A method for high repetition rate ultrafast laser welding of ceramics and transparent materials

Abstract

The present invention provides a method for welding ceramic-transparent materials by high repetition rate ultrafast laser, comprising the following steps: S1, stacking the transparent material to be welded on top of the ceramic material; S2, the laser generator outputs a high repetition rate ultrafast laser, and the optical path is adjusted so that the high repetition rate ultrafast laser is focused on the ceramic material to induce plasma; S3, the laser energy density of the high repetition rate ultrafast laser is controlled to be a preset value, and the plasma generated by the ceramic material is used to shield and absorb the high repetition rate ultrafast laser to form a continuous high-temperature plasma; S4, the ceramic material is heated and melted by the high-temperature plasma, and the transparent material is melted by reverse heating through heat conduction, thereby realizing the welding of the ceramic material and the transparent material. The invention controls the appropriate ultrafast laser energy density under the action of the high repetition rate ultrafast laser, so that the surface of the ceramic material is melted rather than ablated, thereby realizing the ultrafast laser welding of ceramic-transparent materials, with small thermal effect and welding strength of more than 70MPa.

Description

Technical Field

[0001] The invention belongs to the technical field of laser processing, and in particular relates to a method for high-repetition-rate ultrafast laser welding of ceramics and transparent materials. Background Art

[0002] Existing ultrafast laser welding is mainly used in transparent-transparent material welding, which uses the nonlinear absorption and heat accumulation formed by ultrafast laser inside the transparent material to achieve effective melting of the transparent material. For ceramic materials, ultrafast laser will mainly form ablation; in some existing ultrafast welding applications related to ceramic materials, the transparent material and the ceramic material are clamped by a fixture, and then the alumina ceramic material is ablated by ultrafast laser to form sputtering. The high-temperature sputtering is deposited on the lower surface of the transparent material, and the transparent material is heated by heat conduction to melt the transparent material in reverse, and finally the welding of the two is achieved. However, the ceramic-transparent dissimilar material welding formed by ultrafast laser ablation is easy to destroy the optical contact between the ceramic and transparent materials due to ultrafast laser ablation, and the achievable strength is extremely low (less than 5MPa), which is difficult to meet the actual application requirements. Summary of the invention

[0003] The purpose of the present invention is to provide a method for high repetition rate ultrafast laser welding of ceramics and transparent materials, which can at least solve some of the defects existing in the prior art.

[0004] To achieve the above object, the present invention adopts the following technical solution:

[0005] A method for high repetition rate ultrafast laser welding of ceramics and transparent materials, comprising the following steps:

[0006] S1, stacking the transparent material to be welded on top of the ceramic material, and forming optical contact between the transparent material and the ceramic material;

[0007] S2, the laser generator outputs high repetition rate ultrafast laser, and the optical path is adjusted so that the high repetition rate ultrafast laser is focused on the ceramic material to induce plasma;

[0008] S3, controlling the laser energy density of the high repetition rate ultrafast laser to a preset value, utilizing the shielding and absorption effect of the plasma generated by the ceramic material on the high repetition rate ultrafast laser, and forming a continuous high-temperature plasma;

[0009] S4. The ceramic material is heated and melted by the high-temperature plasma, and the transparent material is melted by reverse heating through heat conduction, thereby realizing the welding of the ceramic material and the transparent material.

[0010] Furthermore, the repetition frequency of the high repetition rate ultrafast laser is not less than 500 kHz.

[0011] Furthermore, the laser energy density of the high repetition rate ultrafast laser is 5-20 J / cm2 .

[0012] Furthermore, when the repetition frequency of the high repetition rate ultrafast laser is 1 MHz, the laser energy density of the high repetition rate ultrafast laser is controlled to be 8.2-10.5 J / cm 2 .

[0013] Furthermore, in step S2, the laser optical path is adjusted so that the focus of the high repetition rate ultrafast laser is located on the contact interface between the ceramic material and the transparent material, or is located within 20 microns below the upper surface of the ceramic material.

[0014] Furthermore, in step S2, the high repetition rate ultrafast laser output by the laser generator is shaped into a Burst mode in time and shaped into a Bessel beam or a flat-top beam in space, and then focused on the ceramic material.

[0015] Furthermore, the ceramic material is alumina ceramic, zirconia ceramic or silicon carbide ceramic.

[0016] Furthermore, the transparent material is transparent glass.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The method for high-repetition-rate ultrafast laser welding of ceramics and transparent materials provided by the present invention controls the appropriate ultrafast laser energy density under the action of a high-repetition-rate ultrafast laser, and utilizes the plasma formed when the ultrafast laser acts on the ceramic material at a high repetition rate to shield the ultrafast energy, so that the surface of the ceramic material is melted rather than ablated, thereby enhancing the welding strength between the ceramic material and the transparent material, and the welding strength can reach more than 70MPa.

[0019] The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a flow chart of high repetition rate ultrafast laser welding of ceramics-transparent materials of the present invention;

[0021] Figure 2 Schematic diagram of laser optical path for high repetition rate ultrafast laser welding of ceramic-transparent material in an embodiment of the present invention;

[0022] Figure 3 It is a schematic diagram of the molten structure formed by the high repetition rate ultrafast laser acting on the ceramic material with different laser energy densities in an embodiment of the present invention.

[0023] Explanation of the accompanying drawings: 1. Laser generator; 2. Space-time shaping device; 3. Light speed scanning device; 4. Focusing mirror; 5. Transparent material; 6. Ceramic material. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0026] In the description of the present invention, it should be noted that, unless otherwise clearly stipulated and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, a conflicting connection or an integral connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features; in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0028] like Figure 1 and Figure 2 As shown, this embodiment provides a method for high repetition rate ultrafast laser welding of ceramics and transparent materials, which specifically includes the following steps:

[0029] S1. Stack the transparent material 5 to be welded on the ceramic material 6, and form optical contact between the transparent material 5 and the ceramic material 6. The transparent material 5 may be transparent glass, including but not limited to sapphire glass, quartz glass, soda-lime glass, borosilicate glass, etc.; the ceramic material 6 may be but not limited to alumina ceramic, zirconia ceramic, silicon carbide ceramic, etc.

[0030] S2. The laser generator 1 outputs a high-repetition-rate ultrafast laser, and adjusts the optical path so that the high-repetition-rate ultrafast laser is focused on the ceramic material 6 through the focusing mirror 4 to induce plasma.

[0031] Since the ultrafast laser conventionally used for welding ceramic material 6 directly forms ablation when acting on ceramic material 6, it is difficult to form effective melting. Therefore, in this embodiment, the laser output by the laser generator 1 adopts a high-repetition-rate ultrafast laser with a repetition frequency of not less than 500kHz. The output ultrafast laser can be selected from but not limited to femtosecond laser and picosecond laser.

[0032] S3. Control the laser energy density of the high repetition rate ultrafast laser to a preset value, and use the shielding and absorption effect of the plasma generated by the ceramic material 6 on the high repetition rate ultrafast laser to form a continuous high-temperature plasma.

[0033] S4, the ceramic material 6 is heated by the high temperature plasma and melted, and at the same time, the transparent material 5 is melted by reverse heating through heat conduction, so that the ceramic material 6 and the transparent material 5 are welded.

[0034] Specifically, the purpose of controlling the laser energy density of the high repetition rate ultrafast laser acting on the ceramic material can be achieved by adjusting the laser power of the high repetition rate ultrafast laser, adjusting the laser spot size by the focus position of the focusing mirror 4, and adjusting the scanning speed of the light speed scanning device 3. In this embodiment, the focus of the high repetition rate ultrafast laser is designed to be located at the contact interface between the ceramic material 6 and the transparent material 5, or within 20 microns below the upper surface of the ceramic material 6, so as to ensure that the high repetition rate ultrafast laser can induce plasma when acting on the ceramic material 6.

[0035] In this embodiment, in order to realize the ultrafast laser to melt the ceramic material 6 instead of ablation, the laser energy density of the high repetition rate ultrafast laser needs to be controlled to be 5-20 J / cm 2 The specific laser energy density is determined according to the composition of the targeted ceramic material 6 and the repetition frequency of the high repetition rate ultrafast laser.

[0036] For example, in this embodiment, the laser energy density is 14.6 J / cm 2 , 14.0J / cm 2 , 12.5J / cm 2 , 10.5J / cm 2 , 8.2J / cm 2 Five high repetition rate femtosecond lasers with a repetition rate of 1 MHz were used to act on five identical alumina ceramic materials for experiments. The molten structures of the alumina ceramic materials formed in the five experiments are shown in the following figure. Figure 3 As shown, Figure 3 a, b, c, d, and e correspond to laser energy densities of 14.6 J / cm 2 , 14.0J / cm 2 , 12.5J / cm 2 , 10.5J / cm 2, 8.2J / cm 2 The result of Figure 3 It can be seen that the surface of the alumina ceramic material in the three groups of experiments a, b, and c is ablated, and the surface of the alumina ceramic material in the two groups of experiments d and e is melted. Therefore, the alumina ceramic material has a repetition frequency of 1MHz and a laser energy density of 8.2-10.5J / cm 2 Under the action of high repetition rate, high repetition rate heat accumulation can be formed, so that the surface of the ceramic material is melted rather than ablated under the action of high repetition rate ultrafast laser.

[0037] Optimized, for the laser generator 1 outputting a high repetition rate ultrafast laser, it can be shaped into a Burst mode (i.e., burst mode) in time through the space-time shaping device 2, and shaped into a Bessel beam or a flat-top beam in space before being focused on the ceramic material 6; wherein, shaping the high repetition rate ultrafast laser into the Burst mode is beneficial to further enhance the thermal effect formed by welding, and shaping the high repetition rate ultrafast laser into a Bessel beam or a flat-top beam can optimize the sensitivity to the laser focus during the welding process, improve the welding process window, and thus further improve the welding strength and stability.

[0038] The method of high-repetition-rate ultrafast laser welding of ceramic-transparent materials provided in this embodiment makes full use of the plasma shielding phenomenon formed when the ultrafast laser acts on the ceramic material 6 at a high repetition rate, fully shields the ultrafast energy, and at the same time uses the limited absorption of the ultrafast laser by the plasma to make the ceramic material 6 in the local area in a molten state, so as to achieve the heat accumulation of the ceramic material 6 under the action of the ultrafast laser, and use this accumulated heat to reversely heat and melt the transparent material 5 through heat conduction, and finally achieve the welding of the ceramic material 6 and the transparent material 5. Because in the welding process of the present invention, the surface of the ceramic material 6 is melted rather than ablated under the action of the ultrafast laser, so that the optical contact between the ceramic material 6 and the transparent material 5 will not be destroyed, and the welding strength of the two can be greatly enhanced. Experimental tests show that the welding strength formed by the method of the present invention for welding ceramic-transparent materials is higher than 70MPa, which is much higher than the welding strength of the existing ceramic-transparent materials.

[0039] The above examples are merely illustrative of the present invention and do not constitute a limitation on the protection scope of the present invention. All designs that are the same or similar to the present invention fall within the protection scope of the present invention.

Claims

1. A method for high repetition rate ultrafast laser welding of ceramics and transparent materials, characterized in that: The steps include: S1, stacking the transparent material to be welded on top of the ceramic material, and forming optical contact between the transparent material and the ceramic material; S2, the laser generator outputs high repetition rate ultrafast laser, and the optical path is adjusted so that the high repetition rate ultrafast laser is focused on the ceramic material to induce plasma; S3, controlling the laser energy density of the high repetition rate ultrafast laser to a preset value, utilizing the shielding and absorption effect of the plasma generated by the ceramic material on the high repetition rate ultrafast laser, and forming a continuous high-temperature plasma; S4. The ceramic material is heated and melted by the high-temperature plasma, and the transparent material is melted by reverse heating through heat conduction, thereby realizing welding between the ceramic material and the transparent material; The transparent material is transparent glass; the repetition frequency of the high repetition rate ultrafast laser is not less than 500kHz; the laser energy density of the high repetition rate ultrafast laser is 5-20J / cm 2 .

2. The method for high repetition rate ultrafast laser welding of ceramics and transparent materials according to claim 1, characterized in that: When the repetition frequency of the high repetition rate ultrafast laser is 1 MHz, the laser energy density of the high repetition rate ultrafast laser is controlled to be 8.2-10.5 J / cm 2 .

3. The method for high repetition rate ultrafast laser welding of ceramics and transparent materials according to claim 1, characterized in that: In step S2, the optical path is adjusted so that the focus of the high repetition rate ultrafast laser is located on the contact interface between the ceramic material and the transparent material, or is located within 20 microns below the upper surface of the ceramic material.

4. The method for high repetition rate ultrafast laser welding of ceramics and transparent materials according to claim 1, characterized in that: In the step S2, the high repetition rate ultrafast laser output by the laser generator is shaped into a Burst mode in time and shaped into a Bessel beam or a flat-top beam in space, and then focused on the ceramic material.

5. The method for high repetition rate ultrafast laser welding of ceramics and transparent materials as claimed in claim 1, characterized in that: The ceramic material is alumina ceramic, zirconia ceramic or silicon carbide ceramic.

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