Preparation method of non-stoichiometric molybdenum oxide targets with controllable molybdenum-oxygen ratio

Abstract

This invention discloses a method for preparing a non-stoichiometric molybdenum oxide target with a controllable molybdenum-oxygen ratio. The method includes: S1, calcining ammonium molybdate to obtain MoO3 powder; S2, reacting the MoO3 powder with hydrogen to obtain a non-stoichiometric molybdenum oxide powder; in the non-stoichiometric molybdenum oxide powder, the mass content of Mo9O26 is 0%–99%, the mass content of Mo4O11 is 20%–86%, and the mass content of MoO2 is 0%–40%; S3, molding the non-stoichiometric molybdenum oxide powder; S4, sintering the molded non-stoichiometric molybdenum oxide powder under set conditions to obtain a non-stoichiometric molybdenum oxide target with a specific molybdenum-oxygen ratio, wherein the ratio of molybdenum atoms to oxygen atoms is 1:2–3. The method for preparing a non-stoichiometric molybdenum oxide target with a controllable molybdenum-oxygen ratio disclosed in this invention has a simple preparation process, controllable reaction conditions, and produces a non-stoichiometric molybdenum oxide target with good density.

Description

Technical Field

[0001] This invention belongs to the field of materials preparation technology, specifically relating to a method for preparing non-stoichiometric molybdenum oxide targets with controllable molybdenum-oxygen ratio. Background Technology

[0002] Molybdenum oxide (MoO3) possesses excellent optical and electrical properties and is widely used in battery materials, photosensitive and gas-sensitive sensors, and electronic displays. However, the stable state of MoO3 targets has a low carrier concentration. To overcome this problem, non-stoichiometric molybdenum oxide (MoO3) rich in oxygen vacancies can be prepared. x Target materials are used to adjust carrier concentration. Currently, MoO x Most targets are prepared by mixing powders such as MoO3 and MoO2 and then sintering them. However, MoO3 is slightly soluble in water, which is not conducive to the subsequent mechanical processing of the target. Too much high-melting-point MoO2 in the target will hinder the densification of the target during sintering.

[0003] Because the outer electron structure of molybdenum is 4d 5 5s 1 Therefore, it exists in +6, +5, and +4 valence states, and thus its oxides, in addition to MoO3 and MoO2, also include a series of oxides such as Mo n O 3n-1 (Mo9O 26 Mo8O 23 Mo4O 11 Non-stoichiometric intermediate oxides (e.g., etc.). These non-stoichiometric intermediate oxides possess excellent electronic and optical properties and sintering activity, and can be considered as raw materials for the preparation of MoO. x Target material. Summary of the Invention

[0004] In view of this, some embodiments disclose a method for preparing a non-stoichiometric molybdenum oxide target with controllable molybdenum-oxygen ratio, including the following steps:

[0005] S1. Calcining ammonium molybdate yields MoO3 powder;

[0006] S2 and MoO3 powders react with hydrogen to obtain non-stoichiometric molybdenum oxide powder; in the non-stoichiometric molybdenum oxide powder, Mo9O 26 The mass content is 0%–99%, Mo4O 11 The mass content of is 20%–86%, and the mass content of MoO2 is 0%–40%.

[0007] S3, Non-stoichiometric molybdenum oxide powder compression molding;

[0008] S4. The formed non-stoichiometric molybdenum oxide powder is sintered under set conditions to obtain a non-stoichiometric molybdenum oxide target with a specific molybdenum-oxygen ratio, wherein the ratio of molybdenum atoms to oxygen atoms is 1:2 to 3.

[0009] Some embodiments disclose a method for preparing non-stoichiometric molybdenum oxide targets with controllable molybdenum-oxygen ratio, which further includes the following steps before step S3:

[0010] The step of mixing molybdenum oxide powders with different non-stoichiometric ratios to obtain new non-stoichiometric ratio molybdenum oxide powders.

[0011] The method for preparing non-stoichiometric molybdenum oxide targets with controllable molybdenum-oxygen ratio disclosed in some embodiments includes step S2 specifically comprising:

[0012] Weigh out MoO3 powder and place it in a crucible to form a material layer with a thickness of 5-30 mm;

[0013] Place the crucible into the tube furnace, with a distance of 2-3 cm between the crucible and the top of the tube furnace;

[0014] Argon gas is introduced into the tube furnace as a protective atmosphere, and the temperature of the tube furnace is increased.

[0015] When the tubular furnace reaches the set temperature, a certain flow rate of hydrogen is introduced into the tubular furnace. MoO3 undergoes a reduction reaction with hydrogen to obtain non-stoichiometric molybdenum oxide powder, in which the ratio of molybdenum atoms to oxygen atoms is 1:2 to 3.

[0016] The method for preparing non-stoichiometric molybdenum oxide targets with controllable molybdenum-oxygen ratio disclosed in some embodiments includes step S4 specifically comprising:

[0017] The shaped non-stoichiometric molybdenum oxide powder is placed in a spark plasma sintering furnace;

[0018] Set the sintering temperature, holding pressure, and holding time for the spark plasma sintering furnace;

[0019] Sintering yields a nonstoichiometric molybdenum oxide target with a specific molybdenum-oxygen ratio.

[0020] Some embodiments disclose a method for preparing non-stoichiometric molybdenum oxide targets with controllable molybdenum-oxygen ratio, wherein the calcination temperature of ammonium molybdate is 400–600°C, the calcination time of ammonium molybdate is 1–6 h, the temperature of the tube furnace is 450–600°C, the flow rate of hydrogen is 10–200 sccm, and the reduction reaction time is 20–200 min.

[0021] Some embodiments disclose a method for preparing non-stoichiometric molybdenum oxide targets with controllable molybdenum-oxygen ratio. The sintering temperature of the non-stoichiometric molybdenum oxide powder is 650-790°C, the holding pressure is 30-100 MPa, and the holding time is 5-30 min.

[0022] Some embodiments disclose a method for preparing a non-stoichiometric molybdenum oxide target with controllable molybdenum-oxygen ratio. The calcination temperature of ammonium molybdate is 450°C, and the calcination time of ammonium molybdate is 5 hours. The temperature of the tube furnace is 550°C, the flow rate of hydrogen is 40 sccm, and the reduction reaction time is 30 minutes. The sintering temperature of the non-stoichiometric molybdenum oxide powder is 790°C, the holding pressure is 60 MPa, and the holding time is 15 minutes. The molybdenum-oxygen atomic ratio of the non-stoichiometric molybdenum oxide target is 1:2.89.

[0023] Some embodiments disclose a method for preparing non-stoichiometric molybdenum oxide targets with controllable molybdenum-oxygen ratio. The calcination temperature of ammonium molybdate is 450°C, and the calcination time of ammonium molybdate is 5 hours. The temperature of the tube furnace is 550°C, the flow rate of hydrogen is 90 sccm, and the reduction reaction time is 80 minutes. The sintering temperature of the non-stoichiometric molybdenum oxide powder is 750°C, the holding pressure is 60 MPa, and the holding time is 15 minutes. The molybdenum-oxygen atomic ratio of the non-stoichiometric molybdenum oxide target is 1:2.78.

[0024] Some embodiments disclose a method for preparing a non-stoichiometric molybdenum oxide target with controllable molybdenum-oxygen ratio. The calcination temperature of ammonium molybdate is 450°C, and the calcination time of ammonium molybdate is 5 hours. The temperature of the tube furnace is 550°C, the flow rate of hydrogen is 140 sccm, and the reduction reaction time is 50 minutes. The sintering temperature of the non-stoichiometric molybdenum oxide powder is 770°C, the holding pressure is 70 MPa, and the holding time is 15 minutes. The molybdenum-oxygen atomic ratio of the non-stoichiometric molybdenum oxide target is 1:2.67.

[0025] Some embodiments disclose a method for preparing non-stoichiometric molybdenum oxide targets with controllable molybdenum-oxygen ratio. The calcination temperature of ammonium molybdate is 450°C, and the calcination time of ammonium molybdate is 5 hours. The temperature of the tube furnace is 550°C, the flow rate of hydrogen is 140 sccm, and the reduction reaction time is 90 minutes. The sintering temperature of the non-stoichiometric molybdenum oxide powder is 790°C, the holding pressure is 60 MPa, and the holding time is 15 minutes. The molybdenum-oxygen atomic ratio of the non-stoichiometric molybdenum oxide target is 1:2.49.

[0026] The method for preparing a non-stoichiometric molybdenum oxide target with controllable molybdenum-oxygen ratio disclosed in this invention involves controlling the reaction conditions of the hydrogen reduction reaction to induce an incomplete reaction of MoO3, generating oxygen-vacancy-rich non-stoichiometric molybdenum oxide powder. This non-stoichiometric molybdenum oxide powder is then sintered to prepare the non-stoichiometric molybdenum oxide target. This method uses simple raw materials, employing only MoO3 as the raw material for the hydrogen reduction reaction and only non-stoichiometric molybdenum oxide powder as the raw material for target preparation, without doping with other components. The preparation process is simple, the reaction conditions are controllable, and the resulting non-stoichiometric molybdenum oxide target exhibits good density. The non-stoichiometric molybdenum oxide target with controllable molybdenum-oxygen ratio prepared by this invention facilitates subsequent sputtering preparation of non-stoichiometric molybdenum oxide thin films, avoiding the problems of uneven and uncontrollable film composition caused by using Mo targets for reactive sputtering. Attached Figure Description

[0027] Figure 1 Example 1 MoO 2.89 Powder and MoO under different sintering conditions 2.89 XRD pattern of the target material;

[0028] Figure 2 Example 4: MoO with a magnification of 1000x 2.49 SEM microstructure of the fracture surface of the target material;

[0029] Figure 3 Example 4: MoO with a magnification of 5000x 2.49 SEM microstructure of the fracture surface of the target material. Detailed Implementation

[0030] The term "embodiment" used herein, as an example, is not necessarily to be construed as superior to or better than other embodiments. Performance testing in the embodiments of this application, unless otherwise specified, employs conventional testing methods in the art. It should be understood that the terminology used in this application is merely for describing particular implementations and is not intended to limit the scope of this disclosure.

[0031] Unless otherwise stated, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; other experimental methods and technical means not specifically mentioned herein refer to experimental methods and technical means commonly used by one of ordinary skill in the art.

[0032] The terms “basic” and “approximately” used in this document are to describe small fluctuations. For example, they can mean less than or equal to ±5%, such as less than or equal to ±2%, such as less than or equal to ±1%, such as less than or equal to ±0.5%, such as less than or equal to ±0.2%, such as less than or equal to ±0.1%, such as less than or equal to ±0.05%. Numerical data presented or expressed in range format in this document are used for convenience and brevity only, and should therefore be flexibly interpreted to include not only the explicitly listed values ​​that define the range, but also all independent values ​​or subranges contained within that range. For example, a numerical range of “1–5%” should be interpreted to include not only the explicitly listed values ​​from 1% to 5%, but also the independent values ​​and subranges within the indicated range. Thus, this numerical range includes independent values ​​such as 2%, 3.5%, and 4%, and subranges such as 1%–3%, 2%–4%, and 3%–5%, etc. This principle also applies to ranges that list only one value. Furthermore, this interpretation applies regardless of the width of the range or the characteristics described.

[0033] In this document, including in the claims, conjunctions such as "comprising," "including," "with," "having," "containing," "involving," and "accommodating" are understood to be open-ended, meaning "including but not limited to." Only the conjunctions "consisting of" and "composed of" are closed conjunctions.

[0034] To better illustrate the content of this application, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that this application can be implemented even without certain specific details. In the embodiments, some methods, means, instruments, and devices well-known to those skilled in the art are not described in detail in order to highlight the main points of this application.

[0035] Without conflict, the technical features disclosed in the embodiments of this application can be combined arbitrarily, and the resulting technical solutions belong to the content disclosed in the embodiments of this application. It should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer" used in this application indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing technical features and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention unless they conflict with the context. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance unless they conflict with the context.

[0036] In some embodiments, a method for preparing a non-stoichiometric molybdenum oxide target with a controllable molybdenum-oxygen ratio includes the following steps:

[0037] S1. Calcination of ammonium molybdate yields MoO3 powder; typically, ammonium molybdate is one or a combination of tetramolybdate, hexamolybdate, and octamolybdate; preferably, ammonium molybdate is tetramolybdate, and calcination yields pure MoO3 powder with an orthorhombic crystal structure.

[0038] S2 and MoO3 powders react with hydrogen to obtain non-stoichiometric molybdenum oxide powder; in the non-stoichiometric molybdenum oxide powder, Mo9O 26 The mass content is 0%–99%, Mo4O 11 The mass content of is 20%–86%, and the mass content of MoO2 is 0%–40%.

[0039] Generally, the obtained non-stoichiometric molybdenum oxide powder is subjected to X-ray diffraction analysis, and the Mo9O content is calculated using the K-value method. 26 Mo4O 11 The specific mass content of MoO2 was used to further calculate the ratio of molybdenum atoms to oxygen atoms in the molybdenum oxide powder.

[0040] Generally, the K-value method is a method used in JADE software to analyze the relative content of each phase. For example, it can be used to determine that a non-stoichiometric molybdenum oxide powder contains 90% Mo4O by mass. 11 Mo4O 11 The oxygen atom / molybdenum atom ratio in the MoO2 is 11 / 4 = 2.75; the oxygen atom / molybdenum atom ratio in the 10% MoO2 is 2 / 1 = 2; the relative atomic mass of Mo is 95.94, and the relative atomic mass of O is 16; therefore, the oxygen atom / molybdenum atom ratio of the non-stoichiometric ratio molybdenum oxide powder is {[0.9 / (95.94+16*2.75)]*2.75+[0.1 / (95.94+16*2)]*2} / {[0.9 / (95.94+16*2.75)]*1+[0.1 / (95.94+16*2)]*1} = 2.669; generally, by controlling the reaction conditions, such as the amount of MoO3 powder, reaction temperature, reaction time, or hydrogen flow rate, a molybdenum oxide powder with a specific non-stoichiometric ratio can be obtained, which contains a specific mass content of Mo9O. 26 Mo4O with a specific mass content 11 And / or a specific mass content of MoO2; typically, under different reaction conditions, non-stoichiometric molybdenum oxide powders with different molybdenum-oxygen atomic ratios are obtained, which contain Mo9O. 26 Mo4O 11At least two of the following: MoO2; for example, in some embodiments, X-ray diffraction analysis was performed on the obtained non-stoichiometric molybdenum oxide powder, and Mo9O was calculated by the K-value method. 26 The mass content is 20%, Mo4O 11 The mass content of molten iron is 60%, and the mass content of MoO2 is 20%. Therefore, the ratio of oxygen atoms to molybdenum atoms in the non-stoichiometric molybdenum oxide powder is 2.63, that is, O / Mo = 2.63. Thus, the non-stoichiometric molybdenum oxide powder can be expressed as MoO2. 2.63 In some embodiments, X-ray diffraction analysis was performed on the obtained non-stoichiometric molybdenum oxide powder, and the Mo9O content was calculated using the K-value method. 26 The mass content is 40%, Mo4O 11 The mass content is 60%, and the oxygen to molybdenum atom ratio in the non-stoichiometric molybdenum oxide powder is 2.81, i.e., O / Mo = 2.81. Therefore, the non-stoichiometric molybdenum oxide powder can be expressed as MoO. 2.81 ;

[0041] S3. Compression molding of non-stoichiometric molybdenum oxide powder; typically, the mold is a cemented carbide mold. Non-stoichiometric molybdenum oxide powder is placed in the mold and subjected to pressure to form a non-stoichiometric molybdenum oxide target blank. For example, the cemented carbide mold has a diameter of 20mm. Refractory metal foil is laid inside the mold, and refractory metal pads are placed at the bottom of the mold. Then, non-stoichiometric molybdenum oxide powder is placed in the mold, and refractory metal pads are placed on top of the powder. The refractory metal foil separates the non-stoichiometric molybdenum oxide powder from the mold shell. The refractory metal pads are placed above and below the powder to ensure uniform stress on the powder, resulting in a non-stoichiometric molybdenum oxide target blank. Typically, the compressed non-stoichiometric molybdenum oxide target blank is sintered to obtain a high-density target without the addition of sintering aids.

[0042] S4. The formed non-stoichiometric molybdenum oxide powder is sintered under set conditions to obtain a non-stoichiometric molybdenum oxide target with a specific molybdenum-oxygen ratio, wherein the ratio of molybdenum atoms to oxygen atoms is 1:2 to 3; usually, the molybdenum-oxygen atom ratio in the non-stoichiometric molybdenum oxide target is the same as that in the non-stoichiometric molybdenum oxide powder.

[0043] In some implementations, step S3 is preceded by:

[0044] The step involves mixing molybdenum oxide powders with different non-stoichiometric ratios to obtain new non-stoichiometric molybdenum oxide powders. Typically, molybdenum oxide powders with different non-stoichiometric ratios obtained under different reaction conditions can be mixed again in a V-type mixer at a predetermined ratio to obtain new non-stoichiometric molybdenum oxide powders. For example, in some embodiments, a non-stoichiometric molybdenum oxide powder (MoO₂) with a molybdenum-oxygen ratio of 1:2.63 is used. 2.63 The non-stoichiometric ratio of molybdenum oxide (MoO) with a molybdenum-oxygen ratio of 1:2.81 2.81 Mixing them at a molar ratio of 1:1 yields a non-stoichiometric molybdenum oxide powder (MoO) with a molybdenum-oxygen ratio of 1:2.72. 2.72 .

[0045] In some implementations, step S2 specifically includes:

[0046] Weigh out MoO3 powder and place it in a crucible to form a layer with a thickness of 5–30 mm; the amount of MoO3 powder used and the thickness of the layer in the crucible affect the yield of Mo9O. 26 and Mo4O 11 The powder plays a crucial role. If the layer of MoO3 powder formed in the crucible is thin, hydrogen gas will fully contact and react with the MoO3 powder, resulting in complete reduction of the MoO3 powder to form MoO2. Conversely, if the layer of MoO3 powder formed in the crucible is thick, the amount of MoO3 powder reacting with hydrogen gas will be small, and the product will contain a large amount of unreacted MoO3 powder. Controlling the reaction conditions between MoO3 powder and hydrogen gas is essential for the production of Mo9O. 26 Powder and Mo4O 11 Powder, Mo9O 26 Mo4O 11 It is rich in oxygen vacancies, has high sintering activity, is easy to densify, is insoluble in water, and is also easy to machine.

[0047] The crucible is placed in a tube furnace, with a distance of 2-3 cm between the crucible and the top of the furnace. Due to the relatively low density of hydrogen, the crucible placement method in the tube furnace provided by this embodiment of the invention can maximize the efficiency of hydrogen reaction. Generally, the crucible wall height is 10-12 mm. If the crucible wall is too high, hydrogen will pass over the surface of the MoO3 powder, resulting in insufficient hydrogen content required for the reaction of the MoO3 powder. If the crucible wall is too low, the amount of MoO3 powder loaded will be small, and the MoO3 powder will be fully reduced to form MoO2.

[0048] Argon gas is introduced into the tube furnace as a protective atmosphere, and the temperature of the tube furnace is increased.

[0049] When the tubular furnace reaches the set temperature, a certain flow rate of hydrogen is introduced into the furnace. MoO3 undergoes a reduction reaction with the hydrogen to obtain a non-stoichiometric molybdenum oxide powder, wherein the ratio of molybdenum atoms to oxygen atoms is 1:2 to 3. Typically, in this embodiment of the invention, the reaction between MoO3 powder and hydrogen is an incomplete reaction, and the resulting non-stoichiometric molybdenum oxide powder is an intermediate product of the complete reduction of MoO3 powder to MoO2.

[0050] In some implementations, step S4 specifically includes:

[0051] The formed non-stoichiometric molybdenum oxide is placed in a spark plasma sintering furnace. Typically, the non-stoichiometric molybdenum oxide powder is pre-pressed in a mold, and then the mold containing the non-stoichiometric molybdenum oxide powder is placed in the spark plasma sintering furnace. The spark plasma sintering furnace applies a DC pulse voltage to the mold to heat and pressurize the non-stoichiometric molybdenum oxide powder in the mold. The non-stoichiometric molybdenum oxide powder in the mold is rapidly heated to the sintering temperature and held for a short time to inhibit grain growth and avoid the formation of by-products. For example, in some embodiments, the non-stoichiometric molybdenum oxide powder is heated to 600°C in a spark plasma sintering furnace, and then heated to the sintering temperature at a heating rate of 15°C / min and held for a short time to obtain a non-stoichiometric molybdenum oxide target with a specific molybdenum-oxygen ratio.

[0052] The sintering temperature, holding pressure, and holding time of the discharge plasma sintering furnace are set. Generally, by controlling the sintering temperature, sintering pressure, and sintering holding time, the degree of reduction of molybdenum trioxide can be controlled, the content of different molybdenum oxides in the reduction products can be controlled, and the ratio of molybdenum atoms to oxygen atoms in the reduction product powder can be further controlled to obtain non-stoichiometric molybdenum oxide powder with a specific molybdenum-oxygen atom ratio.

[0053] Sintering yields a non-stoichiometric molybdenum oxide target with a specific molybdenum-oxygen ratio. The non-stoichiometric molybdenum oxide target prepared by the method of this invention exhibits good density and superior electronic properties.

[0054] In some embodiments, the calcination temperature of ammonium molybdate is 400–600°C, the calcination time of ammonium molybdate is 1–6 h; the temperature of the tube furnace is 450–600°C, the flow rate of hydrogen is 10–200 sccm, and the reduction reaction time is 20–200 min.

[0055] In some embodiments, the sintering temperature of the non-stoichiometric molybdenum oxide powder is 650–790°C, the holding pressure is 30–100 MPa, and the holding time is 5–30 min.

[0056] Usually, Mo9O 26 and Mo4O 11It exhibits good thermal stability below 800℃, therefore the sintering temperature is controlled below 800℃; the applied holding pressure can improve the sintering efficiency, enabling the non-stoichiometric molybdenum oxide powder to be rapidly densified.

[0057] Preferably, the calcination temperature of ammonium molybdate is 450℃, and the calcination time is 5h; the temperature of the tube furnace is 550℃, the hydrogen flow rate is 40sccm, and the reduction reaction time is 30min; the sintering temperature of the non-stoichiometric molybdenum oxide powder is 790℃, the holding pressure is 60MPa, and the holding time is 15min; the molybdenum-oxygen atomic ratio of the non-stoichiometric molybdenum oxide target is 1:2.89.

[0058] Preferably, the calcination temperature of ammonium molybdate is 450℃, and the calcination time is 5h; the temperature of the tube furnace is 550℃, the hydrogen flow rate is 90sccm, and the reduction reaction time is 80min; the sintering temperature of the non-stoichiometric molybdenum oxide powder is 750℃, the holding pressure is 60MPa, and the holding time is 15min; the molybdenum-oxygen atomic ratio of the non-stoichiometric molybdenum oxide target is 1:2.78.

[0059] Preferably, the calcination temperature of ammonium molybdate is 450℃, and the calcination time is 5h; the temperature of the tube furnace is 550℃, the hydrogen flow rate is 140sccm, and the reduction reaction time is 50min; the sintering temperature of the non-stoichiometric molybdenum oxide powder is 770℃, the holding pressure is 70MPa, and the holding time is 15min; the molybdenum-oxygen atomic ratio of the non-stoichiometric molybdenum oxide target is 1:2.67.

[0060] Preferably, in some embodiments, the preparation method of non-stoichiometric molybdenum oxide target material with controllable molybdenum-oxygen ratio disclosed includes: calcination temperature of ammonium molybdate at 450°C for 5 hours; tube furnace temperature at 550°C; hydrogen flow rate at 140 sccm; reduction reaction time at 90 minutes; sintering temperature of non-stoichiometric molybdenum oxide powder at 790°C; holding pressure at 60 MPa; holding time at 15 minutes; and molybdenum-oxygen atomic ratio of the non-stoichiometric molybdenum oxide target material at 1:2.49.

[0061] The technical details are further illustrated below with reference to the embodiments.

[0062] Example 1

[0063] The MoO disclosed in this embodiment 2.89 Methods for preparing target materials include:

[0064] Ammonium molybdate was calcined at 450℃ for 5 hours to obtain MoO3 powder;

[0065] Weigh 20g of MoO3 powder and place it in a crucible;

[0066] Place the crucible into the tube furnace, with a distance of 2-3 cm between the crucible and the top of the tube furnace;

[0067] Argon gas is introduced into the tube furnace as a protective atmosphere, and the temperature of the tube furnace is increased.

[0068] After the tube furnace is heated to 550℃, hydrogen gas at 40 sccm is introduced into the furnace, and MoO3 reacts with hydrogen gas for 30 min; non-stoichiometric molybdenum oxide powder is obtained; X-ray diffraction analysis is performed on the non-stoichiometric molybdenum oxide powder, and the composition of the non-stoichiometric molybdenum oxide powder is calculated by the K-value method, which shows that the mass content of the non-stoichiometric molybdenum oxide powder includes 98% Mo9O. 26 With a mass content of 2% MoO3, the oxygen to molybdenum atom ratio in the non-stoichiometric molybdenum oxide powder is 2.89, i.e., O / Mo = 2.89. Therefore, the non-stoichiometric molybdenum oxide powder is expressed as MoO3. 2.89 ;

[0069] Weigh out 9g of MoO 2.89 The powder, after being thoroughly ground, is placed in a 20 μm diameter cemented carbide mold. A refractory metal foil is laid inside the mold, and a refractory metal gasket is placed at the bottom of the mold. Then, MoO2 is... 2.89 The powder is placed in the mold, in MoO 2.89 Place a refractory metal pad on the powder; wrap MoO with refractory metal foil. 2.89 The powder is separated from the mold shell by refractory metal gaskets placed on MoO. 2.89 The top and bottom of the powder make MoO 2.89 The powder is subjected to uniform stress and extruded into shape.

[0070] Will be equipped with MoO 2.89 The powder mold was placed in a spark plasma sintering furnace, and the sintering temperature was set to 790℃, the holding pressure to 60MPa, and the holding time to 15min, resulting in MoO with a relative density of 98.6%. 2.89 The relative density of the target material was determined using Archimedes' displacement method, wherein... Figure 1 The MoO disclosed in Example 1 2.89 Powder and MoO under different sintering conditions 2.89 XRD pattern of the target material; as shown Figure 1 As shown, MoO 2.89 No significant changes were observed in the phase composition before and after sintering.

[0071] Example 2

[0072] The MoO disclosed in this embodiment 2.78 Methods for preparing target materials include:

[0073] Ammonium molybdate was calcined at 450℃ for 5 hours to obtain MoO3 powder;

[0074] Weigh 20g of MoO3 powder and place it in a crucible;

[0075] Place the crucible into the tube furnace, with a distance of 2-3 cm between the crucible and the top of the tube furnace;

[0076] Argon gas is introduced into the tube furnace as a protective atmosphere, and the temperature of the tube furnace is increased.

[0077] After the tube furnace is heated to 550℃, hydrogen gas at 90 sccm is introduced into the furnace, and MoO3 reacts with hydrogen gas for 80 min; non-stoichiometric molybdenum oxide powder is obtained. X-ray diffraction analysis of the non-stoichiometric molybdenum oxide powder is performed, and the composition of the non-stoichiometric molybdenum oxide powder is calculated by the K-value method, which shows that the mass content of the non-stoichiometric molybdenum oxide powder includes 90% Mo4O3. 11 With MoO2 containing 10% by mass;

[0078] Weigh out the non-stoichiometric molybdenum oxide powder (MoO) prepared in Example 1 at a molar ratio of 1:1. 2.89 The non-stoichiometric molybdenum oxide powder prepared in this embodiment was mixed evenly in a V-type mixer to obtain a new non-stoichiometric molybdenum oxide powder. X-ray diffraction analysis was performed on the new non-stoichiometric molybdenum oxide powder, and the composition of the new non-stoichiometric molybdenum oxide powder was calculated using the K-value method, showing that it contained 49.6% Mo9O by mass. 26 Mo4O with a mass content of 45.6% 11 The new non-stoichiometric molybdenum oxide powder, with a MoO2 content of 4.8% by mass, has an oxygen to molybdenum atom ratio of 2.78, i.e., O / Mo = 2.78. Therefore, the new non-stoichiometric molybdenum oxide powder is denoted as MoO2. 2.78 Powder;

[0079] Weigh out 9g of MoO 2.78 The powder was placed in a cemented carbide mold with a diameter of 20 μm, in which a refractory metal foil was laid inside the mold, and a refractory metal gasket was placed at the bottom of the mold. Then, MoO2 was added. 2.78 The powder is placed in the mold, in MoO 2.78 Place a refractory metal pad on the powder; wrap MoO with refractory metal foil. 2.78 The powder is separated from the mold shell by refractory metal gaskets placed on MoO. 2.78 The top and bottom of the powder make MoO 2.78 The powder is subjected to uniform stress and extruded into shape.

[0080] Will be equipped with MoO 2.78The powder mold was placed in a spark plasma sintering furnace, and the sintering temperature was set to 750℃, the holding pressure to 60MPa, and the holding time to 15min, resulting in MoO with a thickness of 5.3mm and a relative density of 98.6%. 2.78 The target material, in which the relative density was determined using the Archimedes displacement method.

[0081] Example 3

[0082] The MoO disclosed in this embodiment 2.67 Methods for preparing target materials include:

[0083] Ammonium molybdate was calcined at 450℃ for 5 hours to obtain MoO3 powder;

[0084] Weigh 200g of MoO3 powder and place it in a crucible;

[0085] Place the crucible into the tube furnace, with a distance of 2-3 cm between the crucible and the top of the tube furnace;

[0086] Argon gas is introduced into the tube furnace as a protective atmosphere, and the temperature of the tube furnace is increased.

[0087] After the tube furnace is heated to 550℃, hydrogen gas at 140 sccm is introduced into the furnace, and MoO3 reacts with hydrogen gas for 50 min; non-stoichiometric molybdenum oxide powder is obtained. X-ray diffraction analysis of the non-stoichiometric molybdenum oxide powder is performed, and the composition of the non-stoichiometric molybdenum oxide powder is calculated by the K-value method, which shows that the mass content of the non-stoichiometric molybdenum oxide powder includes 55% Mo4O3. 11 Mo9O with a mass content of 30% 26 A 15% (by mass) MoO2 non-stoichiometric molybdenum oxide powder has an oxygen to molybdenum atom ratio of 2.67, i.e., O / Mo = 2.67. Therefore, the non-stoichiometric molybdenum oxide powder is expressed as MoO2. 2.67 ;

[0088] Weigh out 9g of MoO 2.67 The powder was placed in a cemented carbide mold with a diameter of 20 μm, in which a refractory metal foil was laid inside the mold, and a refractory metal gasket was placed at the bottom of the mold. Then, MoO2 was added. 2.67 The powder is placed in the mold, in MoO 2.67 Place a refractory metal pad on the powder; wrap MoO with refractory metal foil. 2.67 The powder is separated from the mold shell by refractory metal gaskets placed on MoO. 2.67 The top and bottom of the powder make MoO 2.67 The powder is subjected to uniform stress and extruded into shape.

[0089] Will be equipped with MoO 2.67The powder mold was placed in a spark plasma sintering furnace, and the sintering temperature was set to 770℃, the holding pressure to 70MPa, and the holding time to 15min, resulting in MoO with a relative density of 99%. 2.67 The target material, in which the relative density was determined using the Archimedes displacement method.

[0090] Example 4

[0091] The MoO disclosed in this embodiment 2.49 Methods for preparing target materials include:

[0092] Ammonium molybdate was calcined at 450℃ for 5 hours to obtain MoO3 powder;

[0093] Weigh 200g of MoO3 powder and place it in a crucible;

[0094] Place the crucible into the tube furnace, with a distance of 2-3 cm between the crucible and the top of the tube furnace;

[0095] Argon gas is introduced into the tube furnace as a protective atmosphere, and the temperature of the tube furnace is increased.

[0096] After the tube furnace is heated to 550℃, hydrogen gas at 140 sccm is introduced into the furnace, and MoO3 reacts with hydrogen gas for 90 min; non-stoichiometric molybdenum oxide powder is obtained. X-ray diffraction analysis of the non-stoichiometric molybdenum oxide powder is performed, and the composition of the non-stoichiometric molybdenum oxide powder is calculated by the K-value method, including a mass content of 67% Mo4O. 11 With a mass content of 33% MoO2, the oxygen to molybdenum atom ratio in the non-stoichiometric molybdenum oxide powder is 2.49, i.e., O / Mo = 2.49. Therefore, the non-stoichiometric molybdenum oxide powder is expressed as MoO2. 2.49 ;

[0097] Weigh out 9g of MoO 2.49 The powder was placed in a cemented carbide mold with a diameter of 20 μm, in which a refractory metal foil was laid inside the mold, and a refractory metal gasket was placed at the bottom of the mold. Then, MoO2 was added. 2.49 The powder is placed in the mold, in MoO 2.49 Place a refractory metal pad on the powder; wrap MoO with refractory metal foil. 2.49 The powder is separated from the mold shell by refractory metal gaskets placed on MoO. 2.49 The top and bottom of the powder make MoO 2.49 The powder is subjected to uniform stress and extruded into shape.

[0098] Will be equipped with MoO 2.49The powder mold was placed in a spark plasma sintering furnace, and the sintering temperature was set to 790℃, the holding pressure to 60MPa, and the holding time to 15min, resulting in MoO with a thickness of 5.1mm and a relative density of 99.8%. 2.49 The relative density of the target material was determined using Archimedes' displacement method; among which, Figure 2 The MoO4 with a magnification of 1000x disclosed in Example 4 2.49 SEM microstructure of the fracture surface of the target material; Figure 3 The MoO4 with a magnification of 5000x disclosed in Example 4 2.49 SEM microstructure of the target fracture surface; the melting point of MoO2 is higher than that of Mo4O 11 The high concentration of Mo4O during sintering 11 Liquid phase sintering occurs, such as Figure 2 , Figure 3 As shown, Mo4O 11 In the diagram, MoO2 is shown as a large matrix, with small particles diffusely embedded within it, and Mo4O... 11 There are almost no gaps between the particles and the MoO2 powder.

[0099] Example 5

[0100] The MoO disclosed in this embodiment 2.44 Methods for preparing powders include:

[0101] Ammonium molybdate was calcined at 500℃ for 3 hours to obtain MoO3 powder;

[0102] Weigh 20g of MoO3 powder and place it in a crucible;

[0103] Place the crucible into the tube furnace, with a distance of 2-3 cm between the crucible and the top of the tube furnace;

[0104] Argon gas is introduced into the tube furnace as a protective atmosphere, and the temperature of the tube furnace is increased.

[0105] After the tube furnace is heated to 550℃, hydrogen gas at 140 sccm is introduced into the furnace, and MoO3 reacts with hydrogen gas for 80 min; non-stoichiometric molybdenum oxide powder is obtained. X-ray diffraction analysis of the non-stoichiometric molybdenum oxide powder is performed, and the composition of the non-stoichiometric molybdenum oxide powder is calculated by the K-value method, which shows that the mass content of the non-stoichiometric molybdenum oxide powder includes 61% Mo4O3. 11 With a mass content of 39% MoO2, the oxygen to molybdenum atom ratio in the non-stoichiometric molybdenum oxide powder is 2.44, i.e., O / Mo = 2.44. Therefore, the non-stoichiometric molybdenum oxide powder is expressed as MoO2. 2.44 .

[0106] Example 6

[0107] The MoO disclosed in this embodiment 2.64 Methods for preparing powders include:

[0108] Ammonium molybdate was calcined at 500℃ for 3 hours to obtain MoO3 powder;

[0109] Weigh 20g of MoO3 powder and place it in a crucible;

[0110] Place the crucible into the tube furnace, with a distance of 2-3 cm between the crucible and the top of the tube furnace;

[0111] Argon gas is introduced into the tube furnace as a protective atmosphere, and the temperature of the tube furnace is increased.

[0112] After the tube furnace is heated to 550℃, hydrogen gas at 140 sccm is introduced into the furnace, and MoO3 reacts with hydrogen gas for 60 min; non-stoichiometric molybdenum oxide powder is obtained. X-ray diffraction analysis of the non-stoichiometric molybdenum oxide powder is performed, and the composition of the non-stoichiometric molybdenum oxide powder is calculated by the K-value method, which shows that the mass content of the non-stoichiometric molybdenum oxide powder includes 86% Mo4O3. 11 With a mass content of 14% MoO2, the oxygen to molybdenum atom ratio in the non-stoichiometric molybdenum oxide powder is 2.64, i.e., O / Mo = 2.64. Therefore, the non-stoichiometric molybdenum oxide powder is expressed as MoO2. 2.64 .

[0113] The electrical properties of the non-stoichiometric molybdenum oxide targets prepared in Examples 1 to 4 were tested using a four-probe tester. The test results are shown in Table 1.

[0114] Table 1. Electrical performance test results of non-stoichiometric molybdenum oxide targets prepared in Examples 1-4

[0115]

[0116] As shown in Table 1, the resistivity is relatively high when x = 2.89, and relatively low when x = 2.4 to 2.7. The conductivity of the non-stoichiometric molybdenum oxide target can be adjusted by controlling the value of x.

[0117] The method for preparing a non-stoichiometric molybdenum oxide target with controllable molybdenum-oxygen ratio disclosed in this invention involves controlling the reaction conditions of the hydrogen reduction reaction to induce an incomplete reaction of MoO3, generating oxygen-vacancy-rich non-stoichiometric molybdenum oxide powder. This non-stoichiometric molybdenum oxide powder is then sintered to prepare the non-stoichiometric molybdenum oxide target. This method uses simple raw materials, employing only MoO3 as the raw material for the hydrogen reduction reaction and only non-stoichiometric molybdenum oxide powder as the raw material for target preparation, without doping with other components. The preparation process is simple, the reaction conditions are controllable, and the resulting non-stoichiometric molybdenum oxide target exhibits good density. The non-stoichiometric molybdenum oxide target with controllable molybdenum-oxygen ratio prepared by this invention facilitates subsequent sputtering preparation of non-stoichiometric molybdenum oxide thin films, avoiding the problems of uneven and uncontrollable film composition caused by using Mo targets for reactive sputtering.

[0118] The technical solutions and technical details disclosed in the embodiments of this invention are merely illustrative of the inventive concept of this invention and do not constitute a limitation on the technical solutions of this invention. Any conventional changes, substitutions, or combinations made to the technical details disclosed in the embodiments of this invention have the same inventive concept as this invention and are within the protection scope of the claims of this invention.

Claims

1. A method for preparing a non-stoichiometric molybdenum oxide target with controllable molybdenum-oxygen ratio, characterized in that, Including the following steps: S1. Calcination of ammonium molybdate yields MoO3 powder; the calcination temperature of the ammonium molybdate is 400–600℃, and the calcination time of the ammonium molybdate is 1–6 h; S2 and MoO3 powders react with hydrogen to obtain non-stoichiometric molybdenum oxide powder; in the non-stoichiometric molybdenum oxide powder, Mo9O 26 The mass content is 0%~99%, Mo4O 11 The mass content of the substance is 20%~86%, the mass content of MoO2 is 0%~40%, and the total mass content of the three is 100%; specifically include: Weigh out MoO3 powder and place it in a crucible to form a material layer with a thickness of 5-30 mm; Place the crucible into the tube furnace, with a distance of 2-3 cm between the crucible and the top of the tube furnace; Argon gas is introduced into the tube furnace as a protective atmosphere, and the temperature of the tube furnace is increased. When the tubular furnace reaches the set temperature, a certain flow rate of hydrogen is introduced into the furnace. MoO3 undergoes a reduction reaction with the hydrogen to obtain the non-stoichiometric molybdenum oxide powder, wherein the ratio of molybdenum atoms to oxygen atoms is 1:2-3, and the oxygen atom values ​​are not 2 or 3; the temperature of the tubular furnace is 450-600℃, the flow rate of the hydrogen is 10-200 sccm, and the reduction reaction time is 20-200 min; S3, The non-stoichiometric molybdenum oxide powder is molded; S4. Place the formed non-stoichiometric molybdenum oxide powder in a spark plasma sintering furnace; Set the sintering temperature, holding pressure, and holding time of the spark plasma sintering furnace; wherein the sintering temperature is 650-790℃, the holding pressure is 30-100MPa, and the holding time is 5-30min. Sintering yields a non-stoichiometric molybdenum oxide target with a specific molybdenum-oxygen ratio; wherein the ratio of molybdenum atoms to oxygen atoms is 1:2 to 3.

2. The method for preparing a non-stoichiometric molybdenum oxide target with controllable molybdenum-oxygen ratio according to claim 1, characterized in that, Step S3 is preceded by: The step of mixing molybdenum oxide powders with different non-stoichiometric ratios to obtain new non-stoichiometric ratio molybdenum oxide powders.

3. The method for preparing a non-stoichiometric molybdenum oxide target with controllable molybdenum-oxygen ratio according to claim 1, characterized in that: The calcination temperature of ammonium molybdate is 450℃, and the calcination time is 5 hours. The temperature of the tube furnace was 550℃, the flow rate of hydrogen was 40 sccm, and the reduction reaction time was 30 min. The sintering temperature of the non-stoichiometric molybdenum oxide powder is 790℃, the holding pressure is 60MPa, and the holding time is 15min. The molybdenum-oxygen atomic ratio of the non-stoichiometric molybdenum oxide target is 1:2.

89.

4. The method for preparing a non-stoichiometric molybdenum oxide target with controllable molybdenum-oxygen ratio according to claim 1, characterized in that: The calcination temperature of ammonium molybdate is 450℃, and the calcination time is 5 hours. The temperature of the tube furnace was 550℃, the flow rate of hydrogen was 90 sccm, and the reduction reaction time was 80 min. The sintering temperature of the non-stoichiometric molybdenum oxide powder is 750℃, the holding pressure is 60MPa, and the holding time is 15min. The molybdenum-oxygen atomic ratio of the non-stoichiometric molybdenum oxide target is 1:2.

78.

5. The method for preparing a non-stoichiometric molybdenum oxide target with controllable molybdenum-oxygen ratio according to claim 1, characterized in that: The calcination temperature of ammonium molybdate is 450℃, and the calcination time is 5 hours. The temperature of the tube furnace was 550℃, the flow rate of hydrogen was 140 sccm, and the reduction reaction time was 50 min. The sintering temperature of the non-stoichiometric molybdenum oxide powder is 770℃, the holding pressure is 70MPa, and the holding time is 15min. The molybdenum-oxygen atomic ratio of the non-stoichiometric molybdenum oxide target is 1:2.

67.

6. The method for preparing a non-stoichiometric molybdenum oxide target with controllable molybdenum-oxygen ratio according to claim 1, characterized in that: The calcination temperature of ammonium molybdate is 450℃, and the calcination time is 5 hours. The temperature of the tube furnace was 550℃, the flow rate of hydrogen was 140 sccm, and the reduction reaction time was 90 min. The sintering temperature of the non-stoichiometric molybdenum oxide powder is 790℃, the holding pressure is 60MPa, and the holding time is 15min. The molybdenum-oxygen atomic ratio of the non-stoichiometric molybdenum oxide target is 1:2.49.

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