CN112460996A

CN112460996A - Ultrafast heating sintering device and application thereof

Info

Publication number: CN112460996A
Application number: CN202011349373.1A
Authority: CN
Inventors: 王立国
Original assignee: Shenzhen Guoxin Materials Technology Co ltd
Current assignee: Shenzhen Guoxin Materials Technology Co ltd
Priority date: 2020-11-26
Filing date: 2020-11-26
Publication date: 2021-03-09
Also published as: CN216205255U

Abstract

The invention discloses an ultrafast heating sintering device, comprising: the electric insulation heating cavity is arranged on an electrode plate in the electric insulation heating cavity, and a power supply is electrically connected with the electrode plate; the electric insulation heating cavity is filled with high-melting-point conductive powder, and the high-melting-point conductive powder is electrically connected with the electrode slice. The electrode chip needs to be inserted into a heating cavity filled with conductive powder, the conductive powder needs to be coated with a workpiece to be heated, and current is supplied to the conductive powder in the heating cavity through the electrode chip connected with a power supply, so that the required workpiece is rapidly heated. The device has the advantages of simple structure, strong function and good controllability. The invention discloses an ultrafast heating process, which is characterized in that conductive powder is coated and electrically heated, so that the temperature is controllable, the conductive powder can be repeatedly used, the cost is low, and the process is suitable for industrial production. Besides, the method can also be applied to melting, welding and chemical reaction processes with high efficiency.

Description

Ultrafast heating sintering device and application thereof

Technical Field

The invention belongs to the field of heating devices, and particularly relates to an ultrafast heating sintering device and application thereof.

Background

The traditional heating device is difficult to generate a large-area high-temperature environment in a short time due to the limitation of a heating mode. With the rapid development of material science, many materials require a continuous high-temperature environment which is rapidly generated, and have higher requirements on the stability of the environment.

For example, dense ceramic bodies are traditionally produced by high temperature sintering of green powders, a time and energy intensive process. High energy is required to maintain the ceramic at high temperatures (e.g., above 1000 degrees celsius) and for long periods of time (over 30 minutes).

There is currently a new sintering method based on ultra-fast sintering, which can sinter ceramics within a few seconds. The processing time is much shorter than conventional sintering. This technique is more energy efficient due to the use of graphite felt to heat the sintered material. However, this technique has strong limitations and is only suitable for samples having a thickness of 1 mm. This technique cannot be applied to thicker samples because the thermal gradients formed during the heating and cooling stages can crack the material during heating and cooling.

Rapid heating provides the added benefits of reduced particle growth time (i.e., retention of fine grain microstructure), significantly reduced density activation energy, and controlled reactivity. This has proven to be particularly useful in limiting the reactivity and maintaining the integrity of the thin layers that make up the solid-state battery, reducing the volatilization of volatile elements (i.e., lithium, sodium) during processing. Under the background of the rapid sintering technology, the instantaneous sintering technology is also provided, and the instantaneous sintering technology greatly reduces the time required for sintering, and the minimum time is only a few seconds. The prior art generally employs an external heat source, and although many successful attempts have been made to trigger the flash event at lower temperatures, the instant flash sintering technique is sensitive to the electrical conductivity of the workpiece to be cured, and the geometry of the sample. This means that the technique is difficult to apply at an industrial level.

The core problem of the technology is to have an efficient and quick heating device. Therefore, it is necessary to develop a heating device which is efficient, fast and suitable for large-scale industrial application.

Disclosure of Invention

The invention provides an ultrafast heating sintering device to solve the technical problems that an existing ultrafast heating sintering device is narrow in application range and cannot be industrialized on a large scale.

In order to solve the technical problem, the present invention provides an ultrafast sintering apparatus in one aspect and an ultrafast heating sintering apparatus in another aspect, including:

the electrically insulated heating cavity is electrically connected with the electrode chip, and the electrode chip is electrically connected with the power supply; at the moment, the conductive powder of the heating cavity needs to be coated with a workpiece to be heated, the electrode chip needs to be inserted into the heating cavity filled with the conductive powder, the conductive powder in the heating cavity is subjected to conductive heating through the electrode chip connected with the power supply, and heat is transferred to the workpiece through conduction and/or radiation and/or convection, so that the required workpiece is rapidly heated.

Preferably, the ultrafast thermal sintering apparatus further comprises a pressing device in stress contact with the electrically insulated heating chamber.

Preferably, the ultrafast heating sintering device further comprises a temperature measuring device in thermal contact with the high-melting-point powder in the heating cavity.

Preferably, an electric insulation layer is arranged outside the conductive heating cavity.

Preferably, the high melting point conductive powder material comprises any one or more of graphite, carbon black, graphene, carbon nanotubes, silicon carbide, refractory metals and borides, carbides of tantalum, tungsten, niobium, and molybdenum. The conductivity will be reduced by the addition of non-conductive powder to any one or more of the mixtures of high melting point conductive powders as described above.

Preferably, the thickness of the workpiece to be heated is 0.001 to 400 mm.

An ultrafast sintering process based on the ultrafast heating sintering apparatus of, wherein the workpiece to be heated is a workpiece to be sintered.

Preferably, the material of the workpiece to be sintered comprises any one or more of a metal, a metal compound and a ceramic precursor.

The invention also provides an ultrafast welding process based on the ultrafast heating sintering device, wherein the workpiece to be heated is a workpiece to be welded.

The invention further provides an ultrafast heating reaction kettle based on the ultrafast heating sintering device, and the workpiece to be heated is a high-temperature reaction kettle.

In still another aspect, the present invention provides a smelting process based on the ultrafast heating sintering apparatus as set forth in any one of claims 1 to 6.

Preferably, the smelting material of the smelting process comprises any one or more of a mixture of metal or ceramic precursors.

Compared with the prior art, the ultrafast heating sintering device is simple in structure, the heating temperature can be accurately controlled by matching the control power supply with the temperature measuring device, the high-melting-point conductive powder in the heating cavity can be tightly attached to a workpiece through the pressing device, and the heating effect is better. And energy loss can be reduced by the heating cavity electric insulation heat insulation layer. Therefore, the ultrafast heating sintering device has the advantages of simple structure, strong function and good controllability. The conductive powder that is not subjected to external pressure has a low thermal conductivity (less than 5W/mK), thereby heating the workpiece with limited heat loss.

The ultra-fast sintering process adopts conductive powder coating and electric heating, so that the temperature is controllable, the conductive powder can be repeatedly used, the cost is low, and the ultra-fast sintering process is suitable for industrial popularization. The prior art adopts graphite felt, large-area graphite felt is expensive, can not avoid damaging in the sintering process, needs to be replaced after limited use times, greatly increases cost, and in order to guarantee sintering efficiency, two graphite felts can not be too far apart, therefore has restricted the size of the workpiece to be sintered, the thickness can only be one millimeter. The conductive powder used in the invention has very low cost and can be recycled. Furthermore, carbon contamination can be reduced by using a conductive powder with a lower carbon content in the crucible containing the workpiece. (lower carbon content conductive powders include graphite, carbon black, graphene, carbon nanotubes, silicon carbide, refractory metals and mixtures of any one or more of the borides, carbides of tantalum, tungsten, niobium, molybdenum, as described above, the addition of non-conductive powders to any one or more of the above-described refractory conductive powders will result in a decrease in conductivity.) the cladding process described allows for the processing of workpieces having a size of 0.001-400mm with reduced size limitations. Therefore, the ultra-fast sintering process disclosed by the invention is superior to the existing process in cost, application range and industrialization prospect.

The ultrafast welding process has the greatest advantages of rapid temperature rise, and the control of the temperature far exceeds the traditional welding process, and the energy utilization rate is greatly improved because the process is carried out in a relatively closed space. Therefore, the application range of the ultra-fast welding process is greatly expanded, and processes which cannot be carried out by the traditional welding process can be carried out.

Compared with the existing reaction kettle, the ultrafast temperature rise reaction kettle has the advantages of rapid temperature rise, high temperature upper limit, continuous adjustability, fine control and the like, and therefore has an application prospect of implementing chemical reaction.

Compared with the existing smelting process, the smelting process has the greatest advantages that high temperature can be achieved at ultrahigh heating efficiency, and accurate temperature control can be carried out in a high temperature range. These are important for melting any metallic or ceramic material by using a crucible heated in a heating chamber. Therefore, the smelting process has good application prospect.

Drawings

FIG. 1 is a schematic structural diagram of an ultrafast heating sintering apparatus according to an embodiment of the present invention;

FIG. 2 is a schematic cross-sectional view of an apparatus for ultrafast thermal sintering according to an embodiment of the present invention;

FIG. 3 is a schematic view of temperature control of an ultrafast heating sintering apparatus according to an embodiment of the present invention;

FIG. 4 is a process flow diagram of an ultra-fast sintering process according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of an ultrafast welding process according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of an apparatus for ultrafast temperature rise reaction according to an embodiment of the present invention;

fig. 7 is a schematic diagram of a smelting process of the rapid heating device according to the embodiment of the invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be described below clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive step based on the embodiments of the present invention, are within the scope of the present invention.

It should be noted that all the directional indications (such as up, down, left, right, front, rear … …) in the embodiment of the present invention are only used to explain the relative position relationship between the components, the movement situation, etc. in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indication is changed accordingly.

It will also be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present.

In addition, the descriptions related to "first", "second", etc. in the present invention are for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicit indication of the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the feature. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.

In one aspect of the present invention, there is provided an ultrafast heating sintering apparatus, as shown in fig. 1 and 2, comprising: the device comprises an electric insulation heating cavity 0, an electrode plate 3 electrically connected with the electric insulation heating cavity, and a power supply 4 electrically connected with the electrode plate; in a particular embodiment, the power supply 4 is an adjustable power supply that may be operated in either an AC or DC mode. The electric insulation heating cavity is filled with high-melting-point conductive powder 2, and the high-melting-point conductive powder material comprises any one or a mixture of more of graphite, carbon black, graphene, carbon nano tubes, silicon carbide, refractory metals and carbides of boride, tantalum, tungsten, niobium and molybdenum. The conductivity will be reduced by the addition of non-conductive powder to any one or more of the mixtures of high melting point conductive powders as described above.

Graphite carbon black, graphene, carbon nanotubes, refractory metals and borides and carbides thereof are all materials with ultrahigh conductivity and high melting point, and the powder price of the materials is not expensive, so the cost is controlled while the process requirement is met. The high-melting-point conductive powder is coated on the workpiece 1 to be heated; the size range of the workpiece 1 to be heated is 0.001-400 mm. The electric insulation heating cavity comprises a pressing device 7 in stress contact with high-melting-point conductive powder 2 in the electric insulation heating cavity, and a temperature measuring device 6 in thermal contact with the high-melting-point conductive powder, wherein the temperature measuring device 6 can directly measure the temperature of a workpiece through the conductive powder in specific operation so as to obtain more accurate real-time temperature, a heat insulation electric insulation layer 5 is further arranged outside the electric insulation heating cavity 0, and the heat insulation electric insulation layer 5 comprises an electric insulation layer 51 and a heat insulation layer 52. The electrode plate 3 inserted into the electric insulation heating cavity 0 and used for heating the high-melting-point conductive powder 2 is connected with the power supply 4, and the connected electrode plate 3 can heat the high-melting-point conductive powder 2 through the working principle of current-joule effect so as to transfer heat energy to the workpiece 1 to be sintered coated by the conductive powder 2, so that the workpiece 1 is sintered. The temperature is controlled by adjusting the power of the power supply and by the real-time feedback of the temperature measuring device 6; the pressure applying device 7 is in stress contact with the high melting point conductive powder 2 in the electric insulation heating cavity 0, and can apply pressure uniaxially between the two electrodes 3 as shown in fig. 2d), so that the high melting point conductive powder 2 and the workpiece 1 to be sintered are combined more tightly, and the heat transfer efficiency is higher. The heat insulation electric insulation layer 5 is arranged in a space formed by the outer layer of the electric insulation heating cavity 0 and can be filled with air or protective inert gas such as nitrogen and argon or reserved vacuum and the like, so that heat insulation is achieved, energy loss is reduced, and the heat insulation electric insulation layer also has a protection effect.

The ultrafast sintering process provided by the embodiment of the invention adopts a conductive powder electric heating mode to form a more fitting heating mode, and can accurately control the temperature by regulating and controlling the current, so that the melting point range of the material is greatly expanded. In addition, the graphite felt is not relied on, but graphite powder, so the shape of the workpiece is not required to be finished, and the shape applicability of the workpiece is greatly expanded. But the difference in heating pattern also causes the thickness of the workpiece to increase significantly. The application range of the method is expanded in multiple aspects, so that the high-efficiency rapid sintering process is more widely applied.

The embodiment of the invention also provides an ultrafast sintering process based on the ultrafast heating sintering device, which comprises the following steps:

s01: coating a workpiece to be sintered by using high-melting-point conductive powder;

s02: electrifying to quickly heat the conductive powder and quickly sintering the workpiece to be sintered.

Specifically, in step S01, the material of the sintered workpiece includes any one or more of a metal, a metal oxide and a ceramic precursor. The sintering process has controllable and adjustable temperature, so the method has wide application range, and wide melting point range of metal compounds and ceramic precursors, but is still applicable.

Specifically, in the step S02, the power-on process uses a controllable power source. The control can be realized through conventional regulation control, and can also be more intelligently controlled by using a program. As shown in fig. 3, the output power of the power supply, i.e. the power supply voltage, can be controlled by a controller, specifically by a computer, and applied to the conductive powder, and feedback-regulated by a temperature control device.

Specifically, in the step S01, the thickness of the workpiece to be sintered is 0.001 to 400 mm. Due to the process characteristics of the invention, the coated powder has no problem of rapid attenuation of thermal radiation when the distance is too large, so the size of the workpiece can be larger, and the powder coating preparation process can be suitable for workpieces with various complex shapes.

Specifically, in step S01, the refractory conductive powder is pressed on the workpiece to be sintered. The process can also apply pressure to the conductive powder to enable the conductive powder to be tightly coated on the workpiece, so that the heat transfer efficiency is higher, and the sintering is quicker. More specifically, the pressure applying mode can be realized by adopting uniaxial pressure or isostatic pressure pressurized gas, and the highest pressure can reach 200 MPa.

In particular embodiments, no or little pressure is typically applied, and pressurization is typically used in special cases. The process adopts a closed heat insulation cavity to prevent heat from overflowing, so that the energy efficiency can be greatly improved, and the size range of a workpiece is greatly increased due to the extremely high heating power and the action principle of conductive powder coating, so that the process has high universality and can sinter workpieces with complex shapes. The process is well suited for welding and chemical reaction applications because it allows the by-product gas to evolve freely. The invention has the biggest difference from any other earlier invention that the invention can be used without pressurization, but the existing invention needs pressurization, so the invention has wider application range, uses an electric insulation heating cavity to complete the required process, and has the advantages of safety, high energy utilization rate, convenient adjustment, wide temperature range, wide application range, fineness, controllability and the like.

In a specific implementation, as shown in fig. 4, the method includes preparing a ceramic precursor powder, compacting the ceramic precursor powder into a processable workpiece precursor, and the process includes procedures of binder removal, drying, and the like. And then, the ultrafast sintering process is adopted for rapid sintering to obtain the product.

In another aspect of the embodiments of the present invention, an ultrafast welding process based on the ultrafast heating sintering apparatus is provided, where the workpiece to be heated is a workpiece to be welded. The schematic view is shown in fig. 5, 1 is a workpiece to be heated in the apparatus, here a workpiece to be welded. The specific operation is consistent with the adjustment and the rapid sintering process, and the description is not repeated here. Arrows indicate that heat is supplied electrically.

In another aspect, the embodiments of the present invention provide an ultrafast temperature-rising reaction kettle based on the ultrafast heating sintering apparatus, wherein the workpiece to be heated is heated in the high-temperature reaction kettle. Such a reactor is advantageously used for carrying out any chemical reaction at high temperatures, including solid or liquid calcination, carbothermal reduction or borothermal reduction. The schematic view is shown in fig. 6, 1 is a workpiece to be heated in an

apparatus

2, and 2 is a high-temperature reaction kettle. The specific operation is consistent with the adjustment and the rapid sintering process, and the description is not repeated here. Arrows indicate that joule heating is provided by way of electrical current.

The embodiment of the invention also provides a smelting process based on the ultrafast heating sintering device. In a particular embodiment the smelted smelting material comprises any one or more of a mixture of metal or ceramic precursors. Such a melting device is advantageously used for melting any metallic or ceramic material. The working principle is as shown in a schematic diagram of fig. 7, a workpiece 1 to be heated is placed in a crucible 2 and heated together in a high-temperature reaction kettle 3. The specific operation is consistent with the adjustment and the rapid sintering process, and the description is not repeated here. Arrows indicate that joule heating is provided by way of electrical current.

The ultrafast sintering device disclosed by the embodiment of the invention is simple and has control devices such as control, feedback regulation, pressure regulation and the like, the quality of workpieces can be ensured, and the application range of the device can be expanded. Because no special structure and special device are provided, the manufacturing is easy, the threshold is low, the use is not complicated, and the device is suitable for large-scale popularization and application.

It should be noted that, for the sake of simplicity, all the aforementioned embodiments are expressed as one.

Series of acts may be combined, it will be appreciated by those skilled in the art that the present invention is not limited by the order of acts described, as some steps may occur in other orders or concurrently with other steps in accordance with the invention. Further, those skilled in the art should also appreciate that the embodiments described in the specification are preferred embodiments and that the acts and modules referred to are not necessarily required by the invention.

In the embodiments provided in the present application, it should be understood that the disclosed apparatus may be implemented in other manners. For example, the above-described embodiments of the apparatus are merely illustrative, and for example, the above-described division of the units is only one type of division of logical functions, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or communication connection may be an indirect coupling or communication connection between devices or units through some interfaces, and may be in a telecommunication or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

The above examples are only used to illustrate the technical solutions of the present invention, and do not limit the scope of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from these embodiments without making any inventive step, fall within the scope of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art may still make various combinations, additions, deletions or other modifications of the features of the embodiments of the present invention according to the situation without conflict, so as to obtain different technical solutions without substantially departing from the spirit of the present invention, and these technical solutions also fall within the protection scope of the present invention.

Claims

1. An ultrafast thermal sintering apparatus, comprising:

the electric insulation heating cavity is arranged on an electrode plate in the electric insulation heating cavity, and a power supply is electrically connected with the electrode plate; the electric insulation heating cavity is filled with high-melting-point conductive powder, and the high-melting-point conductive powder is electrically connected with the electrode slice.

2. The apparatus of claim 1, further comprising a pressing means in stress contact with the high melting point conductive powder.

3. The apparatus of claim 1, further comprising a temperature measuring device in thermal contact with the refractory conductive powder.

4. The apparatus according to claim 1, wherein the electrically insulating heating cavity is further provided with a heat insulating layer.

5. The apparatus of claim 1, wherein the high melting point conductive powder material comprises a mixture of any one or more of graphite, carbon black, graphene, carbon nanotubes, silicon carbide, refractory metals and borides, carbides of tantalum, tungsten, niobium, and molybdenum.

6. The ultrafast heating sintering apparatus of claim 1, wherein the thickness of the workpiece to be heated is 0.001-400 mm.

7. An ultrafast sintering process based on the ultrafast heating sintering apparatus as set forth in any one of claims 1 to 6, wherein the workpiece to be heated is a workpiece to be sintered.

8. The ultra-fast sintering process of claim 7 wherein the material of the workpiece to be sintered comprises any one or a mixture of metals, metal compounds and ceramic precursors.

9. An ultrafast welding process based on the ultrafast heating sintering apparatus as set forth in any one of claims 1 to 6, wherein the workpiece to be heated is a workpiece to be welded.

10. An ultrafast heating reactor based on the ultrafast heating sintering apparatus as claimed in any one of claims 1 to 6, wherein the workpiece to be heated is a high temperature reactor.

11. A smelting process based on the ultrafast heating sintering apparatus as claimed in any one of claims 1 to 6.

12. Smelting process as claimed in claim 11, wherein the smelted smelting material comprises any one or more mixtures of metal or ceramic precursors.