JP2000057981A - Heat radiating member, rotary anode type x-ray tube using the radiating member, and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a member having excellent heat radiation characteristic and strong heat resistance by mixing ceramic and metal, and changing the ratio of the ceramic and the metal in the thickness direction. SOLUTION: In the case of using a roller of a rotary anode type X-ray tube as a material to be sprayed for example, a rotor 41 is rotated, and plasma flame 32 is generated from a plasma spraying gun 31, and the plasma spraying gun 31 is reciprocated in the longitudinal direction of the rotor 41 once so as to heat the rotor 41. Then, only a metal material s supplied to the plasma flame, and the plasma spraying gun 31 is reciprocated once so as to form a surface of the rotor 41 with a film of the metal material. The ceramic material and the metal material at 3:7 in weight ratio are supplied to the plasma flame 32 at the same time, and the plasma spraying gun 31 is reciprocated once. Thereafter, the similar operation is performed at 1:1, 7:3 in weight ratio. Finally, a film made of the only ceramic is formed. A film having thickness at several 10 μm to 100 μm over the whole is thereby formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat radiation member which improves the heat emissivity of an anode target portion and a rotor portion constituting a rotary anode type X-ray tube and has good adhesiveness, and uses the same. The present invention relates to a rotating anode type X-ray tube and a method for producing the same.

[0002]

2. Description of the Related Art An X-ray tube accelerates an electron beam under the action of a strong electric field in a vacuum, collides and decelerates a high-speed electron beam with an anode target, and emits X-rays by bremsstrahlung at that time. It has a structure. However, the energy of the electron beam that contributes to the generation of X-rays is about 1%, and the rest is emitted as heat. Therefore, when the X-ray tube is in the operating state, the temperature of the anode target portion that collides with the electron beam and the temperature of the rotor portion that rotates integrally with the anode target increase. Therefore, a heat-radiating coating is provided on the anode target surface other than the irradiation with the electron beam or on the outer surface of the rotor to radiate heat.

[0003] Thermal radiation coatings formed on the anode target surface and the outer surface of the rotor other than the irradiation with the electron beam include:
In consideration of emissivity and heat resistance, titania (Ti
Oxides containing O2) have been used. In addition, in consideration of productivity, etc., the method of forming the heat-radiating film involves melting the above-mentioned oxide powder with a plasma flame and, at the same time, melting the oxide melted with a high-speed jet stream on the outer surface of the anode target or the rotor. The plasma spraying method of spraying the liquid is used.

[0004] The anode target and the rotor on which the heat-radiating coating is formed by the plasma spraying method are then degassed and baked by vacuum heat treatment, and X
Incorporated into a wire tube.

Incidentally, the anode target and the rotor of the rotary anode type X-ray tube rotate at a high speed of about 10,000 rpm in an operating state. At the same time, the anode target is heated by the impact of the electron beam, and the temperature of the portion impacted by the electron beam instantaneously rises to about 2000 ° C. The surface temperature of the rotor reaches several hundred degrees centigrade due to heat radiation and heat conduction of the anode target.

For this reason, materials for the anode target include molybdenum, tungsten, molybdenum alloy,
Tungsten alloys and the like are used. Then, in order to enhance the heat emission characteristics, a heat-resistant heat-radiating coating, for example, 60% by weight alumina (Al2 O3) -40% by weight titania (TiO2) is applied to the surface other than the surface irradiated with the electron beam.
Is formed.

[0007] The rolling bearing incorporated in the rotor portion is made of a high-melting-point, high-hardening high-speed steel so as to withstand conditions such as a vacuum environment, high-speed rotation, and high temperature. However, the quenching temperature for increasing the hardness of high-speed steel is about 500 ° C. For this reason, it is necessary to keep the temperature of the rolling bearing at 500 ° C. or less even during the operation of the X-ray tube. Therefore, a conventional rotary anode type X-ray tube has a thermal spray coating of an oxide containing titania having a high emissivity and excellent heat resistance, for example, 60% by weight alumina (Al2 O3)-.
A thermal spray coating of 40% by weight titania (TiO2) is formed on the rotor surface to improve the heat release characteristics and suppress the temperature rise of the rolling bearing.

[0008]

SUMMARY OF THE INVENTION 60% by weight alumina
The thermal spray coating of 40% by weight titania has a high emissivity and good heat resistance, and is suitable for a heat radiation coating of a rotary anode X-ray tube. However, in the case of the anode target, the above-mentioned sprayed coating adheres to the anode target only by mechanical biting. Therefore, if a thermal shock, a thermal cycle, or a centrifugal force is applied during the operation, the thermal spray coating may be peeled off. Peeling of the thermal spray coating reduces the heat radiation performance of the anode target. Further, when the peeled sprayed coating enters the space between the cathode and the anode target of the X-ray tube, a discharge is caused to deteriorate the withstand voltage characteristics.

In the case of a rotor, the thermal expansion difference between the thermal spray coating and copper, which is the material of the rotor, is large. For example, copper (Cu), alumina (Al2 O3), titania (TiO2), aluminum titanate (Al2 TiO5)
8) shows the coefficient of thermal expansion at room temperature in FIG. As can be seen from the figure, aluminum titanate (Al2 TiO5) formed by the combination of alumina and titania during plasma spraying has a coefficient of thermal expansion at room temperature of about 1 that of copper.
/ 10.

Therefore, the manufacturing process of the X-ray tube, for example,
In a vacuum heat treatment or exhaust process for degassing the rotor on which the sprayed coating is formed, the sprayed coating may be subjected to a thermal cycle or thermal shock, and cracks may be generated in the sprayed coating. Also,
During operation of the X-ray tube, the thermal spray coating may be subjected to a thermal cycle, and at the same time, the thermal spray coating on the rotor surface may be peeled off due to centrifugal force due to high speed rotation. Such peeling of the thermal spray coating lowers the heat radiation performance of the rotor. In addition, when the peeled sprayed coating enters between the cathode and the anode target of the X-ray tube, a discharge is caused to deteriorate the withstand voltage characteristics.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned drawbacks, and has a heat radiation member excellent in heat radiation characteristics and resistant to thermal shock, a rotating anode type X-ray tube using the heat radiation member, and a method of manufacturing the same. The purpose is to provide.

[0012]

Means for Solving the Problems The heat radiation member of the present invention comprises:
It is characterized in that ceramic and metal are mixed and the ratio between the ceramic and the metal varies in the thickness direction.

According to another aspect of the present invention, there is provided a rotary anode type including a cathode for emitting an electron beam, an anode target having a region for generating X-rays by the impact of the electron beam, and a rotor to which the anode target is connected. In the X-ray tube, the above-mentioned heat radiation member is formed on the surface of the rotor.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. 1 taking a rotating anode type X-ray tube as an example. Reference numeral 11 denotes a vacuum envelope made of glass constituting a rotary anode type X-ray tube, and a cathode 12 is eccentrically arranged in the vacuum envelope 11. In addition, an umbrella-shaped anode target 13 is arranged to face the cathode 12. The anode target 13 is made of a high melting point metal such as molybdenum or tungsten, or
The impact portion 13a which is made of such an alloy and collides with the electron beam is made of a rhenium-tungsten alloy.

The anode target 13 is fixed to a rotor 15 via a shaft 14. The rotor 15 is a vacuum envelope 1
The anode target 13 is rotated by the action of the stator 16 disposed outside the apparatus. Further, inside the rotor 15, a rolling bearing is provided between the rotor 15 and a fixed body (not shown).

When the rotating anode X-ray tube having the above-described structure is put into an operating state, an electron beam is emitted from the cathode 12 and collides with the rhenium-tungsten alloy impact portion 13 a on the anode target 13. Rises. When the temperature of the anode target 13 rises, the temperature of the rolling bearing inside the rotor 15 connected by the shaft 14 also rises.

At this time, if the temperature rise is remarkable, the impact portion 1
The rhenium-tungsten alloy 3a may melt. Therefore, the thermal spray coating 17 having good heat radiation is formed on a portion other than the impact portion 13a of the anode target 13 where the electron beam collides, for example, on the back surface of the anode target 13 to enhance the heat dissipation property and to melt the impact portion 13a. I'm preventing.

The rotor 15 is made of copper or the like having excellent thermal conductivity, and a thermal spray coating 15a having good heat radiation is formed on the surface of the rotor 15. Thermal spray coating 15a
It is composed of a thermal spray material (hereinafter, referred to as a ceramic material) composed of 60% by weight of alumina and 40% by weight of titania, and a thermal spray material (hereinafter, referred to as a metallic material) composed of copper. And it has an inclined structure in which the mixing ratio of the ceramic material and the metal material changes in the thickness direction.

The rolling bearing inside the rotor 15 is made of high-speed steel or the like. High speed steels decrease in hardness when annealed. Therefore, the thermal spray coating 15 a is provided on the surface of the rotor 15 to suppress the temperature rise of the rotor 15.

Here, the anode target 13 and the rotor 15
A plasma spraying apparatus for forming a sprayed coating 15a will be described with reference to FIG. Reference numeral 21 denotes a control panel for controlling peripheral devices, and power is supplied from a power supply 22. The control panel 21 controls a supply operation of the carrier gas and the discharge gas to, for example, the first and second carrier gas sources 231 and 232 and the first and second discharge gas sources 241 and 242.

First and second carrier gas sources 231 and 23
2 stores argon (Ar) as a carrier gas. The first discharge gas source 241 contains argon (Ar) serving as a discharge gas.
2 stores hydrogen (H2) as a discharge gas.
Then, under the control of the control panel 21, argon is sent out from the first discharge gas source 241 and supplied to the plasma spraying device 25. The control panel 21 controls the second discharge gas source 24
Hydrogen is sent out from 2 and supplied to the plasma spraying device 25. The plasma spray device 25 mixes argon and hydrogen, and generates a plasma flame by DC arc discharge.

The powdery thermal spray material is conveyed to the plasma thermal spraying device 25 as follows. That is, similarly to the above, under the control of the control panel 21, the argon delivered from the first and second carrier gas sources 231 and 232 respectively
It is sent to the first and second thermal spray material supply devices 261 and 262. First and second thermal spray material supply devices 261, 2
Numeral 62 supplies the powdered ceramic material and the metal material stored in each to the plasma spraying device 25 by the action of argon gas.

The plasma spray device 25 supplies the ceramic material and the metal material supplied from the first and second spray material supply devices 261 and 262 into a plasma flame, melts these materials, and simultaneously jets the materials. Spray on the stream.

The position of the plasma spraying device 25 can be moved by an automatic feeder 27.

The plasma spraying apparatus 25 has a supply port 281
A cooling system is provided for supplying cooling water from the cooling device and discharging the cooling water that has cooled the plasma spraying device 25 from an outlet 282. And, the plasma spraying device 25 and the automatic feeder 2
The operation of 7 is controlled by the control panel 21 similarly to other peripheral devices.

Next, the plasma spraying device 25 will be described with reference to FIG.
Will be described with reference to the schematic diagram of FIG. Reference numeral 31 denotes a plasma spray gun to which a mixed gas of argon and hydrogen is supplied from first and second discharge gas sources 241 and 242, and a plasma flame 32 is generated by a DC arc discharge.
Occurs. A first supply port 331 and a second supply port 332 are disposed in front of the plasma spray gun 31 so as to face each other. The first supply port 331 is provided with the first spray material supply device 26.
The ceramic material housed in 1 is sent through the pipe P1. The second supply port 332 is filled with a metal material stored in the second thermal spray material supply device 262 by a pipe P.
Sent through 2.

The ceramic and metal materials sent to the first and second supply ports 331 and 332 are supplied to the control panel 2.
Under the control of 1, each of them is supplied to the plasma flame 32 independently, or each is simultaneously, or at a different mixing ratio. And plasma flame 32
The ceramic material and the metal material supplied therein are melted and sprayed by spraying a jet stream onto an object to be sprayed 34 such as an anode target or a rotor of a rotary anode X-ray tube.

At this time, during the spraying, the plasma spray gun 31 controls the arrows Y1 and Y1 under the control of the automatic feeder 27 (FIG. 2).
For example, as shown in FIG.
It can be moved along the direction of extension.

Next, a method of forming a thermal spray coating on the object 34 will be described with reference to FIG. 4, taking as an example a case where the object 34 is a rotor of a rotary anode type X-ray tube. In FIG. 4, portions corresponding to FIG. 3 are denoted by the same reference numerals, and a duplicate description will be partially omitted.

Reference numeral 31 denotes a plasma spray gun, and a rotor 41 is disposed in front of the gun. The outer surface of the rotor 41 is blasted. One end of the rotor 41 has a shaft 41 a supported by a three-way chuck 42, and the other end supported by a tailstock 43. The left end of the rotor 41 and a part of the three-way chuck 42 are surrounded by a cylindrical jig 44. A mask steel material 45 is arranged between the right end of the rotor 41 and between the tailstock 43 and the plasma spray gun 31.

In the case of the above arrangement, the range of the arrow Y1 sandwiched between the jig 44 and the mask steel material 45, that is, the rotor 41
A thermal spray coating is formed on the surface in a range indicated by oblique lines A.

First, the three-way chuck 42 and the tailstock 43 are rotated to rotate the rotor 41 in the direction of arrow Y2. At the same time, plasma flame 32
Generate. Then, the plasma spray gun 31 is reciprocated once in the longitudinal direction of the rotor 41 without supplying the ceramic material or the metal material, and the rotor 41 is heated.

Next, only the metal material is supplied to the plasma flame 32, the plasma spray gun 31 is reciprocated once, and the
A coating of a metal material is formed on the surface.

Next, the ceramic material and the metal material are simultaneously supplied to the plasma flame 32 at a weight ratio of 3: 7, the plasma spray gun 31 is reciprocated once, and the coating mixed at the above weight ratio is applied to the metal material. Formed on the film.

Next, the ceramic material and the metal material are supplied to the plasma flame 32 at a weight ratio of 1: 1.

Next, the ceramic material and the metal material are supplied to the plasma flame 32 at a weight ratio of 7: 3.

As described above, a sprayed coating in which a ceramic material and a metal material are mixed is sequentially formed, and finally, a coating of only the ceramic material is formed.

In this way, a total of several tens μm to one
A sprayed coating having a thickness in the range of about
Formed on one surface.

Thereafter, the rotor 41 on which the sprayed coating is formed
Is subjected to a vacuum heat treatment at 750 ° C. for 3 hours to perform a degassing treatment.

Here, in order to confirm the effectiveness of the present invention, the rotor on which the thermal spray coating was formed was heated at 800 ° C.
A hydrogenation treatment was performed five times for 10 minutes, and a peeling test was performed with a cellophane tape. As a result, no peeling of the thermal spray coating was observed. In addition, as a result of measuring the average emissivity from room temperature to the use temperature of the sprayed coating after the hydrogen treatment, the emissivity was 0.9 or more. I was not able to admit.

Next, in the configuration shown in FIG.
The method of forming a thermal spray coating will be described with reference to FIGS. 5 and 6, taking as an example the case where is an anode target of a rotating anode X-ray tube. 5 and 6, parts corresponding to those in FIG. 3 are denoted by the same reference numerals, and overlapping description is partially omitted.

In FIG. 5, reference numeral 31 denotes a plasma spray gun.
Below the anode target 61 is disposed. The base material of the anode target 61 is made of a molybdenum alloy, and the impact portion (part of the lower surface in the figure) of the electron beam is made of rhenium-tungsten. Also, the side opposite to the surface irradiated with the electron beam (upper surface in the figure) is subjected to blast processing, and a thermal spray coating 62 composed of a plurality of layers is formed thereon as described later. A screw hole 63 having a diameter of 10 mm is provided at the center, and a stainless rod 64 having a length of about 200 mm and a diameter of 14 mm is fixed to the screw hole 63.

In the above configuration, first, the stainless steel rod 64 is supported by a three-way chuck (not shown). Next, the three-way chuck is rotated, and the anode target 61 is rotated in the arrow Y direction. At the same time, the plasma spray gun 31
To generate a plasma flame 32. Then, in a state where the ceramic material or the metal material is not supplied to the plasma flame 32,
The anode target 61 is heated. The anode target 61 is heated by the plasma flame 32 as shown by the arrow Z in FIG.
Is about 20 m in the radial direction from the center of the anode target 61.
It is performed by making one round trip horizontally so as to pass through a point separated by m.
In the case of this embodiment, the distance between the anode target 61 and the plasma spray gun 31 is about 80 mm, and the plasma spray gun 31 moves in a direction perpendicular to the plane of the paper of FIG.

Thereafter, a ceramic material or a metal material is supplied to the plasma flame 32, and a thermal spray coating 62 composed of a plurality of layers as shown in FIG. 7 is formed on the surface of the anode target 61. For example, first, only the metal material (molybdenum) is supplied to the plasma flame 32, the plasma spray gun 31 is reciprocated once, and the anode target 6 heated in the above-described process is heated.
For 1, a first thermal spray coating 51 made of a metal material is formed.

Next, the ceramic material and the metal material are simultaneously supplied to the plasma flame 32 so that the weight ratio of the ceramic material and the metal material becomes 3: 7, and the plasma spray gun 31 is reciprocated once to make the above-mentioned reciprocation. A second layer spray coating 52 mixed at a weight ratio is formed on the spray coating 51.

Next, the ceramic material and the metal material are simultaneously supplied to the plasma flame 32 so that the weight ratio of the ceramic material and the metal material becomes 1: 1, and the plasma spray gun 31 is reciprocated once. A third thermal spray coating 53 mixed at a weight ratio is formed on the thermal spray coating 52.

Next, the ceramic material and the metal material are simultaneously supplied to the plasma flame 32 so that the weight ratio of the ceramic material and the metal material becomes 7: 3, and the plasma spray gun 31 is reciprocated once to make the above-mentioned reciprocation. A fourth layer thermal spray coating 54 mixed at a weight ratio is formed on the thermal spray coating 53.

Finally, only the ceramic material is supplied to the plasma flame 32 to form the fifth layer of the thermal spray coating 55 on the thermal spray coating 54.

As described above, a total of several tens μm to one
A thermal spray coating 62 composed of the first to fifth layers is formed on the surface of the anode target 61 to a thickness of about 00 μm. Thereafter, the anode target 61 on which the thermal spray coating 62 is formed is subjected to a vacuum heat treatment at 1500 ° C. for 3 hours to perform a degassing process.

Here, in order to confirm the effectiveness of the present invention,
For the anode target on which the thermal spray coating was formed, 1100
Hydrogen treatment was performed five times at 10 ° C. for 10 minutes, and a peeling test was performed using a cellophane tape. As a result, no peeling of the thermal spray coating was observed. In addition, when the average emissivity from room temperature to the use temperature was measured for the sprayed coating after the hydrogen treatment, the emissivity was 0.9 or more, and the emissivity of the sprayed coating decreased due to diffusion of molybdenum, a constituent material of the sprayed coating. Was not found.

Further, the anode target manufactured by the above-mentioned method was incorporated into a rotating anode X-ray tube and used for 10,000 hours in a sealed state. Further, the rotor manufactured by the above-described method was incorporated in a rotating anode X-ray tube and used in a sealed state for 10,000 hours. In these cases, peeling of the sprayed coating was not observed during use. Thereafter, the rotating anode X-ray tube was disassembled, and a peeling test of the thermal spray coating was performed using a cellophane tape. As a result, no peeling of the thermal spray coating was observed, and strong film adhesion was realized.

In the above embodiment, the ratio of the weight ratio between the ceramic material and the metal material is changed stepwise with the passage of time. However, it is also possible to change the weight ratio so that, for example, the ratio of the ceramic material gradually increases over time. Further, the ratio of the weight ratio between the ceramic material and the metal material is also one example, and the ratio of the weight ratio can be appropriately selected according to the conditions.

In the above embodiment, 60% by weight of alumina and 40% by weight of titania ceramic are used as the ceramic material. However, as a ceramic material, alumina (Al2 O3), titania (TiO2),
From among materials of zirconia (ZrO2), silica (SiO2), calcia (CaO), yttria (Y2 O5), a mixture containing any of the above materials, and a compound containing any of the above materials At least one selected can be used.

The plasma arc spraying is performed in the atmosphere. However, in the case of so-called reduced pressure spraying in which the thermal spraying is performed in an inert gas (for example, argon) of several Torr, a reliable thermal spray coating can be obtained.

As described above, in the present invention, for example,
When the heat radiating object is a metal such as an anode target or a rotor, the inclined structure is such that the ratio of the metal material is increased on the side of the heat radiating object and the ratio of the ceramic material is increased on the side of the surface exposed to the outside. With such a structure, it is possible to realize a heat radiation medium which is stable against severe heat load, has high mechanical strength at high speed rotation, and has good heat radiation. Further, by providing this heat radiation medium on an anode target or a rotor for a rotating anode X-ray tube, for example, a rotating anode X-ray tube having a severe heat load, high speed rotation, and good heat radiation can be realized.

[0056]

According to the present invention, heat radiation characteristics are excellent,
A heat radiation member that is resistant to thermal shock, a rotating anode X-ray tube using the heat radiation member, and a method for manufacturing the same can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a schematic structure of a whole rotary anode X-ray tube to which the present invention is applied.

FIG. 2 is a block diagram illustrating a plasma spraying system used in the present invention.

FIG. 3 is a schematic view showing a plasma spray gun used in the present invention.

FIG. 4 is a schematic configuration diagram for explaining an embodiment of the present invention.

FIG. 5 is a schematic configuration diagram for explaining another embodiment of the present invention.

FIG. 6 is a schematic configuration diagram for explaining a moving direction of a plasma spray gun used in the present invention.

FIG. 7 is a schematic configuration diagram for explaining an example of a thermal spray coating according to the present invention.

FIG. 8 is a diagram for explaining a coefficient of thermal expansion of a material used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Vacuum envelope, 12 ... Cathode, 13 ... Anode turret, 14 ... Shaft 15 ... Rotor 15a ... Thermal radiation spray coating 31 ... Plasma spray gun, 32 ... Plasma flame, 331, 332 ... Spray material supply port 41 ... Rotor, 42: three-way chuck 43: tailstock 44: jig 45: mask steel,

Claims (14)

[Claims] 1. A ceramic and metal mixture is formed,
The ratio of the ceramic and the metal varies in the thickness direction. 2. A ceramic and metal mixture is formed,
A heat radiation member, wherein the proportion of the ceramic is higher on the side closer to the surface that becomes the heat release surface. 3. A front surface portion serving as a heat emission surface is formed of a ceramic layer, a back surface portion is formed of a metal layer, and a ceramic and a metal are mixed between the ceramic layer and the metal layer. The heat radiation member, wherein a portion closer to the surface portion has a higher proportion of the ceramic. 4. The ceramic is made of alumina (Al 2 O 3).
), Titania (TiO2), zirconia (ZrO2),
At least one material selected from silica (SiO2), calcia (CaO), yttria (Y2 O5), a mixture containing any of the above materials, and a compound containing any of the above materials The heat radiation member according to any one of claims 1 to 3, wherein the heat radiation member is a heat radiation member. 5. The method according to claim 1, wherein the metal is copper.
The heat radiation member according to any one of the above. 6. A ratio in which a first sprayed material of ceramic and a second sprayed material of metal are supplied at different ratios into a plasma flame generated by arc discharge, and the first sprayed material and the second sprayed material are mixed. A method for manufacturing a heat radiation member, wherein the thickness of the heat radiation member is changed in the thickness direction. 7. The ceramic is made of alumina (Al2 O3).
), Titania (TiO2), zirconia (ZrO2),
At least one material selected from silica (SiO2), calcia (CaO), yttria (Y2 O5), a mixture containing any of the above materials, and a compound containing any of the above materials The method for manufacturing a heat radiation member according to claim 6. 8. The method according to claim 6, wherein the metal is copper. 9. A rotary anode X-ray tube comprising: a cathode for emitting an electron beam; an anode target having an area for generating X-rays by the impact of the electron beam; and a rotor to which the anode target is connected. A rotating anode type X-ray tube having the heat radiation member according to any one of claims 1 to 3 formed on a surface of the rotor. 10. A rotary anode X-ray tube comprising: a cathode for emitting an electron beam; an anode target having an area for generating X-rays by the impact of the electron beam; and a rotor to which the anode target is connected. A rotating anode type X-ray tube having a heat radiation member according to any one of claims 1 to 3 formed on a portion of said anode target which is not impacted by said electron beam. 11. The rotating anode X-ray tube according to claim 10, wherein the metal is molybdenum or a molybdenum alloy. 12. The ceramic is made of alumina (Al 2 O 3).
), Titania (TiO2), zirconia (ZrO2)
), Silica (SiO2), calcia (CaO), yttria (Y2 O5), a mixture containing any of the above-mentioned materials, and a compound containing any of the above-mentioned materials. The rotating anode X-ray tube according to claim 9 or 10, wherein the number is at least one. 13. A first thermal spray material of ceramic and a second thermal spray material of metal are supplied at different ratios into a plasma flame generated by arc discharge, and the first thermal spray material and the second thermal spray material are mixed. Forming a coating for heat radiation whose proportion changes in the thickness direction on the rotor surface of the rotating anode type X-ray tube;
A step of fixing an anode target having a region for generating X-rays by the impact of an electron beam to the rotor on which the coating for thermal radiation is formed, and applying a vacuum to the rotor to which the anode target is fixed and a cathode for generating the electron beam. A method of manufacturing a rotating anode type X-ray tube, comprising the step of disposing the rotating anode type X-ray tube in an envelope. 14. A first thermal spray material of ceramic and a second thermal spray material of metal are supplied at different ratios into a plasma flame generated by an arc discharge, and mixed with the first thermal spray material and the second thermal spray material. Forming a heat radiation coating whose ratio changes in the thickness direction on a portion of the anode target of the rotary anode X-ray tube which is not impacted by electron beams; and forming a rotor on the anode target on which the heat radiation coating is formed. And a step of arranging the rotor to which the anode target is fixed and the cathode for generating the electron beam in a vacuum envelope.