A surface composite layer of a rotating anode target and a preparation method thereof, and a repair method of a rotating anode target

Abstract

The present invention provides a surface composite layer of a rotating anode target, a preparation method thereof, and a repair method of the rotating anode target, wherein the surface composite layer comprises: a substrate layer, a transition layer, and a tungsten-rhenium alloy surface layer; the composition of the transition layer comprises: Re 0-30wt%, W 0-20wt%, and both do not include 0, and the remainder is Mo; the stress state of the interface between the substrate layer and the transition layer is compressive stress, and the stress state of the interface between the transition layer and the tungsten-rhenium alloy surface layer is tensile stress. The surface composite layer and the repair method provided by the present invention improve the interface bonding force and strength between the tungsten-rhenium surface layer and the original TZM substrate, improve the service performance of the rotating anode target disk, and do not produce interface failure after long-term thermal cycle testing.

Description

Technical Field

[0001] The invention belongs to the technical field of metal surface treatment, and relates to a method for repairing a rotating anode target, in particular to a surface composite layer of a rotating anode target, a preparation method thereof, and a method for repairing a rotating anode target. Background Art

[0002] CT (Computerized X-ray Tomography) is a rapidly developing X-ray imaging technology in modern times. It uses X-ray beams to perform layer-by-layer scanning and uses computer processing to produce detailed images of internal structures. It has the advantages of high imaging resolution and simple operation, and is widely used in medical examinations, industrial inspections, etc. The rotating anode X-ray tube is an important part of the medical CT system. It generates X-rays by generating electrons bombarding the rotating anode target. The rotating anode target is the core component of the X-ray tube.

[0003] The common rotating anode target is based on TZM alloy (molybdenum zirconium titanium alloy), and a layer of tungsten-rhenium alloy is compounded on the upper surface as the track layer. During the use of the rotating anode target, it is bombarded by high-energy electrons, and the local temperature can exceed 1600°C. Long-term and harsh service conditions will cause the tungsten-rhenium layer on the surface of the target to crack, produce microcracks, and ultimately affect the imaging effect of X-rays. Once the tungsten-rhenium layer of the anode target is cracked, the entire target or even the entire tube will be scrapped, causing great waste. Therefore, it is of great value to seek an effective target repair method so that the target can be reused.

[0004] CN116275862A discloses a method for repairing a molybdenum-tungsten alloy composite rotating target, which includes six steps: checking target plate defects, mechanical treatment, preliminary filling, electron beam cladding, stress relief annealing and post-treatment. The specific method is to mechanically treat the target plate defects, remove attachments and oxide layers, cover the target plate defects with repair materials, and then cover the entire target surface, and then perform electron beam cladding and stress relief annealing; the method melts the repair material into liquid and infiltrates it into the substrate defects. On the one hand, the tungsten-rhenium alloy material has a high melting point, and the cladding method has high power and high cost. On the other hand, the defects are partially repaired, and the integrity of the resulting metal layer is poor, and cracks are still easily caused in the later period, and it is not resistant to long-term use.

[0005] CN117779023A discloses a method for preparing and repairing an X-ray tube anode target disk, in which a ring-shaped area is limited to the damaged area on the target disk surface for removal, and then a high-energy beam cladding powder additive manufacturing method is used in the ring-shaped area to form a working layer structure including a target disk substrate and an N-layer tungsten-containing layer structure; this method also adopts a method of locally repairing the defects of the target material, and the bonding strength and integrity of the repaired part with the substrate and the overall surface layer are poor, which is still easy to cause cracking in the later stage. In addition, the use of powder cladding will also cause oxygen segregation at the tungsten grain boundary, causing brittle cracking. In addition, the above two local repair methods can only target specific local areas, such as irregular or subtle distribution of defects or cracks on the target disk surface, and all defects cannot be completely eliminated, resulting in incomplete repair and still causing obstacles to later use.

[0006] Therefore, based on the deficiencies of the prior art, the present invention provides a surface composite layer of a rotating anode target and a preparation method thereof, and a repair method of a rotating anode target. Summary of the invention

[0007] The purpose of the present invention is to provide a surface composite layer of a rotating anode target and a preparation method thereof and a repair method of the rotating anode target. By matching the components of the surface composite layer and designing the stress state, the rotating anode target can be effectively repaired and the bonding strength and service performance of the surface layer of the rotating anode target can be improved.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a surface composite layer of a rotating anode target, the surface composite layer comprising: a substrate layer, a transition layer and a tungsten-rhenium alloy surface layer;

[0010] The transition layer comprises: Re 0-30wt%, W 0-20wt%, both excluding 0, and the balance is Mo;

[0011] The stress state of the interface between the substrate layer and the transition layer is compressive stress, and the stress state of the interface between the transition layer and the tungsten-rhenium alloy surface layer is tensile stress.

[0012] The surface composite layer of the rotary anode target provided by the present invention is designed with a layer structure of a base layer, a transition layer and a tungsten-rhenium alloy surface layer, the base layer is the same TZM alloy as the rotary anode target, and a transition layer composed of Re, W and Mo is arranged in the base layer and the tungsten-rhenium alloy surface layer. Under the composition ratio of Re, W and Mo of the present invention, Re and W can diffuse with Mo to form a single solid solution phase, avoiding the formation of brittle intermetallic compounds, and enhancing the interface bonding force and strength of the composite layer without the need to add other strengthening elements. At the same time, the interlayer interface between the base layer and the transition layer is designed to be in a compressive stress state, and the interlayer interface between the transition layer and the tungsten-rhenium alloy surface layer is designed to be in a tensile stress state. The rotary anode target disk will generate thermal stress along the thickness direction during use. Through the coordination of the stress state between the composite layers and the mutual offset of the stress state, the interface peeling that is easy to occur during the use of the repaired rotary anode target is solved, and the service performance of the rotary anode target disk is improved.

[0013] In the present invention, in the transition layer, the content of Re is 0-30wt%, excluding 0, for example, it can be 0.001wt%, 0.01wt%, 0.1wt%, 0.5wt%, 1wt%, 5wt%, 10wt%, 15wt%, 20wt%, 25wt% or 30wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0014] In the present invention, in the transition layer, the content of W is 0-20wt%, excluding 0, for example, it can be 0.001wt%, 0.01wt%, 0.1wt%, 0.5wt%, 1wt%, 5wt%, 10wt%, 15wt% or 20wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0015] Preferably, the compressive residual stress at the interface between the transition layer and the base layer is 500-2000 MPa, for example, 500 MPa, 800 MPa, 1000 MPa, 1200 MPa, 1500 MPa, 1800 MPa or 2000 MPa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0016] Preferably, the tensile residual stress at the interface between the transition layer and the tungsten-rhenium alloy surface layer is 500-2000 MPa, for example, 500 MPa, 800 MPa, 1000 MPa, 1200 MPa, 1500 MPa, 1800 MPa or 2000 MPa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0017] Preferably, in the transition layer, the content of Re is distributed in a gradient along the thickness direction of the transition layer, and the gradient distribution is specifically: from the surface layer of the tungsten-rhenium alloy to the substrate layer, the transition layer is equally divided into n layers along the thickness direction, and the content of Re in the i-th layer is (i-1) / n×30wt% to i / n×30wt%, and the range of n is 2-5.

[0018] In the present invention, n is an integer in the range of 2-5, for example, 2, 3, 4 or 5, and i is one layer in n.

[0019] Preferably, in each layer, the content of W is 0-60wt% of the content of Re, excluding 0, and the balance is Mo.

[0020] In the present invention, in each layer of the transition layer, the content of W is 0-60% of the content of Re, excluding 0, for example, it can be 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55% or 60%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0021] Preferably, the composition of the tungsten-rhenium alloy surface layer includes: Re 3-25wt%, and the balance is W.

[0022] In the present invention, the Re content in the surface layer of the tungsten-rhenium alloy is 3-25wt%, for example, it can be 3wt%, 5wt%, 10wt%, 15wt%, 20wt% or 25wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0023] Preferably, in the tungsten-rhenium alloy surface layer, the Re content is distributed in a gradient along the thickness direction of the tungsten-rhenium alloy surface layer, and the gradient distribution is specifically: the tungsten-rhenium alloy surface layer is divided into m layers along the thickness direction, from the matrix layer to the tungsten-rhenium alloy surface layer is the inner layer to the outer layer direction, the Re content in the innermost layer is 5-25wt%, the Re content in the outermost layer is 3-10wt%, and the Re content in the remaining layers is 3-25wt%, and the range of m is 2-10.

[0024] In the present invention, m is an integer in the range of 2-10, for example, it can be 2, 3, 4, 5, 6, 7, 8, 9 or 10.

[0025] In the present invention, the Re content in the innermost layer of the tungsten-rhenium alloy surface layer is 5-25wt%, for example, it can be 5wt%, 10wt%, 15wt%, 20wt% or 25wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0026] In the present invention, the Re content in the outermost layer of the tungsten-rhenium alloy surface is 3-10wt%, for example, it can be 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt% or 10wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0027] In the present invention, the content of Re in the remaining layers of the tungsten-rhenium alloy surface layer is 3-25wt%, for example, it can be 3wt%, 5wt%, 10wt%, 15wt%, 20wt% or 25wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0028] In the present invention, the content of Re element in the surface layer of tungsten-rhenium alloy is set to be a gradient distribution, and the content of Re element in the inner layer is relatively high, which can significantly improve the plasticity of Mo-Re-W alloy and play a thermal stress buffering effect. The content of Re element in the outermost layer is relatively low, and the cost is controllable.

[0029] Preferably, the thickness of the base layer is 0.005-0.5 mm, for example, 0.005 mm, 0.01 mm, 0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm or 0.5 mm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0030] Preferably, the thickness of the transition layer is 0.01-0.1 mm, for example, 0.01 mm, 0.03 mm, 0.05 mm, 0.08 mm or 0.1 mm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0031] Preferably, the thickness of the tungsten-rhenium alloy surface layer is 0.5-2 mm, for example, 0.5 mm, 0.8 mm, 1.0 mm, 1.2 mm, 1.5 mm, 1.8 mm or 2 mm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0032] In a second aspect, the present invention provides a method for preparing a surface composite layer of a rotating anode target as described in the first aspect, the preparation method comprising the following steps:

[0033] (1) a substrate layer and a transition layer are sequentially prepared on a rotating anode target substrate by physical vapor deposition and / or thermal spraying, and then a tungsten-rhenium alloy surface layer is prepared on the transition layer by chemical vapor deposition;

[0034] (2) The deposited rotating anode target is subjected to hot isostatic pressing to obtain a rotating anode target having a surface composite layer.

[0035] The method for preparing a surface composite layer provided by the present invention forms a substrate layer and a transition layer with an interface compressive stress state by physical vapor deposition and / or thermal spraying, forms a tungsten-rhenium alloy surface layer with an interface tensile stress state by chemical vapor deposition, achieves coordination of stress states between composite layers, improves interlayer bonding force and strength of the surface of a rotating anode target, and then further densifies the composite layer by hot isostatic pressing. Compared with the cladding method of the prior art, the prepared composite layer has high density, low oxygen impurity content, and excellent mechanical properties.

[0036] Preferably, the physical vapor deposition in step (1) includes but is not limited to any one of multi-arc ion plating, high-pulse magnetron sputtering or ion beam assisted deposition, or a combination of at least two thereof.

[0037] Preferably, the deposition current of the physical vapor deposition in step (1) is 10-500A, for example, 10A, 50A, 100A, 200A, 300A, 400A or 500A, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0038] Preferably, the temperature of the physical vapor deposition in step (1) is 300-600°C, for example, 300°C, 350°C, 400°C, 450°C, 500°C, 550°C or 600°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0039] Preferably, the bias voltage of the physical vapor deposition in step (1) is 50-300 V, for example, 50 V, 100 V, 150 V, 200 V, 250 V or 300 V, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0040] Preferably, the thermal spraying in step (1) includes but is not limited to any one of arc spraying, plasma spraying or supersonic flame spraying, or a combination of at least two of them.

[0041] Preferably, the powder feeding rate of the thermal spraying in step (1) is 5-35 g / min, for example, it can be 5 g / min, 10 g / min, 15 g / min, 20 g / min, 25 g / min, 30 g / min or 35 g / min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0042] Preferably, the shielding gas flow rate of the thermal spraying in step (1) is 20-50 L / min, for example, it can be 20 L / min, 25 L / min, 30 L / min, 35 L / min, 40 L / min, 45 L / min or 50 L / min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0043] Preferably, the power of the thermal spraying in step (1) is 25-50 kW, for example, 25 kW, 30 kW, 35 kWn, 40 kW, 45 kW or 50 kW, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0044] Preferably, the particle size of the spray powder for thermal spraying in step (1) is 20-50 μm, for example, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm or 50 μm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0045] Preferably, the chemical vapor deposition (CVD) in step (1) includes but is not limited to any one of atmospheric pressure CVD, reduced pressure CVD, plasma CVD or hot filament CVD, or a combination of at least two thereof.

[0046] Preferably, the raw material gas for the chemical vapor deposition in step (1) includes WF6 and ReF6.

[0047] Preferably, the volume ratio of WF6 and ReF6 is (6-10):1, for example, it can be 6:1, 7:1, 8:1, 9:1 or 10:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0048] Preferably, the temperature of the chemical vapor deposition in step (1) is 500-800°C, for example, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C or 800°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0049] Preferably, the time of the chemical vapor deposition in step (1) is 2-10 h, for example, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h or 10 h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0050] Preferably, the temperature of the hot isostatic pressing in step (2) is 1300-1500°C, for example, it can be 1300°C, 1320°C, 1350°C, 1380°C, 1400°C, 1420°C, 1450°C, 1480°C or 1500°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0051] Preferably, the pressure of the hot isostatic pressing in step (2) is 130-200 MPa, for example, 130 MPa, 140 MPa, 150 MPa, 160 MPa, 170 MPa, 180 MPa, 190 MPa or 200 MPa, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0052] Preferably, the hot isostatic pressing time in step (2) is 1-3 h, for example, 1 h, 1.5 h, 2 h, 2.5 h or 3 h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0053] In a third aspect, the present invention provides a method for repairing a rotating anode target, the method comprising the following steps:

[0054] The tungsten-rhenium layer and a part of the thickness of the substrate are removed from the rotary anode target disc to be repaired, and the surface is pretreated. Then, the surface composite layer described in the first aspect is prepared on the pretreated rotary anode target disc to obtain a rotary anode target with a surface composite layer. After machining, the repair is completed.

[0055] The repair method provided by the present invention removes the tungsten-rhenium layer with cracks on the target disk to be repaired as a whole, and removes part of the TZM alloy substrate to ensure that all cracks are completely removed, and then deposits a surface composite layer on the rotating target disk substrate. Compared with the repair method of local cladding in the prior art, the repair method provided by the present invention avoids the hidden danger of cracks caused by missed defects during repair, thereby affecting the overall performance of the repaired target disk. At the same time, by adopting an integral coating deposition method, the surface layer has good integrity, high interface bonding strength, low impurity content, excellent performance, and low cost.

[0056] Preferably, the removal thickness of the substrate is 0.1-1 mm, for example, it can be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm or 1 mm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0057] Preferably, the surface pretreatment includes machining, cleaning and degreasing, and drying.

[0058] Preferably, the machining is performed to a surface roughness Ra<0.6, for example, it may be 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5 or 0.59, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0059] Preferably, the surface roughness Ra of the controlled rotating anode target disk after machining is 0.1-0.8, for example, it can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7 or 0.8, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0060] Compared with the prior art, the present invention has the following beneficial effects:

[0061] (1) The surface composite layer of the rotating anode target provided by the present invention is designed with a layer structure of a substrate layer, a transition layer and a tungsten-rhenium alloy surface layer. By regulating the composition of the transition layer and the stress state between the layers, the interface bonding force and strength between the surface composite layers are improved, the density is high, and the service performance of the rotating anode target disk is improved;

[0062] (2) The repair method of the rotating anode target provided by the present invention adopts a method of integrally removing defects and preparing the surface layer by overall deposition to avoid the hidden danger of cracks. The surface layer has good integrity, high interface bonding strength, low impurity content and excellent performance. The repaired anode target disk undergoes more than 1,000 thermal cycle simulation tests without interface failure, delamination and through cracks. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 is a schematic diagram of the cross-sectional structure of the rotating anode target disc to be repaired provided in Application Example 1;

[0064] Figure 2 is a schematic diagram of the cross-sectional structure of the repaired rotating anode target provided in Application Example 1;

[0065] Among them, 1-damaged tungsten-rhenium surface after service; 2-crack; 3-TZM matrix to be removed; 4-retained TZM matrix; 5-TZM matrix; 6-matrix layer; 7-transition layer; 8-tungsten-rhenium alloy surface; 901-interface between matrix layer and transition layer; 902-interface between transition layer and tungsten-rhenium alloy surface. DETAILED DESCRIPTION

[0066] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0067] In order to clearly illustrate the technical solution of the present invention, in a specific implementation manner, the hardness of the deposited layer is determined by a Vickers hardness method, and the residual stress of the deposited layer is determined by an X-ray residual stress detection method. The X-ray residual stress detection method is specifically as follows: the strain of a plane crystal plane whose characteristic direction is a normal vector is calculated according to the Bragg diffraction equation, and the object to be measured uses a standard block co-deposited with the furnace.

[0068] In the present invention, the direction from the substrate layer to the surface layer of the tungsten-rhenium alloy is the inner layer to the outer layer.

[0069] Example 1

[0070] This embodiment provides a surface composite layer of a rotating anode target, wherein the surface composite layer includes: a substrate layer, a transition layer and a tungsten-rhenium alloy surface layer.

[0071] The composition of the base layer includes: Zr 0.1wt%, Ti 0.5wt%, and the balance is Mo; the thickness of the base layer is 0.05mm.

[0072] The transition layer comprises: Re 10wt%, W 5wt%, and the balance Mo; and the thickness of the transition layer is 0.01mm.

[0073] The composition of the tungsten-rhenium alloy surface layer includes: W 97wt%, Re 3wt%; the thickness of the tungsten-rhenium alloy surface layer is 1.3mm.

[0074] The compressive residual stress at the interface between the substrate layer and the transition layer is 1500 MPa, the tensile residual stress at the interface between the tungsten-rhenium alloy surface layer and the transition layer is 1200 MPa, and the surface hardness of the surface composite layer is 350 HV. 0.2 .

[0075] The preparation method of the surface composite layer comprises the following steps:

[0076] (1) Depositing a TZM substrate layer on the surface of a rotating anode target substrate, using a TZM target as a target material and adopting multi-arc ion plating for deposition, wherein the process parameters of the multi-arc ion plating include: a vacuum degree of 5×10 -3 Pa, arc current is 250A, bias voltage is 100V, deposition temperature is 500℃, and deposition time is 15h;

[0077] (2) Depositing a Mo-Re-W transition layer on the TZM substrate layer, using a Mo-Re-W target as a target material, and adopting multi-arc ion plating for deposition. The process parameters of the multi-arc ion plating include: vacuum degree of 5×10 -3 Pa, arc current is 250A, bias voltage is 100V, deposition temperature is 500℃, and deposition time is 3h;

[0078] (3) depositing a W-Re surface layer on the transition layer by chemical vapor deposition, wherein the process parameters of the chemical vapor deposition include: raw gas is WF6 and ReF6, the volume ratio of WF6 to ReF6 is 10:1, the deposition temperature is 700°C, and the deposition time is 3 hours;

[0079] (4) The deposited rotating anode target is subjected to hot isostatic pressing treatment, the hot isostatic pressing pressure is 130 MPa, the hot isostatic pressing temperature is 1500° C., and the heat and pressure are maintained for 2 hours to obtain the surface composite layer.

[0080] Example 2

[0081] This embodiment provides a surface composite layer of a rotating anode target, wherein the surface composite layer includes: a substrate layer, a transition layer and a tungsten-rhenium alloy surface layer.

[0082] The composition of the base layer includes: Zr 0.1wt%, Ti 0.5wt%, and the balance is Mo; the thickness of the base layer is 0.3mm.

[0083] The direction from the substrate layer to the surface layer of the tungsten-rhenium alloy is from the inner layer to the outer layer.

[0084] The transition layer is divided into three layers, which are: the first transition layer, the second transition layer and the third transition layer from the outer layer to the inner layer; the composition of the first transition layer includes: Re 5wt%, W 2wt%, and the balance is Mo; the composition of the second transition layer includes: Re 15wt%, W 8wt%, and the balance is Mo; the composition of the third transition layer includes: Re 25wt%, W 10wt%, and the balance is Mo; the thickness of each transition layer is 0.03mm; the total thickness of the transition layer is 0.09mm.

[0085] The surface layer of the tungsten-rhenium alloy is divided into three layers, which are: a first surface layer, a second surface layer and a third surface layer from the outer layer to the inner layer; the composition of the first surface layer includes: W 95wt%, Re 5wt%, and a thickness of 0.7mm; the composition of the second surface layer includes: W 90wt%, Re 10wt%, and a thickness of 0.2mm; the composition of the third surface layer includes: W 75wt%, Re 25wt%, and a thickness of 0.1mm; the total thickness of the tungsten-rhenium alloy surface layer is 1.0 mm.

[0086] The compressive residual stress at the interface between the substrate layer and the transition layer is 800 MPa, the tensile residual stress at the interface between the tungsten-rhenium alloy surface layer and the transition layer is 1000 MPa, and the surface hardness of the surface composite layer is 382 HV. 0.2 .

[0087] The preparation method of the surface composite layer comprises the following steps:

[0088] (1) Depositing a TZM substrate layer on the surface of a rotating anode target substrate, using TZM alloy powder as a raw material and adopting a plasma spraying method for deposition, wherein the process parameters of the plasma spraying include: a plasma gas Ar flow rate of 40 L / min, a spraying power of 35 kW, and a powder feeding rate of 25 g / min;

[0089] (2) Depositing a Mo-Re-W transition layer on the TZM substrate layer by plasma spraying, mixing tungsten-rhenium-molybdenum powder according to the composition, and the particle size range of the powder is 30-50 μm. The process parameters of the plasma spraying include: the flow rate of plasma gas Ar is 30 L / min, the spraying power is 50 kW, and the powder feeding rate is 15 g / min;

[0090] (3) depositing a W-Re layer on the transition layer by chemical vapor deposition, wherein the process parameters of the chemical vapor deposition include: the raw gas is WF6 and ReF6, firstly WF6 and ReF6 are deposited at a deposition temperature of 500°C for 0.5 h in a volume ratio of 6:1, then the volume ratio of WF6 and ReF6 is adjusted to 8:1 and deposited at 600°C for 1 h, and finally the volume ratio of WF6 and ReF6 is adjusted to 10:1 and deposited for 2 h;

[0091] (4) The deposited rotating anode target is subjected to hot isostatic pressing at a pressure of 200 MPa and a temperature of 1300° C. The hot isostatic pressing is maintained for 1 hour to obtain the surface composite layer.

[0092] Example 3

[0093] This embodiment provides a surface composite layer of a rotating anode target, wherein the surface composite layer includes: a substrate layer, a transition layer and a tungsten-rhenium alloy surface layer.

[0094] The composition of the base layer includes: Zr 0.1wt%, Ti 0.5wt%, and the balance Mo; the thickness of the base layer is 0.5mm.

[0095] The direction from the substrate layer to the surface layer of the tungsten-rhenium alloy is from the inner layer to the outer layer.

[0096] The transition layer is set to 5 layers, which are: the first transition layer, the second transition layer, the third transition layer, the fourth transition layer and the fifth transition layer from the outer layer to the inner layer; the composition of the first transition layer includes: Re 5wt%, W2wt%, and the balance is Mo; the composition of the second transition layer includes: Re 10wt%, W 5wt%, and the balance is Mo; the composition of the third transition layer includes: Re15wt%, W 8wt%, and the balance is Mo; the composition of the fourth transition layer includes: Re 20wt%, W 10wt%, and the balance is Mo; the composition of the fifth transition layer includes: Re 25wt%, W 10wt%, and the balance is Mo; the thickness of each transition layer is 0.02mm; the total thickness of the transition layer is 0.1mm.

[0097] The tungsten-rhenium alloy surface layer is set to 10 layers, from the outer layer to the inner layer: the first surface layer, composed of W 97wt%, Re 3wt%; the second surface layer, composed of W 95wt%, Re 5wt%; the third surface layer, composed of W 93wt%, Re 7wt%; the fourth surface layer, composed of W 90wt%, Re 10wt%; the fifth surface layer, composed of W 88wt%, Re 12wt%; the sixth surface layer, composed of W 85wt%, Re 15wt%; the seventh surface layer, composed of W 82wt%, Re 18wt%; the eighth surface layer, composed of W 80wt%, Re20wt%; the ninth surface layer, composed of W 78wt%, Re 22wt%; the tenth surface layer, composed of W 75wt%, Re 25wt%; the thickness of the first surface layer is 0.5mm, and the thickness of the remaining 9 layers is 0.1mm; the total thickness of the tungsten-rhenium alloy surface layer is 1.4mm.

[0098] The compressive residual stress at the interface between the substrate layer and the transition layer is 800 MPa, the tensile residual stress at the interface between the tungsten-rhenium alloy surface layer and the transition layer is 1000 MPa, and the surface hardness of the surface composite layer is 376 HV. 0.2 .

[0099] The preparation method of the surface composite layer comprises the following steps:

[0100] (1) Depositing a TZM substrate layer on the surface of a rotating anode target substrate, using TZM alloy powder as a raw material and adopting a plasma spraying method for deposition, wherein the process parameters of the plasma spraying include: a plasma gas Ar flow rate of 40 L / min, a spraying power of 35 kW, and a powder feeding rate of 25 g / min;

[0101] (2) Depositing a Mo-Re-W transition layer on the TZM substrate layer by plasma spraying, mixing tungsten-rhenium-molybdenum powder according to the composition, and the particle size range of the powder is 30-50 μm. The process parameters of the plasma spraying include: the flow rate of plasma gas Ar is 40 L / min, the spraying power is 50 kW, and the powder feeding rate is 10 g / min;

[0102] (3) depositing a W-Re layer on the transition layer by chemical vapor deposition, wherein the process parameters of the chemical vapor deposition include: the raw gas is WF6 and ReF6, and the volume ratio of WF6 and ReF6 is set to 6:1, 6.3:1, 6.5:1, 6.8:1, 7.0:1, 7.2:1, 7.5:1, 8.0:1 and 8.5:1 in sequence, and the deposition is performed at 500°C for 10 minutes respectively, and finally the volume ratio of WF6 and ReF6 is adjusted to 10:1 and the deposition is performed for 1 hour;

[0103] (4) The deposited rotating anode target is subjected to hot isostatic pressing at a pressure of 200 MPa and a temperature of 1300° C. The hot isostatic pressing is maintained for 1 hour to obtain the surface composite layer.

[0104] Example 4

[0105] This embodiment provides a surface composite layer of a rotating anode target, wherein the surface composite layer includes: a substrate layer, a transition layer and a tungsten-rhenium alloy surface layer.

[0106] The composition of the base layer includes: Zr 0.1wt%, Ti 0.5wt%, and the balance Mo; the thickness of the base layer is 0.02mm.

[0107] The direction from the substrate layer to the surface layer of the tungsten-rhenium alloy is from the inner layer to the outer layer.

[0108] The transition layer comprises: Re 5wt%, W 10wt%, and the balance Mo; and the thickness of the transition layer is 0.03mm.

[0109] The surface layer of the tungsten-rhenium alloy is divided into three layers, which are: a first surface layer, a second surface layer and a third surface layer from the outer layer to the inner layer; the composition of the first surface layer includes: W 95wt%, Re 5wt%, and a thickness of 1.4mm; the composition of the second surface layer includes: W 90wt%, Re 10wt%, and a thickness of 0.4mm; the composition of the third surface layer includes: W 75wt%, Re 25wt%, and a thickness of 0.2mm; the total thickness of the tungsten-rhenium alloy surface layer is 2.0mm.

[0110] The compressive residual stress at the interface between the substrate layer and the transition layer is 1500 MPa, the tensile residual stress at the interface between the transition layer and the surface layer of the tungsten-rhenium alloy is 1000 MPa, and the surface hardness of the surface composite layer is 380 HV. 0.2 .

[0111] The method for preparing the surface composite layer of the rotating anode target comprises the following steps:

[0112] (1) Depositing a TZM substrate layer on the surface of a rotating anode target substrate, using a TZM target as a target material and adopting multi-arc ion plating for deposition, wherein the process parameters of the multi-arc ion plating include: a vacuum degree of 5×10 -3 Pa, arc current is 250A, bias voltage is 100V, deposition temperature is 500℃, and deposition time is 5h;

[0113] (2) Depositing a Mo-Re-W transition layer on the TZM substrate layer, using a Mo-Re-W target as a target material, and adopting multi-arc ion plating for deposition. The process parameters of the multi-arc ion plating include: vacuum degree of 5×10 -3 Pa, arc current is 200A, bias voltage is 80V, deposition temperature is 550℃, and deposition time is 8h;

[0114] (3) depositing a W-Re layer on the transition layer by chemical vapor deposition, wherein the process parameters of the chemical vapor deposition include: the raw gas is WF6 and ReF6, firstly WF6 and ReF6 are deposited at a deposition temperature of 500°C for 0.5 h in a volume ratio of 6:1, then the volume ratio of WF6 and ReF6 is adjusted to 8:1 and deposited at 600°C for 1 h, and finally the volume ratio of WF6 and ReF6 is adjusted to 10:1 and deposited for 5 h;

[0115] (4) The deposited rotating anode target is subjected to hot isostatic pressing at a pressure of 200 MPa and a temperature of 1300° C. The hot isostatic pressing is maintained for 1 hour to obtain the surface composite layer.

[0116] Example 5

[0117] This embodiment provides a surface composite layer of a rotating anode target, wherein the surface composite layer includes: a substrate layer, a transition layer and a tungsten-rhenium alloy surface layer.

[0118] The composition of the base layer includes: Zr 0.1wt%, Ti 0.5wt%, and the balance is Mo; the thickness of the base layer is 0.3mm.

[0119] The direction from the substrate layer to the surface layer of the tungsten-rhenium alloy is from the inner layer to the outer layer.

[0120] The transition layer is divided into three layers, which are: the first transition layer, the second transition layer and the third transition layer from the outer layer to the inner layer; the composition of the first transition layer includes: Re 5wt%, W 2wt%, and the balance is Mo; the composition of the second transition layer includes: Re 15wt%, W 8wt%, and the balance is Mo; the composition of the third transition layer includes: Re 25wt%, W 10wt%, and the balance is Mo; the thickness of each transition layer is 0.03mm; the total thickness of the transition layer is 0.09mm.

[0121] The composition of the tungsten-rhenium alloy surface layer includes: W 97wt%, Re 3wt%; the thickness of the tungsten-rhenium alloy surface layer is 1.3mm.

[0122] The compressive residual stress at the interface between the substrate layer and the transition layer is 800 MPa, the tensile residual stress at the interface between the transition layer and the tungsten-rhenium alloy surface layer is 1200 MPa, and the hardness is 365 HV 0.2 .

[0123] The preparation method of the surface composite layer comprises the following steps:

[0124] (1) Depositing a TZM substrate layer on the surface of a rotating anode target substrate, using TZM alloy powder as a raw material and adopting a plasma spraying method for deposition, wherein the process parameters of the plasma spraying include: a plasma gas Ar flow rate of 40 L / min, a spraying power of 35 kW, and a powder feeding rate of 25 g / min;

[0125] (2) Depositing a Mo-Re-W transition layer on the TZM substrate layer by plasma spraying, mixing tungsten-rhenium-molybdenum powder according to the composition, and the particle size range of the powder is 30-50 μm. The process parameters of the plasma spraying include: the flow rate of plasma gas Ar is 30 L / min, the spraying power is 50 kW, and the powder feeding rate is 12 g / min;

[0126] (3) depositing a W-Re surface layer on the transition layer by chemical vapor deposition, wherein the process parameters of the chemical vapor deposition include: raw gas is WF6 and ReF6, the volume ratio of WF6 to ReF6 is 10:1, the deposition temperature is 700°C, and the deposition time is 3 hours;

[0127] (4) The deposited rotating anode target is subjected to hot isostatic pressing at a pressure of 200 MPa and a temperature of 1300° C. The hot isostatic pressing is maintained for 1 hour to obtain the surface composite layer.

[0128] Comparative Example 1

[0129] This comparative example provides a surface layer of a rotating anode target. Compared with Example 1, the surface layer does not include a transition layer, and the rest is the same as Example 1.

[0130] Comparative Example 2

[0131] This comparative example provides a surface layer of a rotating anode target. Compared with Example 1, the surface layer does not include a substrate layer and a transition layer, but only includes a tungsten-rhenium alloy surface layer. The rest is the same as Example 1.

[0132] Comparative Example 3

[0133] This comparative example provides a surface layer of a rotating anode target. Compared with Example 1, the composition of the transition layer includes: 15wt% W, the balance is Mo, and the rest is the same as Example 1.

[0134] Comparative Example 4

[0135] This comparative example provides a surface composite layer of a rotating anode target. Compared with Example 1, the tungsten-rhenium alloy surface layer is deposited by plasma spraying technology, the thickness of the tungsten-rhenium alloy surface layer is 1.5 mm, the compressive residual stress at the interface between the substrate layer and the tungsten-rhenium surface layer is 500 MPa, and the surface hardness of the surface composite layer is 330 HV. 0.2 , the rest are the same as in Example 1.

[0136] Compared with Example 1, the preparation method of the surface composite layer adopts a plasma spraying method for deposition in step (3), and the tungsten-rhenium-molybdenum powder is mixed according to the composition, and the particle size range of the powder is 30-50 μm. The process parameters of the plasma spraying include: the flow rate of the gas Ar is 40 L / min, the spraying power is 45 kW, and the powder feeding rate is 20 g / min. The rest are the same as in Example 1.

[0137] Application Example 1

[0138] This application example provides a method for repairing a rotating anode target, and the repair method comprises the following steps:

[0139] The target disc to be repaired was subjected to nondestructive testing. The cracks were distributed on the TZM matrix and the surface of the tungsten-rhenium alloy. Figure 1 As shown in FIG. 1 , the deepest crack position has a depth of 1.2 mm. The target disc to be repaired is mechanically polished to the depth, the tungsten-rhenium alloy surface layer and part of the TZM matrix are removed, the surface roughness Ra of the target disc is controlled to be 0.5, and then the target disc is cleaned, degreased and dried. Then, the surface composite layer provided in Example 1 is prepared on the surface of the target disc to obtain a repaired rotating anode target, as shown in FIG. Figure 2 shown.

[0140] Application Example 2

[0141] This application example provides a method for repairing a rotating anode target, and the repair method comprises the following steps:

[0142] The target disc to be repaired was subjected to nondestructive testing. The cracks were distributed on the TZM substrate and the surface layer of the tungsten-rhenium alloy. The depth of the deepest crack position was 1.5 mm. The target disc to be repaired was mechanically polished to this depth, the surface layer of the tungsten-rhenium alloy and part of the TZM substrate were removed, and the surface roughness Ra of the target disc was controlled to be 0.5. Then, the target disc was cleaned, degreased and dried. Then, the surface composite layer provided in Example 2 was prepared on the surface of the target disc. Finally, the excess material was removed by machining, and the roughness of the surface layer was controlled to be 0.5, thereby obtaining a repaired rotating anode target.

[0143] Application Example 3

[0144] This application example provides a method for repairing a rotating anode target, and the repair method comprises the following steps:

[0145] The target disc to be repaired was subjected to nondestructive testing, and cracks were distributed on the TZM substrate and the surface layer of the tungsten-rhenium alloy. The depth of the deepest crack position was 1.5 mm. The target disc to be repaired was mechanically polished to this depth, and the surface layer of the tungsten-rhenium alloy and part of the TZM substrate were removed. The roughness Ra of the target disc surface was controlled to be 0.5, and then the target disc was cleaned, degreased and dried. Then, the surface composite layer provided in Example 3 was prepared on the surface of the target disc. Finally, the excess material was removed by machining, and the roughness of the surface layer was controlled to be 0.5, thereby obtaining a repaired rotating anode target.

[0146] Application Example 4

[0147] This application example provides a method for repairing a rotating anode target. Compared with Application Example 1, a surface composite layer provided in Example 4 is prepared on the surface of the target disk, and the rest is the same as Application Example 1.

[0148] Application Example 5

[0149] This application example provides a method for repairing a rotating anode target. Compared with Application Example 1, a surface composite layer provided in Example 5 is prepared on the surface of the target disk, and the rest is the same as Application Example 1.

[0150] Comparative application example 1

[0151] This comparative application example provides a method for repairing a rotating anode target. Compared with Application Example 1, a surface layer provided in Comparative Example 1 is prepared on the surface of the target disk, and the rest is the same as Application Example 1.

[0152] Comparative Application Example 2

[0153] This comparative application example provides a method for repairing a rotating anode target, and the repair method comprises the following steps:

[0154] The target disc to be repaired is mechanically polished to the interface between the TZM substrate and the surface layer of the tungsten-rhenium alloy, that is, only the surface layer of the tungsten-rhenium alloy is removed. After cleaning, degreasing and drying, the surface layer provided in Comparative Example 2 is deposited on the surface of the target disc. Finally, the excess material is removed by machining, and the roughness of the surface layer is controlled to be 0.5 to obtain a repaired rotating anode target.

[0155] Comparative Application Example 3

[0156] This comparative application example provides a method for repairing a rotating anode target. Compared with Application Example 1, a surface composite layer provided in Comparative Example 3 is prepared on the surface of the target disk, and the rest is the same as Application Example 1.

[0157] Comparative Application Example 4

[0158] This comparative application example provides a method for repairing a rotating anode target. Compared with Application Example 1, a surface composite layer provided in Comparative Example 4 is prepared on the surface of the target disk, and the rest is the same as Application Example 1.

[0159] Performance Testing

[0160] The rotating anode target plate repaired by the repair method provided in the application example and the comparative application example was subjected to a vacuum steady-state thermal shock test to simulate the service environment of the tube. The parameters of the vacuum steady-state thermal shock test include: the vacuum degree is less than 10 -5 , voltage 60kV, beam current 6-15mA, after 100000 times of thermal cycle shock, optical instrument is used to detect the cross section to obtain the defect situation at the interface, and observe whether there is failure between the target disk TZM and the tungsten-rhenium layer. The judgment basis is interface separation or the occurrence of through cracks. The results are listed in Table 1.

[0161] Table 1

[0162] As can be seen from Table 1, the repair method provided by the present invention adopts a layer structure design of a surface composite layer on the surface of the rotating anode target substrate for repair, and the surface hardness of the repaired anode target is maintained at 350 HV 0.2 As mentioned above, the mechanical properties are good, the chemical vapor deposition of the tungsten-rhenium alloy surface can ensure good density and purity, the target disk has good impact resistance, and no interface failure and obvious defects occur after thermal cycle shock. A stable interface state is maintained to ensure the long-term service stability of the target disk. In particular, when the element content of the transition layer and the tungsten-rhenium alloy surface layer is distributed in a gradient, the performance is better.

[0163] Compared with Application Example 1, there is no buffer layer in Comparative Application Example 1, cracks remain during repair in Comparative Application Example 2, and a brittle buffer layer without rhenium element is set in Comparative Application Example 3. Under the action of thermal stress and thermal fatigue, the interface is prone to cracking; in Comparative Application Example 4, plasma spraying is used, which will produce a higher porosity in the layer, reduce the hardness of the surface layer, and change the stress state between the layer interfaces, resulting in cracking.

[0164] In summary, the surface composite layer structure design and repair method provided by the present invention have good surface layer integrity, high interface bonding strength, low impurity content, excellent performance, and a stable interface state after thermal shock.

[0165] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A surface composite layer of a rotating anode target, characterized in that: The surface composite layer comprises: a substrate layer, a transition layer and a tungsten-rhenium alloy surface layer; The transition layer comprises: Re 0-30wt%, W 0-20wt%, both excluding 0, and the balance is Mo; In the transition layer, the content of Re is distributed in a gradient along the thickness direction of the transition layer, and the gradient distribution is specifically as follows: from the surface layer of the tungsten-rhenium alloy to the substrate layer, the transition layer is equally divided into n layers along the thickness direction, and the content of Re in the i-th layer is (i-1) / n×30wt% to i / n×30wt%, and the range of n is 2-5; in each layer of the transition layer, the content of W is 0-60wt% of the content of Re, excluding 0, and the remainder is Mo; The composition of the tungsten-rhenium alloy surface layer includes: Re 3-25wt%, and the balance is W; In the surface layer of the tungsten-rhenium alloy, the content of Re is distributed in a gradient along the thickness direction of the surface layer of the tungsten-rhenium alloy, and the gradient distribution is specifically as follows: the surface layer of the tungsten-rhenium alloy is divided into m layers along the thickness direction, from the substrate layer to the surface layer of the tungsten-rhenium alloy is the inner layer to the outer layer direction, the content of Re in the innermost layer is 5-25wt%, the content of Re in the outermost layer is 3-10wt%, and the content of Re in the remaining layers is 3-25wt%, and the range of m is 2-10; The stress state of the interface between the substrate layer and the transition layer is compressive stress, and the stress state of the interface between the transition layer and the tungsten-rhenium alloy surface layer is tensile stress.

2. The surface composite layer according to claim 1, characterized in that: The compressive residual stress at the interface between the substrate layer and the transition layer is 500-2000 MPa; The tensile residual stress at the interface between the transition layer and the tungsten-rhenium alloy surface layer is 500-2000 MPa.

3. The surface composite layer according to claim 1, characterized in that: The thickness of the substrate layer is 0.005-0.5 mm; The thickness of the transition layer is 0.01-0.1 mm; The thickness of the tungsten-rhenium alloy surface layer is 0.5-2 mm.

4. A method for preparing a surface composite layer of a rotating anode target according to any one of claims 1 to 3, characterized in that: The preparation method comprises the following steps: (1) a substrate layer and a transition layer are sequentially prepared on a rotating anode target substrate by physical vapor deposition and / or thermal spraying, and then a tungsten-rhenium alloy surface layer is prepared on the transition layer by chemical vapor deposition; (2) The deposited rotating anode target is subjected to hot isostatic pressing to obtain a rotating anode target having a surface composite layer.

5. The preparation method according to claim 4, characterized in that: The current of the physical vapor deposition in step (1) is 10-500A; The spraying power of the thermal spraying in step (1) is 25-50kW; The powder feeding rate of the thermal spraying in step (1) is 5-35 g / min; The raw material gas for chemical vapor deposition in step (1) includes WF6 and ReF6, and the volume ratio of WF6 to ReF6 is (6-10):

1.

6. The preparation method according to claim 4, characterized in that: The temperature of the hot isostatic pressing in step (2) is 1300-1500°C; The hot isostatic pressing pressure in step (2) is 130-200 MPa; The hot isostatic pressing time in step (2) is 1-3 hours.

7. A method for repairing a rotating anode target, characterized in that: The repair method comprises the following steps: The tungsten-rhenium layer and a part of the thickness of the substrate are removed from the rotary anode target disc to be repaired, and the surface is pretreated. Then, the surface composite layer according to any one of claims 1 to 3 is prepared on the pretreated rotary anode target disc to obtain a rotary anode target having a surface composite layer. After machining, the repair is completed.

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