode for an X-ray tube (hereinafter referred to as a target)
is required to withstand high loads and have a high melting point. As a target that meets these demands, there is a two-layered target in which a thin film layer made of Re-W or Re-Mo is housed on a base material layer formed into a whole shape or a truncated cone shape.

FIG. 7(a) shows an example of the above-mentioned target. As shown in the figure, the target has a truncated conical base layer 71 having a through hole in the center, and a thin film layer 72 attached to the outer edge surface of the inclined portion of the base layer 71. In this example, the base layer 71 is made of Mo, while the thin film layer 72 is made of Re-W. A target in which a heat storage material made of graphite is joined by brazing to the flat part of the lower surface of the base material layer 71 of the second horizontal body has also been proposed.

By further improving the characteristics of such targets, high f
In order to use the target as a target for heavy loads, a method is adopted in which the target itself is made larger and thicker, and the heat storage capacity of the target is increased.

[Problems to be Solved by the Invention] Although this method of increasing the size of the target can increase the heat capacity, it also increases the mass of the target itself. There have been problems such as causing various problems in terms of speed and lengthening the time required to reach a steady rotational speed.

For example, when a target having a two-layer laminated structure shown in FIG. 7(a) is used under high load conditions with a large cycle load, the thin Ifi layer 72 is locally heated to high temperatures.

In this case, due to the difference in thermal expansion coefficient between the thin film layer 72 and the base material layer 71, the thin film layer 72 is deformed into a concave shape as shown in FIG. 7(b). This warping deformation is large at the conical surface of the two-layer structure target soto, which is the highest temperature, that is, at the X-ray generation part.
At room temperature, the amount of warpage may be as large as 0.3i+n.

This warpage will be explained using the drawings. FIG. 9 is a schematic diagram of a conventional laminated material with a two-fT4 structure. The linear expansion coefficient of the material 91 shown in the figure is α1, the cross-sectional area A+, Young's modulus El, and the linear expansion coefficient of the material 92 is α2, Cross-sectional area A2
, Young's modulus E2, it is assumed that no stress occurs initially, and the temperatures of material 91 and material *192 are t, ,
t, [C] up y? The thermal stress generated in the materials 91 and 92 is reduced to σ1. If σ2 is assumed, then it can be expressed as follows.

Since the positive and negative signs of σ1 and σ2 are opposite, it can be seen that warping occurs, and furthermore, the material 91 is made of Mo (α1 is 3.7 to 5, 3
x I O-6), material 92W (α2 is 4.5-7X
10-'), α2 × α, so it will warp in a concave shape.

In FIG. 7(a), the MO of the truncated conical inclined part
Or, since the coefficient of thermal expansion on the MO alloy layer 71 side is larger than that on the Re-W lamination layer 72 side, thermal stress generated in the dissimilar metal lamination materials is caused, as shown in FIG. 7(b). R
Permanent strain, ie, warping, occurs in which the surface of the e-W layer becomes concave. The amount of warpage is approximately 0.3 cm at most for a length of 30 cm, but it becomes more noticeable as the diameter of the target lens increases. In other words, in order to use it as a high-load target, it is necessary to increase the heat storage capacity by increasing the size as much as possible, but this increase in size causes warping.

This kind of warping is caused by the focal position of the generated X-rays shifting,
A problem arises in that the rotational balance deteriorates. In addition, when the material is made of graphite and used as a soldering target, separation occurs between the base material layer made of Mo and the soldering part of the graphite heat storage material, resulting in poor thermal conductivity.
This caused the inconvenience of breakage.

The object of the present invention has been made in view of the above-mentioned drawbacks, and the object of the present invention is to provide a laminate material having a width of 3R4 in which warping deformation does not occur in the inclined portion of the truncated cone even when the heat storage capacity increases, that is, even when the size increases. It is to provide.

Furthermore, the purpose of the pond of the present invention is to prevent warping of the truncated conical inclined portion under high loads at the joint between the base material layer and the heat storage material. An object of the present invention is to provide a rotating anode for an X-ray tube that can prevent separation and breakage and has stable performance.

[Means for Solving the Problems] According to the present invention, the first material 7'1 has one surface and a back surface opposite to the one surface, has a substantially truncated conical shape in cross section, and a first material formed of a second material having a coefficient of thermal expansion different from that of the first material; a second thin film layer attached to the sloped portion of the back surface of the base layer and formed of a third material having a coefficient of thermal expansion substantially equal to that of the second material; A laminate material is obtained, characterized in that the first and second thin film layers have substantially equal cross-sections in said cross-section.

Further, according to the present invention, a base material layer comprising a first surface, a back surface opposite to the first surface, having a substantially truncated conical cross-sectional shape, and formed of a first material; A first thin film layer attached to the truncated conical inclined portion on one surface of the material layer and formed of a second material different in thermal expansion coefficient from the first material, and a back surface of the base material layer. a second thin film layer formed of a third material having a coefficient of thermal expansion substantially equal to that of the second material; A rotating anode for an X-ray tube is obtained, characterized in that the layers have a heat storage material layer on the bottom surface of the base material of the laminated material, the layers having substantially the same cross section in the cross section.

Here, the method for preventing warping of the laminated material according to the present invention will be explained.

FIG. 8 shows lamination 411 of lamination materials according to the present invention.
It is a schematic diagram showing an I structure. Linear expansion coefficient α3 of material 81,
Assuming that the cross-sectional area A3 and Young's modulus Es are the linear expansion coefficient α1.1 of the material 82, the cross-sectional area Aa, the non-cross-sectional area A4', and the Young's modulus E4, the material 81.4'4 f-'+ 82 shown in the figure is initially It is assumed that no stress is generated, and from this state material 8
1. The thermal stress generated in the upper and lower parts of the material 81 and the material 82 by increasing the temperature of the material 82 by ts and t4 [°C], respectively, is σ1. σ4. Letting σ4′,
If σ is compression, then from equation (2), (2)', (2
1" formula can be found immediately.

(2)'', (2)', if the cross-sectional areas of the upper and lower parts of the illustrated material 82 are equal, no warping occurs because the magnitudes of the stresses σ2.σ,' are the same.

If the cross-sectional area of the upper and lower parts of the material 82 is made equal, the upper and lower parts will be generated by σ2. Since σ4' is pulled with the same magnitude and balanced, no warping of the bonded material occurs.

In this way, the occurrence of warping of the laminate material having the laminate M3'a and the inclined portion of the rotary anode for an X-ray tube can be prevented by keeping the thermal stress generated on the upper and lower surfaces of the sloping portion even. In order to prevent this warping, conventionally, a laminated O1 structure having a thin film layer on the sloped part on one surface of the base material has a triple structure in which a thin film layer is also laminated on the sloped part of the back surface.

Furthermore, the thin film layer bonded to the back surface cannot have the same shape because a heat storage material with a large heat capacity is provided on the bottom surface of one surface of the bonding material. For this reason, by configuring the base material layer to have the same cross-sectional area as the X-ray generating part of W or W alloy so that the thin film layer on the front surface and the thin film layer on the back surface can maintain substantially the same expansion coefficient. Even if the cross-sectional shapes of the front and back thin film layers are different, it will warp! A JJ stop is performed.

In addition, in the present invention, the base of the strung m corpse, 1'4
A brazing filler metal such as Ru-Pd, which has excellent high-temperature transverse rupture strength and melting point, can be used for bonding with a heat storage material, which has been conventionally used, but the type of bonding method is not limited.

[Example] Embodiments of the present invention will be described with reference to the drawings.

Example 1 FIG. 1 is a sectional view showing a laminated structure according to an example of the present invention. As shown in the figure, the base material 1 has a disk and an inclined portion 121 extending from the periphery of the disk, and has an overall truncated cone shape with a -like thickness. here,
The surface 5 of the convex base material 1 directed upward in the figure is the outer surface 3
The other concave surface 4 facing downward is called the inner surface, and a through hole 2 is provided in the center of the base material 1.

The material of the base material 1 is made of Mo or Mo alloy. A thin film layer 7 made of a Re-W alloy containing 5% Re is laminated onto the inclined portion 5 of the outer surface 3 which is inclined by about 10 degrees with respect to the flat surface of the base material 1.

Further, a thin film layer 8 made of W or W alloy is laminated to the inclined portion 6 of the inner surface 4 of the base material 1, and the base material 1 and the thin film layers 7 and 8 form a three-layer structure. ing. Thin film layer 7 and thin film layer 8 have substantially the same area in a cross section through the center of the illustration. This means that thin film layers 7 and 8 have substantially the same thickness and
Even when viewed from above, it means that they have the same shape, that is, they have a congruent relationship.

Example 2 FIG. 2 shows the f of a rotating electrode for an X-ray tube according to an example of the present invention.
It is a sectional view showing a four-body configuration. In this figure, the base material 10 of the rotating electrode for an X-ray tube has a truncated conical shape between the lines in FIG. 1, but compared to the base material 1 in FIG. '! 31 portion is shortened, and as a result, the flat portion of the inner surface is widened. A through hole 11 is provided in the center of the base material 10, and the base material 10
The heat storage material 1 is placed on the flat surface at the center of the inner surface of the
2 are joined. This heat storage material 12 is made of high-purity, high-density graphite. The base material 10 is M
One inclined surface 13 of the group +410 made of o or Mo alloy
A thin 11i layer 14 made of 5% Re-W alloy is laminated thereon. In addition, a thin film layer 16 made of W or W alloy is laminated on the inclined portion 15 of the base material 10 surrounding the heat storage material 12 attached to the base material. As shown in FIG. 14 is thin IB on the inner surface! Thinner in thickness or wider in bonding area than the layer,
As a result, the thicknesses and bonding areas (widths) of the thin film layers 14 and 16 are selected such that the thin film layers 14 and 16 have substantially equal areas in the illustrated cross-section. In this way, making the thickness of the thin film layer 16 7'7' requires exposing the inner surface of the base material 10 widely in accordance with the outer diameter of the heat storage material 12, and the thin film layer 16 is This is because, of course, there are restrictions. In this way, by making the cross-sectional areas of the thin film layers 14 and 16 equal, the VJj absorption rate of the thin film layer 14 on the surface of the inclined portion 10a can be adjusted to
o Smaller than swelling. Therefore, when the base material 10 made of Mo expands, the outer edge portions 10a on both sides of the base material 10 are held down by a substance with the same expansion coefficient, and since this thermal stress is equal on both surfaces, the inclined portion 10a of the base material layer 10 Does not cause warping.

The equal area structure of the upper thin film layer is the result of trying to maximize the heat capacity of the graphite brazed to the bottom surface of the laminated material V.

Measurement of the amount of warpage of a laminated material according to an example of the present invention will be explained. FIG. 3 shows the laminate material 1 according to the present invention.
An example of a test piece is shown. The test piece in this figure is a prismatic Mo
A base material 18 is provided, and a hole A m+ is provided on the upper surface of the base material 18.
A thin film layer 19 made of 5% Re-W of n, and a thin layer 20 made of pure W having a thickness of AIII++ are provided on the bottom surface of the Mo base material 18. FIG. 4 shows a test piece of a laminated material according to a comparative example. The test piece in this figure has a negative side of 15
It has a prismatic base material 40 with a length of 30 mm, and a thin layer 1 [WNJltt made of a 5% Re-W alloy with a thickness of 1 Bw is laminated on the upper surface of the base material 40.

FIG. 5 shows the heat cycle test method.

A = 1 m+ and A-2m+ according to the embodiments described.
B = 1 + n + n and [3
= 2 n+m test piece subjected to heat cycle test 9
The heat cycle test method was carried out as follows. A tungsten plate current-carrying resistance heating element 21 as shown in FIG.
The test was conducted under the following test conditions by placing the device on top of the device and turning the power ON and OFF.

The heating temperature was within the range of 1100° C. to 2100° C., the R heating time was about 1 minute, the cooling time was about 30 seconds, and the number of cycles was 30 times.

After the above-mentioned cycle treatment, the amount of warpage of the test piece was measured at room temperature using a stylus shape measuring machine.

FIG. 6 is a side view showing warpage in the length direction of the heat cycle test piece of the test piece of FIGS. 3 and 4. In the figure, the warpage of the test piece is indicated by j (μl). -side 1
], the length L is 15+n+n, respectively.

There is 30tnm″'C″.

Table 1 shows the measurement results of the test piece according to the example and the test piece according to the comparative example.

Margin table below 1 As is clear from this table, the two-layer laminated M4 specimen according to the comparative example has a large amount of warpage, and as the thickness B of the thin film layer increases, the warpage tends to decrease. In other words, it can be seen that if there is variation in the thickness of the thin film layer, 1 g will be added to the amount of warpage. In contrast, the three-layer lamination 4 according to the example
The specimen made in 1111 has almost no warping. Furthermore, it was found that even if there were variations in thickness, there was little effect on the amount of warpage.

I. Effects of the Invention] As explained above, according to the present invention, even when the heat storage capacity increases, that is, when the size is increased, it is possible to obtain a laminated material with less warping deformation of the inclined portion at high temperatures. Due to the three-layer structure of this laminated material, there is no warp deformation of the inclined part, so the rotating anode/pole for high-load X-ray tubes is stable with good rotational balance and does not cause deviation of the X-ray focal point. can be provided.

Further, according to the present invention, there is little warping deformation of the inclined portion, so that peeling or breakage of the joint between the base material of the rotary anode for an X-ray tube and the brazing material of the heat storage material can be prevented.

Margin below

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a three-layer structure of a laminated material according to an embodiment of the present invention, FIG. 2 is a sectional view showing a rotating anode for an X-ray tube according to an embodiment of the present invention, and FIG. , FIG. 4 is a perspective view showing a first cycle test piece according to an example of the present invention, FIG. 4 is a diagram showing a first cycle test piece according to a comparative example, and FIG.
A diagram showing a heat cycle test method according to an embodiment of the present invention, FIG. 6 is an explanatory diagram of warping of a heat cycle test piece, and FIG.
FIG. 7(a) is a diagram showing a two-layer structure of the laminated material according to the conventional example, FIG. 7(b) is a diagram for explaining the warping deformation of the laminated material in FIG. The figure is a diagram for explaining the warping deformation of the laminated material according to the present invention, and FIG. 9 is a diagram for explaining the warping deformation of the conventional laminated material. In the figure, 1 and 10 are base material layers, 2 and 11 are through holes, 5 and 13 are surface sloped portions, 6 and 15 are back surface sloped portions, 7 and 14 are thin WA layers, 8 and 16 are thin film layers, and 12 are It is a heat storage material. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Scope of Claims] 1. A base material layer comprising one surface and a back surface opposite to this one surface, having a substantially truncated conical cross-sectional shape, and formed of a first material; A first thin film layer attached to the truncated conical inclined portion on one surface of the base layer and formed of a second material having a coefficient of thermal expansion different from that of the first material, and the base layer. a second thin film layer formed of a third material having a coefficient of thermal expansion substantially equal to that of the second material, the first and second thin film layers being attached to the sloped portion of the back surface of the A laminate material having substantially equal cross-sectional areas in the cross section. 2. The laminate material according to claim 1, wherein the second thin film layer is made of a Re-W alloy containing 5% Re by weight. 3. The laminated material according to claim 1 or 2, wherein the second thin film layer and the third thin film layer have the same cross-sectional shape. 4. A rotating anode for an X-ray tube, characterized in that it has a heat storage material layer on the bottom surface of the base material of the laminated material according to claim 1 or claim 2.