Titanium-aluminum target material and method for manufacturing the same

Abstract

The application belongs to the technical field of target material production, and discloses a preparation method of titanium-aluminum target material, which comprises the following steps: first, titanium powder and aluminum powder are weighed according to a mass ratio of 4-5:5-6; then, the titanium powder, the aluminum powder and an antioxidant are put into a mixer to mix and obtain powder I, the antioxidant is at least one selected from stearic acid, sodium phytate and tea polyphenol, and the adding amount of the antioxidant is 0.1-0.5% of the total mass of the titanium powder and the aluminum powder; then, the powder I is ball milled under the atmosphere of nitrogen or argon to obtain powder II, and the ball milling time is 6-12 hours; finally, the powder II is subjected to hot isostatic pressing sintering, and then cooled and discharged from the furnace to obtain the titanium-aluminum target material; through the preparation method, the titanium-aluminum target material with low oxygen content, high density and excellent mechanical properties is obtained; in addition, the application further discloses a titanium-aluminum target material prepared by the preparation method of the titanium-aluminum target material.

Description

Technical Field

[0001] This invention relates to the field of target preparation technology, and in particular to a titanium-aluminum target and its preparation method. Background Technology

[0002] Carbide coatings are widely used in machining applications such as cutting tools and wear-resistant parts due to their excellent wear resistance, corrosion resistance, and high-temperature oxidation resistance. Currently, materials suitable for coating include titanium aluminum (TiAl), chromium aluminum (CrAl), titanium silicon (TiSi), tungsten carbide (WC), and nitride materials. Among these, titanium aluminum alloy targets, prepared by magnetron sputtering in a nitrogen (N2) atmosphere, can provide anti-oxidation nitride coatings (TiAlN) for tools such as drills, end mills, CNC inserts, and gear hobs, extending tool life. However, the adhesion of the coating is affected by the oxygen content in the coating material. When the oxygen content is high, the adhesion between the coating and the tool is weak, and the coating is prone to detaching from the tool during turning, leading to chipping, dulling, and other problems.

[0003] Because titanium (Ti) and aluminum (Al) have melting points of 1668℃ and 660℃ respectively, a significant difference makes it difficult to prepare TiAl alloys with a relatively uniform microstructure using vacuum melting. Currently, TiAl alloys are often prepared by mixing Ti powder and Al powder and then further densifying them under pressure. Therefore, the oxygen content of TiAl alloys largely depends on the oxygen content in the raw materials and the amount of oxygen introduced during the process. Regarding the oxygen in the raw materials, a dense alumina (Al2O3) film forms on the surface of the aluminum powder, inhibiting further oxidation of the Al powder as a whole. Furthermore, since metallic Al is a reactive metal, even if the surface alumina film is removed by some means, it will oxidize rapidly in actual operation. In addition, when mixing Ti powder and Al powder, ball milling is usually used to ensure uniform mixing. Although inert gases (such as argon and nitrogen) are used for protection, ball milling causes particle breakage, inevitably introducing oxygen during the transport of the mixed powder, thus increasing the oxygen content.

[0004] Chinese patent application 200910043144.4 discloses a rapid hot-pressing sintering process for titanium-aluminum alloy sputtering targets. This process employs a rapid hot-pressing powder molding technique, sintering the material under the combined action of heat and force. Utilizing the low melting point of aluminum in the Ti-Al mixture, titanium powder is bonded together, resulting in titanium-aluminum sputtering targets of various compositions and sizes. This method can produce titanium-aluminum alloy sputtering targets with high density, fine grains, uniform composition, and low cost, meeting the requirements for large-scale industrialization. Further observation of this scheme reveals that during the mixing of titanium powder and aluminum powder, a forming agent with a mass content of 0-3% is added, and the main component of the forming agent is stearic acid. However, observation of Examples 1-3 of this scheme shows that Example 1, without the addition of the forming agent (stearic acid), still yielded a titanium-aluminum target material with uniform composition, high density, and resistance to oxidation. Furthermore, this scheme does not elaborate on the role of the forming agent, nor does it measure the oxygen content of the target material or the mechanical properties of the coating subsequently formed on the target material.

[0005] Chinese patent application 201911425902.9 discloses a titanium-aluminum alloy target and its preparation method. In this method, yttrium is added to the titanium-aluminum alloy target at a mass percentage of 0.3-2 wt%. Through the strengthening effect of yttrium on grain boundaries, the slippage of grain boundaries is prevented, and the diffusion of oxygen at grain boundaries is also organized.

[0006] Chinese patent application 201410842607.4 discloses a titanium-aluminum alloy target and its preparation method. This method involves doping the titanium-aluminum target with at least two elements selected from Co, Cr, Ta, W, Nb, Mo, Zr, V, B, Si, Y, La, Ce, or Se. This invention allows for the formation of various morphologies of nitrided, carburized, and nitrocarbonized composite film materials through the addition of multiple elements; the improved heat treatment process facilitates further densification of the product; and the improved powder mixing and degassing process effectively controls the oxygen content. The powder mixing and degassing process in this solution is as follows:

[0007] (1) Select raw materials and mix them according to the proportions;

[0008] (2) The mixed material is placed into the steel ladle sleeve and argon arc welding is performed to ensure no air leakage;

[0009] (3) Place the steel ladle in a pit-type heat treatment furnace for degassing treatment;

[0010] (4) Weld the degassed steel bladder together;

[0011] (5) Place the degassed steel ladle into a hot isostatic pressing equipment for hot isostatic pressing treatment.

[0012] (6) Remove the container when the temperature drops to 100-200℃, and let the insulated container cool down to room temperature at a rate of 10-50℃ / hour.

[0013] (7) Remove the casing and cut the target material into the specified shape;

[0014] (8) Detect the purity, oxygen content, density, grain size and metallographic parameters of the target material.

[0015] The problem this solution aims to solve is: how to provide a titanium-aluminum target material with low oxygen content, high density, and good mechanical properties in the subsequent coating, as well as its preparation method. Summary of the Invention

[0016] The purpose of this invention is to provide a method for preparing titanium-aluminum target material. This method can produce a titanium-aluminum target material with low oxygen content and good mechanical properties after the coating is made, without requiring high oxygen content in the raw materials.

[0017] To achieve the above objectives, this application discloses a method for preparing a titanium-aluminum target, comprising the following steps:

[0018] Step 1: Weigh the materials according to the mass ratio of titanium powder to aluminum powder of 4-5:5-6. Then, put the titanium powder, aluminum powder and antioxidant into a mixer and mix them to obtain powder one. The antioxidant is selected from at least one of stearic acid, sodium phytate and tea polyphenols. The amount of antioxidant added is 0.1-0.5% of the total mass of titanium powder and aluminum powder.

[0019] Step 2: Powder 1 obtained in Step 1 is ball-milled under a nitrogen or argon atmosphere to obtain powder 2. The ball-milling time is 6 to 12 hours.

[0020] Step 3: The powder obtained in Step 2 is subjected to hot isostatic pressing sintering, followed by cooling and removal from the furnace to obtain titanium-aluminum target material.

[0021] Preferably, in step 1, the titanium powder is acid-washed titanium powder, which is obtained by washing titanium powder with a weak acid of 0.5-3 mol / L for 2-10 min and then drying it. The weak acid is selected from at least one of glacial acetic acid, dilute hydrochloric acid, and silicic acid.

[0022] Preferably, step 3 specifically involves: placing the powder obtained in step 2 into a sleeve whose inner surface is covered with graphite paper and sealing the sleeve with a cover plate to complete the molding process;

[0023] After the mold is installed, the sleeve is degassed. The degassed sleeve is then placed in a hot isostatic pressing (HIP) sintering furnace for HIP sintering. The heating rate during HIP sintering is 2-10℃ / min. After the temperature rises to 400-550℃, it is held for 3-8 hours. The pressure during HIP sintering is 80-140MPa.

[0024] After hot isostatic pressing sintering is completed, the furnace is cooled to 100°C or below and the pressure is reduced to standard atmospheric pressure before being removed from the furnace to obtain titanium-aluminum sputtering targets.

[0025] Preferably, step 1 is performed in an inert gas glove box.

[0026] Preferably, the degassing temperature in step 3 is 400–550°C.

[0027] In addition, this application also discloses a titanium-aluminum target material, which is prepared by the above-described method for preparing titanium-aluminum target materials.

[0028] Preferably, the oxygen content of the titanium-aluminum target is less than 1700 ppm.

[0029] Preferably, the density of the titanium-aluminum target is greater than 99.5%.

[0030] The beneficial effects of this application are: by adding antioxidants to titanium powder and aluminum powder while mixing them, stearic acid can block the contact between metal ions and substances such as oxygen and water, thereby reducing the oxidation reaction of metals.

[0031] Meanwhile, the hydroxyl and phenolic groups in tea polyphenols can coordinate with metal ions to form stable complexes. This complexation can block metal ions from participating in oxidation reactions, reducing oxidative damage to metals.

[0032] Furthermore, stearic acid can form a protective oxide film on the metal surface. This oxide film can prevent the metal from contacting external substances such as oxygen and water, thereby reducing the oxidation reaction of the metal. The carboxyl groups in the stearic acid molecule can form complexes with the metal surface, further stabilizing the formation of the oxide film. Detailed Implementation

[0033] The present invention will now be clearly and completely described in conjunction with embodiments thereof. It should be noted that, unless specific conditions are specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0034] Example 1

[0035] Step 1: Wash the Ti powder with 2 mol / L glacial acetic acid for 3 minutes to fully remove the surface oxides, and dry it in a vacuum oven at 110℃ for 1 hour. After drying, quickly transfer it to an inert gas glove box. In the inert gas glove box, weigh the titanium powder and aluminum powder according to the Ti:Al mass ratio of 46.64:53.36, and add 0.15% stearic acid of the total mass of titanium powder and aluminum powder. Then, in the inert gas glove box, perform preliminary mixing of the powder using a three-dimensional mixer for 20 minutes to obtain powder one.

[0036] Step 2: Powder 1 obtained in Step 1 is ball-milled and mixed under an argon atmosphere to further mix the titanium powder and aluminum powder in Powder 1. The mixing time is 8 hours to obtain Powder 2.

[0037] Step 3: Prepare the enclosure, which includes a base plate, outer side plates, partitions, graphite paper, a cover plate, and a degassing pipe. The base plate is installed at the bottom of the outer side plates, and the cover plate is installed at the top of the outer side plates. The cover plate has a through hole, through which the degassing pipe is installed. The partitions and graphite paper are placed within the cylindrical space formed by the base plate, outer side plates, and cover plate. The partitions are 3mm thick; the graphite paper is 0.38mm thick; the degassing pipe has an outer diameter of 10mm and a wall thickness of 3mm; the base plate, outer side plates, partitions, cover plate, and degassing pipe are all made of low-carbon steel. The base plate is fixed to the outer side plates, the cover plate to the outer side plates, and the cover plate to the degassing pipe using argon arc welding.

[0038] Assemble the base plate and outer plate to form a semi-finished package with one open end. Place graphite paper on the inner wall of the outer plate. Place graphite paper, a partition, and another graphite paper at the bottom of the semi-finished package in sequence. Then pour the mixed powder II onto the graphite paper and compact it. Place graphite paper, a partition, and another graphite paper on top in sequence. Finally, use a cover plate to seal and fix the opening of the semi-finished package. Install a degassing pipe at the through hole of the cover plate to complete the molding.

[0039] The molded package is placed into the furnace, and while heating, a vacuum is evacuated through the degassing pipe. The vacuum level inside the package is reduced to less than 5 × 10⁻⁶. -4 After Pa, stop heating and degassing, and seal the degassing pipe, where the degassing temperature is 460℃.

[0040] The degassed casing is placed in a hot isostatic pressing (HIP) furnace for vacuuming, pressurization, sintering, cooling, and pressure recovery. During sintering, the heating rate is 5℃ / min, the sintering temperature is 500℃, the pressure is 120MPa, and the holding time is 4 hours. After sintering, cooling and pressure recovery are performed until the temperature is below 100℃ and the furnace pressure is at standard atmospheric pressure. The casing is then removed from the furnace to obtain the titanium-aluminum sputtering target.

[0041] Example 2

[0042] Step 1: Wash the Ti powder with 0.5 mol / L dilute hydrochloric acid for 3 minutes to fully remove the surface oxides, and dry it in a vacuum oven at 110℃ for 1 hour. After drying, quickly transfer it to an inert gas glove box. In the inert gas glove box, weigh the titanium powder and aluminum powder according to the Ti:Al mass ratio of 40:60, and add 0.1% stearic acid of the total mass of titanium powder and aluminum powder. Then, in the inert gas glove box, perform preliminary mixing of the powder using a three-dimensional mixer for 20 minutes to obtain powder one.

[0043] Step 2: Powder 1 obtained in Step 1 is ball-milled and mixed under an argon atmosphere to further mix the titanium powder and aluminum powder in Powder 1. The mixing time is 6 hours to obtain Powder 2.

[0044] Step 3: Prepare the enclosure, which includes a base plate, outer side plates, partitions, graphite paper, a cover plate, and a degassing pipe. The base plate is installed at the bottom of the outer side plates, and the cover plate is installed at the top of the outer side plates. The cover plate has a through hole, through which the degassing pipe is installed. The partitions and graphite paper are placed within the cylindrical space formed by the base plate, outer side plates, and cover plate. The partitions are 3mm thick; the graphite paper is 0.38mm thick; the degassing pipe has an outer diameter of 10mm and a wall thickness of 3mm. The base plate, outer side plates, partitions, cover plate, and degassing pipe are all made of low-carbon steel. The connection between the base plate and the outer side plates, the cover plate and the outer side plates, and the cover plate and the degassing pipe are all fixed by argon arc welding.

[0045] Assemble the base plate and outer plate to form a semi-finished package with one open end. Place graphite paper on the inner wall of the outer plate. Place graphite paper, a partition, and another graphite paper at the bottom of the semi-finished package in sequence. Then pour the mixed powder II onto the graphite paper and compact it. Place graphite paper, a partition, and another graphite paper on top in sequence. Finally, use a cover plate to seal and fix the opening of the semi-finished package. Install a degassing pipe at the through hole of the cover plate to complete the molding.

[0046] The molded package is placed into the furnace, and while heating, a vacuum is evacuated through the degassing pipe. When the vacuum level inside the package is less than 5 × 10⁻⁶... -4 After Pa, stop heating and degassing, and seal the degassing pipe, where the degassing temperature is 400℃.

[0047] The degassed casing is placed in a hot isostatic pressing (HIP) furnace for vacuuming, pressurization, sintering, cooling, and pressure recovery. During the sintering process, the heating rate is 2℃ / min, the sintering temperature is 400℃, the pressure is 140MPa, and the holding time is 8 hours. After sintering, cooling and pressure recovery are performed until the temperature is below 100℃ and the furnace pressure is at standard atmospheric pressure. The material is then removed from the furnace, the casing is removed, and the titanium-aluminum sputtering target is obtained.

[0048] Example 3

[0049] Step 1: Wash Ti powder with 3 mol / L silica for 3 minutes to fully remove surface oxides, and dry it in a vacuum oven at 110℃ for 1 hour. After drying, quickly transfer it to an inert gas glove box. In the inert gas glove box, weigh titanium powder and aluminum powder according to a Ti:Al mass ratio of 50:50, and add 0.5% stearic acid of the total mass of titanium powder and aluminum powder. Then, in the inert gas glove box, perform preliminary mixing of powders using a three-dimensional mixer for 20 minutes to obtain powder one.

[0050] Step 2: Powder 1 obtained in Step 1 is ball-milled and mixed under an argon atmosphere to further mix the titanium powder and aluminum powder in Powder 1. The mixing time is 12 hours to obtain Powder 2.

[0051] Step 3: Prepare the enclosure, which includes a base plate, outer side plates, partitions, graphite paper, a cover plate, and a degassing pipe. The base plate is installed at the bottom of the outer side plates, and the cover plate is installed at the top of the outer side plates. The cover plate has a through hole, through which the degassing pipe is installed. The partitions and graphite paper are placed within the cylindrical space formed by the base plate, outer side plates, and cover plate. The partitions are 3mm thick; the graphite paper is 0.38mm thick; the degassing pipe has an outer diameter of 10mm and a wall thickness of 3mm. The base plate, outer side plates, partitions, cover plate, and degassing pipe are all made of low-carbon steel. The connection between the base plate and the outer side plates, the cover plate and the outer side plates, and the cover plate and the degassing pipe are all fixed by argon arc welding.

[0052] Assemble the base plate and outer plate to form a semi-finished package with one open end. Place graphite paper on the inner wall of the outer plate. Place graphite paper, a partition, and another graphite paper at the bottom of the semi-finished package in sequence. Then pour the mixed powder II onto the graphite paper and compact it. Place graphite paper, a partition, and another graphite paper on top in sequence. Finally, use a cover plate to seal and fix the opening of the semi-finished package. Install a degassing pipe at the through hole of the cover plate to complete the molding.

[0053] The molded package is placed into the furnace, and while heating, a vacuum is evacuated through the degassing pipe. When the vacuum level inside the package is less than 5 × 10⁻⁶... -4 After Pa, stop heating and degassing, and seal the degassing pipe, where the degassing temperature is 550℃.

[0054] The degassed casing is placed in a hot isostatic pressing (HIP) furnace for vacuuming, pressurization, sintering, cooling, and pressure recovery. During the sintering process, the heating rate is 10℃ / min, the sintering temperature is 550℃, the pressure is 80MPa, and the holding time is 3 hours. After sintering, cooling and pressure recovery are performed until the temperature is below 100℃ and the furnace pressure is at standard atmospheric pressure. The material is then removed from the furnace, the casing is removed, and the titanium-aluminum sputtering target is obtained.

[0055] Example 4

[0056] This is basically the same as Example 1, except that in this example, titanium powder is washed with 5 mol / L glacial acetic acid for 3 minutes.

[0057] Example 5

[0058] It is basically the same as Example 1, except that the antioxidant is a mixture of stearic acid and tea polyphenols, and the mass ratio of stearic acid to tea polyphenols is 1:1.

[0059] Example 6

[0060] It is basically the same as Example 1, except that the antioxidant is a mixture of stearic acid and sodium phytate, and the mass ratio of stearic acid to tea polyphenols is 1:1.

[0061] Example 7

[0062] The method is basically the same as in Example 1, except that the antioxidant is a mixture of stearic acid, sodium phytate and tea polyphenols, and the mass ratio of stearic acid, sodium phytate and tea polyphenols is 2:1:1.

[0063] Comparative Example 1

[0064] It is basically the same as Example 1, except that no antioxidant is added during the mixing process of titanium powder and aluminum powder in step 1.

[0065] Comparative Example 2

[0066] It is basically the same as Example 1, except that in step 1, ascorbic acid is used instead of stearic acid.

[0067] Comparative Example 3

[0068] It is basically the same as Example 1, except that in step 1, sodium sulfite is used instead of stearic acid.

[0069] Comparative Example 4

[0070] The process is basically the same as in Example 1, except that in step 1, the amount of antioxidant added is 2.0% of the total mass of titanium powder and aluminum powder.

[0071] Performance testing:

[0072] 1. The oxygen content in the target material is tested using an oxygen-nitrogen analyzer;

[0073] 2. The prepared target material was used to form a coating on the surface of a milling cutter by magnetron sputtering. The life standard was tested by milling and turning. The milling cutter specification was WNGU080608-GM, the workpiece material was TH250 gray cast iron, the machining method was square shoulder milling, and the life standard was a chipping value ≥0.3mm. Example 1 was used as a 100% comparison. The turning cutter specification was CNMG120408-LM, the workpiece material was 304 stainless steel, and the machining method was continuous.

[0074] 3. The density of the target material was tested using the Archimedes displacement method;

[0075] The test results are shown in Table 1:

[0076] Table 1

[0077]

[0078] Results analysis:

[0079] 1. As can be seen from Examples 1-3, when the mass ratio of titanium and aluminum and the amount of stearic acid added are adjusted, there is no significant difference in the oxygen content, density and mechanical properties of the coating obtained by subsequent processing of the target material.

[0080] 2. As can be seen from Examples 1 and 5-7, when the antioxidant is compounded, the oxygen content in the target material is significantly reduced and the density is increased to a certain extent. More notably, the mechanical properties of the coatings subsequently prepared from the target materials obtained in Examples 5-7 are significantly improved, and Example 7 achieved an unexpected improvement effect.

[0081] 3. As can be seen from Example 1 and Comparative Examples 1-3, whether the addition of antioxidant is omitted or other substances with antioxidant capacity are used to replace the antioxidant in this application, the oxygen content, density of the target material and the mechanical properties of the coating obtained by subsequent processing all decrease to varying degrees. It can be seen that the antioxidant in this application is indispensable and irreplaceable.

[0082] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a titanium-aluminum target, characterized in that, Includes the following steps: Step 1: Weigh the materials according to the mass ratio of titanium powder to aluminum powder of 4-5:5-6, then put the titanium powder, aluminum powder and antioxidant into a mixer and mix them to obtain powder one. The antioxidant is a mixture of stearic acid, sodium phytate and tea polyphenols, and the mass ratio of stearic acid, sodium phytate and tea polyphenols is 2:1:

1. The amount of antioxidant added is 0.1% to 0.5% of the total mass of titanium powder and aluminum powder; Step 2: Powder 1 obtained in Step 1 is ball-milled under a nitrogen or argon atmosphere to obtain powder 2. The ball-milling time is 6 to 12 hours. Step 3: The powder obtained in Step 2 is subjected to hot isostatic pressing sintering, followed by cooling and removal from the furnace to obtain titanium-aluminum target material.

2. The method for preparing the titanium-aluminum target material according to claim 1, characterized in that, In step 1, the titanium powder is acid-washed titanium powder, which is obtained by washing titanium powder with a weak acid of concentration of 0.5-3 mol / L for 2-10 minutes and then drying it. The weak acid is selected from at least one of glacial acetic acid, dilute hydrochloric acid, and silicic acid.

3. The method for preparing the titanium-aluminum target material according to claim 1, characterized in that, Step 3 specifically involves placing the powder obtained in step 2 into a sleeve whose inner surface is covered with graphite paper and sealing the sleeve with a cover plate to complete the molding process. After the mold is installed, the sleeve is degassed. The degassed sleeve is then placed in a hot isostatic pressing (HIP) sintering furnace for HIP sintering. The heating rate during HIP sintering is 2-10℃ / min. After the temperature rises to 400-550℃, it is held for 3-8 hours. The pressure during HIP sintering is 80-140MPa. After hot isostatic pressing sintering is completed, the furnace is cooled to 100°C or below and the pressure is reduced to standard atmospheric pressure before being removed from the furnace to obtain titanium-aluminum sputtering targets.

4. The method for preparing the titanium-aluminum target material according to claim 1, characterized in that, Step 1 is completed in an inert gas glove box.

5. The method for preparing the titanium-aluminum target material according to claim 3, characterized in that, The degassing temperature in step 3 is 400–550℃.

6. A titanium-aluminum target material, characterized in that, The titanium-aluminum target is prepared by any one of the preparation methods described in claims 1-5.

7. The titanium-aluminum target material according to claim 6, characterized in that, The oxygen content of the titanium-aluminum target is less than 1700 ppm.

8. The titanium-aluminum target material according to claim 6, characterized in that, The density of the titanium-aluminum target is greater than 99.5%.

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