A method for welding quartz ceramics based on laser synchronous powder feeding technology

Abstract

The present invention belongs to the technical field of welding of quartz ceramic materials, and specifically discloses a method for welding quartz ceramics based on laser synchronous powder feeding technology. The method includes the following steps: irradiating a laser beam on the surface of the area to be welded of the quartz ceramic at a preset power, and simultaneously synchronously feeding a filler powder to the position irradiated by the laser beam in the area to be welded at a preset powder feeding gas flow rate and powder feeding rate; a depression is formed on the surface of the area to be welded due to gasification under the action of the laser beam, and a molten pool without base material melt is formed. The filler powder melts under the dual action of the laser beam and the molten pool to fill the molten pool, thereby realizing the welding of the quartz ceramic. The weld formed by the method of the present invention has a full shape, a dense texture, and high welding quality, and solves the problem that the quartz ceramic material is prone to gasification during laser welding, resulting in poor weld quality.

Description

Technical Field

[0001] The present invention belongs to the technical field of quartz ceramic material welding, and more specifically, relates to a method for welding quartz ceramics based on laser synchronous powder feeding technology. Background Art

[0002] The radome is an important component of a hypersonic aircraft. It is installed outside the antenna of the hypersonic aircraft and can protect its internal structure. The radome needs to meet good dielectric properties, thermal shock resistance, structural properties, and low temperature sensitivity in terms of material selection. Therefore, high-temperature resistant ceramic materials such as Al2O3 ceramics and quartz ceramics are often selected. With the advent of the information age, new requirements and challenges have been put forward for the materials and forming processes of radomes. In terms of material selection, in addition to the basic properties required by the radome, it also needs to have the characteristics of printed circuits and welding properties. However, high-temperature resistant ceramic materials have poor machining properties, low ductility and impact toughness, and weak thermal shock resistance. Their extremely high melting point and brittleness make it impossible for ceramics to be cast and machined like metals. Therefore, welding has become a new method for radome preparation.

[0003] Conventional welding methods for high-temperature resistant ceramics include brazing, friction welding, microwave welding, and solid-phase diffusion welding. Among them, the brazing and solid-phase diffusion welding have relatively high joint strength, but there are problems such as the need for heating in a closed space, adding brazing filler metal and intermediate layers, and applying pressure; the friction welding and microwave welding have relatively low joint strength, and there are also problems such as difficult uniform heating and the need for a specific workpiece shape.

[0004] Laser welding technology is an efficient welding method that uses a laser beam with a high energy density as a heat source. Compared with traditional welding methods such as arc welding, gas welding, and resistance welding widely used at present, laser welding has the advantages of fast welding speed, small deformation, and high welding quality. In the prior art, there have been applications of using laser welding for high-temperature resistant ceramics, such as methods of using a double laser beam to weld high-temperature resistant ceramic materials, directly laser welding metal materials to high-temperature resistant ceramics, or using laser welding for high-temperature resistant ceramics after preheating in a furnace to 1400 °C, laser filler brazing for high-temperature resistant ceramics, etc.

[0005] Although laser welding has the advantages of high flexibility, high energy density, non-contact welding, local heating, and high welding efficiency, when directly laser welding quartz ceramics, a large number of depressions will appear in the weld due to the easy gasification of the quartz ceramic material, which affects the welding quality. Summary of the Invention

[0006] Aiming at the defects of the prior art, the purpose of the present invention is to provide a method for welding quartz ceramics based on laser synchronous powder feeding technology to solve the problem that when welding quartz ceramics to quartz ceramics using traditional welding methods, a large number of depressions and poor quality will occur in the weld due to the easy gasification of the quartz ceramic material.

[0007] To achieve the above object, the present invention provides a method for welding quartz ceramics based on laser synchronous powder feeding technology, and the method includes the following steps:

[0008] A method for welding quartz ceramics based on laser synchronous powder feeding technology, and the method includes the following steps:

[0009] S1. Irradiate the surface of the area to be welded on the quartz ceramics with a laser beam of a preset power, and simultaneously synchronously feed the filling powder to the position irradiated by the laser beam in the area to be welded at a preset powder feeding gas flow rate and powder feeding rate;

[0010] S2. The surface of the area to be welded is vaporized under the action of the laser beam to form a molten pool that sinks downward and has no base material melt. The filling powder is melted under the dual action of the laser beam and the heat conduction of the molten pool to fill the molten pool, thereby realizing the welding of quartz ceramics.

[0011] Furthermore, the filling powder is an oxide powder, and the filling powder is an oxide powder with a melting point higher than that of quartz ceramics; preferably, the filling powder is Al2O3 powder.

[0012] Furthermore, the particle size of the filling powder is 50μm - 150μm; preferably, the particle size of the filling powder is 100μm - 120μm.

[0013] Furthermore, the power P of the laser beam is set to 350W ≤ P ≤ 650W; preferably, the power P of the laser beam is set to 450W ≤ P ≤ 550W.

[0014] Furthermore, the moving speed v of the laser beam relative to the area to be welded is set to 3mm / s ≤ v ≤ 5mm / s.

[0015] Furthermore, the powder feeding rate v f is set to 15g / min ≤ v f ≤ 20g / min; preferably, the powder feeding rate v f is set to 16g / min ≤ v f ≤ 18g / min.

[0016] Furthermore, the powder feeding gas flow rate v q is set to 8atm / min ≤ v q ≤ 11atm / min; preferably, the powder feeding gas flow rate v q is set to 9atm / min ≤ v q ≤ 10atm / min.

[0017] Furthermore, the minimum spot diameter of the laser beam is 2mm.

[0018] Furthermore, the laser beam is perpendicular to the surface of the quartz ceramic, and the defocus amount of the laser beam is 0 mm.

[0019] Furthermore, the distance between the powder outlet position of the filled powder and the surface of the quartz ceramic is 10 mm - 20 mm; preferably, the distance between the powder outlet position of the filled powder and the surface of the quartz ceramic is 15 mm - 18 mm.

[0020] Through the above technical solution conceived by the present invention, compared with the prior art, it mainly has the following advantages:

[0021] 1. The method of using laser synchronous powder feeding to weld quartz ceramics in the present invention. Since the gasification temperature range of quartz ceramics is lower than the laser irradiation temperature, irradiating the surface of the quartz ceramic base material with a laser will cause the material to rapidly gasify, forming a base material molten pool with a downward depression and no molten base material (i.e., the base material directly gasifies to form a pit-shaped molten pool). The filled powder is synchronously fed into the base material molten pool at the laser irradiation position. After being irradiated by the laser and the heat conduction of the base material molten pool, the filled powder will gradually melt to form a molten liquid state; specifically, since the melting point of quartz ceramics as the base material and the melting point of the filled powder differ greatly, during the laser synchronous powder feeding process, a sunken molten pool will be formed first, and then the filled powder will melt under the dual action of laser irradiation and the temperature of the base material molten pool to fill the position where the surface material gasifies and depresses during the laser welding process. In the prior art, there is no method of using laser synchronous powder feeding to weld quartz ceramic materials to quartz ceramic materials. The present invention avoids the problems of easy material gasification on the surface of quartz ceramics during laser welding, resulting in weld depression and poor quality, thereby obtaining a weld with a beautiful and full appearance and high welding quality, and further improving the weld connection strength.

[0022] 2. The filled powder conveyed in the present invention is an oxide powder with a boiling point higher than the boiling point temperature range of quartz ceramics. Preferably, the filled powder is Al2O3 powder. Al2O3 powder has a high melting point and a high boiling point in laser synchronous powder feeding welding. Its melting point is close to the laser irradiation temperature (i.e., 3000 °C). When the surface of the quartz ceramic gasifies under the action of laser irradiation, the Al2O3 powder melts into a liquid state, and the molten Al2O3 can be tightly combined with the quartz ceramic material; the particle size of the filled powder is selected to be 50 μm - 150 μm. If the powder particle size exceeds this range, it is difficult to form a weld with higher quality. For example, when the particle size is too large, the filled powder has not completely melted, and the quartz ceramic material continuously starts to gasify to form large depressions, which are difficult to fill. Or when the particle size is too small, the filled powder melts too fast, resulting in insufficient filled powder, and the weld shape is too prominent and the texture is not tight.

[0023] 3. The welding method of the present invention has simple operation steps compared with the conventional high-temperature resistant quartz ceramic welding methods and is not restricted by welding conditions. For example, brazing and solid-phase diffusion welding require heating in a closed space, adding brazing filler metal and intermediate layers, and applying pressure, while the present invention can be realized in a conventional atmosphere. Compared with friction welding and microwave welding, which have problems such as difficult uniform heating and the need for specific workpiece shapes, the present invention can be applied to the welding of quartz ceramic materials of various shapes without being restricted by the workpiece shape.

[0024] 4. Specific laser working parameters are designed in the laser synchronous powder feeding welding of the present invention. For example, the laser power is set to 350W ≤ P ≤ 650W, the moving speed is set to 3mm / s ≤ v ≤ 5mm / s, the powder feeding rate is set to 15g / min ≤ v f ≤ 25g / min, and the powder feeding gas flow rate is set to 8atm / min ≤ v q ≤ 11atm / min. Within this parameter range, the formation speed of the concave molten pool can be matched with the filling speed of the molten powder into the concave molten pool to obtain a weld seam with a full shape, neither sunken nor overly protruding, and there are no problems such as porosity cracking inside the weld seam, and the weld seam quality is high. If the above parameter range is exceeded, problems such as an unfilled weld seam shape, porosity in the weld seam, or an unfilled weld seam will occur. Brief Description of the Drawings

[0025] Figure 1 It is a schematic flow chart of the method for laser synchronous powder feeding welding of quartz ceramics provided in the embodiment of the present invention;

[0026] Figure 2 It is a schematic diagram of the quartz ceramic weld seam welded by the method described in Comparative Example 1 of the present invention;

[0027] Figure 3 It is a schematic diagram of five quartz ceramic weld seams welded by the method described in Example 1 of the present invention;

[0028] Figure 4 It is a schematic diagram of five quartz ceramic weld seams welded by the method described in Example 2 of the present invention;

[0029] Figure 5 It is a schematic diagram of five quartz ceramic weld seams welded by the method described in Example 3 of the present invention;

[0030] Figure 6 It is a schematic diagram of five quartz ceramic weld seams welded by the method described in Example 4 of the present invention;

[0031] Figure 7 It is a schematic diagram of the workpiece clamping provided in the embodiment of the present invention;

[0032] Figure 8It is a schematic structural diagram of the laser synchronous powder feeding welding equipment provided in the embodiment of the present invention;

[0033] Figure 9 It is a schematic structural diagram of the laser powder feeding head of the laser synchronous powder feeding welding provided in the embodiment of the present invention.

[0034] In the figure: 1 - welding fixture, 2 - quartz ceramic plate, 3 - welding head, 4 - laser, 5 - water cooler, 6 - protective gas device, 7 - powder feeding device, 8 - moving machine tool, 9 - powder feeding pipe, 10 - powder feeding port, 11 - main body of the welding head, 12 - laser inlet, 13 - welding fixture body, 14 - left quartz ceramic plate, 15 - right quartz ceramic plate, 16 - pressing block, 17 - pressing screw. Detailed implementation manners

[0035] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0036] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0037] In the present invention, unless otherwise clearly defined and limited, the terms "mounted", "connected", "connected with", "fixed" and other terms should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0038] As Figure 1 shown, the present invention provides a method for welding quartz ceramics based on the laser synchronous powder feeding technology. The method includes the following steps:

[0039] Before welding, the surface of the quartz ceramics to be welded needs to be kept smooth and clean. Therefore, first, the surfaces of the two parts of the quartz ceramics to be welded can be polished smoothly with 800-mesh sandpaper and then cleaned with a cleaning solution (such as ethanol), and then the two are clamped and fixed;

[0040] S1. Adjust the focus of the laser beam and the focus of the powder feeding beam of the laser synchronous powder feeding welding equipment to align the two foci with the position to be welded. Irradiate the surface of the area to be welded on the quartz ceramic with the laser beam at a preset power. At the same time, synchronously feed the filling powder to the irradiation position of the laser beam in the area to be welded at a preset powder feeding gas flow rate and powder feeding rate.

[0041] S2. The surface of the area to be welded is vaporized under the action of the laser beam to form a depression and a molten pool without the melt of the base material. The filling powder is melted under the dual action of the laser beam and the molten pool to fill the depressed molten pool, and then a weld seam is formed to realize the welding of the quartz ceramic.

[0042] In a preferred embodiment, the filling powder is an oxide powder with a melting point higher than that of the quartz ceramic. The melting point of the quartz ceramic is not higher than 2000 °C, about 1700 °C. Specifically, the preferred filling powder is Al2O3 powder. Compared with powders with lower melting points such as SiO2 powder, this powder has the advantage of being not easily vaporized at the laser irradiation temperature. The melting point of SiO2 powder is generally 1723 °C, and its boiling point is about 2230 °C, while the melting point of Al2O3 powder is about 2980 °C, and its boiling point temperature is higher. The laser welding temperature is generally about 3000 °C. At this temperature, the quartz ceramic will be vaporized first under the laser irradiation to generate a depression of the base material molten pool without the melt of the base material. And the Al2O3 powder will slowly melt into a liquid state under the dual action of the laser irradiation and the base material molten pool, and is not easily vaporized, can completely fill the depressed molten pool, and obtain a weld seam with high strength and a more plump shape.

[0043] In a more preferred embodiment, the particle size of the filling powder is 50 μm - 150 μm; the more preferred numerical range of the particle size of the filling powder is 100 μm - 120 μm. When the particle size is too large, the filling powder has not been completely melted, and the quartz ceramic material continuously starts to be vaporized to form large depressions, which are difficult to fill. When the particle size is too small, the filling powder melts too fast, resulting in insufficient filling powder, and the weld seam shape is too prominent and the texture is not compact.

[0044] In a preferred embodiment, the power P of the laser beam is set to 350 W ≤ P ≤ 650 W, and the more preferred laser power is 450 W - 550 W.

[0045] In a preferred embodiment, during welding, the moving speed v of the laser beam relative to the surface of the quartz ceramic is set to 3 mm / s ≤ v ≤ 5 mm / s, that is, the relative movement speed of the laser beam and the quartz ceramic is 3 mm / s ≤ v ≤ 5 mm / s.

[0046] In a preferred embodiment, the aforementioned powder feeding rate v f is set to 15 g / min ≤ v f ≤ 20 g / min, and the more preferred numerical range of the powder feeding rate is 16 g / min - 18 g / min.

[0047] In a preferred embodiment, the powder feeding gas flow rate is set to 8 atm / min ≤ vq ≤ 11 atm / min, and the more preferred numerical range of the powder feeding gas flow rate v q is 9 atm / min ≤ v q ≤ 10 atm / min.

[0048] In a preferred embodiment, the minimum spot diameter of the laser beam is 2 mm to ensure that the filled powder can be fully melted.

[0049] In a preferred embodiment, the laser beam is perpendicular to the surface of the quartz ceramic to be welded, and the defocus amount of the laser beam is 0 mm. Its function is to fully melt the filled powder to obtain a smaller weld width and a larger penetration depth.

[0050] In a preferred embodiment, the distance between the powder outlet position of the filled powder and the surface of the quartz ceramic is 10 mm - 20 mm; preferably, the distance between the powder outlet position of the filled powder and the surface of the quartz ceramic is 15 mm - 18 mm. If the powder feeding distance exceeds this range, the powder feeding amount per unit time will be affected, and the change in the powder feeding amount will affect the weld shape and texture. For example, if the powder feeding amount is insufficient, the weld will not fill the gasification depression area, and if the powder feeding amount is excessive, the weld shape will protrude too much from the welding surface.

[0051] To illustrate the present invention, the foregoing method provided by the present invention will be described in detail below in conjunction with comparative examples and examples. However, the following examples should not be construed as limiting the protection scope of the present invention.

[0052] Comparative Example 1

[0053] In this example, the workpieces to be welded are two polished and surface-cleaned quartz ceramic plates with dimensions of 40 mm × 30 mm × 5 mm. The processing requirement is to connect the two quartz ceramic plates together by butt welding.

[0054] The welding process parameters adopted in this example are: welding laser power is 450 W, spot radius is 1 mm, moving speed is 25 mm / s, defocus amount is 0 mm, the included angle between the laser beam and the workpiece surface is 90°, and no powder is added during the welding process.

[0055] During welding, the two quartz ceramic plates are clamped together by a welding fixture to position the quartz ceramic plates, and then the two quartz ceramic plates are clamped tightly by a screw. Then, the powder feeding welding head is turned on to emit a laser beam for welding. During the entire welding process, the position of the quartz ceramic plates remains fixed and does not move, and the laser welding of the quartz ceramic is completed by moving the powder feeding welding head.

[0056] As Figure 2As shown, this is the quartz ceramic weld seam after welding in this comparative example. Since only laser welding is used during the welding process and no powder is added, due to the high laser energy density, the quartz ceramic material is prone to gasification, and large pits are formed in the weld seam, resulting in poor welding quality.

[0057] Example 1

[0058] In this Example 1, the laser spot radius is 1 mm, the defocus amount is 0 mm, and the angle between the laser beam and the workpiece surface is 90°. The difference from Comparative Example 1 is that Al2O3 powder is filled in synchronously during the welding process.

[0059] In this example, the following 5 groups of welding process parameters are used to weld two quartz ceramic sheets identical to those in Comparative Example 1 respectively. The welding speed is the moving speed of the aforementioned laser beam relative to the ceramic to be welded:

[0060] (a) Laser power P = 200 W, welding speed v = 3 mm / s, powder feeding rate v f = 20 g / min, powder feeding gas flow rate v q = 9 atm / min;

[0061] (b) Laser power P = 350 W, welding speed v = 3 mm / s, powder feeding rate v f = 20 g / min, powder feeding gas flow rate v q = 9 atm / min;

[0062] (c) Laser power P = 500 W, welding speed v = 3 mm / s, powder feeding rate v f = 20 g / min, powder feeding gas flow rate v q = 9 atm / min;

[0063] (d) Laser power P = 650 W, welding speed v = 3 mm / s, powder feeding rate v f = 20 g / min, powder feeding gas flow rate v q = 9 atm / min;

[0064] (e) Laser power P = 800 W, welding speed v = 3 mm / s, powder feeding rate v f = 20 g / min, powder feeding gas flow rate v q = 9 atm / min.

[0065] Except for the different laser power P among the above 5 groups of parameters, other parameters are the same. Figure 3As shown, by comparing the weld shapes obtained under the above Comparative Example 1 and the working parameters of groups (a)-(e), it is found that the weld shape obtained by the laser synchronous powder feeding method is fuller than that of the weld obtained by laser welding in Comparative Example 1; by comparing the five welds obtained under the working parameters of groups (a)-(e), it is found that the overall surface of the weld is white, and there are no cracking phenomena at the weld center and the base material. However, if the laser power is too small, the weld cannot be formed. If the laser power is too large, the weld shows varying degrees of concave, and the larger the laser power, the greater the amount of concavity. Therefore, it is concluded that when laser synchronous powder feeding is used to weld quartz ceramics, the weld with the fullest shape and the best joint strength can be obtained when the laser power is in the range of 350W to 650W.

[0066] Example 2

[0067] In this example, the laser spot radius is 1mm, the defocus amount is 0mm, and the angle between the laser beam and the workpiece surface is 90°. The difference from Comparative Example 1 is that Al2O3 powder is filled synchronously during the welding process; the difference from Example 1 is that the welding process parameters are different.

[0068] In this example, the following 5 groups of welding process parameters are used to weld two quartz ceramic sheets identical to those in Comparative Example 1 respectively:

[0069] (a) Laser power P = 350W, welding speed v = 2mm / s, powder feeding rate v f = 20g / min, powder feeding gas flow rate v q = 9atm / min;

[0070] (b) Laser power P = 350W, welding speed v = 3mm / s, powder feeding rate v f = 20g / min, powder feeding gas flow rate v q = 9atm / min;

[0071] (c) Laser power P = 350W, welding speed v = 4mm / s, powder feeding rate v f = 20g / min, powder feeding gas flow rate v q = 9atm / min;

[0072] (d) Laser power P = 350W, welding speed v = 5mm / s, powder feeding rate v f = 20g / min, powder feeding gas flow rate v q = 9atm / min;

[0073] (e) Laser power P = 350W, welding speed v = 6mm / s, powder feeding rate v f = 20g / min, powder feeding gas flow rate v q = 9atm / min;

[0074] Among the above 5 groups of parameters, other parameters are the same except for the welding speed v.

[0075] As Figure 4 shown, by comparing the weld shapes obtained under the above Comparative Example 1 and the working parameters of groups (a)-(e) respectively, it is found that the weld shape obtained by the laser synchronous powder feeding method is more plump than the weld shape obtained by laser welding in Comparative Example 1. The overall surface of the weld presents a white surface, and there are no cracking phenomena at the weld center and the base material, while the weld in Comparative Example 1 has a rupture situation.

[0076] By comparing the 5 kinds of welds obtained under the working parameters of groups (a)-(e) respectively, it is found that individual welds will have problems such as the falling off of the filler material, forming ruptures and a large number of pores. As shown in group (a), when the welding speed is too low, a large number of pores and ruptures will occur; as shown in group (e), when the welding speed is too high, the amount of concave of the weld is too large. Therefore, when laser synchronous powder feeding is used to weld quartz ceramics, keeping the welding speed within the range of 3 mm / s to 5 mm / s can obtain the weld with the most plump shape and the best connection strength.

[0077] Example 3

[0078] In this example, the laser spot radius is 1 mm, the defocus amount is 0 mm, and the angle between the laser beam and the workpiece surface is 90°. The difference from Comparative Example 1 is that Al2O3 powder is filled synchronously during the welding process; the difference from Example 1 and Example 2 is that the welding process parameters are different.

[0079] In this example, the following 5 groups of welding process parameters are used to weld two quartz ceramic sheets identical to those in Comparative Example 1 respectively:

[0080] (a) Laser power P = 350 W, welding speed v = 3 mm / s, powder feeding rate v f = 10 g / min, powder feeding gas flow rate v q = 9 atm / min;

[0081] (b) Laser power P = 350 W, welding speed v = 3 mm / s, powder feeding rate v f = 15 g / min, powder feeding gas flow rate v q = 9 atm / min;

[0082] (c) Laser power P = 350 W, welding speed v = 3 mm / s, powder feeding rate v f = 20 g / min, powder feeding gas flow rate v q = 9 atm / min;

[0083] (d) Laser power P = 350 W, welding speed v = 3 mm / s, powder feeding rate vf = 25 g / min, powder feeding gas flow rate v q = 9 atm / min;

[0084] (e) Laser power P = 350 W, welding speed v = 3 mm / s, powder feeding rate v f = 30 g / min, powder feeding gas flow rate v q = 9 atm / min;

[0085] Among the above 5 groups of parameters, except for the powder feeding rate v f being different, other parameters are the same.

[0086] As Figure 5 shown, by comparing the weld shapes obtained under the working parameters of the above Comparative Example 1 and groups (a)-(e) respectively, it is found that the weld shapes obtained by the laser synchronous powder feeding method are all fuller than those of the welds obtained by laser welding in Comparative Example 1. The overall surface of the welds presents a white surface, and there are no cracking phenomena at the weld center and the base material;

[0087] By comparing the 5 kinds of welds obtained under the working parameters of groups (a)-(e) respectively, individual welds will have problems of pores and depressions. As shown in group (a), when the powder feeding rate is too low, pores appear in the weld; as shown in group (d), when the welding speed is too high, pores will also appear in the weld. Therefore, when laser synchronous powder feeding is used to weld quartz ceramics, the powder feeding rate within the range of 15 g / min to 20 g / min can obtain the weld with the fullest shape and the best joint strength.

[0088] Example 4

[0089] In this example, the laser spot radius is 1 mm, the defocus amount is 0 mm, and the angle between the laser beam and the workpiece surface is 90°. The difference from Comparative Example 1 is that Al2O3 powder is filled synchronously during the welding process; the difference from Example 1 and Example 2 is that the welding process parameters are different.

[0090] In this example, the following 5 groups of welding process parameters are used to weld two quartz ceramic sheets identical to those in Comparative Example 1 respectively:

[0091] (a) Laser power P = 350 W, welding speed v = 3 mm / s, powder feeding rate v f = 20 g / min, powder feeding gas flow rate v q = 2 atm / min;

[0092] (b) Laser power P = 350 W, welding speed v = 3 mm / s, powder feeding rate v f = 20 g / min, powder feeding gas flow rate v q = 5 atm / min;

[0093] (c) Laser power P = 350 W, welding speed v = 3 mm / s, powder feeding rate v f = 20 g / min, powder feeding gas flow rate v q = 8 atm / min;

[0094] (d) Laser power P = 350 W, welding speed v = 3 mm / s, powder feeding rate v f = 20 g / min, powder feeding gas flow rate v q = 11 atm / min;

[0095] (e) Laser power P = 350 W, welding speed v = 3 mm / s, powder feeding rate v f = 20 g / min, powder feeding gas flow rate v q = 14 atm / min;

[0096] Among the above 5 groups of parameters, except for the different powder feeding gas flow rate v q , other parameters are the same.

[0097] As Figure 6 shown, by comparing the weld shapes obtained under the above Comparative Example 1 and the working parameters of groups (a)-(e) respectively, it is found that the weld shapes obtained by the laser synchronous powder feeding method are more plump than those of the welds obtained by laser welding in Comparative Example 1. The overall surface of the weld presents a white surface, and there are no cracking phenomena at the weld center and the base material;

[0098] By comparing the 5 kinds of welds obtained under the working parameters of groups (a)-(e) respectively, it is found that with the gradual increase of the powder feeding gas flow rate, individual welds will have the problem of depression. As shown in group (a), the powder feeding gas flow rate is too low, the powder filling amount is small, and the weld morphology is not plump; as shown in group (e), the powder feeding gas flow rate is too high, then the amount of weld depression increases. Therefore, when laser synchronous powder feeding is used to weld quartz ceramics, the powder feeding gas flow rate in the range of 8 atm / min to 11 atm / min can obtain the weld with the most plump shape and the best joint strength.

[0099] Compared with traditional processing methods such as laser direct welding, high-temperature furnace preheating welding, and brazing, the laser synchronous powder feeding welding method for quartz ceramics provided by the present invention has the following advantages: (1) high processing quality; (2) fast processing speed; (3) will not damage the internal parts of the welded parts; (4) the welded joint is high-temperature resistant.

[0100] The structures of the laser synchronous powder feeding welding equipment used in the foregoing Examples (1)-(4) are the same, as Figure 7As shown in the figure, the welding fixture 1 of the laser synchronous powder feeding welding equipment includes a welding fixture body 13, a pressing block 16 and a pressing screw 17. Before welding, the quartz ceramic plate 2 composed of the left quartz ceramic plate 14 and the right quartz ceramic plate 15 is clamped in the welding fixture body 13. The pressing screw 17 is tightened, and the pressing block 16 is pushed to clamp the left quartz ceramic plate 14 and the right quartz ceramic plate 15, completing the clamping.

[0101] As Figure 8 shown in the figure, the laser synchronous powder feeding welding equipment includes a welding fixture 1, a welding head 3, a laser 4, a water cooler 5, a shielding gas device 6, a powder feeding device 7 and a motion machine tool 8. Before welding, the quartz ceramic plate 2 is clamped and fixed by using the welding fixture 1. The laser 4 and the water cooler 5 are turned on, and the shielding gas device 6 and the powder feeding device 7 are introduced into the welding head 3. The welding head 3 performs welding under the control of the motion machine tool 8.

[0102] As Figure 9 shown in the figure, the welding head 3 of the laser synchronous powder feeding welding equipment includes a powder feeding pipe 9, a powder feeding port 10, a welding head main body 11, and a laser inlet 12. The laser beam emitted from the laser inlet 12 irradiates the surface of the base material, causing the material to vaporize and form a base material molten pool. The powder feeder sends the filling powder into the base material molten pool through the powder feeding port 10. After being irradiated by the laser beam emitted from the laser inlet 12 and the heat conduction of the base material molten pool, the powder melts to form molten powder to complete the welding. Except for the above-mentioned laser synchronous powder feeding welding equipment, other welding equipment that can implement the welding method of the present invention can also be applicable to the present invention.

[0103] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for welding quartz ceramics based on laser synchronous powder feeding technology, characterized in that, The method includes the following steps: S1. Irradiate the surface of the area to be welded on the quartz ceramic with a laser beam of a preset power, and simultaneously send the filling powder to the laser beam irradiation position of the area to be welded at a preset powder feeding gas flow rate and powder feeding rate; the filling powder is an oxide powder with a melting point higher than that of the quartz ceramic; S2. The surface of the area to be welded is vaporized under the action of the laser beam to form a molten pool that sinks downward and has no base material melt, and the filling powder is melted under the dual action of the laser beam and the heat conduction of the molten pool to fill the molten pool, thereby realizing the welding of the quartz ceramic.

2. The method for welding quartz ceramics based on laser synchronous powder feeding technology according to claim 1, characterized in that, The filling powder is Al2O3 powder.

3. The method for welding quartz ceramics based on laser synchronous powder feeding technology according to any one of claims 1 or 2, characterized in that, The particle size of the filling powder is 50μm - 150μm.

4. The method for welding quartz ceramics based on laser synchronous powder feeding technology according to claim 3, characterized in that, The particle size of the filling powder is 100μm - 120μm.

5. The method for welding quartz ceramics based on laser synchronous powder feeding technology according to claim 1, characterized in that, The power P of the laser beam is set to 350W ≤ P ≤ 650W.

6. The method for welding quartz ceramics based on laser synchronous powder feeding technology according to claim 1, characterized in that, The power P of the laser beam is set to 450W ≤ P ≤ 550W.

7. The method for welding quartz ceramics based on laser synchronous powder feeding technology according to claim 1, characterized in that, The moving speed v of the laser beam relative to the area to be welded is set to 3mm / s ≤ v ≤ 5mm / s.

8. The method for welding quartz ceramics based on laser synchronous powder feeding technology according to claim 1, characterized in that, The powder feeding rate v f is set to 15 g / min ≤ v f ≤ 20 g / min.

9. The method for welding quartz ceramics based on laser synchronous powder feeding technology according to claim 1, characterized in that, The powder feeding rate v f is set to 16 g / min ≤ v f ≤ 18 g / min.

10. The method for welding quartz ceramics based on laser synchronous powder feeding technology according to claim 1, characterized in that, The powder feeding gas flow rate v q is set to 8 atm / min ≤ v q ≤ 11 atm / min.

11. The method for welding quartz ceramics based on laser synchronous powder feeding technology according to claim 1, characterized in that, The powder feeding gas flow rate v q is set to 9 atm / min ≤ v q ≤ 10 atm / min.

12. The method for welding quartz ceramics based on laser synchronous powder feeding technology according to claim 1, characterized in that, The minimum spot diameter of the laser beam is 2mm.

13. The method for welding quartz ceramics based on laser synchronous powder feeding technology according to claim 1, characterized in that, The laser beam is perpendicular to the surface of the quartz ceramic, and the defocus amount of the laser beam is 0mm.

14. The method for welding quartz ceramics based on laser synchronous powder feeding technology according to claim 1, characterized in that, The distance between the powder outlet position of the filling powder and the surface of the quartz ceramic is 10mm - 20mm.

15. A method for welding quartz ceramics based on laser synchronous powder feeding technology as described in claim 1, characterized in that, The distance between the powder outlet position of the filling powder and the surface of the quartz ceramic is 15mm - 18mm.

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