WO2021196004A1

WO2021196004A1 - Method for strengthening joining performance of ceramic material by means of texturing

Info

Publication number: WO2021196004A1
Application number: PCT/CN2020/082550
Authority: WO
Inventors: 薛佳祥; 舒睿; 廖业宏; 刘彤; 任啟森; 翟剑晗; 马海滨; 李锐; 陈蒙腾; 张显生
Original assignee: 深圳市合众清洁能源研究; 中广核研究院有限公司; 中国广核集团有限公司; 中国广核电力股份有限公司
Priority date: 2020-03-31
Filing date: 2020-03-31
Publication date: 2021-10-07

Abstract

Disclosed are a method for strengthening the joining performance of a ceramic material by means of texturing, and a method for joining the ceramic material. The method for strengthening the joining performance of a ceramic material by means of texturing comprises the following steps: S1.1, ultrasonically cleaning and then drying a ceramic material; S1.2, determining a processing face of the ceramic material and fixing the processing face on a laser workbench; S1.3, determining a processing region of the processing face and performing focusing; and S1.4, performing surface texturing on the processing region with a laser, such that the processing face forms a joining face of the ceramic material. On the basis of not needing to change the ceramic material, and by means of a laser texturing treatment performed on the joining face of the ceramic material, the function of enhancing joining strength in a subsequent sintering and joining process can be achieved.

Description

Method for texture strengthening ceramic material connection performance and ceramic material connection method

Technical field

The present invention relates to the technical field of nuclear fuels, in particular to a method for texture-strengthening the connection performance of ceramic materials and a method for connecting ceramic materials.

Background technique

Silicon carbide (SiC) ceramic materials have received extensive attention from the material science community because of their high-temperature strength, strong oxidation resistance, good thermal stability, low density, wear resistance, and corrosion resistance. At present, SiC ceramic materials have been widely used in machinery, petroleum, chemical and other fields; in cutting-edge fields such as aviation, aerospace, military and nuclear energy, it is also considered to be the future manufacturing of high-temperature components such as rocket combustion chamber linings, aircraft turbine engine blades, and nuclear reactors. One of the most promising candidate materials, but due to the inherent brittleness and low impact toughness of SiC ceramics, its processing performance is poor, and it is difficult to manufacture large-sized and complex-shaped parts. It usually requires ceramic-ceramic connection technology To prepare parts with complex shapes or sealed pipes. Therefore, ceramic joining technology has become an important means for the practical application of SiC ceramics.

At present, there is relatively little research on the connection process of ceramic materials at home and abroad, and the exploration of its connection mechanism has not yet been systematic. The connection technology for ceramic materials is mainly for the connection of SiC materials. Nowadays, the methods of connecting ceramics mainly include brazing, solid phase diffusion bonding reaction forming method, transition liquid phase bonding, etc., usually vacuum sintering, gas pressure sintering and spark plasma sintering (SPS), etc. The current research is focused on the SiC bonding layer Exploration of material composition. For example: MJ Sherwood and others used active metal Al, Ti, Si powder and Nicalon short fibers coated with C and a precursor polymer with high SiC content to form a slurry, which was used as a connecting material to connect SiC-based composite materials. Coat the slurry on the base surface and make a joint sample, heat it to 400°C under inert gas, fire the polymer, then heat it to 1000°C for 1 hour, and pass the successfully connected sample 5 times The thermal decomposition of the above impregnation to strengthen the connection joint (Ceramic Engineering and Science Proceedings, 1997,18(3A): 177-184). Sherwood Others also studied the influence of factors such as the length of the fiber in the slurry, the composition of the slurry, and the shape of the connecting surface, and the following conclusions were obtained: long fibers (2~4mm) are more advantageous than short fibers (<1.5mm); After adding fine silicon powder to the material, the joint strength can be effectively improved; the joint strength is higher when the joint interface is designed in the shape of a dovetail groove. Peter Tatarkoa et al. coated the connecting surface of the CVD-SiC sample with a layer of Ti, and realized the flash burning technology of the sample through a discharge plasma device, and obtained a SiC connector with a connection strength of 31.4MPa (Journal of the European Ceramic Society Volume 37, Issue 13, October 2017, Pages 3841-3848). Yutai Katoh et al. used active titanium and molybdenum insert diffusion welding, pressure and pressureless transient eutectic sintering methods to prepare various SiC joints with certain connection strength (Development of SiC Joining Technologies for Fusion: Pre-Irradiation Experiment).

In the existing literature reports, researchers have focused on the study of the material components of the connecting layer or the study of sintering methods and preparation methods.

The existing method of enhancing the connection strength of the SiC base material is mainly to add or adjust the second phase in the connection material, in order to obtain a connection member with a higher connection strength than the original connection. This method is difficult to explore due to its mechanism of action, and it is usually impossible to make repeated experiments, and the procedure for adjusting the additives is cumbersome, and this method has limited effect on the enhancement of the connection strength. The existing methods are all adjustments of the connection layer material for a specific sintering process, and their applicability is limited.

technical problem

The technical problem to be solved by the present invention is to provide a method for enhancing the connection strength of the ceramic material of the nuclear fuel with a texture strengthening the connection performance of the ceramic material and the connection method of the ceramic material.

Technical solutions

The technical solution adopted by the present invention to solve its technical problems is to provide a method for texture-strengthening the connection performance of ceramic materials, which includes the following steps:

S1.1. Dry the ceramic material after ultrasonic cleaning;

S1.2. Determine the processing surface of the ceramic material and fix it on the laser workbench;

S1.3. Determine and focus on the processing area of the processing surface;

S1.4. Using a laser to texture the surface of the processing area, so that the processing surface forms a connecting surface of the ceramic material.

Preferably, the ceramic material is silicon carbide ceramics, zirconia ceramics, alumina ceramics or silicon nitride ceramics.

Preferably, in step S1.1, the ceramic material is placed in absolute ethanol or acetone for ultrasonic cleaning; the ultrasonic cleaning time is 15-30 min.

Preferably, in step S1.4, the parameters of the laser are as follows: pulse frequency 40 kHz -100kHz, output power is 10%-100%, scanning speed is 100 mm/s -600mm/s.

Preferably, in step S1.4, the pattern formed by surface texturing includes at least one of concentric circles, radial shapes, and spider web shapes.

Preferably, it further includes the following steps:

S1.5. Ultrasonic cleaning and drying the ceramic material with surface texture.

Preferably, in step S1.5, the ultrasonic cleaning includes: using absolute ethanol or acetone, and deionized water to perform ultrasonic cleaning in sequence.

The present invention also provides a ceramic material connection method, the ceramic material is processed by any one of the above method for texture-enhancing the connection performance of a ceramic material; the ceramic material connection method includes the following steps:

S2.1. Place the two ceramic materials facing each other with a connecting surface;

S2.2. Place an intermediate connecting material between the connecting surfaces of the two ceramic materials;

S2.3. High-temperature sintering, where the two ceramic materials are connected into one body through the intermediate connecting material.

Preferably, the intermediate connecting material is a ceramic precursor polymer, aluminum, silicon, titanium or molybdenum.

Preferably, the high-temperature sintering adopts vacuum sintering, air pressure sintering or external field assisted sintering.

Preferably, the two ceramic materials are the cladding and the end plug of the nuclear fuel assembly, respectively.

Beneficial effect

The present invention does not need to change the ceramic material, by performing laser texturing treatment on the connection surface of the ceramic material, so that the connection surface material of the ceramic material in the sintering process is more completely wetted and diffused on the textured surface. The activity is increased, the surface roughness is increased, and the connection strength is enhanced, and the connection is uniform.

The invention has simple operation, strong repeatability and obvious strengthening effect; it can be widely used for the connection of various ceramic materials to achieve strengthening effect and has strong applicability.

Description of the drawings

The present invention will be further described below in conjunction with the accompanying drawings and embodiments. In the accompanying drawings:

Figure 1 is a flow chart of the method for texture-strengthening the connection performance of a ceramic material according to the present invention;

2 is a schematic diagram of the connection surface structure of a ceramic material after being processed by the method for texture strengthening the connection performance of a ceramic material of the present invention;

Fig. 3 is a flowchart of the ceramic material connection method of the present invention.

Embodiments of the present invention

The method for texture-strengthening the connection performance of ceramic materials of the present invention is used for the ceramic material of nuclear fuel to improve the connection performance of the ceramic material of nuclear fuel. Referring to Figure 1, the method may include the following steps:

S1.1. Dry the ceramic material after ultrasonic cleaning.

The ceramic materials are silicon carbide (SiC) ceramics, zirconia (ZrO ₂ ) ceramics, alumina (Al ₂ O ₃ ) ceramics, or silicon nitride (Si ₃ N ₄ ) ceramics.

During ultrasonic cleaning, put the ceramic material in absolute ethanol or acetone for ultrasonic cleaning for 15-30 minutes to remove oil and impurities on the surface of the ceramic material. After cleaning, put it into the oven to dry.

Before this step S1.1, the ceramic material is processed into a desired shape according to the shape of the ceramic piece. For example, for nuclear fuels, ceramic materials are processed into structural parts such as cladding tubes and end plugs.

S1.2. Determine the processing surface of the ceramic material and fix it on the laser table.

S1.3. Determine the processing area of the processing surface and focus.

S1.4. Use a laser to texture the surface of the processing area so that the processing surface forms a connecting surface of ceramic materials.

Among them, the parameters of the laser are as follows: the pulse frequency is 40 kHz -100 kHz, the output power is 10% -100%, and the scanning speed is 100 mm/s -600mm/s.

The laser control system is pre-set with the required pattern, and the surface texture is performed on the processing surface of the ceramic material according to the preset pattern during the laser.

The pattern formed by surface texturing is preferably a regular and symmetrical pattern, for example, including but not limited to at least one of concentric circles, radials, and spider webs.

As shown in Figure 2, it shows a concentric pattern 20 formed by surface texturing on the connecting surface of the ceramic material 10. The concentric pattern 20 consists of a number of laser-formed circular ribs from the inside to the outside. The interval distribution is formed.

Further, the above method also includes the following steps:

S1.5. Ultrasonic cleaning and drying the ceramic material with surface texture.

Ultrasonic cleaning includes: using absolute ethanol or acetone and deionized water to perform ultrasonic cleaning in sequence. Use absolute ethanol or acetone as the cleaning solution to perform ultrasonic cleaning at least once. When performing multiple cleanings, replace the cleaning solution with a new one each time the ultrasonic cleaning is performed. In the same way, deionized water is used for ultrasonic cleaning at least once, and when multiple cleanings are performed, new deionized water is replaced every time the ultrasonic cleaning is performed.

After the ceramic material processed by the above method, the connecting surface has a pattern formed by a texturing treatment, which improves the roughness of the connecting surface. The two processed ceramic materials are connected to each other on the connecting surface, and the intermediate connecting material is used. Two ceramic materials can be connected into one body.

Referring to Figure 3, in the ceramic material connection method of the present invention, the ceramic material is processed by any one of the above methods for texture strengthening the connection performance of the ceramic material; the ceramic material connection method includes the following steps:

S2.1. Place the two ceramic materials facing each other with the connecting surface.

S2.2. Place an intermediate connecting material between the connecting surfaces of the two ceramic materials.

The intermediate connection material is ceramic precursor polymer, aluminum, silicon, titanium or molybdenum.

For example, for two silicon carbide ceramics, the intermediate connecting material can be a precursor polymer of silicon carbide, or aluminum foil, titanium foil, and so on.

S2.3. High temperature sintering, two ceramic materials are connected into one body through an intermediate connecting material.

High temperature sintering adopts vacuum sintering, air pressure sintering or external field assisted sintering. Among them, the external field assisted sintering can choose microwave, brazing, pulse and other methods.

When the present invention is applied to nuclear fuel, the two ceramic materials are the cladding and the end plug of the nuclear fuel assembly, respectively.

The connecting surfaces of the cladding and the end plug are processed by the above-mentioned method of texture strengthening the connection performance of the ceramic material, and have a textured pattern. The connecting surface of the cladding and the end plug is placed with an intermediate connecting material and matched with each other, and then connected together after high-temperature sintering to form a closed cladding tube.

The present invention will be further illustrated below with specific examples.

Example 1:

The SiC base material is made into a 10*10*3mm square block, which is placed in a beaker containing absolute ethanol, washed with ultrasonic for 15 minutes, and dried in an oven. Determine the processing surface, fix the SiC square block on the laser workbench, determine the processing area, and use manual focus to complete the calibration and focus. Import the designed pattern into the laser control system, select the processing parameters as the number of pulses: 5; pulse frequency: 100kHz; output power: 50%; scanning speed: 600mm/s, and perform laser processing on the processed surface. The processed SiC square block was ultrasonically cleaned with absolute ethanol and deionized water for 3 times in sequence, and the ultrasonic solution was changed after each ultrasonic for 10 minutes; and then dried in an oven.

Two SiC square blocks are sandwiched with aluminum foil on top and bottom, and they are heated to 900°C for 4 hours in a muffle furnace to complete the connection of the two SiC square blocks. The measured connection strength between the two is 100MPa.

Example 2:

The SiC base material is made into a 10*10*3mm square block, which is placed in a beaker containing absolute ethanol, washed with ultrasonic for 15 minutes, and dried in an oven. Determine the processing surface, fix the SiC square block on the laser workbench, determine the processing area, and use manual focus to complete the calibration and focus. Import the designed pattern into the laser control system, select the processing parameters as the number of pulses: 5; pulse frequency: 50kHz; output power: 10%; scanning speed: 100mm/s, and perform laser processing on the processed surface. The processed SiC square block was ultrasonically cleaned with absolute ethanol and deionized water for 3 times in sequence, and the ultrasonic solution was changed after each ultrasonic for 10 minutes; and then dried in an oven.

Two SiC square blocks are sandwiched with aluminum foil on top and bottom to form a sandwich shape and heated to 900°C for 10 minutes in a microwave sintering furnace to complete the connection. The measured connection strength is 60MPa.

Example 3:

The SiC base material is made into a 10*10*3mm square block, which is placed in a beaker containing absolute ethanol, washed with ultrasonic for 15 minutes, and dried in an oven. Determine the processing surface, fix the SiC square block on the laser workbench, determine the processing area, and use manual focus to complete the calibration and focus. Import the designed pattern into the laser control system and select the processing parameters as pulse number: 5; pulse frequency: 10kHz; output power: 100%; scanning speed: 300mm/s, and laser processing the processing surface. The processed SiC square block was ultrasonically cleaned with absolute ethanol and deionized water for 3 times in sequence, and the ultrasonic solution was changed after each ultrasonic for 10 minutes; and then dried in an oven. Two SiC square blocks are sandwiched with aluminum foil on top and bottom to form a sandwich shape, and they are heated to 900°C for 4 hours in a muffle furnace to complete the connection. The measured connection strength is 110MPa.

Comparative example 1:

The SiC base material is made into a 10*10*3mm square block, which is placed in a beaker containing absolute ethanol, washed with ultrasonic for 15 minutes, and dried in an oven. Without any treatment on the surface, the two SiC square blocks were directly cleaned and dried. The aluminum foil was sandwiched between the top and bottom to form a sandwich shape. The muffle furnace was heated to 900°C for 4 hours to complete the connection. The measured connection strength was 40MPa.

Comparative example 2:

The SiC base material is made into a 10*10*3mm square block, which is placed in a beaker containing absolute ethanol, washed with ultrasonic for 15 minutes, and dried in an oven. Without any treatment on the surface, the two SiC square blocks were directly cleaned and dried. The aluminum foil was sandwiched between the upper and lower sides to form a sandwich shape. The connection was completed by heating to 900°C for 10 minutes in a microwave sintering furnace. The measured connection strength was 21MPa.

It can be seen from the foregoing Examples 1-3 and Comparative Examples 1-2 that the present invention greatly improves the connection strength between the ceramic materials through the surface texture treatment of the ceramic materials.

The above are only the embodiments of the present invention, which do not limit the scope of the present invention. Any equivalent structure or equivalent process transformation made by using the content of the description and drawings of the present invention, or directly or indirectly applied to other related technologies In the same way, all fields are included in the scope of patent protection of the present invention.

Claims

A method for texture-enhancing the connection performance of ceramic materials is characterized in that it comprises the following steps:

S1.1. Dry the ceramic material after ultrasonic cleaning;

S1.2. Determine the processing surface of the ceramic material and fix it on the laser workbench;

S1.3. Determine and focus on the processing area of the processing surface;

S1.4. Using a laser to texture the surface of the processing area, so that the processing surface forms a connecting surface of the ceramic material.
The method for texture-enhancing the connection performance of a ceramic material according to claim 1, wherein the ceramic material is silicon carbide ceramics, zirconia ceramics, alumina ceramics or silicon nitride ceramics.
The method for texture-strengthening the connection performance of a ceramic material according to claim 1, wherein in step S1.1, the ceramic material is placed in absolute ethanol or acetone for ultrasonic cleaning; the ultrasonic cleaning time is 15- 30min.
The method for texture-strengthening the connection performance of ceramic materials according to claim 1, wherein in step S1.4, the parameters of the laser are as follows: pulse frequency 40 kHz-100 kHz, output power 10%-100%, The scanning speed is 100 mm/s -600mm/s.
The method for texture strengthening the connection performance of a ceramic material according to claim 1, wherein in step S1.4, the pattern formed by the surface texture includes at least one of concentric circles, radial shapes, and spider web shapes.
The method for texture-strengthening the connection performance of ceramic materials according to any one of claims 1-5, further comprising the following steps:

S1.5. Ultrasonic cleaning and drying the ceramic material with surface texture.
The method for texture-strengthening the connection performance of ceramic materials according to claim 6, wherein in step S1.5, the ultrasonic cleaning comprises: using absolute ethanol or acetone, and deionized water to perform ultrasonic cleaning in sequence.
A method for connecting ceramic materials, wherein the ceramic material is processed by the method according to any one of claims 1-7; the method for connecting ceramic materials includes the following steps:

S2.1. Place the two ceramic materials facing each other with a connecting surface;

S2.2. Place an intermediate connecting material between the connecting surfaces of the two ceramic materials;

S2.3. High-temperature sintering, where the two ceramic materials are connected into one body through the intermediate connecting material.
The ceramic material connection method according to claim 8, wherein the intermediate connection material is a ceramic precursor polymer, aluminum, silicon, titanium, or molybdenum.
The method for connecting ceramic materials according to claim 8, wherein the high-temperature sintering adopts vacuum sintering, air pressure sintering or external field assisted sintering.
The method for connecting ceramic materials according to any one of claims 8-10, wherein the two ceramic materials are the cladding and the end plug of a nuclear fuel assembly, respectively.