CN114592136A - A device and method for ultrasonic-assisted preparation of magnesium-based hydrogen storage alloys - Google Patents

Abstract

The invention belongs to the technical field of hydrogen storage material preparation and processing, and relates to a device and a method for preparing magnesium-based hydrogen storage alloy by ultrasonic assistance. The invention has the advantages that: the bottom of the corundum crucible is connected with the ultrasonic melt processing system, so that impurity elements are reduced, the shape of the crucible is reasonably designed, ultrasonic waves fully act on the alloy melt, the volatilization and oxidation of the alloy melt are avoided through the efficient gas protection system, elements in the prepared magnesium-based hydrogen storage alloy are uniformly distributed, the microstructure is obviously refined, and the hydrogen absorption and desorption performance is obviously improved.

Description

A kind of device and method for ultrasonic-assisted preparation of magnesium-based hydrogen storage alloy

technical field

The invention belongs to the technical field of preparation and processing of hydrogen storage materials, and relates to a device and method for ultrasonically assisted preparation of magnesium-based hydrogen storage alloys.

Background technique

As a clean energy, hydrogen has the highest energy density per unit mass except nuclear energy, so hydrogen energy is considered as one of the most potential energy carriers. Efficient production of hydrogen, safe storage and transportation, and rational application are the three key links in the development and utilization of hydrogen energy. With the maturity of hydrogen production technology and the rapid development of fuel cell technology, safe, efficient and economical hydrogen storage and transportation technology has become a bottleneck restricting the application of hydrogen energy. Under normal temperature and pressure, hydrogen has the lowest gas density among all energy sources, and is flammable and explosive. At present, the storage methods of hydrogen mainly include high-pressure gaseous, cooled liquid and solid materials for hydrogen storage. High-pressure gaseous hydrogen storage has low density and is easy to leak or even explode; the energy loss of cooling liquid hydrogen storage accounts for about 30% to 45% of the total energy of hydrogen storage, and the cost of ultra-low temperature containers for liquid hydrogen storage is extremely high.

Hydrogen storage in solid materials is a way of storing hydrogen by means of physical adsorption or chemical bonding of materials to hydrogen. Its hydrogen storage density is high, safe and reliable, and its mass and volume hydrogen storage density is even higher than that of cryogenic liquid hydrogen storage. Among many solid hydrogen storage materials, Mg-based hydrogen storage materials have the advantages of high theoretical hydrogen storage density (7.6 wt.%), good reversibility of hydrogen absorption and desorption, abundant resources, and non-toxicity, and have good application prospects. However, the thermodynamic stability of the Mg-H bond is too high, resulting in the dehydrogenation temperature of MgH2 being higher _than 300 °C and the enthalpy change of the dehydrogenation reaction as high as 75 kJ/mol. At the same time, the dissociation of H molecules on the surface of metal Mg and the recombination of H atoms on the surface of MgH ₂ are relatively difficult, and the diffusion of H atoms in Mg, especially MgH ₂ is difficult, resulting in unsatisfactory _hydrogen absorption and desorption kinetics of Mg-based hydrogen storage materials. .

The inventors found that for high-capacity Mg-based hydrogen storage alloys, too many alloying elements will greatly reduce the hydrogen storage capacity of the system, while a small amount of alloying elements is usually easy to segregate and distribute, resulting in coarse primary α-Mg dendrites in the alloy. , resulting in a "blocking effect", which hinders the diffusion of H atoms and the nucleation and decomposition of the hydrogen phase, which affects the further optimization of the hydrogen absorption and desorption performance. For example, transition metal Ni is considered to be the most effective alloying element for Mg-based hydrogen storage alloys, wherein Mg ₂ Ni can undergo hydrogenation reaction at 200 °C to generate Mg ₂ NiH _0.3 and Mg ₂ NiH ₄ . In high-capacity Mg-Ni alloys, the Mg content is high and the Mg-Mg ₂ Ni eutectic structure is included. Therefore, compared with metal Mg, the hydrogen storage performance of Mg-Ni alloy is significantly improved. However, the size of primary α-Mg dendrites in the alloy is coarse and the distribution of solidification structure is uneven, which limits the further improvement of hydrogen storage performance. Therefore, there is an urgent need to develop a high-capacity Mg-Ni hydrogen storage alloy preparation and processing method with simple operation, low cost and suitable for industrial application.

SUMMARY OF THE INVENTION

Purpose of invention

The core technical problem of the present invention is to solve the problems of large primary α-Mg dendrite size, uneven distribution of alloying elements and solidification structure, and easy contamination of alloy melt in high-capacity Mg-based hydrogen storage alloys caused by traditional melting methods. The invention develops a device and method for preparing magnesium-based hydrogen storage alloys assisted by ultrasonic waves. The device and method provide a simple, efficient and low-cost way to obtain a high-purity Mg-based hydrogen storage alloy, so that the prepared alloy has a uniform and refined solidification structure, uniform distribution of elements and extremely low impurity content.

To achieve the above object, the present invention provides the following technical solutions:

A device for ultrasonic-assisted preparation of magnesium-based hydrogen storage alloys, comprising an alloy smelting system, a gas protection system, an ultrasonic melt processing system and a control system, the alloy smelting system includes a smelting furnace, a corundum crucible and a crucible support, the crucible support The corundum crucible is arranged on the bottom plate in the smelting furnace, the vertical section of the corundum crucible is an inverted trapezoid, and the corundum crucible is arranged on the crucible support, and the crucible support is provided with an ultrasonic vibration connection port; the gas protection system is connected to the melting furnace. The ultrasonic melt processing system abuts against the bottom of the corundum crucible through the ultrasonic vibration connection port.

As a further description of the above solution, the smelting furnace includes a furnace body, a furnace cover, and an induction heating coil. The induction heating coil is arranged along the circumferential direction of the side wall of the furnace body to form an induction heating zone. The induction heating zone is provided at the bottom. The height is the same as the height of the bottom of the corundum crucible, and the height of the top of the induction heating zone is the same as the height of the top of the corundum crucible; the furnace cover is provided with an observation port, and the top of the furnace cover is also provided with an air pressure for detecting the pressure in the furnace body surface.

As a further description of the above solution, the gas protection system includes a protection gas cylinder, a SF ₆ +CO ₂ mixed gas cylinder, a vacuum pump and a communication pipeline system.

The communication pipeline system includes a first pressure pipeline, a second pressure pipeline, a vacuum pipeline and an exhaust pipeline; the protective gas cylinder is communicated with the furnace body through the first pressure pipeline, and the first pressure pipeline is connected to the furnace body. A first pressure valve is arranged on a pressure pipeline; the SF ₆ +CO ₂ mixed gas cylinder is communicated with the furnace body through a second pressure pipeline, and a second pressure valve is arranged on the second pressure pipeline valve; the vacuum pump is communicated with the furnace body through a vacuum pipeline, and a vacuum exhaust valve is arranged on the vacuum pipeline; one end of the exhaust pipeline is communicated with the furnace body, and the other end of the exhaust pipeline is connected to the furnace body through an exhaust valve. The gas sealing device is connected.

As a further description of the above solution, the ultrasonic melt processing system includes an ultrasonic transducer, an ultrasonic horn and a tool head, the ultrasonic transducer is arranged on the bottom plate of the furnace body through a connector, and the ultrasonic horn is The tool head is connected with the ultrasonic transducer, and the ultrasonic horn is located above the ultrasonic transducer; the tool head is connected with the ultrasonic horn, the tool head is located above the ultrasonic horn, and the tool head passes through the crucible The ultrasonic vibration connection port of the bracket is attached to the bottom of the corundum crucible.

As a further description of the above scheme, the control system includes a display device, an induced current controller, an ultrasonic vibration output current controller, an ultrasonic vibration frequency controller, a temperature sensor and a temperature detection module;

The temperature sensor is arranged in the detection corundum crucible, and the temperature sensor is electrically connected to the temperature detection module; the ultrasonic vibration output current controller is electrically connected to the ultrasonic transducer; the ultrasonic vibration frequency controller is electrically connected to the ultrasonic transducer. The amplifier is electrically connected; the induction current controller is electrically connected with the induction heating coil;

The display device is connected with the induction current controller, the ultrasonic vibration output current controller, the ultrasonic vibration frequency controller, the temperature sensor and the temperature detection module, and displays the operation of the ultrasonic horn, the ultrasonic transducer and the induction heating coil in real time. Status and temperature information of the melt in the corundum crucible.

As a further description of the above solution, the gas sealing device includes an exhaust duct, an oil seal box, an elastic seal assembly and a release pipe, and the exhaust duct has an exhaust pipe connecting pipe section, a sealing connecting pipe section and a sealing box connecting section One end of the exhaust pipe connecting pipe section is connected with the exhaust pipe through a flange, and the other end of the exhaust pipe connecting pipe section penetrates from the top of the oil sealing box and is connected with the top of the sealing connecting pipe section; the sealing connection The pipe diameter of the pipe section is larger than the pipe diameter of the exhaust pipe connecting pipe section; the sealing box connecting section includes grate bars and end plates; the grate bars are multiple, and the plurality of grate bars are arranged at intervals along the circumferential direction in the sealing connection At the bottom end of the pipe section, a plurality of the grate bars extend downward and are connected with the end plate; the end plate is fixedly connected with the bottom plate of the oil sealing box; the elastic sealing assembly includes a seal, a first coil spring and a second A coil spring, the seal includes a pipe blocking section and a spring connecting section, the vertical section of the pipe blocking section is a trapezoid, wherein the diameter of the upper end face of the pipe blocking section is smaller than the inner diameter of the exhaust pipe connecting pipe section, and the pipe A predetermined distance is reserved between the lower end surface of the sealing section and the inner wall of the sealing connection pipe section, the spring connection section is fixedly connected to the lower end surface of the sealing section of the pipe, the first coil spring is sleeved on the spring connection section, and the second coil spring is sleeved on the spring connection section. The other end of a coil spring extends downward and is connected to the end plate; one end of the second coil spring is connected to the bottom of the spring connecting section, and the other end of the second coil spring extends downward and is connected to the end plate; the The drain pipe is arranged on the upper part of the oil-tight box.

As a further description of the above solution, the gas sealing device further includes a liquid level gauge, the liquid level gauge is arranged on the outer side of the oil sealing box, the first coil spring and the second coil spring are in a pre-compressed state, and the The cross-sectional size of the spring connecting section is smaller than the size of the lower end face of the pipe blocking section.

A method of using an ultrasonic-assisted preparation of a magnesium-based hydrogen storage alloy device, comprising the following steps:

Step 1: Put the magnesium-based hydrogen storage alloy raw material in the corundum crucible, close the furnace cover and lock it tightly;

Step 2: Turn on the vacuum pump and the vacuum pump in turn. When the air pressure gauge shows that the air pressure value is zero, close the vacuum pump and the vacuum pump in turn;

Step 3: Open the first pressurized valve and pass in the protective gas, when the air pressure gauge shows that the air pressure value is the standard air pressure, close the first pressurized valve and the protective gas cylinder;

Step 4: Repeat steps 2 to 3;

Step 5: turn on the induction current controller, turn on the SF ₆ +CO ₂ mixed gas cylinder and the second pressurizing valve in turn for smelting;

Step 6: adjust the output power and vibration frequency of the ultrasonic wave through the ultrasonic vibration output current controller and the ultrasonic vibration frequency controller, and carry out the ultrasonic melt treatment;

Step 7: cooling and sampling the magnesium-based hydrogen storage alloy.

As a further description of the above scheme, in the step 6, after the ultrasonic melt is treated for 15 minutes, the induction current controller is turned off, and the melt is cooled naturally; when the temperature shows that the melt temperature is lower than 500 ° C, the ultrasonic vibration output current control is turned off. to complete the ultrasonic melt treatment.

As a further description of the above scheme, the rated temperature in the furnace body 1 in the step 5 is 750°C, the heating rate is 30°C/min, the state of the alloy melt is observed through the observation port every 10 minutes, and when the display device reaches the rated temperature, continue Keep warm for 30 minutes;

The cooling and sampling of the magnesium-based hydrogen storage alloy in the seventh step also includes the following steps:

Close the second pressurized valve and the SF ₆ +CO ₂ mixed gas cylinder, then open the protective gas cylinder and the first pressurized valve to pass in the protective gas; when the temperature shows below 50°C, close the first pressurized valve and the protective gas bottle; open the furnace cover, take out the magnesium-based hydrogen storage alloy and save it.

Advantages and Effects

1. The present invention utilizes the ultrasonic vibration device to connect the corundum crucible bottom to avoid introducing impurity elements into the Mg alloy melt through the alloy head; by rationally designing the crucible shape to be an inverted trapezoid, the efficiency of ultrasonic vibration is improved, and by means of "cavitation effect", "sound" The primary α-Mg dendrites in Mg-based hydrogen storage alloys are significantly refined, and the alloying elements and microstructures are uniformly distributed.

2. In the present invention, high-purity Ar gas and SF ₆ +CO ₂ protective gas are introduced into the ultrasonic melt treatment process to reduce the volatilization and oxidation of the Mg alloy melt and prepare a high-purity Mg-based hydrogen storage alloy. Among them, the role of high-purity Ar gas is to discharge the air inside the furnace body and maintain the balance of air pressure inside and outside the furnace body, and the role of SF ₆ +CO ₂ protective gas is to further reduce the volatilization and oxidation of the alloy melt by forming a protective film. Different from other Mg alloy smelting devices, in the present invention, SF ₆ +CO ₂ protective gas is introduced into the closed furnace body to avoid the contact of oxygen and water vapor with the alloy melt, thereby realizing the preparation of high-purity Mg-based hydrogen storage alloy.

3. The present invention utilizes induction melting combined with ultrasonic vibration to fully flow the Mg alloy melt, thereby avoiding the introduction of impurities and volatilization of the melt caused by mechanical stirring and long-term heat preservation, which is beneficial to the cleaning of the alloy melt and precise composition control. At the same time, the inverted trapezoidal crucible can effectively improve the effect of ultrasonic vibration on the melt at the bottom of the crucible. effect of .

Description of drawings

1 is a schematic structural diagram of an ultrasonic melt processing device for magnesium-based hydrogen storage alloys according to an embodiment of the present invention;

Fig. 2 is the structural representation of the gas sealing device of Fig. 1;

Fig. 3 is a microstructure diagram of the refining effect of ultrasonic melt treatment on the microstructure of Mg ₉₈ Ni ₂ alloy, in which: Fig. 3-(a) is without ultrasonic treatment; Fig. 3-(b) The alloy after ultrasonic treatment;

Figure 4 is a graph showing the comparison of hydrogen absorption and desorption performance of Mg ₉₈ Ni ₂ alloy before and after ultrasonic melt treatment, in which: Figure 4-(a) Comparison curve of hydrogen absorption performance; Figure 4-(b) Comparison curve of hydrogen desorption performance.

Description of reference numbers:

1-furnace body; 2-furnace cover; 3-induction heating coil; 4-corundum crucible; 5-observation port; 6-crucible holder; 7-protective gas cylinder; 8-SF ₆ +CO ₂ mixed gas cylinder; 9- Vacuum pump; 10-gas sealing device; 101-flange; 102-exhaust pipe connecting pipe section; 103-oil sealing box; 104-oil; 105-sealing connecting pipe section; 106-grate bar; 107-end plate; 108- Elastic sealing assembly; 1081-pipe blocking section; 1082-spring connection section; 1083-first coil spring; 1084-second coil spring; 109-liquid level gauge; 12-Second pressure valve; 13-Vacuum exhaust valve; 14-Exhaust valve; 15-Ultrasonic transducer; 16-Ultrasonic horn; 17-Tool head; 18-Display device; 19-Induction current control module; 20-ultrasonic vibration output current control module; 21-ultrasonic vibration frequency control module; 23-first pressurization pipeline; 24-second pressurization pipeline; 25-exhaust pipeline; 26-vacuum pipeline.

Detailed ways

The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are a part of the embodiments of the present invention, but not all of the embodiments.

In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the accompanying drawings that need to be used in the description of the specific embodiments or the prior art. Obviously, the accompanying drawings in the following description These are some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can also be obtained from these drawings without any creative effort.

The components of the embodiments of the invention generally described and shown in the drawings herein may be arranged and designed in a variety of different configurations. Thus, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention.

As shown in Figures 1-4, the present invention provides the following technical solution:

A device for ultrasonic-assisted preparation of magnesium-based hydrogen storage alloys, including an alloy melting system, a gas protection system, an ultrasonic melt processing system and a control system, wherein the alloy melting system includes a melting furnace, a corundum crucible 4 and a crucible support 6, and the crucible support 6 It is arranged on the bottom plate in the smelting furnace, and the vertical section of the corundum crucible 4 is an inverted trapezoid, and the corundum crucible 4 is arranged on the crucible support 6, and the crucible support 6 is provided with an ultrasonic vibration connection port; the gas protection system is communicated with the smelting furnace; The ultrasonic melt processing system abuts against the bottom of the corundum crucible 4 through the ultrasonic vibration connection port. The design of the present invention uses an ultrasonic vibration device to connect the bottom of the corundum crucible 4 to avoid introducing impurity elements into the Mg alloy melt through the alloy head; by reasonably designing the shape of the crucible to be an inverted trapezoid, the efficiency of ultrasonic vibration is improved, with the help of "cavitation effect", "" "Acoustic flow effect" and "mechanical effect", the primary α-Mg dendrites in Mg-based hydrogen storage alloys are significantly refined, and the alloying elements and microstructures are uniformly distributed.

The gas protection system of the embodiment of the present invention includes a protection gas cylinder 7, a SF ₆ +CO ₂ mixed gas cylinder 8 , a vacuum pump 9 and a communication pipeline system. The communication pipeline system includes a first pressurized pipeline 23 and a second pressurized pipeline 24, vacuum pipeline 26 and exhaust pipeline 25; the protective gas cylinder 7 is communicated with the furnace body 1 through the first pressurizing pipeline 23, and the first pressurizing pipeline 23 is provided with the first pressurizing valve 11; SF ₆ +CO ₂ mixed gas cylinder 8 is communicated with furnace body 1 through a second pressurizing pipeline 24, which is provided with a second pressurizing valve 12; vacuum pump 9 is connected to furnace body 1 through vacuum pipeline 26 The vacuum pipeline 26 is provided with a vacuum exhaust valve 13; one end of the exhaust pipeline 25 is communicated with the furnace body 1, and the other end of the exhaust pipeline 25 is communicated with the gas sealing device 10 through the exhaust valve 14. The design of the invention is to introduce high-purity Ar gas and SF ₆ +CO ₂ protective gas in the ultrasonic melt treatment process to reduce the volatilization and oxidation of the Mg alloy melt, so as to prepare a high-purity Mg-based hydrogen storage alloy. Among them, the role of the high-purity Ar gas is to discharge the air inside the furnace body 1 and maintain the balance of the air pressure inside and outside the furnace body, and the role of the SF ₆ +CO ₂ protective gas is to further reduce the volatilization and oxidation of the alloy melt by forming a protective film. Different from other Mg alloy smelting devices, in the present invention, SF ₆ +CO ₂ protective gas is introduced into the closed furnace body to avoid the contact of oxygen and water vapor with the alloy melt, thereby realizing the preparation of high-purity Mg-based hydrogen storage alloy.

The protective gas cylinder 7 in the embodiment of the present invention is preferably a high-purity argon gas cylinder, but the protective gas is not limited to using only high-purity argon gas.

The ultrasonic melt processing system of the device according to the above embodiment of the invention includes an ultrasonic transducer 15, an ultrasonic horn 16 and a tool head 17. The ultrasonic transducer 15 is arranged on the bottom plate in the furnace body 1 through a connector, and the ultrasonic horn 16 is connected with the ultrasonic transducer 15, and the ultrasonic horn 16 is located above the ultrasonic transducer 15; the tool head 17 is connected with the ultrasonic horn 16, the tool head 17 is located above the ultrasonic horn, and the tool head 17 The ultrasonic vibration connection port passing through the crucible support 6 is in contact with the bottom of the corundum crucible 4 . The design of the present invention enables the Mg alloy melt to flow sufficiently, thereby avoiding the introduction of impurities and volatilization of the melt caused by mechanical stirring and long-term heat preservation, which is beneficial to the cleaning of the alloy melt and the precise control of the composition. At the same time, the inverted trapezoidal crucible can effectively improve the effect of ultrasonic vibration on the melt at the bottom of the crucible. effect of .

Specifically, the smelting furnace of the embodiment of the present invention includes a furnace body 1, a furnace cover 2, and an induction heating coil 3. The induction heating coil 3 is arranged along the circumferential direction of the inner wall of the furnace body 1 to form an induction heating area. The bottom of the induction heating area is arranged The height is the same as that of the bottom of the corundum crucible 4, and the height of the top of the induction heating zone is the same as that of the top of the corundum crucible 4; barometer. The induction heating coil 3 designed in the present invention can further promote the flow of the alloy melt, and at the same time, the induction heating method and the method of introducing ultrasonic vibration through the outer bottom of the crucible can make the magnesium-based hydrogen storage alloy flow more fully, so that the magnesium-based hydrogen storage alloy can flow more fully. The tissue is highly uniformly refined.

The furnace body 1 of this embodiment is also provided with a furnace lining for heat preservation and heat insulation, which is located on the outer periphery of the corundum crucible 4. The inner diameter of the furnace lining gradually decreases from top to bottom. The inner wall of the furnace lining is also provided with an installation for fixing the induction heating coil The groove and the installation groove are arranged spirally along the inner wall of the furnace lining. This design can adjust the heating range of the induction heating coil 3 according to the crucible with variable diameter, which makes the adjustment of the induction heating coil 3 easier and more stable. It is also conducive to induction heating. Heating coil 3 maintenance and replacement later.

The control system of the embodiment of the present invention includes a display device 18, an induced current controller 19, an ultrasonic vibration output current controller 20, an ultrasonic vibration frequency controller 21, a temperature sensor and a temperature detection module. The temperature sensor is arranged in the detection corundum crucible 4, The temperature sensor is electrically connected with the temperature detection module; the ultrasonic vibration output current controller 20 is electrically connected with the ultrasonic transducer 15; the ultrasonic vibration frequency controller 21 is electrically connected with the ultrasonic horn 16; the induced current controller 19 is electrically connected with the The induction heating coil 3 is electrically connected; wherein the display device 18 is connected with the induction current controller 19, the ultrasonic vibration output current controller 20, the ultrasonic vibration frequency controller 21, the temperature sensor and the temperature detection module, and displays the ultrasonic horn 16, The working state of the ultrasonic transducer 15 and the induction heating coil 3 and the temperature information of the melt in the corundum crucible 4 are more convenient for the operator to control and improve the accuracy of the operation. The gas sealing device 10 according to the embodiment of the present invention includes an exhaust duct, an oil seal box 103, an elastic seal assembly 108 and a release pipe 1010. The exhaust duct has an exhaust pipe connecting pipe section 102, a sealing connecting pipe section 105 and a sealing box connecting section , one end of the exhaust pipe connecting pipe section 102 is connected with the exhaust pipe 25 through the flange 101, and the other end of the exhaust pipe connecting pipe section 102 penetrates from the top of the oil sealing box 103 and is connected with the top of the sealing connecting pipe section 105; The pipe diameter of the sealing connection pipe section 105 is larger than the pipe diameter of the exhaust pipe connection pipe section 102; the sealing box connection section includes a grate bar 106 and an end plate 107; The bottom end of the pipe section 105 is sealed and connected, and a plurality of grate bars 106 extend downward to connect with the end plate 107; the end plate 107 is fixedly connected with the bottom plate of the oil sealing box 103; and the second coil spring 1084, the seal includes a pipe blocking section 1081 and a spring connecting section 1082, the vertical section of the pipe blocking section 1081 is a trapezoid, and the diameter of the upper end face of the pipe blocking section 1082 is smaller than that of the exhaust pipe connecting pipe section 102 The inner diameter of the pipe plugging section 1082 and the inner wall of the sealing connection pipe section 105 leave a predetermined distance, the spring connecting section 1082 is fixedly connected with the lower end face of the pipe blocking section 1081, and the first coil spring 1083 is sleeved on the spring connecting section. On the segment 1082, the other end of the first coil spring 1083 extends downward to connect with the end plate 107; The end plate 107 is connected;

The gas sealing device 10 of the above-mentioned embodiment further includes a liquid level gauge 109. The liquid level gauge 109 is arranged on the outer side of the oil sealing box 103. The first coil spring 1083 and the second coil spring 1084 are in a pre-compressed state. The cross-sectional size is smaller than the size of the lower end surface of the pipe blocking section 1081. Specifically, the elastic sealing assembly 108 has a sealing state and an exhausting state. In the exhausting state, the first coil spring 1083 and the second coil spring 1084 are compressed, and the seal When moving downward, the gas in the furnace body is discharged through the gap of the grate bar 106 of the sealing box connecting section; in the sealed state, under the action of the first coil spring 1083 and the second coil spring 1084, the pipeline of the seal is blocked The section 1081 is in close contact with the inner wall of the exhaust pipe connecting pipe section 102 to form a seal.

The ultrasonic transducer 15 in the embodiment of the present invention is a piezoelectric ceramic type, and the output amplitude of the ultrasonic transducer 15 is 5-7 μm; the ultrasonic horn 16 is made of aluminum alloy; the tool head 17 is made of T8 tool steel.

Embodiments of the present invention include the following steps:

Step 1: place the magnesium-based hydrogen storage alloy raw material in the corundum crucible 4, close the furnace cover 2 and lock it tightly;

Step 2: turn on the vacuum pump 9 and the vacuum pump 13 in turn, when the air pressure gauge 22 shows that the air pressure value is zero, close the vacuum pump 13 and the vacuum pump 9 in turn;

Step 3: open the first pressurizing valve 11, and feed argon gas, when the air pressure gauge 22 shows that the air pressure value is the standard air pressure, close the first pressurizing valve 11 and the argon gas cylinder;

Step 4: Repeat steps 2 to 3 to carry out gas washing; magnesium-based hydrogen storage alloys are extremely sensitive to oxygen and water vapor in the air, and even a trace amount of oxygen and water vapor pollution will greatly reduce the hydrogen storage performance of the alloy, so During the high-temperature smelting process of magnesium-based hydrogen storage alloys, oxygen and water vapor inclusions should be avoided. By repeatedly carrying out the scrubbing process of introducing high-purity argon gas and vacuuming, the impurity gas content in the furnace during the alloy smelting process can be significantly reduced, and the impurity gas content can be several orders of magnitude lower than the simple vacuuming process.

Step 5: Turn on the induction current controller 19, turn on the SF ₆ +CO ₂ mixed gas cylinder 8 and the second pressurizing valve 12 for smelting, wherein the furnace body 1 is set to a rated temperature of 750° C. and a heating rate of 30° C./min. Observe the alloy melt state through the observation port 5 every 10 minutes, and continue to keep the temperature for 30 minutes when the display reaches the rated temperature;

Step 6: adjust the output power and vibration frequency of the ultrasonic wave through the ultrasonic vibration output current controller 20 and the ultrasonic vibration frequency controller 21, then carry out the ultrasonic melt treatment, and close the induced current controller 19 after the ultrasonic melt treatment for 15 minutes, Allow the melt to cool naturally; when the temperature shows that the melt temperature is lower than 500°C, turn off the ultrasonic vibration output current controller 20 to complete the ultrasonic melt treatment;

Step 7: To cool and sample the magnesium-based hydrogen storage alloy, first close the second pressurizing valve 12 and the SF ₆ +CO ₂ mixed gas cylinder 8 , then open the argon cylinder and the first pressurizing valve 11 in turn, and pass high Pure argon gas; when the temperature shows that 18 is lower than 50°C, close the first pressurizing valve 11 and the protective gas cylinder 7; open the furnace cover 2, take out the magnesium-based hydrogen storage alloy and save it.

Fig. 3-(a) is the microstructure of the Mg ₉₈ Ni ₂ alloy without ultrasonic melt treatment in the embodiment of the present invention, and Fig. 3-(b) is the Mg ₉₈ Ni ₂ alloy treated by ultrasonic melt in the embodiment of the present invention. Microstructure, it can be seen that the microstructure of the Mg ₉₈ Ni ₂ alloy prepared by the ultrasonic melt processing device and method of the present invention is obviously uniform and refined, and the size of the primary α-Mg dendrite is significantly reduced. The maximum α-Mg dendrite size in Fig. 3-(a) decreases from 300 μm in Fig. 3-(a) to 200 μm in Fig. 3-(b). It can be seen from this that the ultrasonic-assisted preparation device and method for magnesium-based hydrogen storage alloys according to the present invention can achieve uniform refinement of the structure of magnesium-based hydrogen storage alloys.

Fig. 4-(a) and Fig. 4-(b) are respectively the effects of ultrasonic melt treatment on the hydrogen absorption and desorption performance of Mg ₉₈ Ni ₂ alloy in the embodiment of the present invention, wherein the hydrogen absorption conditions are 300°C and 2.5MPa hydrogen pressure , the dehydrogenation conditions were 300 °C and 0.1 MPa hydrogen pressure. It can be seen that through the ultrasonic melt processing device and method of the present invention, the hydrogen absorption and desorption performance of the Mg ₉₈ Ni ₂ alloy in the embodiment can be significantly improved. For the hydrogen absorption process, the hydrogen absorption capacity in 6 minutes is increased by 4.83 wt.% To 5.01wt.%, the amount of hydrogen absorption in 150 minutes increased from 5.75wt.% to 5.99wt.%; for the hydrogen desorption process, the amount of hydrogen desorption in 3 minutes increased from 4.34wt.% to 4.71wt.%, the hydrogen desorption was completed Time reduced from 9 minutes to 5.75 minutes. It can be seen that the ultrasonic-assisted preparation device and method of magnesium-based hydrogen storage alloy according to the present invention can achieve synergistic optimization of hydrogen absorption and desorption performance by regulating the structure of magnesium-based hydrogen storage alloy.

Compared with the prior art, the present invention reduces the introduction of impurity elements by connecting the bottom of the corundum crucible through the ultrasonic melt processing system, makes the ultrasonic wave fully act on the alloy melt by reasonably designing the crucible shape, and avoids the alloy melt through an efficient gas protection system. After volatilization and oxidation, the elements in the prepared magnesium-based hydrogen storage alloy are uniformly distributed, and the microstructure is significantly refined, so that the hydrogen absorption and desorption performance is significantly improved.

Claims (10)

1. a device for preparing a magnesium-based hydrogen storage alloy with ultrasonic assistance, is characterized in that: comprise alloy smelting system, gas protection system, ultrasonic melt processing system and control system, The alloy melting system comprises a melting furnace, a corundum crucible (4) and a crucible support (6), the crucible support (6) is arranged on the bottom plate in the melting furnace, and the vertical section of the corundum crucible (4) is inverted. The corundum crucible (4) is trapezoidal, and the corundum crucible (4) is arranged on the crucible support (6), and the crucible support (6) is provided with an ultrasonic vibration connection port; the gas protection system is communicated with the melting furnace; the ultrasonic melt processing system passes through The connection port is abutted against the bottom of the corundum crucible (4) through ultrasonic vibration. 2. The ultrasonic-assisted preparation device for magnesium-based hydrogen storage alloys according to claim 1, wherein the smelting furnace comprises a furnace body (1), a furnace cover (2), an induction heating coil (3), and the The induction heating coil (3) is arranged along the circumferential direction of the inner side wall of the furnace body (1) to form an induction heating zone, and the setting height of the bottom of the induction heating zone is the same as the height of the bottom of the corundum crucible (4). The setting height is the same as the height of the top of the corundum crucible (4). 3. The device for preparing magnesium-based hydrogen storage alloys with ultrasonic assistance according to claim 2, wherein the gas protection system comprises a protective gas cylinder (7), a SF ₆ +CO ₂ mixed gas cylinder (8), a vacuum pump (9) and the connecting piping system, The communication pipeline system comprises a first pressurizing pipeline (23), a second pressurizing pipeline (24), a vacuum pipeline (26) and an exhaust pipeline (25); the protective gas cylinder (7) passes through The first pressurizing pipeline (23) is communicated with the furnace body (1), and the first pressurizing pipeline (23) is provided with a first pressurizing valve (11); the SF ₆ +CO ₂ mixed gas The bottle (8) is communicated with the furnace body (1) through a second pressurizing pipeline (24), and a second pressurizing valve (12) is arranged on the second pressurizing pipeline (24); the vacuum pump ( 9) The furnace body (1) is communicated with the furnace body (1) through a vacuum pipeline (26), and a vacuum exhaust valve (13) is arranged on the vacuum pipeline (26); one end of the exhaust pipeline (25) is connected to the furnace body (1). ) is connected, and the other end of the exhaust pipe (25) is communicated with the gas sealing device (10) through the exhaust valve (14). 4. The device for preparing magnesium-based hydrogen storage alloys assisted by ultrasonic waves according to claim 3, wherein the ultrasonic melt processing system comprises an ultrasonic transducer (15), an ultrasonic horn (16) and a tool head (17), the ultrasonic transducer (15) is arranged on the bottom plate in the furnace body (1) through the connecting piece, the ultrasonic horn (16) is connected with the ultrasonic transducer (15), and the ultrasonic transducer The horn (16) is located above the ultrasonic transducer (15); the tool head (17) is connected to the ultrasonic horn (16), the tool head (17) is located above the ultrasonic horn, and the tool The head (17) passes through the ultrasonic vibration connection port of the crucible support (6) and is attached to the bottom of the corundum crucible (4). 5. The ultrasonic-assisted preparation device for magnesium-based hydrogen storage alloys according to any one of claims 1 to 4, wherein the control system comprises a display device (18), an induced current controller (19), an ultrasonic vibration an output current controller (20), an ultrasonic vibration frequency controller (21), a temperature sensor and a temperature detection module; The temperature sensor is arranged in the detection corundum crucible (4), and the temperature sensor is electrically connected to the temperature detection module; the ultrasonic vibration output current controller (20) is electrically connected to the ultrasonic transducer (15); The ultrasonic vibration frequency controller (21) is electrically connected to the ultrasonic horn (16); the induction current controller (19) is electrically connected to the induction heating coil (3); The display device (18) is connected with an induced current controller (19), an ultrasonic vibration output current controller (20), an ultrasonic vibration frequency controller (21), a temperature sensor and a temperature detection module, and displays the ultrasonic amplitude in real time The working state of the device (16), the ultrasonic transducer (15) and the induction heating coil (3) and the temperature information of the melt in the corundum crucible (4). 6. The device for preparing magnesium-based hydrogen storage alloys assisted by ultrasonic waves according to claim 4, wherein the gas sealing device (10) comprises an exhaust duct, an oil sealing box (103), an elastic sealing assembly (108) ) and a venting tube (1010); The exhaust duct has an exhaust pipe connection pipe section (102), a sealed connection pipe section (105) and a sealed box body connection section, and one end of the exhaust pipe connection pipe section (102) and the exhaust pipe (25) pass through a flange (101) is connected, the other end of the exhaust pipe connecting pipe section (102) penetrates from the top of the oil sealing box (103), and is connected with the top end of the sealing connecting pipe section (105); The pipe diameter is larger than the pipe diameter of the exhaust pipe connecting pipe section (102); The sealing box body connecting section includes a grate bar (106) and an end plate (107); the grate bar (106) is plural, and the plurality of the grate bar (106) are arranged at intervals along the circumferential direction on the sealing connection pipe section (107). 105) at the bottom end, a plurality of the grate bars (106) extend downward to be connected with the end plate (107); The end plate (107) is fixedly connected with the bottom plate of the oil sealing box (103); The elastic sealing assembly (108) includes a sealing member and a first coil spring (1083) and a second coil spring (1084), the sealing member includes a pipe blocking section (1081) and a spring connecting section (1082), the The vertical section of the pipe blocking section (1081) is a trapezoid, wherein the diameter of the upper end face of the pipe blocking section (1082) is smaller than the inner diameter of the exhaust pipe connecting pipe section (102), and the lower end face of the pipe blocking section (1082) is the same as the diameter of the inner diameter of the exhaust pipe connecting pipe section (102). A predetermined distance is left on the inner wall of the sealing and connecting pipe section (105), the spring connecting section (1082) is fixedly connected with the lower end surface of the pipe blocking section (1081), and the first coil spring (1083) is sleeved on the spring On the connecting section (1082), the other end of the first coil spring (1083) extends downward and is connected to the end plate (107); one end of the second coil spring (1084) is connected to the bottom of the spring connecting section (1082) connected, the other end of the second coil spring (1084) extends downward to connect with the end plate (107); The release pipe (1010) is arranged on the upper part of the oil sealing box (103). 7. The ultrasonic-assisted preparation device for magnesium-based hydrogen storage alloys according to claim 6, wherein the gas sealing device (10) further comprises a liquid level gauge (109), and the liquid level gauge (109) is provided with On the outside of the oil sealing box (103), the first coil spring (1083) and the second coil spring (1084) are in a pre-compressed state, and the cross-sectional dimension of the spring connecting section (1082) is smaller than the pipe blocking section (1081) Dimensions of the lower end face. 8. a method of using ultrasonic-assisted preparation of magnesium-based hydrogen storage alloy device as claimed in claim 4 to prepare magnesium-based hydrogen storage alloy with ultrasonic assistance, it is characterized in that, comprises the following steps: Step 1: place the magnesium-based hydrogen storage alloy raw material in the corundum crucible (4), close the furnace cover (2) and lock it tightly; Step 2: turn on the vacuum pump (9) and the vacuum pump (13) in turn, when the air pressure gauge (22) shows that the air pressure value is zero, close the vacuum pump (13) and the vacuum pump (9) in turn; Step 3: open the first pressurizing valve (11), pass in the protective gas, when the air pressure gauge (22) shows that the air pressure value is the standard air pressure, close the first pressurizing valve (11) and the protective gas cylinder (7); Step 4: Repeat steps 2 to 3; Step 5: turn on the induced current controller (19), turn on the SF ₆ +CO ₂ mixed gas cylinder (8) and the second pressurizing valve (12) in turn for smelting; Step 6: adjust the output power and vibration frequency of the ultrasonic wave through the ultrasonic vibration output current controller (20) and the ultrasonic vibration frequency controller (21), and carry out ultrasonic melt processing; Step 7: cooling and sampling the magnesium-based hydrogen storage alloy. 9. The method for ultrasonically assisted preparation of magnesium-based hydrogen storage alloy using ultrasonic-assisted preparation of magnesium-based hydrogen storage alloy device according to claim 8, wherein in the step 6, the induced current is turned off after 15 minutes of ultrasonic melt treatment The controller (19) cools the melt naturally; when the temperature shows (18) that the melt temperature is lower than 500°C, the ultrasonic vibration output current controller (20) is turned off to complete the ultrasonic melt treatment. 10. The method of using ultrasonic-assisted preparation of magnesium-based hydrogen storage alloy device for ultrasonic-assisted preparation of magnesium-based hydrogen storage alloy according to claim 8, characterized in that: in step 5, the furnace body 1 is set to a rated temperature of 750°C, and the temperature rises The rate is 30°C/min, the state of the alloy melt is observed through the observation port (5) every 10 minutes, and the temperature is maintained for 30 minutes when the display device (18) reaches the rated temperature; The cooling and sampling of the magnesium-based hydrogen storage alloy in the seventh step includes the following steps: Close the second pressurized valve (12) and the SF ₆ +CO ₂ mixed gas cylinder (8), then open the protective gas cylinder (7) and the first pressurized valve (11) in turn to introduce the protective gas; when the temperature displays (18 ) when the temperature is lower than 50°C, close the first pressurizing valve (11) and the protective gas cylinder (7); open the furnace cover (2), take out the magnesium-based hydrogen storage alloy and save it.

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