Hot isostatic pressing treatment method for zinc sulfide plate

Abstract

The zinc sulfide plate hot isostatic pressing treatment method comprises the steps that S1, a plurality of zinc sulfide plates with the same length and width are vertically placed through a tool for zinc sulfide plate hot isostatic pressing and are arranged and clamped in the thickness direction of the zinc sulfide plates, and the zinc sulfide plates are multispectral zinc sulfide polycrystals prepared through chemical vapor deposition; s2, the tool for hot isostatic pressing of the zinc sulfide plates and the multiple clamped zinc sulfide plates are hoisted and vertically placed into a cylindrical vertical constant-temperature area of a hot isostatic pressing furnace, the axial length of the cylindrical constant-temperature area is larger than the diameter, and the axial direction of the cylindrical constant-temperature area is located in the vertical direction, the diagonal length of the plate surface formed by the length and width of the zinc sulfide plate is greater than the diameter of the constant-temperature area, the length and width of the zinc sulfide plate are both smaller than the axial length of the constant-temperature area, and the width of the zinc sulfide plate is smaller than the diameter of the constant-temperature area; s3, closing the hot isostatic pressing furnace, and lifting out the hot isostatic pressing furnace after treatment; and S5, the zinc sulfide plate is detached from the tool for hot isostatic pressing of the zinc sulfide plate, polished and detected.

Description

Technical Field

[0001] This disclosure relates to the field of infrared optical materials technology, and more specifically to a hot isostatic pressing method for zinc sulfide plates. Background Technology

[0002] Multispectral zinc sulfide (M-ZnS) is an infrared window material prepared using chemical vapor deposition (CVD) and hot isostatic pressing (HIP) processes.

[0003] In a standard hot isostatic pressing (HIP) furnace, the isothermal zone is a vertical cylinder, meaning its axis is vertical. The conventional loading method involves horizontally installing zinc sulfide sheets within the isothermal zone of the HIP furnace.

[0004] However, the dimensions (diameter mm * axial length mm) of the isothermal zone of commonly used hot isostatic pressing furnaces are φ400*1300, φ500*1500, φ750*1500, etc. These hot isostatic pressing furnaces can only be used when the diagonal length of the plate surface formed by the length and width of the zinc sulfide plate is smaller than the diameter of the isothermal zone of the hot isostatic pressing furnace.

[0005] When the diagonal length of the zinc sulfide sheet, formed by its length and width, is greater than the diameter of the isothermal zone in a hot isostatic pressing (HIP) furnace, a larger diameter HIP furnace is required because the zinc sulfide sheet is horizontally installed within the isothermal zone. The larger the isothermal zone diameter, the more expensive the HIP furnace and the higher its operating costs. Summary of the Invention

[0006] In view of the problems existing in the background art, one object of this disclosure is to provide a hot isostatic pressing (HIP) treatment method for zinc sulfide sheets, which enables the HIP furnace to process larger zinc sulfide sheets without changing the HIP furnace, and the treated zinc sulfide sheets have good permeability, transmittance and stress that meet the requirements.

[0007] Therefore, the hot isostatic pressing (HIP) treatment method for zinc sulfide plates includes the following steps: S1, using a hot isostatic pressing fixture to vertically place multiple zinc sulfide plates of the same length and width, arranged along the thickness direction of the zinc sulfide plates, and clamping them together, wherein the zinc sulfide plates are multi-spectral polycrystalline zinc sulfide prepared by chemical vapor deposition; S2, hoisting the hot isostatic pressing fixture along with the clamped multiple zinc sulfide plates and vertically placing them into a cylindrical, vertical isothermal zone in the hot isostatic pressing furnace, where the axial length is greater than the diameter, the diagonal length of the plate surface formed by the length and width of the zinc sulfide plates is greater than the diameter of the isothermal zone, the length and width of the zinc sulfide plates are both less than the axial length of the isothermal zone, and the width of the zinc sulfide plates is less than the diameter of the isothermal zone; S3, closing the hot isostatic pressing furnace, evacuating the isothermal zone, and filling it with inert gas. The constant temperature zone is cleaned multiple times by vacuuming and filling with inert gas to replace the air inside; S4, inert gas is filled into the constant temperature zone to the initial pressure, and the programmed heating to the target temperature is started and held. Inert gas is continued to be filled until the target pressure is reached and then held. After holding for a certain period of time, a two-stage annealing cooling program is started. The first stage of cooling is to the preset temperature, which is in the range of 400-700℃. After reaching the preset temperature, it is held. After the holding is completed, the second stage of cooling is carried out to the room temperature. During the second stage of cooling, when the temperature drops below 300℃, the inert gas in the constant temperature zone is released to the room pressure. After the temperature drops to the room temperature, the constant temperature zone is opened, and the hot isostatic pressing fixture for zinc sulfide plates, along with multiple treated zinc sulfide plates, is lifted out; S5, the zinc sulfide plates are removed from the hot isostatic pressing fixture for zinc sulfide plates and polished for inspection.

[0008] The beneficial effects of this disclosure are as follows.

[0009] In the background art, when the diagonal length of the zinc sulfide plate formed by its length and width is greater than the diameter of the constant temperature zone, it is obviously not feasible to install the zinc sulfide plate horizontally in the constant temperature zone while keeping the hot isostatic pressing furnace unchanged. However, when the zinc sulfide plate is adjusted to be vertical and the length and width of the zinc sulfide plate are both less than the axial length of the constant temperature zone and the width of the zinc sulfide plate is less than the diameter of the constant temperature zone, the zinc sulfide plate can be placed vertically in the constant temperature zone. In the vertical position, the zinc sulfide plate is at least horizontal in width and vertical in length (i.e., the axial direction of the constant temperature zone). (Of course, if the length of the zinc sulfide plate is also less than the diameter of the constant temperature zone, then the zinc sulfide plate can be horizontal in length and vertical in width). Thus, without changing the hot isostatic pressing furnace, it can process large-sized zinc sulfide plates (i.e., the diagonal length of the plate formed by its length and width is greater than the diameter of the isothermal zone, both its length and width are less than the axial length of the isothermal zone, and its width is less than the diameter of the isothermal zone). In other words, for large-sized zinc sulfide plates, there is no need to use a hot isostatic pressing furnace with a larger diameter isothermal zone; simply placing the zinc sulfide plates vertically allows for processing using the existing hot isostatic pressing furnace. In other words, without modifying the hot isostatic pressing furnace (i.e., using an existing one), it is possible to process larger-sized zinc sulfide plates, thereby controlling costs associated with the hot isostatic pressing furnace.

[0010] Furthermore, as verified by the testing process, after the zinc sulfide sheet is vertically placed into the constant temperature zone of the hot isostatic pressing furnace using the tooling for hot isostatic pressing of zinc sulfide sheet according to the present disclosure, the zinc sulfide sheet treated by the hot isostatic pressing method of the present disclosure has good permeability, and the transmittance and stress also meet the requirements. Attached Figure Description

[0011] Figure 1 This is an assembly perspective view of a tooling for hot isostatic pressing of zinc sulfide sheet according to the present disclosure, wherein the zinc sulfide sheet is shown.

[0012] Figure 2 yes Figure 1 The exploded diagram.

[0013] Figure 3 This is a schematic front view of the tooling used for hot isostatic pressing of zinc sulfide sheets, along with the zinc sulfide sheets, being loaded into the constant temperature zone of the hot isostatic pressing furnace.

[0014] Figure 4 This is a schematic top view of the tooling used for hot isostatic pressing of zinc sulfide sheets, along with the zinc sulfide sheets, being loaded into the constant temperature zone of the hot isostatic pressing furnace.

[0015] The reference numerals in the attached figures are explained below.

[0016] 23-hole tooling for hot isostatic pressing of 100 galvanized sheet

[0017] D1 Front and rear directions 3 metal sheets

[0018] D2 Left and right directions 4 graphite pressure plates

[0019] D3 Up and down direction 5 graphite pads

[0020] 1 metal lifting device 6 graphite paper

[0021] 11 U-shaped space 7 graphite fixtures

[0022] 12 Metal bases 71 Clamping graphite strips

[0023] 121 Limiting protrusion 711 Lower through hole

[0024] 122 protrusion 712 through hole

[0025] 122a Through Hole 713 Positioning Hole

[0026] 13 Metal lifting plate 72 Lower tightening graphite screw

[0027] 131 frame body 73 lower graphite nut

[0028] 131a Perforated 74 Support Graphite Plate

[0029] 131b lower opening 741 channel

[0030] 131c upper opening 75 upper clamping graphite screw

[0031] 132 hook 76 with graphite nut

[0032] 14 metal bolts, 200 zinc sulfide sheet

[0033] 15 Metal Nut T Thickness Direction

[0034] 2 Graphite base plate 300 hot isostatic pressing furnace

[0035] 21 grooves 300a constant temperature zone

[0036] 22 Containment recess Detailed Implementation

[0037] It will be understood that the disclosed embodiments are merely examples of this disclosure, which can be implemented in various forms. Therefore, the specific details disclosed herein should not be construed as limiting, but are intended only as the basis for the claims and as an illustrative basis to teach those skilled in the art how to implement this disclosure in various ways.

[0038] [Tooling for hot isostatic pressing of zinc sulfide sheets]

[0039] Reference Figures 1 to 4 According to the present disclosure, the tooling 100 for hot isostatic pressing of zinc sulfide plates is used to vertically place multiple zinc sulfide plates 200 with the same length and width, arrange them in the thickness direction T of the zinc sulfide plates 200, and clamp them together. The zinc sulfide plates 200 are multi-spectral zinc sulfide polycrystalline prepared by chemical vapor deposition. The tooling 100 for hot isostatic pressing of zinc sulfide plates is also used to vertically place them in the vertical isothermal zone 300a of the hot isostatic pressing furnace 300, where the axial length is greater than the diameter and the axial direction is D3. The diagonal length of the plate surface formed by the length and width of the zinc sulfide plates 200 is greater than the diameter of the isothermal zone 300a. The length and width of the zinc sulfide plates 200 are both less than the axial length of the isothermal zone 300a, and the width of the zinc sulfide plates 200 is less than the diameter of the isothermal zone 300a.

[0040] In the background art, when the diagonal length of the plate surface formed by the length and width of the zinc sulfide plate 200 is greater than the diameter of the constant temperature zone 300a, it is obviously not feasible to install the zinc sulfide plate 200 horizontally in the constant temperature zone 300a while keeping the hot isostatic pressing furnace 300 unchanged. However, when the zinc sulfide plate 200 is adjusted to be vertical and the length and width of the zinc sulfide plate 200 are both less than the axial length of the constant temperature zone 300a and the width of the zinc sulfide plate 200 is less than the diameter of the constant temperature zone 300a, the zinc sulfide plate 200 can be placed vertically in the constant temperature zone 300a. In the vertical position, the zinc sulfide plate 200 can be at least horizontal in width and vertical in length (i.e., the axial direction of the constant temperature zone 300a). (Of course, if the length of the zinc sulfide plate 200 is also less than the diameter of the constant temperature zone 300a, then the zinc sulfide plate 200 can be horizontal in length and vertical in width (D3). Thus, without changing the hot isostatic pressing furnace 300, it can process large-sized zinc sulfide plates 200 (i.e., the diagonal length of the plate surface formed by the length and width of the zinc sulfide plate 200 is greater than the diameter of the isothermal zone 300a, the length and width of the zinc sulfide plate 200 are both less than the axial length of the isothermal zone 300a, and the width of the zinc sulfide plate 200 is less than the diameter of the isothermal zone 300a). In other words, for large-sized zinc sulfide plates 200, there is no need to use a hot isostatic pressing furnace with a larger diameter isothermal zone; the zinc sulfide plate 200 can be processed using the existing hot isostatic pressing furnace 300 simply by placing it vertically. That is to say, without changing the hot isostatic pressing furnace 300 (i.e., using the existing hot isostatic pressing furnace 300), it is possible to process larger-sized zinc sulfide plates 200, thereby controlling costs associated with the hot isostatic pressing furnace.

[0041] Furthermore, as verified by the testing process, after the zinc sulfide sheet 200 is vertically placed into the constant temperature zone 300a of the hot isostatic pressing furnace 300 using the hot isostatic pressing fixture 100 according to the present disclosure, the zinc sulfide sheet 200 treated by the hot isostatic pressing method of the present disclosure has good permeability, and the transmittance and stress also meet the requirements.

[0042] Note that the length of zinc sulfide sheet 200 refers to the longer side of the larger dimension, and the width refers to the shorter side of the smaller dimension. When the length and width are equal, they can be interchanged. That is, the length and width conform to the general definition, and the length is not less than the width.

[0043] like Figure 1 and Figure 2 As shown, in one example, the hot isostatic pressing fixture 100 for zinc sulfide sheets includes: a metal lifting device 1 for lifting the fixture 100 into the constant temperature zone 300a of the hot isostatic pressing furnace 300, having an upwardly and left-right open U-shaped space 11; a graphite base plate 2 for placing in the U-shaped space 11, the graphite base plate 2 for supporting a plurality of vertically placed zinc sulfide sheets 200 arranged along the thickness direction T, the plurality of zinc sulfide sheets 200 arranged along the thickness direction T in the front-back direction D1, the length and width of each zinc sulfide sheet 200 being in one of the left-right direction D2 and the up-down direction D3; and a plurality of metal sheets 3 for alternating arrangement with the plurality of zinc sulfide sheets 200, such that there is one metal sheet on each side of the thickness direction T of each zinc sulfide sheet 200. 3. Metal sheets 3 are used to remove zinc and hydrogen elements from zinc sulfide plates 200 during hot isostatic pressing; two graphite pressure plates 4 are placed on graphite base plates 2 and located in U-shaped space 11, and the two graphite pressure plates 4 are used to abut against the combination formed by multiple metal sheets 3 and multiple zinc sulfide plates 200 from the two outer sides in the front-rear direction D1; two graphite pads 5 are placed on metal base 12 and located in U-shaped space 11, and the two graphite pads 5 are used to abut against the two graphite pressure plates 4 from the two outer sides in the front-rear direction D1 respectively; at least two graphite papers 6 are sandwiched between the corresponding graphite pressure plates 4 and graphite pads 5 along the front-rear direction D1; and a graphite clamp 7 is used to clamp the combination of graphite base plate 2, two graphite pads 5, at least two graphite papers 6, two graphite pressure plates 4, multiple metal sheets 3 and multiple zinc sulfide plates 200.

[0044] Specifically, such as Figure 1 and Figure 2As shown, in one example, the metal lifting device 1 includes: a metal base 12 for placing a graphite base plate 2 thereon; and two metal lifting plates 13 fixed on opposite sides of the metal base 12 in the front-rear direction D1 to form a U-shaped space 11 with the metal base 12. The two metal lifting plates 13 are used to lift the tooling 100 for hot isostatic pressing of zinc sulfide sheet into the constant temperature zone 300a of the hot isostatic pressing furnace 300.

[0045] For example, the metal base 12 is a stainless steel base. In one example, refer to... Figures 1 to 3 The metal base 12 has multiple limiting protrusions 121 protruding upwards along its four sides (front, back, left, and right); the graphite base plate 2 is positioned by these multiple limiting protrusions 121 on its four sides. Furthermore, the graphite base plate 2 has grooves 21 at the bottom corners on both sides in the left-right direction D2. These grooves 21 cooperate with the limiting protrusions 121 of the metal base 12 in the left-right direction D2 to limit the position of the graphite base plate 2 in the left-right direction D2. In this way, the positioning of the combination of graphite base plate 2, two graphite pads 5, at least two graphite papers 6, two graphite pressure plates 4, multiple metal sheets 3 and multiple zinc sulfide plates 200 clamped by graphite clamp 7 in metal lifting fixture 1 can be improved, and the combination of graphite base plate 2, two graphite pads 5, at least two graphite papers 6, two graphite pressure plates 4, multiple metal sheets 3 and multiple zinc sulfide plates 200 clamped by graphite clamp 7 can be prevented from sliding out of the U-shaped space 11 from the opening D2 in the left and right directions of the U-shaped space 11 due to accidental force.

[0046] For example, each of the metal lifting plates 13 is a stainless steel lifting plate. (Refer to...) Figure 1 and Figure 2 In one example, each metal lifting plate 13 includes a frame 131 and a hook 132; the bottom of the frame 131 is fixed to one side of the metal base 12 in the front-rear direction D1, and the hook 132 is disposed on the top of the frame 131. The hooks 132 of the two metal lifting plates 13 are used to lift the tooling 100 for hot isostatic pressing of zinc sulfide sheets into the constant temperature zone 300a of the hot isostatic pressing furnace 300. The hooks 132 can be formed by bending stainless steel wire and welded to the top of the frame 131.

[0047] like Figure 1 and Figure 2As shown, in one example, the metal base 12 has four protrusions 122 located on both sides of the front-rear direction D1 and near the four corners, each protrusion 122 having a through hole 122a; the bottom of the frame 131 of each metal lifting plate 13 has a through hole 131a corresponding to the through hole 122a of the protrusion 122; the metal lifting device 1 also includes four metal bolts 14 and four metal nuts 15, each metal bolt 14 being used to pass through the through hole 131a of the corresponding frame 131 and the through hole 122a of the protrusion 122 and to be screwed into the corresponding metal nut 15 to fix the metal lifting plate 13 and the metal base 12 together. For example, each metal bolt 14 is a stainless steel bolt, and each metal nut 15 is a stainless steel nut.

[0048] like Figure 1 and Figure 2 As shown, in one example, the frame 131 of each metal lifting plate 13 has a lower opening 131b extending along the front-rear direction D1. The lower opening 131b is located between two perforations 131a on one side of the frame 131 in the front-rear direction D1, and the projection of the lower opening 131b in the front-rear direction D1 covers the height of the graphite base plate 2. Furthermore, the frame 131 of each metal lifting plate 13 also has an upper opening 131c extending along the front-rear direction D1. The upper opening 131c and the lower opening 131b are spaced apart in the vertical direction D3 and are not connected.

[0049] Each metal sheet 3 is made of one of silver, platinum, rhodium, palladium, iridium, ruthenium, or osmium. For example, the thickness of each metal sheet 3 is 0.1-0.5 mm, and the length and width of each metal sheet 3 are not less than the length and width of the zinc sulfide plate 200, respectively.

[0050] For example, the length and width of each graphite pressure plate 4 are equal to the length and width of the zinc sulfide sheet 200, respectively. In one example, the parallelism and flatness of the two surfaces of each graphite pressure plate 4 are controlled within 0.05 mm. In another example, the surface roughness (e.g., through grinding and polishing) of the two surfaces of each graphite pressure plate 4 is controlled at Ra of 0.2-0.5 μm.

[0051] Reference Figure 1 In one example, the length of each graphite pad 5 is greater than the length of the zinc sulfide plate 200; the width of each graphite pad 5 is greater than the width of the zinc sulfide plate 200.

[0052] Because the coefficient of thermal expansion of zinc sulfide sheet 200 is greater than that of graphite material, and graphite paper 6 possesses a certain degree of flexibility and compressibility, it can be used to measure the difference in expansion between graphite material and zinc sulfide sheet during hot isostatic pressing. For example, the length and width of each piece of graphite paper 6 are not less than the length and width of zinc sulfide sheet 200, respectively. In one example, the thickness of each piece of graphite paper 6 is 0.5-2 mm.

[0053] Reference Figure 1 and Figure 2 In one example, the graphite base plate 2 has multiple pairs of receiving recesses 22 on both sides of the front-rear direction D1, and the graphite base plate 2 has multiple openings 23 that pass through along the front-rear direction D1. The openings of each opening 23 on both sides of the front-rear direction D1 are in the corresponding pair of receiving recesses 22, and the bottom 221 of the multiple pairs of receiving recesses 22 are coplanar on each side of the front-rear direction D1. The graphite clamp 7 includes: multiple pairs of clamping graphite strips 71, each pair of clamping graphite strips 71 being positioned on the outer side of the two graphite pads 5 in the front-rear direction D1, the lower end of each clamping graphite strip 71 in the vertical direction D3 being at least partially received into the corresponding receiving recess 22 of the graphite base plate 2, each clamping graphite strip 71 having a lower through hole 711 near the lower end and an upper through hole 712 near the upper end; multiple lower clamping graphite screws 72 and multiple pairs of lower graphite nuts 73, each lower clamping graphite screw 72 passing through the lower through hole 712 of the corresponding pair of clamping graphite strips 71 in the front-rear direction D1. The openings 23 of the graphite base plate 2 and the graphite nut 73 of each pair are used to screw the corresponding lower clamping graphite screw 72 from the outer side of the corresponding pair of clamping graphite strips 71 in the front-back direction D1; the upper support graphite plate 74 is used to position the upper end of the multiple pairs of clamping graphite strips 71 and is suspended above the two graphite pads 5. The size of the upper support graphite plate 74 in the front-back direction D1 is not greater than the interval of the groove bottom 221 of the paired receiving recesses 22 of the graphite base plate 2 in the front-back direction D1. The upper support graphite plate 74 has multiple channels 741 that run through in the front-back direction D1; The system includes multiple upper clamping graphite screws 75 and multiple pairs of upper graphite nuts 76. Each upper clamping graphite screw 75 passes through the upper through hole 712 of the corresponding pair of clamping graphite strips 71 and the corresponding channel 741 of the upper supporting graphite plate 74 in the front-back direction D1. Each pair of upper graphite nuts 76 is used to screw onto both ends of the corresponding upper clamping graphite screw 75 from the outside of the corresponding pair of clamping graphite strips 71 in the front-back direction D1. The system also includes multiple lower clamping graphite screws 72 and multiple pairs of lower graphite nuts 73, an upper supporting graphite plate 74, multiple upper clamping graphite screws 75 and multiple pairs of upper graphite nuts 76, and graphite... The base plate 2 is configured such that when multiple upper clamping graphite screws 75 and multiple pairs of upper graphite nuts 76 are screwed and tightened, multiple pairs of clamping graphite strips 71 move from both sides of the front-rear direction D1 along their respective receiving recesses 22 of the graphite base plate 2 and clamp the combination of two graphite pads 5, the at least two graphite papers 6, two graphite pressure plates 4, multiple metal sheets 3 and multiple zinc sulfide plates 200 on the graphite base plate 2, and the multiple pairs of clamping graphite strips 71 abut against the upper supporting graphite plate 74 from both sides of the front-rear direction D1.

[0054] In one example, refer to Figures 1 to 3Each clamping graphite strip 71 also has a positioning hole 713 located between the lower through hole 711 and the upper through hole 712 in the vertical direction D3; the graphite clamp 7 also includes a plurality of graphite positioning posts 77, which are fixed (e.g., screwed) to one of the graphite pads 5 and are used to be inserted into the positioning hole 713 of the corresponding clamping graphite strip 71.

[0055] In one example, the dimension of the upper supporting graphite plate 74 in the front-rear direction D1 is equal to the spacing of the groove bottoms 221 of the paired receiving recesses 22 of the graphite base plate 2 in the front-rear direction D1. Figure 2 As shown, for example, the channel 741 supporting the upper graphite plate 74 also opens downwards.

[0056] In one example, such as Figure 1 As shown, the metal lifting device 1 includes two metal lifting plates 13. Each metal lifting plate 13 includes a frame 131. The frame 131 of each metal lifting plate 13 has a lower opening 131b that runs through in the front-back direction D1. The two ends of each lower tightening graphite screw 72 and each pair of lower graphite nuts 73 are respectively located in the lower openings 131b of the two metal lifting plates 13.

[0057] For example, the lower graphite nut 73 is screwed into the lower tightening graphite screw 72, and the upper graphite nut 76 is screwed into the upper tightening graphite screw 75, using a torque wrench. The torque wrench ensures that the tightening torque of each lower graphite nut 73 and each upper graphite nut 76 is the same, thus ensuring that the graphite pressure plate 4 is subjected to uniform force.

[0058] [Hot Isostatic Pressing Treatment Method for Zinc Sulfide Sheets]

[0059] The hot isostatic pressing (HIP) method for zinc sulfide sheets according to this disclosure uses the aforementioned tooling 100 for hot isostatic pressing of zinc sulfide sheets. The hot isostatic pressing method for zinc sulfide sheets includes the following steps:

[0060] S1, using a hot isostatic pressing fixture 100, multiple zinc sulfide plates 200 of the same length and width are placed vertically and arranged and clamped in the thickness direction T of the zinc sulfide plates 200. The zinc sulfide plates 200 are multi-spectral zinc sulfide polycrystalline prepared by chemical vapor deposition.

[0061] S2, the hot isostatic pressing fixture 100 for zinc sulfide plates, together with multiple clamped zinc sulfide plates 200, is hoisted and vertically placed in the vertical constant temperature zone 300a of the hot isostatic pressing furnace 300, where the axial length is greater than the diameter and the axial direction is D3. The diagonal length of the plate surface formed by the length and width of the zinc sulfide plate 200 is greater than the diameter of the constant temperature zone 300a, the length and width of the zinc sulfide plate 200 are both less than the axial length of the constant temperature zone 300a, and the width of the zinc sulfide plate 200 is less than the diameter of the constant temperature zone 300a.

[0062] S3, hot isostatic pressing furnace 300 is assembled, constant temperature zone 300a is evacuated and filled with inert gas. The constant temperature zone 300a is cleaned by evacuating and filling with inert gas multiple times to replace the air in the constant temperature zone 300a.

[0063] S4. Inert gas is introduced into the constant temperature zone 300a to the initial pressure, and the programmed heating is started to reach the target temperature and held. Inert gas is introduced again and held at the target pressure. After holding for a certain period of time, the programmed two-stage annealing and cooling begins. The first stage is cooling to the preset temperature, which is in the range of 400-700℃. After reaching the preset temperature, it is held. After the holding is completed, the second stage of cooling is carried out to cool to room temperature. During the second stage of cooling, when the temperature drops below 300℃, the inert gas in the constant temperature zone 300a is released to room pressure. After the temperature drops to room temperature, the constant temperature zone 300a is opened, and the hot isostatic pressing of the zinc sulfide plate, together with the multiple treated zinc sulfide plates 200, is lifted out using tool 100.

[0064] S5, Remove zinc sulfide sheet 200 from tooling 100 for hot isostatic pressing of zinc sulfide sheet and polish and inspect it.

[0065] The composition, operation, and effects of the aforementioned tooling 100 for hot isostatic pressing of zinc sulfide sheets used in the hot isostatic pressing method of zinc sulfide sheets according to this disclosure are described above and will not be repeated here.

[0066] In steps S3 and S4, for example, the inert gas is argon.

[0067] In step S4, in one example, the initial pressure is 60-80 MPa; the temperature rise rate of the programmed heating is less than 2℃ / min, the target temperature is 800-1100℃, the target pressure is 100-200 MPa, and the holding time is 50-150 h; the cooling rate of the first stage of cooling is less than 2℃ / min, the holding time is 20-60 h, and the cooling rate of the second stage of cooling is less than 2℃ / min.

[0068] In one embodiment, after step S5, the polished zinc sulfide plate 200 is completely transparent, without any patch defects, and the transmittance in the 1064nm, 3-5μm and 8-10μm bands is not less than 70%, with an average stress of 13-16nm / cm.

[0069] [test]

[0070] Assembly of tooling 100 for hot isostatic pressing of zinc sulfide sheets

[0071] Fixture 100 for hot isostatic pressing of zinc sulfide sheets Figure 1 and Figure 2 Assemble all the components shown. The assembly process of tooling 100 for hot isostatic pressing of zinc sulfide sheets is as follows:

[0072] The graphite base plate 2 is placed on the metal base 12. The graphite base plate 2 is restricted in position by four limiting protrusions 121 on the front, back, left and right sides. The metal base 12 is a stainless steel base. The grooves 21 at the bottom corners on both sides of the graphite base plate 2 in the left and right direction D2 cooperate with the limiting protrusions 121 of the metal base 12 in the left and right direction D2 to restrict the position of the graphite base plate 2 in the left and right direction D2.

[0073] Each metal bolt 14 passes through the through hole 131a of the frame 131 of the corresponding metal lifting plate 13 and the through hole 122a of the protrusion 122 and is screwed into the corresponding metal nut 15 to fix the metal lifting plate 13 and the metal base 12. Each metal bolt 14 is a stainless steel bolt, each metal nut 15 is a stainless steel nut, and the hook 132 is formed by bending stainless steel wire and welded to the top of the frame 131.

[0074] Nine graphite positioning posts 77 are fixed to one of the graphite pads 5 by screws, and the graphite pad 5 is placed on the graphite base plate 2. The lower ends of the three clamping graphite strips 71 in the vertical direction D3 are respectively received into the three receiving recesses 22 on the coplanar side of the graphite base plate 2 in the front-back direction D1 corresponding to the nine graphite positioning posts 77. Each graphite positioning post 77 is inserted into the positioning hole 713 of the corresponding clamping graphite strip 71. Starting from the graphite pad 5, two sheets of graphite paper 6 and one graphite pressure plate 4 are sequentially placed. The following are placed on the graphite base plate 2: a metal sheet 3, a zinc sulfide plate 200, a metal sheet 3, a zinc sulfide plate 200… The metal sheet 3 (i.e., the metal sheet and the zinc sulfide plate 200 are arranged alternately so that there is one metal sheet 3 on each side of the thickness direction T of each zinc sulfide plate 200), another graphite pressure plate 4, two more graphite papers 6, and another graphite pad 5. Then, the lower ends of the three clamping graphite strips 71 in the vertical direction D3 are respectively received into the other side of the graphite base plate 2 in the front-back direction D1. In the three coplanar receiving recesses 22 on the sides, each zinc sulfide plate 200 is a multi-spectral polycrystalline zinc sulfide prepared by chemical vapor deposition. All zinc sulfide plates 200 have the same dimensions (i.e., length, width, and thickness). The width direction of the zinc sulfide plate 200 is in the left-right direction D2, and the length direction of the zinc sulfide plate 200 is in the up-down direction D3. Each metal sheet 3 is made of palladium, and the thickness of each metal sheet 3 is 0.2 mm. The length and width of each metal sheet 3 are respectively equal to the length of the zinc sulfide plate 200. The length and width of each graphite pressure plate 4 are equal to the length and width of the zinc sulfide plate 200, respectively. The surface roughness of the two surfaces of each graphite pressure plate 4 is controlled at Ra of 0.3μm. The parallelism and flatness of the two surfaces of each graphite pressure plate 4 are controlled at 0.04mm. The length and width of each graphite pad 5 are greater than the length and width of the zinc sulfide plate 200, respectively. The length and width of each graphite paper 6 are equal to the length and width of the zinc sulfide plate 200, respectively. The thickness of each graphite paper 6 is 1mm.

[0075] Each lower tightening graphite screw 72 passes through the lower through hole 711 of the corresponding pair of clamping graphite strips 71 and the opening 23 of the graphite base plate 2 along the front-back direction D1. Each pair of lower graphite nuts 73 is screwed to both ends of the corresponding lower tightening graphite screw 72 from the outside of the corresponding pair of clamping graphite strips 71 in the front-back direction D1. The two ends of each lower tightening graphite screw 72 and each pair of lower graphite nuts 73 are respectively located in the lower opening 131b of the two metal lifting plates 13.

[0076] Each upper clamping graphite screw 75 passes through the upper through hole 712 of the corresponding pair of clamping graphite strips 71 and the corresponding channel 741 of the upper supporting graphite plate 74 in the front-back direction D1. Each pair of upper graphite nuts 76 are screwed to both ends of the corresponding upper clamping graphite screw 75 from the outside of the corresponding pair of clamping graphite strips 71 in the front-back direction D1. The size of the upper supporting graphite plate 74 in the front-back direction D1 is equal to the interval of the groove bottom 221 of the paired receiving recesses 22 of the graphite base plate 2 in the front-back direction D1. The channel 741 of the upper supporting graphite plate 74 is open downward.

[0077] The lower graphite nut 73 and the lower tightening graphite screw 72 are screwed together, and the upper graphite nut 76 and the upper tightening graphite screw 75 are screwed together using a torque wrench. When the three upper tightening graphite screws 75 and the three pairs of upper graphite nuts 76 are screwed together (the torque wrench finally displays a torque of 2.0 Nm), the three pairs of clamping graphite strips 71 move from both sides of the front-rear direction D1 along their respective receiving recesses 22 of the graphite base plate 2 and clamp the combination of the two graphite pads 5, four graphite papers 6, two graphite pressure plates 4, multiple metal sheets 3 and multiple zinc sulfide plates 200 on the graphite base plate 2. The multiple pairs of clamping graphite strips 71 abut against the upper supporting graphite plate 74 from both sides of the front-rear direction D1.

[0078] Example 1

[0079] Example 1 uses tooling 100 for hot isostatic pressing of the previously assembled zinc sulfide sheet.

[0080] The hot isostatic pressing method for zinc sulfide sheets in Example 1 uses the following steps:

[0081] S1. Using the assembly process of the hot isostatic pressing fixture 100 for zinc sulfide plates, multiple zinc sulfide plates 200 are placed vertically and arranged and clamped along the thickness direction T of the zinc sulfide plates 200 using the hot isostatic pressing fixture 100 for zinc sulfide plates. The specifications of each zinc sulfide plate 200 are 600mm (width) * 700mm (length) * 20mm (thickness). The diagonal length of the plate surface formed by the length and width of each zinc sulfide plate 200 is 921.95mm. The number of zinc sulfide plates 200 is 11 pieces.

[0082] S2, the hot isostatic pressing fixture 100 for zinc sulfide plates, together with multiple clamped zinc sulfide plates 200, is hoisted and placed into the constant temperature zone 300a of the hot isostatic pressing furnace 300. The specifications of the constant temperature zone 300a of the hot isostatic pressing furnace 300 are φ750mm (diameter) * 1500mm (axial length).

[0083] S3, hot isostatic pressing furnace 300 is assembled, constant temperature zone 300a is evacuated and filled with inert gas. Constant temperature zone 300a is cleaned by evacuating and filling with inert gas 5 times to replace the air in constant temperature zone 300a. The inert gas is argon.

[0084] S4. Inert gas is introduced into the constant temperature zone 300a to the initial pressure. The programmed heating process begins, reaching and holding the target temperature. Once the target pressure is reached, the pressure is maintained. After a certain holding time, a two-stage annealing cooling process begins. The first stage cools to a preset temperature (500℃), which is then held. After this holding period, the second stage cools to room temperature. During this second stage, when the temperature drops below 300℃, the inert gas in the constant temperature zone 300a is released back to atmospheric pressure. After cooling to room temperature, the constant temperature zone 300a is opened, and the hot isostatic pressing tool 100, along with multiple treated zinc sulfide plates 200, is lifted out. The inert gas is argon, the initial pressure is 70MPa, the temperature rise rate is 0.8℃ / min, the target temperature is 950℃, the target pressure is 150MPa, the holding time is 60h, the first cooling rate is 1℃ / min, the holding time is 50h, and the second cooling rate is 0.5℃ / min.

[0085] S5, Remove zinc sulfide sheet 200 from tooling 100 for hot isostatic pressing of zinc sulfide sheet and polish and inspect it.

[0086] Example 2

[0087] Except for the following in the hot isostatic pressing method for zinc sulfide plates: in step S1, the thickness of each zinc sulfide plate 200 is 25 mm; in step S4, the initial pressure is 60 MPa; the temperature rise rate of the programmed heating is 1.0℃ / min; the target temperature is 960℃; the target pressure is 140 MPa; the holding time is 70 h; the preset temperature is 600℃; the cooling rate of the first cooling stage is 1℃ / min; the holding time is 40 h; and the cooling rate of the second cooling stage is 0.5℃ / min, the rest is the same as in Example 1.

[0088] Example 3

[0089] Except for the following in the hot isostatic pressing method for zinc sulfide plates: in step S1, the thickness of each zinc sulfide plate 200 is 30 mm; in step S4, the initial pressure is 80 MPa; the temperature rise rate of the programmed heating is 1.0℃ / min; the target temperature is 960℃; the target pressure is 170 MPa; the holding time is 100 h; the preset temperature is 700℃; the first cooling rate is 1℃ / min; the holding time is 30 h; and the second cooling rate is 0.5℃ / min, the rest is the same as in Example 1.

[0090] The zinc sulfide plates 200 from Examples 1-3 were all completely transparent after polishing, without any patch defects. The transmittance and average stress in the 1064nm, 3-5μm, and 8-10μm wavelengths of one zinc sulfide plate 200 polished after each of Examples 1-3 were used as representative values. The average stress was measured using a stress birefringence meter.

[0091] Table 1. Transmittance and average stress of zinc sulfide sheets in Examples 1-3

[0092]

[0093] As shown in Table 1, the minimum transmittance in the 1064nm, 3-5μm, and 8-10μm bands is not less than 70%.

[0094] Several exemplary embodiments have been described in detail above, but this document is not intended to limit itself to the explicitly disclosed combinations. Therefore, unless otherwise stated, the various features disclosed herein can be combined to form several other combinations, which are not shown for simplicity.

Claims

1. A method of hot isostatic pressing of a zinc sulfide plate material, characterized by, The method comprises the steps of: S1, vertically placing and clamping a plurality of zinc sulfide plates (200) of the same length and width using a zinc sulfide plate hot isostatic pressing tool (100) in the thickness direction (T) of the zinc sulfide plate (200), wherein the zinc sulfide plate (200) is a polycrystalline zinc sulfide prepared by chemical vapor deposition; S2, vertically placing the zinc sulfide plate hot isostatic pressing tool (100) together with the clamped plurality of zinc sulfide plates (200) into the axial direction of the cylindrical constant temperature zone (300a) of the hot isostatic pressing furnace (300) in the upper and lower direction (D3), wherein the diagonal length of the plate surface formed by the length and width of the zinc sulfide plate (200) is greater than the diameter of the constant temperature zone (300a), the length and width of the zinc sulfide plate (200) are both less than the axial length of the constant temperature zone (300a), and the width of the zinc sulfide plate (200) is less than the diameter of the constant temperature zone (300a); S3, the hot isostatic pressing furnace (300) is closed, the constant temperature zone (300a) is vacuumed and filled with inert gas, the constant temperature zone (300a) is cleaned multiple times by vacuuming and filling with inert gas, and the air in the constant temperature zone (300a) is replaced clean; S4, filling inert gas into the constant temperature zone (300a) to an initial pressure, starting to program the temperature to the target temperature, continuing to fill the inert gas to the target pressure, and then holding the pressure, holding the temperature for a certain period of time, and then starting the two-stage annealing cooling, the first stage cooling to a preset temperature, the preset temperature is in the range of 400-700℃, holding the temperature after reaching the preset temperature, after the holding temperature is over, continuing to carry out the second stage cooling, and cooling to room temperature, releasing the inert gas in the constant temperature zone (300a) to normal pressure when the temperature is below 300℃ in the second stage cooling, opening the constant temperature zone (300a) after the temperature is cooled to room temperature, and hoisting out the zinc sulfide plate hot isostatic pressing tool (100) together with the plurality of treated zinc sulfide plates (200); S5, removing the zinc sulfide plate (200) from the zinc sulfide plate hot isostatic pressing tool (100) and polishing and detecting.

2. The zinc sulfide plate hot isostatic pressing treatment method according to claim 1, wherein in steps S3 and S4, the inert gas is argon.

3. The zinc sulfide plate hot isostatic pressing treatment method according to claim 1, wherein in step S4, the initial pressure is 60-80MPa; the temperature rising rate of the programmed temperature rising is less than 2℃ / min, the target temperature is 800-1100℃, the target pressure is 100-200MPa, and the holding pressure time is 50-150h; the temperature falling rate of the first stage cooling is less than 2℃ / min, and the holding temperature is 20-60h, the temperature falling rate of the second stage cooling is less than 2℃ / min.

4. The zinc sulfide plate hot isostatic pressing treatment method according to claim 1, wherein the zinc sulfide plate hot isostatic pressing tool (100) comprises: ​ ​ ​ A metal hanger (1) for hoisting a zinc sulfide plate hot isostatic pressing tooling (100) into a constant temperature zone (300a) of a hot isostatic pressing furnace (300), having a U-shaped space (11) open upward and left and right; A graphite base plate (2) for being placed in the U-shaped space (11), the graphite base plate (2) being used to support a plurality of zinc sulfide plate materials (200) arranged vertically and in a thickness direction (T), the direction in which the plurality of zinc sulfide plate materials (200) are arranged in the thickness direction (T) of the zinc sulfide plate materials (200) being a front-rear direction (D1), and the length and width of each zinc sulfide plate material (200) being in one of a left-right direction (D2) and an up-down direction (D3); A plurality of metal foils (3) for being arranged alternately with the plurality of zinc sulfide plate materials (200) so that there is one metal foil (3) on each side of the thickness direction (T) of each zinc sulfide plate material (200), the metal foils (3) being used to discharge zinc and hydrogen elements in the zinc sulfide plate materials (200) during hot isostatic pressing; Two graphite pressing plates (4) for being placed on the graphite base plate (2) and in the U-shaped space (11), the two graphite pressing plates (4) being used to abut against a combination of the plurality of metal foils (3) and the plurality of zinc sulfide plate materials (200) from the two outer sides in the front-rear direction (D1); Two graphite backing plates (5) for being placed on the metal base (12) and in the U-shaped space (11), the two graphite backing plates (5) being used to abut against the two graphite pressing plates (4) from the two outer sides in the front-rear direction (D1), respectively; At least two sheets of graphite paper (6), at least one sheet of graphite paper (6) being sandwiched between a corresponding graphite pressing plate (4) and graphite backing plate (5) in the front-rear direction (D1); and A graphite clamp (7) for clamping the combination of the graphite base plate (2), the two graphite backing plates (5), the at least two sheets of graphite paper (6), the two graphite pressing plates (4), the plurality of metal foils (3), and the plurality of zinc sulfide plate materials (200).

5. The zinc sulfide plate hot isostatic pressing processing method according to claim 4, wherein the metal hanger (1) comprises: a metal base (12) for placing the graphite base plate (2) thereon; two metal hoisting plates (13) fixed on opposite sides in the front-rear direction (D1) of the metal base (12) to form the U-shaped space (11) with the metal base (12), the two metal hoisting plates (13) being used for hoisting the zinc sulfide plate hot isostatic pressing tooling (100) into the constant temperature zone (300a) of the hot isostatic pressing furnace (300).

6. The zinc sulfide plate hot isostatic pressing processing method according to claim 5, wherein the metal base (12) has a plurality of limiting protrusions (121) protruding upward at four edges in the front-rear-left-right directions; and the graphite base plate (2) is positionally limited by the plurality of limiting protrusions (121) at four sides in the front-rear-left-right directions.

7. The zinc sulfide plate hot isostatic pressing processing method according to claim 4, wherein each metal foil (3) is made of one of silver, platinum, rhodium, palladium, iridium, ruthenium, and osmium; and / or ​ ​ ​ ​ The thickness of each metal sheet (3) is 0.1-0.5mm, and the length and width of each metal sheet (3) are not less than the length and width of the zinc sulfide plate (200) respectively; and / or The length and width of each graphite pressing plate (4) are equal to the length and width of the zinc sulfide plate (200) respectively; and / or The parallelism and flatness of the two plate surfaces of each graphite pressing plate (4) are controlled within 0.05mm; and / or The surface roughness of the two plate surfaces of each graphite pressing plate (4) is controlled to be Ra 0.2-0.5μm; and / or The length of each graphite pad plate (5) is greater than the length of the zinc sulfide plate (200), and the width of each graphite pad plate (5) is greater than the width of the zinc sulfide plate (200); and / or The thickness of each graphite paper (6) is 0.5-2mm. The length and width of each graphite paper (6) are not less than the length and width of the zinc sulfide plate (200) respectively.

8. The zinc sulfide plate hot isostatic pressing treatment method according to claim 4, characterized in that, The graphite base plate (2) has a plurality of pairs of receiving recesses (22) on both sides of the front-rear direction (D1), and has a plurality of through holes (23) along the front-rear direction (D1), the openings of each through hole (23) on both sides of the front-rear direction (D1) correspond to a pair of receiving recesses (22), and the groove bottoms (221) of the plurality of pairs of receiving recesses (22) are coplanar on each side of the front-rear direction (D1); The graphite jig (7) comprises: A plurality of pairs of clamping graphite bars (71), each pair of clamping graphite bars (71) is located on the outside of the front-rear direction (D1) of the two graphite pad plates (5), the lower end of each clamping graphite bar (71) in the up-down direction (D3) is at least partially received into the corresponding receiving recess (22) of the graphite base plate (2), and each clamping graphite bar (71) has a lower via (711) near the lower end and an upper via (712) near the upper end; A plurality of lower tightening graphite screws (72) and a plurality of pairs of lower graphite nuts (73), each lower tightening graphite screw (72) passes through the lower via (711) of the corresponding pair of clamping graphite bars (71) and the through hole (23) of the graphite base plate (2) along the front-rear direction (D1), and each pair of lower graphite nuts (73) is used to be screwed with both ends of the corresponding lower tightening graphite screw (72) from the outside of the front-rear direction (D1) of the corresponding pair of clamping graphite bars (71); An upper supporting graphite plate (74) is used to be positioned to the upper end of the plurality of pairs of clamping graphite bars (71) and suspended above the two graphite pad plates (5), the size of the upper supporting graphite plate (74) in the front-rear direction (D1) is not greater than the interval of the groove bottoms (221) of the pairs of receiving recesses (22) of the graphite base plate (2) in the front-rear direction (D1), and the upper supporting graphite plate (74) has a plurality of passages (741) along the front-rear direction (D1); and An upper supporting graphite plate (74) is used to be positioned to the upper end of the plurality of pairs of clamping graphite bars (71) and suspended above the two graphite pad plates (5), the size of the upper supporting graphite plate (74) in the front-rear direction (D1) is not greater than the interval of the groove bottoms (221) of the pairs of receiving recesses (22) of the graphite base plate (2) in the front-rear direction (D1), and the upper supporting graphite plate (74) has a plurality of passages (741) along the front-rear direction (D1); and a plurality of upper tightening graphite screws (75) and a plurality of pairs of upper graphite nuts (76), each upper tightening graphite screw (75) passing through a corresponding pair of clamping graphite bars (71) in the front-rear direction (D1) and a corresponding passage (741) of the upper support graphite plate (74), and each pair of upper graphite nuts (76) being used for screwing with both ends of the corresponding upper tightening graphite screw (75) from the outside of the front-rear direction (D1) of the corresponding pair of clamping graphite bars (71); wherein the plurality of lower tightening graphite screws (72) and the plurality of pairs of lower graphite nuts (73), the upper support graphite plate (74), the plurality of upper tightening graphite screws (75) and the plurality of pairs of upper graphite nuts (76), and the graphite base plate (2) are configured such that when the plurality of upper tightening graphite screws (75) and the plurality of pairs of upper graphite nuts (76) are screwed and tightened, the plurality of pairs of clamping graphite bars (71) move along the respective receiving recesses (22) of the graphite base plate (2) from both sides of the front-rear direction (D1) and clamp the combination of the two graphite backing plates (5), the at least two sheets of graphite paper (6), the two graphite pressing plates (4), the plurality of metal foils (3), and the plurality of zinc sulfide plates (200) on the graphite base plate (2), and the plurality of pairs of clamping graphite bars (71) abut against the upper support graphite plate (74) from both sides of the front-rear direction (D1).

9. The zinc sulfide plate hot isostatic pressing method according to claim 8, characterized in that each clamping graphite bar (71) further has a positioning hole (713) between the lower through hole (711) and the upper through hole (712) in the up-down direction (D3); the graphite clamp (7) further comprises a plurality of graphite positioning columns (77) fixed to one of the graphite backing plates (5) and used for being inserted into the positioning hole (713) of the corresponding clamping graphite bar (71); the upper support graphite plate (74) has a dimension in the front-rear direction (D1) equal to the interval of the groove bottoms (221) of the pairs of receiving recesses (22) of the graphite base plate (2) in the front-rear direction (D1).

10. The zinc sulfide plate hot isostatic pressing method according to claim 8, characterized in that the metal lifting device (1) comprises two metal lifting plates (13), each metal lifting plate (13) comprising a frame body (131), the frame body (131) of each metal lifting plate (13) having a lower opening (131b) passing through in the front-rear direction (D1), both ends of each lower tightening graphite screw (72) and each pair of lower graphite nuts (73) are located in the lower opening (131b) of the two metal lifting plates (13), respectively; the screwing and tightening of the lower graphite nuts (73) and the lower tightening graphite screws (72) and the screwing and tightening of the upper graphite nuts (76) and the upper tightening graphite screws (75) are performed by using a torque wrench.

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