A method of fabricating a structure of a diamond optical window

Abstract

The application discloses a preparation method of a structure of a diamond optical window, and the structure of the diamond optical window comprises a diamond layer, a diamond slice drag, a slice drag support and a flange which are stacked in sequence; the combination of the diamond layer and the diamond slice drag, the diamond slice drag and the slice drag support and the slice drag support and the flange is coated with welding material to fix them; the welding process of the diamond optical window structure and the flange is realized, the welding difficulty of the diamond film and the flange can be obviously reduced, and the thermal stress caused by the welding temperature is greatly reduced under the premise of meeting the mechanical performance and the leakage rate.

Description

TECHNICAL FIELD

[0001] The application is a preparation method of a structure of a diamond optical window, and belongs to the fields of optics and material processing. BACKGROUND

[0002] Diamond has excellent hardness, oxidation resistance and corrosion resistance, and has extremely important application value in the fields of optics, microwave transmission, electrochemistry and aerospace. Especially in the fields of microwaves and optics, the wavelengths applicable to the related components of optical windows basically cover all wavebands from X-rays, deep ultraviolet to microwaves. The existing infrared window materials (such as sapphire, spinel and MgF2) have strong infrared spontaneous radiation at high temperatures and obvious mechanical decline, and it is increasingly difficult to meet various extreme application scenarios such as infrared windows and radomes. Diamond has good mechanical properties under the premise of meeting excellent optical transmission performance, and shows advantages in optical communication.

[0003] The connection process of traditional optical windows and mechanical flanges mainly includes electroplating, welding and mechanical sealing.

[0004] At present, researchers mainly use polycrystalline diamond or nanodiamond to weld the diamond film to the flange based on solder. Although the performance of the diamond film is improved compared with that of sapphire, spinel and MgF2 optical windows, the diamond film is prone to graphitization or even breakage during welding due to the thermal stress and mismatch of the thermal expansion coefficient with the flange, which reduces the optical transmission of the diamond and greatly increases the production cost.

[0005] These application fields not only require diamond films with low roughness and high transmission, but also need to solve the problem of how to connect the diamond to the components. The traditional connection of diamond films and flanges is increasingly difficult to meet the requirements of transmission, stability and leakage rate. SUMMARY

[0006] In view of the deficiencies of the prior art, the application aims to provide a preparation method of a structure of a diamond optical window to solve the problems.

[0007] To achieve the above-mentioned purpose, the application is implemented by the following technical solution: a preparation method of a structure of a diamond optical window, comprising the following steps:

[0008] Step 1: according to the actual optical wavelength and the design of the required optical window, a diamond film with a certain thickness and size is selected, and the double-sided grinding, polishing and laser scribing and cutting process of the diamond film is performed to make the surface of the diamond film free of cracks and the roughness meet the requirements to obtain a diamond layer;

[0009] Step 2; after the diamond layer is cleaned by alcohol and acetone and dried, a mask of certain thickness and size is attached to the center of the diamond layer, and a selected metal layer is deposited on the edge of the diamond layer by an external suitable coating equipment. After the deposition of the metal layer, a layer of low-temperature metal solder is coated on the metal layer;

[0010] Step 3; the diamond sheet drag is tightly attached to the solder, and then the welding between the diamond layer and the diamond sheet drag is realized by an external vacuum welding equipment;

[0011] Step 4; a layer of low-temperature metal solder is coated on the edge of the diamond sheet drag to realize the tight attachment of the diamond sheet drag to the sheet drag support, and then the welding between the diamond sheet drag and the sheet drag support is realized by an external vacuum welding equipment;

[0012] Step 5; the gap between the sheet drag support and the flange is filled with solder, and then the connection and fixation between the sheet drag support and the flange are realized by an external high-temperature welding equipment after compaction.

[0013] Preferably, in step 1, the double-sided diamond is subjected to grinding, polishing, laser, and scribing and cutting treatment to meet the requirements of optical grade.

[0014] Preferably, the thickness of the original diamond substrate is 20 μm to 1000 μm, and the size of the diamond is 1 inch to 10 inches; the surface roughness Ra of the diamond layer is less than or equal to 2 nm.

[0015] Preferably, in step 2, the diamond layer is cleaned and dried.

[0016] Preferably, in step 2, a metal layer with a thickness of 0.5 μm to 500 μm is plated on the unmasked outer edge.

[0017] Preferably, in step 3, the solder includes but is not limited to Ag-based, Cu-based, and Mo-based solder, and the welding temperature is controlled at 400℃ to 800℃.

[0018] Preferably, in step 4, the solder used is a low-temperature active solder, and the welding temperature is controlled at 400℃ to 800℃.

[0019] Preferably, in step 5, the solder used is a sealing solder, and the welding temperature is controlled at 400℃ to 1200℃.

[0020] A structure of a diamond optical window, which comprises a diamond layer, a diamond sheet drag, a sheet drag support, and a flange stacked in sequence; the junctions between the diamond layer and the diamond sheet drag, the diamond sheet drag and the sheet drag support, and the sheet drag support and the flange are coated with solder to fix them to each other.

[0021] Advantages

[0022] The advantage of the present application is that diamond concentrates various excellent performances in one, and the super high optical transmittance enables diamond as a window material to be applied in the field of microwave and ray detection.

[0023] The welding process of the diamond optical window structure and the flange realized by the method can obviously reduce the welding difficulty of the diamond film and the flange, greatly reduces the thermal stress problem caused by the welding temperature on the premise of meeting the mechanical properties and the leakage rate.

[0024] The outstanding advantage of the present application is that the multiple solder welding is used to connect the diamond film and the flange with the intermediate components, and the traditional diamond flange window directly welds the diamond on the flange.

[0025] The significant advantage of the present application is that the high mechanical bonding strength, high vacuum degree and heat shock resistance can be realized, the product quality is optimized, and the operation is simple. BRIEF DESCRIPTION OF DRAWINGS

[0026] Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments, made with reference to the following drawings:

[0027] Figure 1 It is a structure schematic diagram of a diamond layer of the present application;

[0028] Figure 2 It is a structure schematic diagram of a diamond layer plated with a metal layer of the present application;

[0029] Figure 3 It is a structure schematic diagram of a diamond layer installed with a diamond piece of the present application;

[0030] Figure 4 It is a structure schematic diagram of a diamond piece of the present application installed with a piece of support;

[0031] Figure 5 It is a structure schematic diagram of a diamond piece of the present application installed with a flange. DETAILED DESCRIPTION

[0032] In order to make the technical means, creative features, purposes and effects of the present application easy to understand, the present application is further described below in combination with specific embodiments.

[0033] Example 1

[0034] A preparation method of a structure of a diamond optical window includes the following steps:

[0035] Step 1; according to the actual optical wavelength used as a polycrystalline diamond as the original substrate, the size of the original substrate is 50MMx50MM, and the thickness is 500μm; the double-sided diamond is ground, polished, laser scribing and cutting, etc. Process treatment, so that the diamond surface has no cracks, and the roughness can meet the requirement of Ra less than or equal to 2nm, so as to facilitate the plating of the metal layer 2, which can be stabilized on the original substrate, as shown in Figure 1 ;

[0036] Step 2; the middle area of the original substrate is shielded with a metal mask (not shown in the figure), and the metal layer 2 is plated only in the edge area. According to the requirement of brazing, the thickness of the metal layer 2 is selected as 50μm, and the range of the metal layer 2 is selected as a ring with a width of 3MM;

[0037] Step 3; the original substrate is cleaned, ultrasonic cleaned with ethanol for 5min, then transferred to acetone for ultrasonic cleaning for 10min, and dried by hot air for standby. The original substrate is put into an external sputtering device, vacuumed to below 5Pa, argon gas is introduced at a flow rate of 60sccm, the gas pressure is maintained at about 10Pa, the bias power is turned on to clean the surface adsorbed air molecules in the constant power mode, the time is 20min, then the molecular pump is opened to make the vacuum degree of the cavity reach 1x10 -3 Pa;

[0038] Step 4; start Ni metal plating; adjust the Ar gas flow to 10sccm, the sputtering power to 100W, the cavity pressure to 0.6Pa, and the deposition time to 40min, complete the Ni metal plating process, as shown in Figure 2 ;

[0039] Step 5; start the roughening treatment of the diamond sheet 3, select W25 diamond particles, use hard alloy to roughen the diamond sheet 3 for 10min, then use alcohol ultrasonic cleaning for 10min, and then use acetone hot air drying;

[0040] Step 6; coat the Ni-based low-temperature solder 6 at the position of the sputtered metal layer 2 on the edge of the diamond layer 1, after coating, place the diamond layer 1 on the diamond sheet 3, then coat the Ni low-temperature solder 6 on the side of the diamond layer 1;

[0041] Step 7; place the coated diamond layer 1 and the diamond sheet 3 into a vacuum brazing furnace, when the vacuum degree is 1.5x10 -5 Pa, turn on the vacuum brazing furnace and slowly heat to 600℃, the brazing furnace heating power is kept at 15KW, the gas pressure is kept at 0.2Pa, and the welding time is kept for 30min, then slowly reduce the temperature and power, so that the temperature of the vacuum cavity cools to room temperature, as shown in Figure 3 ;

[0042] Step 8; Cu-based low-temperature solder 6 is coated at the joint between the diamond sheet 3 and the sheet support 4, and the thickness of the solder 6 is controlled at 100 μm;

[0043] Step 9; the welded diamond sheet 3 and the sheet support 4 are placed into a vacuum brazing furnace, when the vacuum degree is 1.5 x 10-5 Pa, the vacuum brazing furnace is started to slowly heat to 800 °C, the brazing furnace heating power is kept at 15 KW, the welding time is kept for 30 min, then the temperature and power are slowly reduced, so that the temperature of the vacuum cavity is cooled to room temperature, as shown in Figure 4

[0044] Step 10; solder 6 coating between the sheet support 4 and the flange 5; the welding surface is roughened by diamond powder with a particle size of W25 μm, so that the roughness Ra is about 200 μm, then Cu-based low-temperature solder 6 is coated at the welding joint between the sheet support 4 and the flange 5, and the thickness of the solder 6 is controlled at 100 μm;

[0045] Step 11; welding between the sheet support 4 and the flange 5; the welded sheet support 4 and the flange 5 are placed into a vacuum brazing furnace, slowly heated to 800 °C, the brazing furnace heating power is kept at 15 KW, the gas pressure is kept at 0.2 Pa, the welding time is kept for 30 min, then the temperature and power are slowly reduced, so that the temperature of the vacuum cavity is cooled to room temperature, as shown in Figure 5

[0046] Example 2

[0047] A preparation method of a structure of a diamond optical window comprises the following steps;

[0048] Step 1; polycrystalline diamond is used as the original substrate according to the actual optical wavelength, the size of the original substrate is 80 MM x 80 MM, and the thickness is 300 μm; the diamond is processed by grinding, polishing, laser scribing and cutting, so that the diamond surface has no cracks, and the roughness can meet the requirement of Ra less than or equal to 2 nm, as shown in Figure 1

[0049] Step 2; the middle area of the original substrate is shielded by a metal mask, and a metal layer 2 is plated only in the edge area, according to the brazing requirement, the thickness of the metal layer 2 is selected as 30 μm, and the range of the metal layer 2 is selected as a ring with a width of 10 MM;

[0050] ​​​Step 3; the original substrate is cleaned by ultrasonic cleaning with ethanol for 5 min, then transferred to acetone for ultrasonic cleaning for 10 min, and dried with hot air. The original substrate is placed in an external sputtering device, vacuumed to below 5 Pa, argon gas is introduced at a flow rate of 60 sccm to maintain a pressure of about 10 Pa, the bias power is turned on to clean the surface adsorbed air molecules in the constant power mode, the time is 20 min, then the molecular pump is opened to make the vacuum degree of the cavity reach 1 × 10 -3 Pa;

[0051] Step 4; adjust the argon gas flow to 30 sccm, the sputtering power to 90 W, the cavity pressure to 0.6 Pa, and the deposition time to 50 min to complete the Ni metal film deposition process, as shown in Figure 2 ;

[0052] Step 5; start the roughening process of the diamond sheet 3, select W25 diamond particles to roughen the diamond sheet 3 with a hard alloy for 10 min, then ultrasonic clean with alcohol for 10 min, and then dry with acetone hot air;

[0053] Step 6; apply Ni-based low-temperature solder 6 to the edge of the diamond layer 1 where the metal layer 2 is sputtered, then place the diamond layer 1 on the diamond sheet 3, and then apply Ni low-temperature solder 6 to the side of the diamond layer 1;

[0054] Step 7; place the coated diamond layer 1 and the diamond sheet 3 into a vacuum brazing furnace, when the vacuum degree is 1.5 × 10 -5 Pa, turn on the vacuum brazing furnace and slowly heat it to 800℃, the brazing furnace heating power is kept at 20KW, the gas pressure is kept at 0.2Pa, the welding time is kept for 60 min, then slowly reduce the temperature and power, so that the temperature of the vacuum cavity cools to room temperature, as shown in Figure 3 ;

[0055] Step 8; apply Cu-based low-temperature solder 6 between the diamond sheet 3 and the sheet holder support 4, the thickness of the solder 6 is controlled at 150μm;

[0056] Step 9; place the welded diamond sheet 3 and the sheet holder support 4 into a vacuum brazing furnace, when the vacuum degree is 1.5 × 10 -5 Pa, turn on the vacuum brazing furnace and slowly heat it to 600℃, the brazing furnace heating power is kept at 20KW, the welding time is kept for 30 min, then slowly reduce the temperature and power, so that the temperature of the vacuum cavity cools to room temperature, as shown in Figure 4 ;

[0057] Step 10; solder 6 coating between the tile support 4 and the flange 5; roughen the welding surface with diamond powder with particle size of W25μm, so that the roughness Ra is about 200μm, then coat the Cu-based low-temperature solder 6 at the welding joint between the tile support 4 and the flange 5, and the thickness of the solder 6 is controlled at 300μm;

[0058] Step 11; welding between the tile support 4 and the flange 5; place the welded tile support 4 and the flange 5 into a vacuum brazing furnace, slowly heat to 800℃, the brazing furnace heating power is kept at 20KW, the gas pressure is kept at 0.2Pa, keep the welding time for 60min, then slowly reduce the temperature and power, so that the temperature of the vacuum cavity cools to room temperature, as shown in Figure 5 .

[0059] The technical scheme of the structure of a diamond optical window comprises a diamond layer 1, a diamond tile support 3, a tile support 4, and a flange 5 stacked in sequence; the joint between the diamond layer 1 and the diamond tile support 3, the joint between the diamond tile support 3 and the tile support 4, and the joint between the tile support 4 and the flange 5 are all coated with solder 6 to fix them to each other; the edge area of the diamond layer 1 is plated with a metal layer 2, and the solder 6 between the diamond layer 1 and the diamond tile support 3 is on the metal layer 2.

[0060] Preferably, the metal layer 2 between the diamond layer 1 and the diamond tile support 3 in the steps 2 of the embodiments 1 and 2 comprises but is not limited to Fe, Co, Ni, Mo, Ta and other metals and compounds thereof which are easy to form carbide with diamond, so as to reduce the welding difficulty and avoid the thermal stress and the mismatch of the thermal expansion coefficient of the flange during brazing;

[0061] Preferably, the solder 6 used at the joint between the diamond layer 1 and the diamond tile support 3, the joint between the diamond tile support 3 and the tile support 4, and the joint between the tile support 4 and the flange 5 comprises but is not limited to Ag-based, Cu-based and Mo-based solder 6, which can realize high mechanical bonding strength, high vacuum degree and heat shock resistance, optimize the product quality, and is easy to operate.

[0062] First, deposit a metal layer in the edge area of the diamond layer 1, then realize the welding between the diamond layer 1 and the diamond tile support 3, the welding between the diamond tile support 3 and the tile support 4, and the welding between the tile support 4 and the flange 5; such optical window has super-high vacuum characteristics, and the experiment verifies that it can reach 10 -11 Pa at the minimum, and can be used for infrared signal transmission and detection window on vacuum equipment.

[0063] The foregoing merely illustrates the principles of the application and application of its leading features. This application is not limited to the illustrative embodiments shown and described herein. Rather, this application is capable of operating within a further range of conditions and environments than those specifically described herein, and further modifications can be made without departing from the spirit or scope of the application. Accordingly, the description is to be construed as illustrative only and not restrictive of the broad disclosure or application of the application. The specification and drawings are, accordingly, to be regarded simply as illustrative and with the scope of the application being measured by the appended claims, and not with the specification. No admission is made that any reference constitutes prior art. It is my intent, therefore, to be limited only as appears in the following claims.

[0064] Furthermore, it should be understood that although the description above relates to embodiments, not every embodiment contains only one independent technical solution, and the description above is only for the sake of clarity, and those skilled in the art should understand the description as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that those skilled in the art can understand.

Claims

1. A method of fabricating a structure of a diamond optical window, characterized by: The method comprises the following steps: Step 1: Polycrystalline diamond is used as a raw substrate according to the actual optical wavelength, and the double surfaces of the diamond are processed to obtain a diamond layer, the surface of the diamond layer is free of cracks and has roughness; Step 2: A mask is attached to the center of the diamond layer, and a metal layer is plated on the outer edge of the diamond layer and coated with solder, and the metal layer is annular; Step 3: Start the roughening treatment of the diamond sheet, and select diamond particles to use hard alloy to roughen the diamond sheet; the solder on the outer edge of the diamond layer is used to realize brazing fixation with the diamond sheet, specifically: the solder is coated at the position where the metal layer is sputtered on the edge of the diamond layer, after the coating is completed, the diamond layer is placed on the diamond sheet, and then the solder is coated on the side edge of the diamond layer; Step 4: The solder is coated on the outer edge of the diamond sheet and brazed with the sheet support; Step 5: The gap reserved for solder filling between the sheet support and the flange is brazed after being tightly pressed.

2. A method of producing a structure of a diamond optical window according to claim 1, characterized by: In step 1, the double surfaces of the diamond are ground, polished, laser, and scribed and cut to meet the requirements of optical grade.

3. A method of producing a structure of a diamond optical window according to claim 2, characterized by: The thickness of the raw diamond substrate used is 20 μm to 1000 μm, and the size of the diamond is 1 inch to 10 inches; the surface roughness Ra of the diamond layer is less than or equal to 2 nm.

4. The method of claim 1, wherein: In step 2, the diamond layer needs to be cleaned and dried.

5. The method of claim 1, wherein: In step 2, the outer edge of the unmasked edge is plated with a metal layer with a thickness of 0.5 μm to 500 μm.

6. The method of claim 1, wherein: In step 3, the solder includes but is not limited to Ag-based, Cu-based and Mo-based solder, and the soldering temperature is controlled at 400-800°C.

7. The method of claim 1, wherein: In step 4, the solder used is a low-temperature active solder, and the soldering temperature is controlled at 400-800°C.

8. The method of claim 1, wherein: In step 5, the solder used is a sealing solder, and the soldering temperature is controlled at 400-1200°C.

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