Low-temperature connection method of glass and C / C composite material

Abstract

The invention discloses a low-temperature connecting method for glass and a C / C composite material, and relates to a connecting method for the glass and the C / C composite material. The problems that the performance of a base material is reduced and interface bonding is poor due to the fact that the connection temperature of an existing C / C composite material and glass is too high are solved. According to the method, firstly, a metal modified layer is prepared on the surface of the C / C composite material through magnetron sputtering, a carbide reaction layer is generated at the interface of the composite material, then connection of the C / C composite material and microcrystalline glass is achieved at the temperature of 580-660 DEG C through Bi2O3-B2O3-ZnO glass brazing filler metal, a microstructure mainly comprising a glass phase is formed in a welding seam, and the welding seam is formed. A continuous reaction layer is generated at the interface of the glass brazing filler metal and a glass base material, the glass brazing filler metal and the C / C composite material are connected through direct combination of oxides on the surface of a metal modified layer, and formed welding seams are compact and free of defects such as air holes and cracks. And the shear strength of the obtained joint can reach 13MPa.

Description

Technical Field

[0001] The invention relates to a method for connecting glass and a C / C composite material. Background Art

[0002] With the rapid development of space astronomical optics, satellite remote sensing technology, and large-scale ground-based optical systems, increasingly stringent requirements are placed on the imaging resolution, thermal stability, and system quality of optical systems. Among them, the reflector is an important component that determines the quality of the optical system, which determines that the requirements for the surface flatness, mechanical strength, corrosion resistance, expansion coefficient, etc. of optical elements such as reflectors are getting higher and higher. Achieving high-quality connection between glass and C / C composite materials is expected to obtain lightweight reflector optical components that meet service requirements.

[0003] Traditional active metal brazing has problems such as high connection temperature and cracks caused by mismatch of linear expansion coefficient. High connection temperature can also lead to oxidation and severe crystallization of the base material.

[0004] At present, there are few reports on the connection method of C / C composite materials and glass using glass solder. The team of Northwestern Polytechnical University reported the method of using LMAS high-temperature glass solder to connect LAS glass and silicon carbide embedded modified C / C composite materials (document: Fu Qiangang, Zhao Fengling, Li Hejun, Peng Han, Nan Xiaoying. A multi-interlayer LMAS joint of C / C-SiC composites and LAS glass ceramics. Journal of Materials Science and Technology. 2015, 31: 467-472.) The embedding method needs to be carried out under conditions exceeding 2000K, and the thickness of the modified layer is difficult to control and uneven. The experiment was carried out in a muffle furnace, with a connection temperature of up to 1200-1300°C and a connection time of 30min. However, the connection temperature is too high, which will lead to large residual stress, easy cracking of the interface, and for some glasses with poor high temperature performance, the higher temperature will cause the base material to crystallize, seriously damaging the base material performance.

[0005] Therefore, in order to achieve high-quality connection between glass and C / C composite materials and enable the joints to serve stably for a long time in the working environment, it is urgent to develop a low-temperature glass solder connection method. Summary of the invention

[0006] The purpose of the present invention is to solve the problem of degradation of parent material performance and poor interface bonding caused by excessively high connection temperature of existing C / C composite materials and glass, and to propose a low-temperature connection method for glass and C / C composite materials.

[0007] The low temperature connection method of glass and C / C composite material of the present invention is carried out according to the following steps:

[0008] Step 1: Bi 2 O 3 Powder, B 2 O 3 The powder and ZnO powder are uniformly mixed and subjected to low-energy ball milling to obtain mixed oxide powder; the mixed oxide powder is then melted at high temperature to obtain a glass melt with uniform composition; the glass melt is poured into deionized water for water quenching, and then subjected to high-energy ball milling to obtain glass powder; finally, the glass powder is sieved and dried to obtain glass solder powder;

[0009] The mixed oxide powder contains B 2 O 3 The content of is 2wt.%~15wt.%, the content of ZnO is 1wt.%~6wt.%, and the content of Bi is 2 O 3 is the remainder;

[0010] The high temperature melting temperature is 950-1200°C, and the holding time is 1-3h;

[0011] Step 2: using a tablet press to press the glass solder powder prepared in step 1 into sheets to obtain glass solder sheets;

[0012] Step 3: using magnetron sputtering equipment to prepare a metal modified layer on the surface of the C / C composite material, followed by heat treatment; the heat treatment causes the metal modified layer to generate a carbide reaction layer, thereby improving the bonding between the metal modified layer and the C / C composite material; and at the same time, an oxide layer is generated on the surface of the metal modified layer after the heat treatment;

[0013] The metal modification layer is Ti, Cr, W, Mo, V or Nb;

[0014] The heat treatment process is as follows: the heat treatment temperature is 300-600°C and the heat preservation time is 1-3h;

[0015] Step 4: grinding, polishing, ultrasonic cleaning and drying the surface to be connected of the glass mother material and the surface to be connected of the C / C composite material obtained in step 3 in sequence using sandpaper; the surface to be connected of the C / C composite material is the surface of the metal modified layer;

[0016] Step 5: placing the glass solder sheet of step 2 between the surface to be connected of the glass mother material and the surface to be connected of the C / C composite material to obtain an assembly to be welded;

[0017] Step 6: Place the assembly to be welded obtained in step 5 into a muffle furnace for welding;

[0018] The welding process is as follows: heating to 580-660° C. at a heating rate of 2-15° C. / min, keeping the temperature for 5-120 minutes, cooling to room temperature, and completing the connection between the glass and the C / C composite material.

[0019] The principles and beneficial effects of the present invention are:

[0020] The present invention proposes a method for indirect brazing of C / C composite material and glass using low-temperature glass solder, which completes reliable connection between glass and C / C composite material in the temperature range of 580-660°C; on the glass side, the glass solder and glass have good compatibility and generate a continuous reaction layer; on the C / C composite material side, elements between the glass solder and the oxide layer on the surface of the metal modified layer diffuse mutually to form a reliable connection.

[0021] The present invention uses low-temperature glass solder to connect the C / C composite material with glass. The weld structure is mainly glass phase without any crystalline phase. The glass solder reacts with the glass interface to form a gray continuous reaction layer, which forms a direct interface bonding structure with the oxide layer on the surface of the modified layer.

[0022] The connection temperature of the present invention is 100-200°C lower than that of the traditional active metal brazing method, and the brazing seam is dense and has no defects such as pores and cracks. The heterogeneous connection joint obtained by the present invention is reliable, and the room temperature shear strength reaches 13MPa.

[0023] The oxide components used in the low-temperature glass solder used in the present invention are widely available, low in cost, simple to operate during the soldering process, and do not require a vacuum environment, thus having broad application prospects and great practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a backscattered electron photograph of the interface structure of the glass / C / C composite material joint in Example 1;

[0025] Figure 2 This is a magnified backscattered electron photograph of the interface of the glass / C / C composite material joint on the glass-ceramic side in Example 1;

[0026] Figure 3 This is an enlarged backscattered electron photograph of the side interface of the glass / C / C composite material joint to the C / C composite material in Example 1. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is not limited to the specific implementation modes listed below, but also includes any reasonable combination of the specific implementation modes.

[0028] Specific implementation method 1: The low temperature connection method of glass and C / C composite material in this implementation method is carried out according to the following steps:

[0029] Step 1: Bi 2 O 3 Powder, B 2 O 3 The powder and ZnO powder are uniformly mixed and subjected to low-energy ball milling to obtain mixed oxide powder; the mixed oxide powder is then melted at high temperature to obtain a glass melt with uniform composition; the glass melt is poured into deionized water for water quenching, and then subjected to high-energy ball milling to obtain glass powder; finally, the glass powder is sieved and dried to obtain glass solder powder;

[0030] The mixed oxide powder contains B 2 O 3 The content of is 2wt.%~15wt.%, the content of ZnO is 1wt.%~6wt.%, and the content of Bi is 2 O 3 is the remainder;

[0031] The high temperature melting temperature is 950-1200°C, and the holding time is 1-3h;

[0032] Step 2: using a tablet press to press the glass solder powder prepared in step 1 into sheets to obtain glass solder sheets;

[0033] Step 3: using magnetron sputtering equipment to prepare a metal modified layer on the surface of the C / C composite material, followed by heat treatment; the heat treatment causes the metal modified layer to generate a carbide reaction layer, thereby improving the bonding between the metal modified layer and the C / C composite material; and at the same time, an oxide layer is generated on the surface of the metal modified layer after the heat treatment;

[0034] The metal modification layer is Ti, Cr, W, Mo, V or Nb;

[0035] The heat treatment process is as follows: the heat treatment temperature is 300-600°C and the heat preservation time is 1-3h;

[0036] Step 4: grinding, polishing, ultrasonic cleaning and drying the surface to be connected of the glass mother material and the surface to be connected of the C / C composite material obtained in step 3 in sequence using sandpaper; the surface to be connected of the C / C composite material is the surface of the metal modified layer;

[0037] Step 5: placing the glass solder sheet of step 2 between the surface to be connected of the glass mother material and the surface to be connected of the C / C composite material to obtain an assembly to be welded;

[0038] Step 6: Place the assembly to be welded obtained in step 5 into a muffle furnace for welding;

[0039] The welding process is as follows: heating to 580-660° C. at a heating rate of 2-15° C. / min, keeping the temperature for 5-120 minutes, cooling to room temperature, and completing the connection between the glass and the C / C composite material.

[0040] This implementation has the following beneficial effects:

[0041] This embodiment proposes a method for indirect brazing of C / C composite materials and glass using low-temperature glass solder, which completes a reliable connection between glass and C / C composite materials in the temperature range of 580 to 660°C; on the glass side, the glass solder and the glass have good compatibility and generate a continuous reaction layer; on the C / C composite side, the elements between the glass solder and the surface oxide layer of the metal modified layer diffuse into each other to form a reliable connection.

[0042] This embodiment uses low-temperature glass solder to achieve the connection between the C / C composite material and the glass. The structure of the weld is mainly glass phase, and no crystalline phase appears. The glass solder reacts with the glass interface to form a gray continuous reaction layer, which forms a direct interface bonding structure with the oxide layer on the surface of the modified layer.

[0043] The connection temperature of this embodiment is 100-200°C lower than that of the traditional active metal brazing method, and the brazing seam is dense and has no defects such as pores and cracks. The heterogeneous connection joint obtained in this embodiment is reliable, and the room temperature shear strength reaches 13MPa.

[0044] The oxide components used in the low-temperature glass solder used in this embodiment are widely available and low in cost. The brazing process is simple to operate and does not require a vacuum environment. It has broad application prospects and great practical value.

[0045] Specific implementation method 2: This implementation method is different from specific implementation method 1 in that: the rotation speed of the low-energy ball mill in step 1 is 100-200 rpm, and the ball milling time is 4-7 hours.

[0046] Specific implementation method three: This implementation method is different from specific implementation methods one or two in that: the rotation speed of the high-energy ball mill described in step one is 300 to 500 rpm, and the ball milling time is 6 to 12 hours.

[0047] Specific implementation method 4: This implementation method is different from any one of specific implementation methods 1 to 3 in that: the thickness of the glass solder sheet in step 2 is 50 to 400 μm.

[0048] Specific implementation method five: This implementation method is different from any one of specific implementation methods one to four in that: the magnetron sputtering process described in step three is: the power is 50 to 250 W, the working gas pressure is 0.2 to 10 Pa, and the sputtering time is 0.5 to 3 hours.

[0049] Specific implementation method 6: The difference between this implementation method and any one of specific implementation methods 1 to 5 is that the glass mother material in step 4 is amorphous oxide glass or microcrystalline oxide glass.

[0050] Specific implementation method seven: This implementation method is different from any one of specific implementation methods one to six in that: the polishing described in step four is performed using 400#, 800#, 1500#, 2000# and 3000# SiC sandpaper in sequence.

[0051] Specific implementation eight: This implementation differs from any one of specific implementations one to seven in that: Step four, polishing, is performed using a 1 μm diamond polishing agent.

[0052] Specific implementation method 9: This implementation method is different from any one of specific implementation methods 1 to 8 in that: the cooling rate in step 6 is 1 to 10° C. / min.

[0053] Specific implementation method ten: The difference between this implementation method and any one of specific implementation methods one to nine is that the heat treatment process in step three is: the heat treatment temperature is 500° C., and the insulation time is 2 hours.

[0054] Example 1

[0055] The low temperature bonding method of glass and C / C composite material in this embodiment is carried out according to the following steps:

[0056] Step 1: Bi 2 O 3 Powder, B 2 O 3 The powder and ZnO powder are uniformly mixed and subjected to low-energy ball milling to obtain mixed oxide powder; the mixed oxide powder is then melted at high temperature to obtain a glass melt with uniform composition; the glass melt is poured into deionized water for water quenching, and then subjected to high-energy ball milling to obtain glass powder; finally, the glass powder is sieved and dried to obtain glass solder powder;

[0057] The mixed oxide powder contains B 2 O 3 The content of ZnO is 4wt.%, and the content of Bi is 10wt.%. 2 O 3 86wt.%;

[0058] The high temperature melting temperature is 1100°C and the holding time is 1h;

[0059] The rotation speed of the low-energy ball mill is 200 rpm, and the ball milling time is 4 hours; the rotation speed of the high-energy ball mill is 400 rpm, and the ball milling time is 12 hours;

[0060] Step 2: using a tablet press to press the glass solder powder prepared in step 1 into sheets to obtain glass solder sheets;

[0061] The thickness of the glass solder sheet is 300 μm;

[0062] Step 3: using magnetron sputtering equipment to prepare a metal modified layer on the surface of the C / C composite material, followed by heat treatment; the heat treatment causes the metal modified layer to generate a carbide reaction layer, thereby improving the bonding between the metal modified layer and the C / C composite material; and at the same time, an oxide layer is generated on the surface of the metal modified layer after the heat treatment;

[0063] The metal modified layer is metal Cr;

[0064] The magnetron sputtering process is as follows: power is 240W, working pressure is 0.5Pa, and sputtering time is 2h;

[0065] The heat treatment process is as follows: the heat treatment temperature is 500°C and the heat preservation time is 2h;

[0066] Step 4: grinding, polishing, ultrasonic cleaning and drying the surface to be connected of the glass mother material and the surface to be connected of the C / C composite material obtained in step 3 in sequence using sandpaper; the surface to be connected of the C / C composite material is the surface of the metal modified layer;

[0067] The glass matrix is ​​Al-Si based microcrystalline oxide glass;

[0068] The grinding is performed using 400#, 800#, 1500#, 2000# and 3000# SiC sandpaper in sequence, and polishing is performed using 1 μm diamond polishing agent;

[0069] Step 5: placing the glass solder sheet of step 2 between the surface to be connected of the glass mother material and the surface to be connected of the C / C composite material to obtain an assembly to be welded;

[0070] Step 6: Place the assembly to be welded obtained in step 5 into a muffle furnace for welding;

[0071] The welding process is as follows: heating to 600°C at a heating rate of 5°C / min, keeping the temperature for 30 minutes, cooling to room temperature, and completing the connection between the glass and the C / C composite material;

[0072] The cooling rate is 3°C / min.

[0073] Figure 1 This is a backscattered electron photograph of the interface structure of the glass / C / C composite material joint in Example 1; Figure 2 This is a magnified backscattered electron photograph of the interface of the glass / C / C composite material joint on the glass-ceramic side in Example 1; Figure 3 This is a backscattered electron photo of the glass / C / C composite material joint and the C / C composite material side interface enlarged in Example 1. Figure 1 It can be seen that the low-temperature glass solder used to connect glass-ceramics and C / C composite materials has a dense and defect-free joint, and the structure of the brazing seam is mainly glass phase. Figure 2From the magnified observation of the interface, it can be seen that the solder and the microcrystalline glass react to form a good bond. Figure 3 The enlarged observation of the interface structure on one side of the C / C composite material is given. Figure 3 It can be seen that the glass forms a direct bond with the oxide layer on the surface of the modified layer, and the obtained joint can meet the requirements for service in optical devices. The joint of the microcrystalline glass and the C / C composite material in this embodiment is obtained at 600°C, which is 100-200°C lower than the connection temperature of other existing methods; the solder does not react violently with the parent materials on both sides, and the brazing seam structure is mainly glass phase; at the same time, the room temperature shear strength of the joint can reach 13MPa, indicating that the method of the present invention can achieve low-temperature connection of microcrystalline glass and C / C composite material, with good connection strength.

[0074] Example 2

[0075] The difference between this embodiment and embodiment 1 is that the welding process is: heating to 640°C at a heating rate of 5°C / min, keeping the temperature for 60 minutes, cooling to room temperature, and completing the connection between the glass and the C / C composite material, and the rest is the same as embodiment 1. The room temperature shear strength of the joint obtained in this embodiment is 11Mpa.

[0076] Example 3

[0077] The difference between this embodiment and embodiment 1 is that the glass matrix used is transparent fused quartz glass, wherein SiO 2 The content is not less than 99.98%, and the others are the same as those in Example 1. The room temperature shear strength of the joint obtained in this example is 9 Mpa.

Claims

1. A low temperature connection method for glass and C / C composite material, characterized in that: The low temperature joining method of glass and C / C composite material is carried out according to the following steps: Step 1: Evenly mix Bi2O3 powder, B2O3 powder and ZnO powder and perform low-energy ball milling to obtain mixed oxide powder; then melt the mixed oxide powder at high temperature to obtain a glass melt with uniform composition; pour the glass melt into deionized water for water quenching, and then perform high-energy ball milling to obtain glass powder; finally, sieve and dry the glass powder to obtain glass solder powder; The content of B2O3 in the mixed oxide powder is 2wt.% to 15wt.%, and the content of ZnO is 1wt.% to 6wt.%, with Bi2O3 being the balance; The high temperature melting temperature is 950-1200°C, and the holding time is 1-3h; Step 2: using a tablet press to press the glass solder powder prepared in step 1 into sheets to obtain glass solder sheets; Step 3: using magnetron sputtering equipment to prepare a metal modified layer on the surface of the C / C composite material, followed by heat treatment; the heat treatment causes the metal modified layer to generate a carbide reaction layer, thereby improving the bonding between the metal modified layer and the C / C composite material; and at the same time, an oxide layer is generated on the surface of the metal modified layer after the heat treatment; The metal modification layer is Ti, Cr, W, Mo, V or Nb; The heat treatment process is as follows: the heat treatment temperature is 300-600°C and the heat preservation time is 1-3h; Step 4: grinding, polishing, ultrasonic cleaning and drying the surface to be connected of the glass mother material and the surface to be connected of the C / C composite material obtained in step 3 in sequence using sandpaper; the surface to be connected of the C / C composite material is the surface of the metal modified layer; Step 5: placing the glass solder sheet of step 2 between the surface to be connected of the glass mother material and the surface to be connected of the C / C composite material to obtain an assembly to be welded; Step 6: Place the assembly to be welded obtained in step 5 into a muffle furnace for welding; The welding process is as follows: heating to 580-660° C. at a heating rate of 2-15° C. / min, keeping the temperature for 5-120 minutes, cooling to room temperature, and completing the connection between the glass and the C / C composite material.

2. The low temperature joining method of glass and C / C composite material according to claim 1, characterized in that: The rotation speed of the low-energy ball mill in step 1 is 100-200 rpm, and the ball milling time is 4-7 hours.

3. The low temperature joining method of glass and C / C composite material according to claim 1, characterized in that: The rotation speed of the high-energy ball mill in step 1 is 300-500 rpm, and the ball milling time is 6-12 hours.

4. The low temperature joining method of glass and C / C composite material according to claim 1, characterized in that: In step 2, the thickness of the glass solder sheet is 50-400 μm.

5. The low temperature joining method of glass and C / C composite material according to claim 1, characterized in that: The magnetron sputtering process in step 3 is as follows: power is 50-250W, working gas pressure is 0.2-10Pa, and sputtering time is 0.5-3h.

6. The low temperature joining method of glass and C / C composite material according to claim 1, characterized in that: In step 4, the glass matrix is ​​amorphous oxide glass or microcrystalline oxide glass.

7. The low temperature joining method of glass and C / C composite material according to claim 1, characterized in that: The polishing described in step 4 is performed using 400#, 800#, 1500#, 2000# and 3000# SiC sandpaper in sequence.

8. The low temperature joining method of glass and C / C composite material according to claim 1, characterized in that: Step 4: Polishing: Polishing is performed using a 1 μm diamond polishing agent.

9. The low temperature joining method of glass and C / C composite material according to claim 1, characterized in that: The cooling rate in step six is ​​1-10°C / min.

10. The low temperature joining method of glass and C / C composite material according to claim 1, characterized in that: The heat treatment process in step 3 is: the heat treatment temperature is 500° C. and the insulation time is 2 h.

Images