A method for preparing a cuprous telluride powder and a target

Abstract

The application belongs to the field of material preparation, and discloses a preparation method of cuprous telluride powder and target material. The preparation method of the cuprous telluride powder comprises the following steps: mixing tellurium powder and copper powder, and performing a heating reaction under the condition of a hydrogen atmosphere and a temperature of 350-400 DEG C to obtain cuprous telluride powder. The cuprous telluride powder is used as raw material to perform a heating reaction to obtain cuprous telluride target material; the heating mode of the heating reaction is as follows: under vacuum condition, the temperature is raised to 600-650 DEG C, and the temperature is kept for 90-120 min; after the temperature is raised to the highest temperature, the pressure is increased to 60-70 Mpa, and the pressure is kept until the temperature keeping time is over. The cuprous telluride powder is prepared by adopting a tubular furnace low-temperature powder synthesis method, and can be mass-produced with low requirement on equipment; the cuprous telluride target material is prepared by adopting vacuum hot-pressing sintering, and the process flow is short and the operation is simple; the obtained cuprous telluride target material has low oxygen content and high relative density.

Description

Technical Field

[0001] This invention belongs to the field of materials preparation and relates to a method for preparing cuprous telluride powder and a target material. Background Technology

[0002] Cuprous telluride (Cu₂Te) is an important semiconductor material with an octahedral crystal structure, belonging to the metal chalcogenide group. It possesses unique ionic conductivity and thermoelectric properties, making it widely used in solar cells and thermoelectric materials. In CdS / CdTe solar cells, Cu₂Te, as an interlayer, allows the work function of the external electrodes to balance with the valence state of the CdTe material, promoting the formation of a back-side electric field that reduces the probability of carrier loading, thereby significantly improving the efficiency of the solar cell.

[0003] Numerous studies on the preparation of Cu₂Te exist in the literature. For example, patent document CN106241752B discloses a method for preparing cuprous telluride, including the following steps: mixing elemental copper and elemental telluride, and heating the mixture under vacuum to obtain cuprous telluride. The heating method is as follows: A) heating to 400℃~550℃ and holding for 1h~2h, with a heating rate of 5℃ / min~10℃ / min; B) heating to 850℃~950℃ and holding for 1h~3h, with a heating rate of 3℃ / min~6℃ / min; C) heating to 1100℃~1180℃ and holding for 2h~4h, with a heating rate of 3℃ / min~6℃ / min. This preparation method is complex, involving a three-stage sintering process with numerous steps. The preparation process requires sophisticated equipment and stringent temperature control conditions. Summary of the Invention

[0004] One of the objectives of this invention is to provide a method for preparing cuprous telluride powder that is simple and easy to control.

[0005] The second objective of this invention is to provide a method for preparing a copper telluride target.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing cuprous telluride powder includes the following steps:

[0008] Tellurium powder and copper powder are mixed and heated in a hydrogen atmosphere at a temperature of 350~400℃ to obtain cuprous telluride powder.

[0009] Considering that copper powder has a high vapor pressure and is difficult to remove, an excess of tellurium powder can allow the copper to react fully, making it easier to remove any free tellurium that may remain. Furthermore, tellurium powder and copper powder are mixed evenly at a molar ratio of 1.1~1.2:2.

[0010] Furthermore, use -100 mesh tellurium powder and -100 mesh copper powder. The smaller the powder particles, the better, as they increase activity, ensure a more complete reaction, and can lower the reaction temperature.

[0011] Considering the low-temperature reaction of the powder, the reaction rate is too fast and the reaction is incomplete at this temperature, while too low a temperature will cause more tellurium to volatilize. Therefore, during the heating reaction, the temperature is increased to 350-400℃ at a heating rate of 5-10℃ / min, and the reaction time is 90-120min.

[0012] Furthermore, during the heating reaction, the hydrogen flow rate is 5-10 L / min. In this application, the introduction of hydrogen during the reaction serves a reducing function, preventing high oxygen levels after cuprous telluride synthesis. Simultaneously, the large specific surface area of ​​the powder allows for greater contact with hydrogen, facilitating oxygen removal.

[0013] A method for preparing a cuprous telluride target involves using the cuprous telluride powder prepared by the above-mentioned method as a raw material and subjecting it to a heating reaction to obtain the cuprous telluride target.

[0014] The heating method for the heating reaction is as follows:

[0015] Under vacuum conditions, heat to 600~650℃ and hold for 90~120 minutes;

[0016] After heating to the maximum temperature, pressurize to 60-70 MPa and maintain the pressure until the holding time ends.

[0017] Furthermore, during the heating reaction: the temperature is increased to 600-650℃ at a rate of 8-12℃ / min, and held for 90-120 minutes; after reaching the maximum temperature, the pressure is increased to 60-70 MPa within 20 minutes, and held at that pressure until the holding time ends. At a certain temperature, the powder is allowed to fully expand, while the pressure rate is controlled to achieve densification.

[0018] Further, the cuprous telluride powder is loaded into a mold and placed in a vacuum hot press furnace for heating and reaction.

[0019] Furthermore, during the reaction, the vacuum condition is specifically a vacuum degree of no more than 10 Pa.

[0020] Furthermore, after the heat preservation is completed, cooling is also included, which is carried out along with the furnace.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] This invention uses a tube furnace low-temperature powder synthesis method to prepare cuprous telluride powder, which can be mass-produced, has low equipment requirements, and the reaction graphite boat used can be reused, resulting in low cost. Hydrogen gas is directly introduced during the synthesis process to achieve the purpose of direct oxygen removal.

[0023] This invention uses vacuum hot pressing sintering to prepare copper telluride targets. The process is short and easy to operate, and the resulting copper telluride targets have low oxygen content and high relative density. Detailed Implementation

[0024] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0025] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0026] Example 1

[0027] Includes the following steps:

[0028] (1) Load -100 mesh tellurium powder and -100 mesh copper powder into a tube furnace at a molar ratio of 1.1:2.

[0029] (2) First, nitrogen gas is introduced at a flow rate of 10 L / min for 30 min. Then, heating is started, and the nitrogen gas is switched to hydrogen gas. The temperature is increased to 400℃ at 6℃ / min and held for 90 min.

[0030] (3) After cooling, turn off the hydrogen gas, introduce an inert gas to replace the hydrogen gas in the tube, and then remove the copper telluride powder from the furnace.

[0031] (4) Crush the cuprous telluride powder to -325 mesh, put it into a mold, put it into a vacuum hot press furnace for hot pressing, raise the temperature to 630℃ at 12℃ / min, and keep it at 100min; after raising the temperature to the highest temperature, pressurize it to 70MPa within 20min and keep it at the pressure until the temperature drops.

[0032] (5) After cooling to room temperature, demold and then mechanically process to obtain copper telluride target material.

[0033] Example 2

[0034] Includes the following steps:

[0035] (1) Load -100 mesh tellurium powder and -100 mesh copper powder into a tube furnace at a molar ratio of 1.2:2.

[0036] (2) First, nitrogen gas is introduced at a flow rate of 5L / min for 50min. Then, heating is started, and the nitrogen gas is switched to hydrogen gas. The temperature is increased to 350℃ at 10℃ / min and held for 100min.

[0037] (3) After cooling, turn off the hydrogen gas, introduce an inert gas to replace the hydrogen gas in the tube, and then remove the copper telluride powder from the furnace.

[0038] (4) Crush the cuprous telluride powder to -325 mesh, put it into a mold, put it into a vacuum hot press furnace for hot pressing, raise the temperature to 600℃ at 8℃ / min, and keep it at 90min; after raising the temperature to the highest temperature, pressurize it to 70MPa within 20min and keep it at the pressure until the temperature drops.

[0039] (5) After cooling to room temperature, demold and then mechanically process to obtain copper telluride target material.

[0040] Example 3

[0041] Includes the following steps:

[0042] (1) Load -100 mesh tellurium powder and -100 mesh copper powder into a tube furnace at a molar ratio of 1.2:2.

[0043] (2) First, nitrogen gas is introduced at a flow rate of 8L / min for 40min. Then, heating is started, and the nitrogen gas is switched to hydrogen gas. The temperature is increased to 380℃ at 5℃ / min and held for 100min.

[0044] (3) After cooling, turn off the hydrogen gas, introduce an inert gas to replace the hydrogen gas in the tube, and then remove the copper telluride powder from the furnace.

[0045] (4) Crush the cuprous telluride powder to -325 mesh, put it into a mold, put it into a vacuum hot press furnace for hot pressing, raise the temperature to 650℃ at 12℃ / min, and keep it at 120min; after raising the temperature to the highest temperature, pressurize it to 60MPa within 20min and keep it at the pressure until the temperature drops.

[0046] (5) After cooling to room temperature, demold and then mechanically process to obtain copper telluride target material.

[0047] Comparative Example 1

[0048] Comparative Example 1 is basically the same as Example 1, except that in steps (2) and (3) of Comparative Example 1, hydrogen gas is not introduced, but nitrogen gas is introduced continuously. Specifically:

[0049] (2) Introduce nitrogen gas at a flow rate of 10 L / min for 30 min, then turn on the heater and raise the temperature to 400℃ at a rate of 6℃ / min, and hold for 90 min.

[0050] (3) After cooling, maintain a nitrogen atmosphere and remove the furnace to obtain cuprous telluride powder.

[0051] Comparative Example 2

[0052] Comparative Example 2 is basically the same as Example 1, except for the difference in step (2), specifically:

[0053] (2) First, nitrogen gas is introduced at a flow rate of 10 L / min for 30 min. Then, heating is started, and the nitrogen gas is switched to hydrogen gas. The temperature is increased to 600℃ at 6℃ / min and held for 90 min.

[0054] The comparative synthesis of cuprous telluride powder failed, and there was incomplete reaction of metallic copper.

[0055] The copper telluride targets obtained in Examples 1-3 and Comparative Example 1 / 2 were tested, and the test data are shown in Table 1.

[0056] Table 1 Test Data

[0057]

[0058] It can be seen that the copper telluride target product prepared by this invention has stable quality, low oxygen content, and high relative density.

[0059] The above are merely preferred embodiments of the present invention and are not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of the present invention.

Claims

1. A method for preparing a cuprous telluride target, characterized in that, Tellurium powder and copper powder are mixed evenly at a molar ratio of 1.1~1.2:2, and a first heating reaction is carried out under a hydrogen atmosphere and a temperature of 350~400℃ to obtain cuprous telluride powder. A second heating reaction is carried out using cuprous telluride powder as raw material to obtain cuprous telluride target material. The heating method for the second heating reaction is as follows: under vacuum conditions, the temperature is increased to 600-650℃ at a rate of 8-12℃ / min, and held for 90-120min; after the temperature reaches the maximum, the pressure is increased to 60-70MPa within 20min, and the pressure is maintained until the holding time ends.

2. The method for preparing the copper telluride target as described in claim 1, characterized in that, Cuprous telluride powder is loaded into a mold and placed in a vacuum hot press furnace for a second heating reaction.

3. The method for preparing the copper telluride target as described in claim 1, characterized in that, During the second heating reaction, the vacuum condition is specifically that the vacuum degree is no greater than 10 Pa.

4. The method for preparing the copper telluride target as described in claim 1, characterized in that, In the second heating reaction process, after the heat preservation is completed, cooling is also included, which is carried out in the furnace.

5. The method for preparing the copper telluride target as described in claim 1, characterized in that, Use -100 mesh tellurium powder and -100 mesh copper powder.

6. The method for preparing the copper telluride target as described in claim 1, characterized in that, During the first heating reaction: the temperature is increased to 350-400℃ at a heating rate of 5-10℃ / min, and the reaction time is 90-120min.

7. The method for preparing the copper telluride target as described in claim 1, characterized in that, During the first heating reaction: the flow rate of hydrogen is 5~10 L / min.

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