High-purity zirconium-niobium-oxygen zirconium alloy ingot, preparation method and application thereof

Abstract

This invention discloses a high-purity Zr-Nb-O zirconium alloy ingot, its preparation method, and its application. The invention uses zirconium slabs, Nb wire, and ZrO2 powder to prepare an electrode for electron beam melting. The zirconium slabs are prepared from sponge zirconium through iodination purification, reducing the content of metallic impurities such as Fe, Al, Ni, and V in the zirconium raw material. By drilling axial holes in the zirconium slabs and placing ZrO2 powder inside, the problem of adding oxygen in the electron beam melting process is solved. The use of Nb wire not only enables the addition of Nb but also allows the zirconium slabs to be bundled into an electrode suitable for electron beam melting.

Description

Technical Field

[0001] This invention relates to the field of materials preparation technology, and in particular to a high-purity Zr-Nb-O zirconium alloy ingot, its preparation method, and its application. Background Technology

[0002] Zr-Nb-O zirconium alloy is a novel medical metal material for manufacturing artificial joints due to its good biocompatibility and the ability to significantly improve its wear resistance by forming a dense zirconium oxide film on its surface through in-situ oxidation. To ensure the biocompatibility of Zr-Nb-O zirconium alloy, the content of metallic impurity elements such as Fe, Al, Ni, and V, which have potential effects on the human body, must be strictly controlled. Furthermore, to balance the strength, plasticity, and fatigue resistance of Zr-Nb-O zirconium alloy, the oxygen content must be kept within specified limits. The composition of the Zr-Nb-O zirconium alloy ingot determines the composition of the processed profile; therefore, the content of metallic impurity elements such as Fe, Al, Ni, and V must be reduced during the Zr-Nb-O zirconium alloy ingot preparation stage, and the oxygen content must be controlled within specified limits.

[0003] The commonly used method for smelting Zr-Nb-O zirconium alloys is vacuum arc remelting. This method uses sponge zirconium as raw material and follows the steps of "intermediate alloy preparation → sponge zirconium fabrication → electrode pressing → electrode welding" to add Nb and O elements to the sponge zirconium and prepare the electrodes required for vacuum arc remelting. Then, Zr-Nb-O zirconium alloy ingots are prepared through three vacuum arc remelting processes. However, vacuum arc remelting is difficult to remove metallic impurities such as Fe, Al, Ni, and V from the zirconium raw material, resulting in a high content of these impurities in the Zr-Nb-O zirconium alloy ingots prepared by this method. Summary of the Invention

[0004] The present invention aims to at least partially solve one of the technical problems in the related art.

[0005] Therefore, embodiments of the present invention propose a high-purity Zr-Nb-O zirconium alloy ingot, its preparation method, and its application.

[0006] In a first aspect, the present invention proposes a method for preparing high-purity Zr-Nb-O zirconium alloy ingots, comprising the following steps:

[0007] (1) Nuclear-grade sponge zirconium is selected and high-purity crystalline zirconium is prepared by iodination purification method; (2) Calculate the Nb and O content added to the ingot according to the composition requirements of Zr-Nb-O zirconium alloy ingot, and calculate the weight of Nb wire and ZrO2 powder; (3) Use a deep hole drill to drill axial holes in N high-purity zirconium strips, wherein 1 / 2N zirconium strips drilled from the head to the bottom are AU type zirconium strips, 1 / 2N zirconium strips drilled from the bottom to the head are AD type zirconium strips, and the un-drilled zirconium strips are B type zirconium strips. (4) The ZrO2 powder is evenly packed into the axial holes of AU-type and AD-type zirconium strips and partially sealed with Nb wire. Then all the zirconium strips are evenly arranged and awaited binding. (5) The remaining Nb wires are evenly distributed in a spiral from top to bottom, and all the zirconium crystals are bundled into a whole electrode during the spiral winding process; (6) The electrodes are subjected to electron beam melting and impurity removal to obtain zirconium alloy ingots.

[0008] Furthermore, the high-purity zirconium crystal contains Fe ≤ 100 ppm, Al ≤ 20 ppm, Ni ≤ 20 ppm, and V ≤ 20 ppm.

[0009] Furthermore, the ZrO2 powder is used to supplement the oxygen element required for the Zr-Nb-O zirconium alloy ingot.

[0010] Furthermore, the diameter of the axial hole is 4-5 mm, and the depth is half the length of the high-purity zirconium strip.

[0011] Furthermore, in step (3), N represents the number of high-purity zirconium strips required for drilling.

[0012] Furthermore, the sum of the AU-type zirconium, AD-type zirconium, and B-type zirconium is the total amount of zirconium required for ingot casting.

[0013] Furthermore, the total amount of zirconium bars required for the ingot is the ratio of the ingot weight to the weight of a single zirconium bar.

[0014] Furthermore, in step (4), the zirconium crystals are arranged in a dispersed and interwoven manner according to the AU type zirconium crystals, AD type zirconium crystals, and B type zirconium crystals, so that the zirconium oxide is evenly distributed at the head and tail of the entire electrode, forming a cylinder.

[0015] Furthermore, in step (6), the impurity removal involves peeling the electrode after electron beam melting and then machining to remove surface oxides.

[0016] Secondly, the present invention provides a high-purity Zr-Nb-O zirconium alloy ingot prepared by the method proposed in the first aspect above.

[0017] Thirdly, the present invention proposes the application of high-purity Zr-Nb-O zirconium alloy ingots prepared by the method proposed in the first aspect above, or high-purity Zr-Nb-O zirconium alloy ingots proposed in the second aspect above, in medical metal materials.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention uses zirconium slabs, Nb wire, and ZrO2 powder to prepare electrodes for electron beam melting. The zirconium slabs are prepared by purifying sponge zirconium through iodination, which reduces the content of metallic impurities such as Fe, Al, Ni, and V in the zirconium raw materials. By drilling axial holes in the zirconium slabs and placing ZrO2 powder inside, the problem of adding oxygen in the electron beam melting process is solved. The use of Nb wire not only enables the addition of Nb but also allows the zirconium slabs to be bundled into an electrode suitable for electron beam melting.

[0019] The method of the present invention can produce Zr-Nb-O zirconium alloy ingots with low contents of metallic impurity elements such as Fe, Al, Ni, and V, and uniform distribution of Nb and O elements.

[0020] This invention addresses the compositional requirements of high-purity Zr-Nb-O zirconium alloys and the characteristics of electron beam melting processes. It develops an electrode preparation method that can be used for electron beam melting and allows the addition of Nb and O elements, thereby enabling the preparation of high-purity Zr-Nb-O zirconium alloy ingots using electron beam melting. Attached Figure Description

[0021] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a flowchart illustrating the preparation method of the high-purity Zr-Nb-O zirconium alloy ingot of the present invention; Figure 2 This is a schematic diagram of the iodination purification process of the present invention. Detailed Implementation

[0022] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0023] Existing methods for preparing zirconium alloy ingots often employ vacuum arc remelting (CAR) processes. This involves first arranging granular sponge zirconium and alloying element additives (granular or powdered) according to a specific pattern and pressing them into a fixed shape with structural strength. Multiple blocks are then welded together to form an electrode suitable for vacuum arc remelting. Finally, the electrode is subjected to three vacuum arc remelting processes to prepare the ingot. The impurity element content of zirconium alloy ingots prepared using this method is consistent with that of sponge zirconium, failing to reduce metallic impurities such as Fe, Al, Ni, and V. This proposed method uses granular sponge zirconium as raw material. First, iodination purification technology is used to reduce metallic impurities such as Fe, Al, Ni, and V in the sponge zirconium. Simultaneously, the granular sponge zirconium is purified by iodination into rod-shaped zirconium crystals. Then, axial holes are drilled in the rod-shaped zirconium crystals, and ZrO2 powder required for Zr-Nb-O alloys is placed inside to address the issue of O element addition. Additionally, Nb wire is used to bind the zirconium crystals into an electrode suitable for electron beam melting. Finally, electron beam melting was used to melt the prepared electrodes into Zr-Nb-O ingots.

[0024] like Figure 1 As shown, the method for preparing high-purity Zr-Nb-O zirconium alloy ingots of the present invention includes the following steps: (1) Nuclear-grade sponge zirconium was selected and high-purity crystalline zirconium was prepared by iodination purification method; (2) Calculate the Nb and O content added to the ingot according to the composition requirements of Zr-Nb-O zirconium alloy ingot, and calculate the weight of Nb wire and ZrO2 powder; (3) Use a deep hole drill to drill axial holes in N high-purity zirconium strips. Among them, 1 / 2N zirconium strips drilled from the head to the bottom are AU type zirconium strips, 1 / 2N zirconium strips drilled from the bottom to the head are AD type zirconium strips, and the un-drilled zirconium strips are B type zirconium strips. (4) Pack ZrO2 powder evenly into the axial holes of AU-type and AD-type zirconium strips and seal them with some Nb wire. Then, arrange all the zirconium strips evenly and wait for them to be bundled. (5) The remaining Nb wires are evenly distributed in a spiral from top to bottom, and all the zirconium crystals are bundled into a whole electrode during the spiral winding process; (6) The electrodes are subjected to electron beam melting and impurity removal to obtain zirconium alloy ingots.

[0025] Step (1) is the preparation process of crystalline zirconium. Nuclear-grade sponge zirconium refers to sponge zirconium that has undergone zirconium-hafnium separation to remove hafnium. The nuclear-grade sponge zirconium is purified by iodination to prepare high-purity crystalline zirconium. The high-purity crystalline zirconium prepared contains Fe≤100ppm, Al≤20ppm, Ni≤20ppm, and V≤20ppm.

[0026] In the production of high-purity zirconium, the iodination purification method is used to produce high-purity zirconium crystals, such as... Figure 2 As shown, the principle involves a molybdenum mesh drum inside a sealed vacuum tank. Sponge zirconium raw material is placed between the molybdenum mesh drum and the sealed tank. Two water-cooled electrodes connected in series are attached to the sealed tank lid. Two zirconium master wires, each 3 mm in diameter and 1-1.4 meters long, are connected to the water-cooled electrodes. The sealed tank heats molten salt to approximately 300°C in a low-temperature zone. The sponge zirconium reacts with iodine to generate zirconium iodide vapor. Then, electricity is applied to the water-cooled electrodes, and the zirconium master wires are heated to approximately 1500°C through resistance heating, creating a high-temperature zone. At this point, the zirconium iodide vapor from the low-temperature zone diffuses into the high-temperature zone, contacts the 1500°C master wire, and undergoes a decomposition reaction, generating metallic zirconium and iodine vapor. The metallic zirconium is deposited on the master wire, and the iodine vapor diffuses back into the low-temperature zone to repeat the synthesis reaction. This cycle continues until the zirconium master wire expands into a crystalline zirconium rod with a diameter of 30-50 mm and a length of 1-1.4 meters. Multiple iodination purification processes effectively remove gaseous elements and other impurities from the raw material, producing high-purity metallic zirconium.

[0027] Step (2) is the batching process. The raw materials for the ingot consist of zirconium bars, niobium wire, and zirconium oxide. According to the composition requirements of the Zr-Nb-O zirconium alloy ingot, the Nb and O content to be added to the ingot is calculated, and the weights of Nb wire and ZrO2 powder are also calculated. ZrO2 powder is used to supplement the O element required for the Zr-Nb-O zirconium alloy ingot.

[0028] Step (3) is the process of drilling zirconium strips. A deep hole drill is used to drill axial holes in N high-purity zirconium strips. Among them, 1 / 2N zirconium strips drilled from the head to the bottom are AU type zirconium strips, 1 / 2N zirconium strips drilled from the bottom to the head are AD type zirconium strips, and the un-drilled zirconium strips are B type zirconium strips. N is the number of high-purity zirconium strips that need to be drilled.

[0029] In some embodiments, the diameter of the axial hole is 4-5 mm, preferably 5 mm, and the depth of the axial hole is half the length of the high-purity zirconium strip.

[0030] The sum of AU-type zirconium, AD-type zirconium, and B-type zirconium is the total amount of zirconium required for ingot casting. The total amount of zirconium required for ingot casting is equal to the ratio of the weight of the ingot to the weight of a single zirconium bar.

[0031] Understandably, the number of zirconium strips used is determined by the weight of the required zirconium alloy ingot. The amount of zirconium strips, zirconium oxide, and niobium wire needed is determined based on the amount of material fed. Since this type of zirconium alloy requires very little zirconium oxide, it is generally not necessary to drill and fill every zirconium strip with zirconium oxide to adjust the oxygen composition in the zirconium alloy ingot. It is only necessary to drill and fill a portion of the zirconium strips with zirconium oxide and evenly mix this portion of zirconium strips with the un-drilled and unfilled zirconium oxide zirconium strips.

[0032] In step (4), ZrO2 powder is weighed according to the calculated component ratio and evenly packed into the axial holes of AU-type and AD-type zirconium crystals. Based on the calculated niobium component ratio, a portion of the Nb wire is used to seal the axial holes of the AU-type and AD-type zirconium crystals containing the ZrO2 powder, preventing the ZrO2 powder from spilling out. In some embodiments, the diameter of the Nb wire is 5 mm.

[0033] It is understood that in some embodiments, zirconium wire can also be used for sealing, and the weight of the zirconium wire used to seal the axial hole is included in the total amount of zirconium fed.

[0034] After sealing is completed, all zirconium crystals are evenly placed and awaited binding. The zirconium crystals are arranged in a dispersed and interlaced manner according to AU-type zirconium crystals, AD-type zirconium crystals, and B-type zirconium crystals, so that the zirconium oxide is evenly distributed at the head and tail of the entire electrode, forming a cylinder.

[0035] Step (5) is the binding process, in which the remaining Nb wires are evenly distributed and spiraled from top to bottom, binding all the zirconium crystals into a single electrode during the spiral winding process. It can be understood that if Nb wires are used for sealing in step (4), then the remaining Nb wires are used for binding in step (5); if zirconium wires are used for sealing in step (4), then all the Nb wires are used for binding in step (5).

[0036] Step (6) is the electron beam melting and impurity removal process. After the electrodes obtained in step (5) are electron beam melted, they are peeled and machined to remove surface oxides to obtain zirconium alloy ingots.

[0037] The high-purity Zr-Nb-O zirconium alloy ingot of this invention is prepared by the method of this invention. The high-purity Zr-Nb-O zirconium alloy ingot has low contents of metallic impurity elements such as Fe, Al, Ni, and V, and the Nb and O elements are uniformly distributed. The high-purity Zr-Nb-O zirconium alloy ingot of this invention is used as a novel medical metal material for manufacturing artificial joints.

[0038] The present invention will now be described in detail with reference to specific embodiments.

[0039] Example 1 Step 1: Sponge zirconium was purified into crystalline zirconium using iodide purification technology to reduce the content of impurity elements in the sponge zirconium, resulting in 42 crystalline zirconium bars. The crystalline zirconium bars contained 16.6 ppm Fe, 6.3 ppm Al, and 0.78 ppm Ni.

[0040] Step 2: Prepare a 200kg Zr-2.5Nb ingot. Calculations show that 5kg of Nb wire (30 meters long) and 0.7kg of ZrO2 powder are needed.

[0041] Step 3: Drilling Zirconium Strips: Divide the 42 zirconium strips into three groups (18 strips in group AU, 18 strips in group AB, and 6 strips in group B). Use a deep hole drill to prepare axial (from top to bottom) 600mm deep, 5mm outer diameter holes in the zirconium strips of group AU; similarly, prepare axial (from bottom to top) 600mm deep, 5mm outer diameter holes in the zirconium strips of group AB.

[0042] Step 4: Add ZrO2 powder and Nb wire to the zirconium strip: Cut the 30-meter-long Nb wire into 36 Nb wires of 500mm length. The remaining 18 meters of Nb wire will be used for subsequent binding of the zirconium strip. 0.7kg of ZrO2 powder is evenly packed into the holes of the AU and AB group zirconium strips, and the holes are sealed with the cut 500mm-long Nb wire.

[0043] Step 5: Bundle the zirconium strips with Nb wire. Disperse and cross the AU, AB, and B group zirconium strips, and use the remaining 18 meters of niobium wire to bundle the zirconium strips into one electrode.

[0044] Step 6: Perform electron beam melting twice on the prepared electrode.

[0045] Step 7: Use a lathe to take samples from the ingot for chemical composition analysis. The analysis results are shown in Table 1 below.

[0046] Comparative Example 1 A 200 kg Zr-2.5Nb ingot was prepared using a traditional vacuum arc remelting method. Calculations showed that 5 kg of Nb and 0.7 kg of ZrO2 powder needed to be added.

[0047] Step 1: Pressing an electrode block using zirconium sponge, Nb shavings, and ZrO2 powder. Layers of zirconium sponge are laid in a mold, with Nb shavings and ZrO2 powder evenly sprinkled into the middle layers. A hydraulic press is then used to press the laid-out zirconium sponge into a single electrode block with a certain density and strength.

[0048] Step 2: Use a vacuum consumable furnace to melt the pressed electrodes twice.

[0049] Step 3: Use a lathe to take samples from the ingot for chemical composition analysis. The analysis results are shown in Table 1 below.

[0050] Table 1: Impurity content (mass fraction, wt%) of Zr-2.5Nb alloy ingots.

[0051]

[0052] As shown in Table 1, the Zr-2.5Nb alloy ingot prepared in Example 1 has a lower impurity content, while the Zr-2.5Nb alloy ingot prepared in Comparative Example 1 has a relatively higher impurity content.

[0053] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms may refer to different embodiments or examples. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0054] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0055] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for preparing a high-purity Zr-Nb-O zirconium alloy ingot, characterized in that, Includes the following steps: (1) Nuclear-grade sponge zirconium is selected and high-purity crystalline zirconium is prepared by iodination purification method; (2) Calculate the Nb and O content added to the ingot according to the composition requirements of Zr-Nb-O zirconium alloy ingot, and calculate the weight of Nb wire and ZrO2 powder; (3) Use a deep hole drill to drill axial holes in N high-purity zirconium strips, wherein 1 / 2N zirconium strips drilled from the head to the bottom are AU type zirconium strips, 1 / 2N zirconium strips drilled from the bottom to the head are AD type zirconium strips, and the un-drilled zirconium strips are B type zirconium strips. (4) The ZrO2 powder is evenly packed into the axial holes of AU-type and AD-type zirconium strips and partially sealed with Nb wire. Then all the zirconium strips are evenly arranged and awaited binding. (5) The remaining Nb wires are evenly distributed in a spiral from top to bottom, and all the zirconium crystals are bundled into a whole electrode during the spiral winding process; (6) The electrodes are subjected to electron beam melting and impurity removal to obtain zirconium alloy ingots.

2. The preparation method according to claim 1, characterized in that, The high-purity zirconium crystals contain Fe ≤ 100 ppm, Al ≤ 20 ppm, Ni ≤ 20 ppm, and V ≤ 20 ppm.

3. The preparation method according to claim 1, characterized in that, The ZrO2 powder is used to supplement the oxygen element required for the Zr-Nb-O zirconium alloy ingot.

4. The preparation method according to claim 1, characterized in that, The diameter of the axial hole is 4-5 mm, and the depth is half the length of the high-purity zirconium strip.

5. The preparation method according to claim 1, characterized in that, In step (3), N represents the number of high-purity zirconium crystals required for drilling.

6. The preparation method according to claim 1, characterized in that, The sum of the AU-type zirconium, AD-type zirconium, and B-type zirconium is the total amount of zirconium required for ingot casting.

7. The preparation method according to claim 6, characterized in that, The total amount of zirconium crystals required for the ingot is the ratio of the ingot weight to the weight of a single zirconium crystal.

8. The preparation method according to claim 1, characterized in that, In step (4), the zirconium crystals are arranged in a dispersed and interwoven manner according to the AU type zirconium crystals, AD type zirconium crystals, and B type zirconium crystals, so that the zirconium oxide is evenly distributed at the head and tail of the entire electrode, forming a cylinder; And / or, in step (6), the impurity removal is performed by peeling and machining the surface oxides after electron beam melting of the electrode.

9. A high-purity Zr-Nb-O zirconium alloy ingot, characterized in that, Prepared by the method described in any one of claims 1 to 8.

10. The application of the high-purity Zr-Nb-O zirconium alloy ingot prepared by the method according to any one of claims 1 to 8 or the high-purity Zr-Nb-O zirconium alloy ingot according to claim 9 in medical metal materials.

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