Joule heat treatment technology and device capable of rapidly heating and cooling

Abstract

The invention relates to a material heat treatment technology and device for rapidly heating and cooling by using a Joule heat effect. The technology aims at solving the problems of low heating speed, high energy consumption, inaccurate temperature control and the like in the traditional heat treatment technology, and the rapid heating and cooling process is realized by directly generating Joule heat in the material. According to the technology, the required high temperature (1500-3500 DEG C) can be reached within millisecond-level time (105 DEG C / s) by adopting heat energy generated when current (0.1-200.0 A) passes through a conductor electrode, so that the heat treatment efficiency is remarkably improved. The electrode plates can be replaced according to needs and comprise carbon materials, alloy electrodes and metal carbides and oxides, so that diversified heat treatment requirements are met, and the cleanliness of the heating environment is guaranteed. The reaction chamber can provide various atmosphere environments such as vacuum, nitrogen and argon, and the atmosphere environments are adjusted through the gas valve system. The device is further provided with a water cooling circulation system so as to guarantee normal operation of the reaction chamber during long-time heating. The device comprises a reaction chamber, a temperature monitoring unit, an observation window, an air valve system, a heating electrode fixing device, a heating electrode, a power supply system and a circuit control system. Through the technology, technical breakthrough in multiple fields of catalyst preparation, integrated circuit manufacturing, nano material synthesis and the like can be realized.

Description

Technical Field

[0001] The invention relates to a material heat treatment technology, in particular to a material heat treatment technology and device that utilizes the Joule heat effect to rapidly increase and decrease the temperature. Background Art

[0002] Traditional heat treatment technologies play an important role in fields such as material processing and catalyst preparation. These technologies usually rely on external heat sources, such as resistance furnaces, induction furnaces or other radiation heating equipment, to heat and cool materials. However, these traditional methods have some limitations, such as slow heating speed, high energy consumption, imprecise temperature control, and possible oxidation and agglomeration of materials during long heating. With the increasing attention to energy efficiency and environmental protection, researchers have begun to seek more efficient and environmentally friendly heat treatment technologies. Among them, Joule heating technology has attracted attention due to its rapid heating and high energy utilization efficiency. Joule heating technology uses the Joule heating effect generated by the passage of current through a conductor to quickly heat the material, and can reach high temperatures in a very short time, thereby significantly improving the efficiency of heat treatment. In the field of catalyst preparation, Joule heating technology has shown great potential. For example, the research team of Ocean University of China used Joule heating to quickly heat the material to prepare high-performance hydrogen evolution catalytic materials, which showed excellent HER performance, fast preparation speed and low energy consumption. In addition, the research team of Hunan University used ultrafast Joule heating technology to synthesize porous graphene-based Co-NC integrated catalysts with excellent electrocatalytic performance. In addition to catalyst preparation, Joule heating technology is also used in the rapid thermal processing (RTP) process in integrated circuit manufacturing. For example, spike annealing focuses on the rapid temperature rise and fall process, which is mainly used to activate doping elements and is widely used in ultra-shallow junction processes after 65nm. However, although Joule heating technology has shown advantages in some applications, its widespread application in the field of materials science still faces challenges. For example, for the ultra-fast preparation of nano-heterostructures, the current theory and control methods are not mature enough, and further research is needed to improve its controllability and expand its application range. In addition, pulse high-temperature synthesis, as an emerging research direction, provides new possibilities for the research of new materials by creating a transient ultra-high temperature experimental environment. However, the thermodynamic and kinetic theories and mechanisms of chemical reactions and phase transitions in transient ultra-high temperature environments are not fully understood, and more research is needed to reveal these processes.

[0003] In summary, the present invention aims to overcome the limitations of the prior art and provide a Joule heat treatment technology and device for rapid temperature rise and fall to achieve a more efficient, energy-saving and environmentally friendly material heat treatment process. Through the innovative application of Joule heat technology, the present invention is expected to bring technological breakthroughs in many fields such as catalyst preparation, integrated circuit manufacturing and nanomaterial synthesis. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a Joule heat treatment technology and device for rapid temperature rise and fall, aiming to solve the problems of slow heating speed, high energy consumption, inaccurate temperature control, and possible oxidation and agglomeration of materials in existing heat treatment technologies. This technology generates Joule heat directly inside the material to achieve rapid heating and cooling processes, and has the following innovations and advantages:

[0005] 1. The present invention adopts the Joule heating effect and utilizes the heat energy generated by the current (0.1~200.0A) passing through the conductor electrode to generate a 5 ℃ / s) to reach the required high temperature (1500~3500℃), significantly improving the efficiency of heat treatment.

[0006] 2. The electrode plates used in the present invention can be replaced as needed, and are currently mainly divided into three categories: the first category is carbon materials, including carbon-based materials such as carbon paper, carbon felt, carbon fiber cloth and carbon nanotube film, which are easy to cut and suitable for diverse heating needs. The second category is alloy electrodes such as nickel-chromium alloy wire, which are suitable for the preparation of metal-based composite materials. The third category is metal carbides and oxides such as tungsten carbide and aluminum oxide, which are suitable for the preparation of materials such as honeycomb ceramics. The replaceable electrode material can not only meet diverse heat treatment needs, but also ensure the cleanliness of the heating environment and eliminate the contamination of the sample caused by heat diffusion into the heating electrode.

[0007] 3. The reaction chamber of the present invention can provide a variety of atmospheres, such as vacuum, nitrogen, argon, etc. This device has a total of 4 pipeline valves, namely vacuum valve, nitrogen valve, argon valve, and liquid nitrogen valve. Since the carbon heating electrode is easy to react with oxygen to generate carbon dioxide at high temperature, it needs inert gas protection. For some samples that need ultra-fast cooling, nitrogen can be added through a vacuum pump (10 4 ℃ / s), or even liquid nitrogen (10 5 The cooling rate can be adjusted by the method of (℃ / s).

[0008] 4. The device of the present invention is equipped with a water cooling cycle to ensure long-term heating of the reaction chamber. Most of the heat treatments performed by this device are extremely short (completed within 200 seconds), and there is no problem of overheating of the chamber. However, for samples such as bulk ceramics, it is usually necessary to keep the temperature at 2000°C for 10 minutes, which will cause overheating of the chamber. Therefore, the water cooling cycle is used to ensure the normal operation of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a schematic diagram of the structure of the device of the present invention.

[0010] Figure 2 2 is a circuit diagram of the device of the present invention.

[0011] Figure 3 This is a projection electron microscope image of the nanocomposite material synthesized in Example 1 based on the device of the present invention.

[0012] Figure 4 This is a scanning electron microscope image of the nanocomposite material synthesized in Example 2 based on the device of the present invention. DETAILED DESCRIPTION

[0013] Reference Figure 1 The device of the present invention includes a reaction chamber 1, a temperature monitoring unit 2, an observation window 3, a gas valve system 4, a heating electrode fixing device 5, a heating electrode 6, a power supply system 7 and a circuit control system 8. The powder sample can be directly compounded on the surface of the heating electrode 6, or the block sample can be sandwiched between the double-layer heating electrode 6 and fixed. The gas valve system 4 ensures that the reaction chamber 1 is in a vacuum or filled with protective gas. The circuit control system 8 adjusts the current to generate Joule heat. Rapid cooling of the sample is achieved by cooling the sample itself or introducing low-temperature nitrogen.

[0014] Example 1: Preparation of carbon-based hydrogen evolution catalyst. Chloroplatinic acid, ferric chloride, cobalt chloride, nickel chloride, and cerium chloride were dissolved in water and immersed in the acidified carbon nanotube film; the vacuum-dried carbon nanotube film was fixed in the device as a heating electrode, heated to 1500°C, kept warm for 5 seconds, and then cooled naturally; the sample was taken out and characterized, and it was found that the prepared composite material had excellent hydrogen evolution performance, and the transmission electron microscope photo was as shown in FIG. Figure 3 shown.

[0015] Example 2: Preparation of metal sulfide nanoparticles. Dissolve chloroplatinic acid, ferric chloride, cobalt chloride, zinc chloride, and cerium chloride in water and immerse in the acidified nickel foam; fix the vacuum-dried nickel foam in the device as a heating electrode, heat to 1300°C, keep warm for 1 second, and then cool naturally; then put the sample into a tube furnace for surface sulfurization treatment to further increase the specific surface area, and characterize it. The scanning electron microscope photo of the prepared composite material is as follows: Figure 4 shown.

[0016] Example 3: Rapid heat treatment of the surface of fluorescent ceramic materials. Blocks of YAG:Ce and YAG:Cr fluorescent ceramics were stacked and fixed in a carbon felt electrode, heated to 1450°C, maintained for 30 seconds, and cooled naturally. It can be observed that the two ceramics were welded together.

Claims

1. A Joule heat treatment device for rapid temperature rise and fall, characterized in that: include: (1) An electric heating element used to apply direct current or alternating current to the material placed inside it to generate Joule heat, mainly carbon-based materials and silicon carbide; (2) A power control unit connected to the electric heating element and used to adjust the frequency and intensity of the current to control the heating process; (3) A temperature monitoring unit used to monitor the temperature changes of the material in real time; (4) A rapid cooling system connected to the material and used to achieve rapid cooling of the material; (5) A computer control system used to integrate and process signals from the power control unit and the temperature monitoring unit, and control the start and stop of the rapid cooling system.

2. The device according to claim 1, characterized in that The power control unit can adjust the frequency and intensity of the current according to a preset temperature curve.

3. The device according to claim 1, characterized in that The electromagnetic coil surrounds the periphery of the material to be processed to achieve uniform heating.

4. The device according to claim 1, characterized in that The rapid cooling system includes a low-temperature nitrogen and liquid nitrogen injection device.

5. The device according to claim 1, characterized in that The temperature monitoring unit includes a thermocouple directly contacting the sample or a non-contact infrared sensor.

6. A method for rapid temperature rise and fall Joule heat treatment using the device as claimed in claim 1, characterized in that: The following steps are involved: (1) Place the material to be treated in the electric heating element; (2) Apply DC / AC current through the power control unit to generate Joule heat and quickly heat it to the target temperature; (3) Monitor the temperature of the material in real time to ensure that the predetermined heating temperature is reached; (4) Once the target temperature is reached, it can be maintained for a period of time or the rapid cooling system can be started to cool it down until the material drops to room temperature; (5) Take out the cooled material for subsequent processing.

7. The method according to claim 6, characterized in that The heating rate of the rapid heating process can reach 10^4 K / s to 10^5 K / s.

8. The method according to claim 6, characterized in that The cooling rate of the rapid cooling process matches the heating rate to achieve a rapid temperature change.

9. The method according to claim 6, characterized in that The materials are catalyst precursors, metal salts, ceramics, and semiconductor materials.

10. The method according to claim 6, characterized in that The target temperature is set according to the specific heat treatment requirements of the material to be treated.

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