Thick zinc selenide plate and processing method thereof

Abstract

The invention belongs to the technical field of thick-size plate processing, and discloses a thick-size zinc selenide plate and a processing method thereof.The processing method of the thick-size zinc selenide plate comprises the steps that 1, the upper surface and the lower surface of the thick-size zinc selenide plate are subjected to flat grinding treatment; 2, the thick zinc selenide plate obtained after flat grinding treatment is heated to 50 DEG C and then subjected to heat preservation for 20-30 min, and then the thick zinc selenide plate is heated to 60 DEG C at the heating speed of 1-2 DEG C / min and then subjected to heat preservation for 20-30 min; 3, after heat preservation in the step 2 is finished, the temperature is increased to 75 DEG C at the temperature increasing speed of 1-2 DEG C / min, then heat preservation is conducted for 10 min, and heat preservation is conducted for 10 min every time the temperature is increased by 5 DEG C And 4, the temperature is raised to 90 DEG C at the temperature raising speed of 1-1.5 DEG C / min, then polishing joint bonding is conducted, and standing is conducted for 12-14 h after natural cooling is conducted to the room temperature. The invention discloses a processing method of a thick zinc selenide plate, which can effectively reduce the probability of internal cracking of the thick zinc selenide plate by controlling the heating rate, the heating amplitude, the heat preservation time and the standing treatment time in the heating process of a bonding and polishing joint.

Description

Technical Field

[0001] The invention relates to the technical field of thick-sized plate processing, and in particular to a thick-sized zinc selenide plate and a processing method thereof. Background Art

[0002] Thick-size zinc selenide is a high-tech product for both military and civilian use. It has low absorption and high transmittance at 10.6 microns and can be processed into optical windows such as prisms, lenses, and fairings. It is widely used in infrared guidance, infrared detection, infrared imaging, high-power carbon dioxide lasers, infrared night vision systems, etc. It is a core key material in my country and plays an important basic supporting role in the development of my country's weapons and equipment, major scientific instruments and other social fields.

[0003] At present, zinc selenide is grown by chemical vapor deposition (CVD) technology. The process of chemical vapor deposition is complicated and the cycle is long. During this process, changes in process parameters and stability will affect the material properties. Various forms of defects may appear inside the material, such as fog layer, bright spots, etc. In order to determine the internal material, it is necessary to polish it before use. The existing technology is a processing method designed for conventional CVD zinc selenide deposition plate processing, and the main steps are: (1) flat grinding the upper and lower surfaces of the thick zinc selenide plate; (2) directly heating the thick zinc selenide plate after flat grinding to 90°C for bonding the polishing joint of the polishing machine; (3) polishing after cooling the heat sink to room temperature.

[0004] The thickness of conventional CVD zinc selenide deposited plates is 20-35mm. When conventional zinc selenide plates are processed by the existing technology, the stress during the processing is small due to the small thickness, and no problems will occur; however, when used for thick-sized zinc selenide plates (above 35mm), the overall stress is large, and stress superposition is generated in the transportation, machining, polishing, heating, cooling and other links during the processing, which makes it easy for internal cracks to occur during the product processing, resulting in product scrapping.

[0005] Therefore, it is necessary to find a processing method for thick-sized zinc selenide plates to avoid internal cracks during the processing process, which would lead to product scrapping. Summary of the invention

[0006] One of the purposes of the present invention is to provide a processing method for a thick zinc selenide plate, which can fully release and reduce the generation of stress during the processing and can significantly reduce the probability of internal cracks during the processing of the thick zinc selenide plate.

[0007] Another object of the present invention is to provide a thick zinc selenide plate, which has no internal cracks and has extremely high application value.

[0008] To achieve the above object, the present invention provides a processing method for a thick zinc selenide plate, wherein the thickness of the thick zinc selenide plate is 35-70 mm, and the processing method comprises the following steps:

[0009] Step 1: Grind the upper and lower surfaces of the thick zinc selenide sheet;

[0010] Step 2: Heat the thick zinc selenide plate after flat grinding to 50°C and keep it warm for 20-30 minutes, then heat it to 60°C at a heating rate of 1-2°C / min and keep it warm for 20-30 minutes;

[0011] Step 3: After the end of step 2, heat the temperature to 75°C at a rate of 1-2°C / min and keep it for 10 minutes. During the process, keep it for 10 minutes for every 5°C increase in temperature.

[0012] Step 4: Heat to 90°C at a rate of 1-1.5°C / min, then polish and bond the joints. Cool to room temperature naturally and let stand for 12-14 hours.

[0013] Step 5: Polishing the thick zinc selenide plate obtained in step 4.

[0014] Since the stress generated in step 1 is relatively high, it is very important to control the thermal stress during the heating process of the bonded and polished joint. In the present invention, in step 2, the first heat preservation is performed after the temperature is raised to 50° C. to ensure that the thick-sized zinc selenide plate is heated uniformly, so that the stress difference at various locations inside the thick-sized zinc selenide plate is reduced, and the probability of internal cracks is reduced. Then, the temperature is further raised to 60° C. for heat preservation to reduce the stress difference. In steps 3 and 4, the stress difference at various locations inside the thick-sized zinc selenide plate is reduced by controlling the subsequent heating rate, heating amplitude, heat preservation time and static operation, while effectively eliminating the stress generated in step 1, and greatly reducing the probability of internal cracks in the thick-sized zinc selenide plate.

[0015] Preferably, the step 3 and the step 4 further include a step a: placing the thick zinc selenide plate after the heat preservation in step 3 at rest, and cooling naturally to reduce the temperature of the thick zinc selenide plate to 68-71°C.

[0016] Through the cooling in step a, the thermal stress generated during the heating process of the entire bonded and polished joint can be effectively eliminated, further reducing the probability of internal cracks in thick-sized zinc selenide plates.

[0017] Furthermore, the specific operation of step 1 is: the upper and lower surfaces of the thick zinc selenide plate are subjected to coarse grinding, fine grinding and polishing treatment in sequence, and then left to stand for 12 hours, the thickness of the rough grinding of the upper surface is 3-5 mm or the polished area is ≥85%, the thickness of the fine grinding is 0.3 mm, the thickness of the rough grinding of the lower surface is 0.5-1 mm or the polished area is ≥95%, the thickness of the fine grinding is 0.3 mm, and the polishing time is 60 s.

[0018] After the upper and lower surfaces of the thick zinc selenide plate are flat-ground in step 1, standing for a period of time can effectively reduce the stress retention caused by the flat-ground treatment. Combined with the operations of steps 2-4, the probability of internal cracks in the thick zinc selenide plate can be effectively reduced.

[0019] Preferably, the rotation speed of coarse grinding is 10-20RPM and the feed speed is 0.2-0.8mm / min; the rotation speed of fine grinding is 10-20RPM and the feed speed is 0.2-0.8mm / min; the rotation speed of light grinding is 10-20RPM.

[0020] As a preferred technical solution, the stress generated during the flat grinding process can be effectively reduced by controlling the rotation speed and feed speed of the rough grinding, fine grinding and light grinding processes during the flat grinding process.

[0021] Furthermore, the specific operation of step 5 is: the thick-sized zinc selenide plate bonded with the polishing joint in step 4 is subjected to fine grinding, rough polishing, and fine polishing in a polishing machine in sequence to obtain a processed thick-sized zinc selenide plate; wherein the spindle speed of the fine grinding is 30RPM and the swing shaft speed is 20RPM; the spindle speed of the rough polishing is 50RPM and the swing shaft speed is 30RPM; the spindle speed of the fine polishing is 30RPM and the swing shaft speed is 20RPM.

[0022] Similarly, by controlling the spindle speed and swing shaft speed of fine grinding, rough polishing and fine polishing, the stress generated during the polishing process can be effectively reduced, and the probability of internal cracks in thick-sized zinc selenide plates can be effectively reduced.

[0023] The invention also discloses a thick-sized zinc selenide plate, which is obtained by processing using the above-mentioned thick-sized zinc selenide plate processing method.

[0024] Preferably, the size of the thick zinc selenide plate is 600mm*600mm*55mm or 400mm*400mm*45mm.

[0025] Beneficial Effects

[0026] Compared with the prior art, the present invention discloses a processing method for a thick-sized zinc selenide plate. By controlling the heating rate, heating amplitude, insulation time and static treatment time in the heating process of the bonded and polished joint, it can effectively ensure that the thick-sized zinc selenide plate is heated uniformly, reduce the internal thermal stress difference of the thick-sized zinc selenide plate, and eliminate part of the thermal stress to a certain extent, thereby reducing the probability of internal cracks in the thick-sized zinc selenide plate and improving the product yield. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with the embodiments, but it does not constitute any limitation to the present invention. Any limited number of modifications made within the scope of the claims of the present invention are still within the scope of the claims of the present invention.

[0028] In order to explain the technical content of the present invention in detail, further description is given below in conjunction with the implementation modes.

[0029] In the following examples and comparative examples, the thickness of the zinc selenide plate is 600mm*600mm*55mm.

[0030] Example 1

[0031] A method for processing a thick zinc selenide plate comprises the following steps:

[0032] Step 1: The upper and lower surfaces of the thick zinc selenide plate are subjected to coarse grinding, fine grinding and polishing treatment in sequence, wherein the speed of coarse grinding is 20RPM, the feed speed is 0.8mm / min, the upper surface grinding area is 90%, and the lower surface grinding area is 95%, the speed of fine grinding is 20RPM, the feed speed is 0.8mm / min, the thickness is 0.3mm, and the speed of polishing is 18RPM and the time is 60s;

[0033] Step 2: Heat the thick zinc selenide plate after flat grinding to 50°C and keep it warm for 20 minutes, then heat it to 60°C at a heating rate of 2°C / min and keep it warm for 20 minutes;

[0034] Step 3: After the end of step 2, the temperature is raised to 75°C at a rate of 2°C / min and then kept for 10 minutes. During the process, the temperature is kept for 10 minutes for every 5°C increase;

[0035] Step 4: Heat to 90°C at a rate of 1.5°C / min, then polish and bond the joints, cool naturally to room temperature, and leave to stand for 12 hours;

[0036] Step 5: The thick-sized zinc selenide plate with the polishing joint bonded in step 4 is subjected to fine grinding, rough polishing and fine polishing in a polishing machine in sequence to obtain a processed thick-sized zinc selenide plate; wherein the spindle speed of the fine grinding is 30RPM and the swing shaft speed is 20RPM; the spindle speed of the rough polishing is 50RPM and the swing shaft speed is 30RPM; the spindle speed of the fine polishing is 30RPM and the swing shaft speed is 20RPM.

[0037] Example 2

[0038] A method for processing a thick zinc selenide plate comprises the following steps:

[0039] Step 1: The upper and lower surfaces of the thick zinc selenide plate are subjected to coarse grinding, fine grinding and polishing treatment in sequence, wherein the speed of coarse grinding is 30RPM, the feed speed is 0.8mm / min, the upper surface grinding area is 90%, and the lower surface grinding area is 95%, the speed of fine grinding is 25RPM, the feed speed is 0.8mm / min, the thickness is 0.3mm, and the speed of polishing is 18RPM and the time is 60s;

[0040] Step 2: Heat the thick zinc selenide plate after flat grinding to 50°C and keep it warm for 20 minutes, then heat it to 60°C at a heating rate of 2°C / min and keep it warm for 20 minutes;

[0041] Step 3: After the end of step 2, the temperature is raised to 75°C at a rate of 2°C / min and then kept for 10 minutes. During the process, the temperature is kept for 10 minutes for every 5°C increase;

[0042] Step 4: Heat to 90°C at a rate of 1.5°C / min, then polish and bond the joints, cool naturally to room temperature, and leave to stand for 12 hours;

[0043] Step 5: The thick-sized zinc selenide plate with the polishing joint bonded in step 4 is subjected to fine grinding, rough polishing and fine polishing in a polishing machine in sequence to obtain a processed thick-sized zinc selenide plate; wherein the spindle speed of the fine grinding is 30RPM and the swing shaft speed is 20RPM; the spindle speed of the rough polishing is 50RPM and the swing shaft speed is 30RPM; the spindle speed of the fine polishing is 30RPM and the swing shaft speed is 20RPM.

[0044] Example 3

[0045] A method for processing a thick zinc selenide plate comprises the following steps:

[0046] Step 1: The upper and lower surfaces of the thick zinc selenide plate are subjected to coarse grinding, fine grinding and polishing treatment in sequence and then left to stand for 12 hours, wherein the speed of coarse grinding is 20RPM, the feed speed is 0.8mm / min, the upper surface grinding area is 90%, the lower surface grinding area is 95%, the speed of fine grinding is 20RPM, the feed speed is 0.8mm / min, the thickness is 0.3mm, and the speed of polishing is 18RPM and the time is 60s;

[0047] Step 2: Heat the thick zinc selenide plate after flat grinding to 50°C and keep it warm for 20 minutes, then heat it to 60°C at a heating rate of 2°C / min and keep it warm for 20 minutes;

[0048] Step 3: After the end of step 2, the temperature is raised to 75°C at a rate of 2°C / min and then kept for 10 minutes. During the process, the temperature is kept for 10 minutes for every 5°C increase;

[0049] Step 4: Heat to 90°C at a rate of 1.5°C / min, then polish and bond the joints, cool naturally to room temperature, and leave to stand for 12 hours;

[0050] Step 5: The thick-sized zinc selenide plate with the polishing joint bonded in step 4 is subjected to fine grinding, rough polishing and fine polishing in a polishing machine in sequence to obtain a processed thick-sized zinc selenide plate; wherein the spindle speed of the fine grinding is 30RPM and the swing shaft speed is 20RPM; the spindle speed of the rough polishing is 50RPM and the swing shaft speed is 30RPM; the spindle speed of the fine polishing is 30RPM and the swing shaft speed is 20RPM.

[0051] Example 4

[0052] A method for processing a thick zinc selenide plate comprises the following steps:

[0053] Step 1: The upper and lower surfaces of the thick zinc selenide plate are subjected to coarse grinding, fine grinding and polishing treatment in sequence and then left to stand for 12 hours, wherein the speed of coarse grinding is 20RPM, the feed speed is 0.8mm / min, the upper surface grinding area is 90%, the lower surface grinding area is 95%, the speed of fine grinding is 20RPM, the feed speed is 0.8mm / min, the thickness is 0.3mm, and the speed of polishing is 18RPM and the time is 60s;

[0054] Step 2: Heat the thick zinc selenide plate after flat grinding to 50°C and keep it warm for 20 minutes, then heat it to 60°C at a heating rate of 2°C / min and keep it warm for 20 minutes;

[0055] Step 3: After the end of step 2, the temperature is raised to 75°C at a rate of 2°C / min and then kept for 10 minutes. During the process, the temperature is kept for 10 minutes for every 5°C increase;

[0056] Step 4: After the insulation in step 3 is completed, the thick-sized zinc selenide plate is left to stand and cooled naturally to reduce the temperature of the thick-sized zinc selenide plate to 71°C;

[0057] Step 5: Heat to 90°C at a rate of 1.5°C / min, then polish and bond the joints, cool naturally to room temperature, and leave to stand for 12 hours;

[0058] Step 6: The thick zinc selenide plate with the polished joint bonded in step 4 is subjected to fine grinding, rough polishing and fine polishing in a polishing machine in sequence to obtain a processed thick zinc selenide plate; wherein the spindle speed of the fine grinding is 30RPM and the swing shaft speed is 20RPM; the spindle speed of the rough polishing is 50RPM and the swing shaft speed is 30RPM; the spindle speed of the fine polishing is 30RPM and the swing shaft speed is 20RPM.

[0059] Example 5

[0060] A method for processing a thick zinc selenide plate comprises the following steps:

[0061] Step 1: The upper and lower surfaces of the thick zinc selenide plate are subjected to coarse grinding, fine grinding and polishing treatment in sequence and then left to stand for 12 hours, wherein the speed of coarse grinding is 20RPM, the feed speed is 0.8mm / min, the upper surface grinding area is 90%, the lower surface grinding area is 95%, the speed of fine grinding is 20RPM, the feed speed is 0.8mm / min, the thickness is 0.3mm, and the speed of polishing is 18RPM and the time is 60s;

[0062] Step 2: Heat the thick zinc selenide plate after flat grinding to 50°C and keep it warm for 20 minutes, then heat it to 60°C at a heating rate of 2°C / min and keep it warm for 20 minutes;

[0063] Step 3: After the end of step 2, the temperature is raised to 75°C at a rate of 2°C / min and then kept for 10 minutes. During the process, the temperature is kept for 10 minutes for every 5°C increase;

[0064] Step 4: After the insulation in step 3 is completed, the thick-sized zinc selenide plate is left to stand and cooled naturally to reduce the temperature of the thick-sized zinc selenide plate to 68°C;

[0065] Step 5: Heat to 90°C at a rate of 1.5°C / min, then polish and bond the joints, cool naturally to room temperature, and leave to stand for 12 hours;

[0066] Step 6: The thick zinc selenide plate with the polished joint bonded in step 4 is subjected to fine grinding, rough polishing and fine polishing in a polishing machine in sequence to obtain a processed thick zinc selenide plate; wherein the spindle speed of the fine grinding is 30RPM and the swing shaft speed is 20RPM; the spindle speed of the rough polishing is 50RPM and the swing shaft speed is 30RPM; the spindle speed of the fine polishing is 30RPM and the swing shaft speed is 20RPM.

[0067] Example 6

[0068] A method for processing a thick zinc selenide plate comprises the following steps:

[0069] Step 1: The upper and lower surfaces of the thick zinc selenide plate are subjected to coarse grinding, fine grinding and polishing treatment in sequence and then left to stand for 12 hours, wherein the speed of coarse grinding is 20RPM, the feed speed is 0.8mm / min, the upper surface grinding area is 90%, the lower surface grinding area is 95%, the speed of fine grinding is 20RPM, the feed speed is 0.8mm / min, the thickness is 0.3mm, and the speed of polishing is 18RPM and the time is 60s;

[0070] Step 2: Heat the thick zinc selenide plate after flat grinding to 50°C and keep it warm for 20 minutes, then heat it to 60°C at a heating rate of 2°C / min and keep it warm for 20 minutes;

[0071] Step 3: After the end of step 2, the temperature is raised to 75°C at a rate of 2°C / min and then kept for 10 minutes. During the process, the temperature is kept for 10 minutes for every 5°C increase;

[0072] Step 4: After the insulation in step 3 is completed, the thick-sized zinc selenide plate is left to stand and cooled naturally to reduce the temperature of the thick-sized zinc selenide plate to 65°C;

[0073] Step 5: Heat to 90°C at a rate of 1.5°C / min, then polish and bond the joints. Cool to room temperature naturally and let stand for 12 hours.

[0074] Step 6: The thick zinc selenide plate with the polished joint bonded in step 4 is subjected to fine grinding, rough polishing and fine polishing in a polishing machine in sequence to obtain a processed thick zinc selenide plate; wherein the spindle speed of the fine grinding is 30RPM and the swing shaft speed is 20RPM; the spindle speed of the rough polishing is 50RPM and the swing shaft speed is 30RPM; the spindle speed of the fine polishing is 30RPM and the swing shaft speed is 20RPM.

[0075] Example 7

[0076] A method for processing a thick zinc selenide plate comprises the following steps:

[0077] Step 1: The upper and lower surfaces of the thick zinc selenide plate are subjected to coarse grinding, fine grinding and polishing treatment in sequence and then left to stand for 12 hours, wherein the speed of coarse grinding is 20RPM, the feed speed is 0.8mm / min, the upper surface grinding area is 90%, the lower surface grinding area is 95%, the speed of fine grinding is 20RPM, the feed speed is 0.8mm / min, the thickness is 0.3mm, and the speed of polishing is 18RPM and the time is 60s;

[0078] Step 2: Heat the thick zinc selenide plate after flat grinding to 50°C and keep it warm for 20 minutes, then heat it to 60°C at a heating rate of 2°C / min and keep it warm for 20 minutes;

[0079] Step 3: After the end of step 2, the temperature is raised to 75°C at a rate of 2°C / min and then kept for 10 minutes. During the process, the temperature is kept for 10 minutes for every 5°C increase;

[0080] Step 4: After the insulation in step 3 is completed, the thick-sized zinc selenide plate is left to stand and cooled naturally to reduce the temperature of the thick-sized zinc selenide plate to 73°C;

[0081] Step 5: Heat to 90°C at a rate of 1.5°C / min, then polish and bond the joints, cool naturally to room temperature, and leave to stand for 12 hours;

[0082] Step 6: The thick zinc selenide plate with the polished joint bonded in step 4 is subjected to fine grinding, rough polishing and fine polishing in a polishing machine in sequence to obtain a processed thick zinc selenide plate; wherein the spindle speed of the fine grinding is 30RPM and the swing shaft speed is 20RPM; the spindle speed of the rough polishing is 50RPM and the swing shaft speed is 30RPM; the spindle speed of the fine polishing is 30RPM and the swing shaft speed is 20RPM.

[0083] Example 8

[0084] A method for processing a thick zinc selenide plate comprises the following steps:

[0085] Step 1: The upper and lower surfaces of the thick zinc selenide plate are subjected to coarse grinding, fine grinding and polishing treatment in sequence, wherein the speed of coarse grinding is 20RPM, the feed speed is 0.8mm / min, the upper surface grinding area is 90%, and the lower surface grinding area is 95%, the speed of fine grinding is 20RPM, the feed speed is 0.8mm / min, the thickness is 0.3mm, and the speed of polishing is 18RPM and the time is 60s;

[0086] Step 2: Heat the thick zinc selenide plate after flat grinding to 50°C and keep it warm for 20 minutes, then heat it to 60°C at a heating rate of 2°C / min and keep it warm for 20 minutes;

[0087] Step 3: After the end of step 2, the temperature is raised to 75°C at a rate of 2°C / min and then kept for 10 minutes. During the process, the temperature is kept for 10 minutes for every 5°C increase;

[0088] Step 4: Heat to 90°C at a rate of 1.5°C / min, then polish and bond the joints, cool naturally to room temperature, and leave to stand for 12 hours;

[0089] Step 5: The thick zinc selenide plate with the polished joint bonded in step 4 is subjected to fine grinding, rough polishing and fine polishing in a polishing machine in sequence to obtain a processed thick zinc selenide plate; wherein the spindle speed of the fine grinding is 50RPM and the swing shaft speed is 30RPM; the spindle speed of the rough polishing is 55RPM and the swing shaft speed is 35RPM; the spindle speed of the fine polishing is 55RPM and the swing shaft speed is 30RPM.

[0090] Example 9

[0091] A method for processing a thick zinc selenide plate comprises the following steps:

[0092] Step 1: The upper and lower surfaces of the thick zinc selenide plate are subjected to coarse grinding, fine grinding and polishing treatment in sequence and then left to stand for 12 hours, wherein the speed of coarse grinding is 20RPM, the feed speed is 0.8mm / min, the upper surface grinding area is 90%, the lower surface grinding area is 95%, the speed of fine grinding is 20RPM, the feed speed is 0.8mm / min, the thickness is 0.3mm, and the speed of polishing is 18RPM and the time is 60s;

[0093] Step 2: Heat the thick zinc selenide plate after flat grinding to 50°C and keep it warm for 20 minutes, then heat it to 60°C at a heating rate of 2°C / min and keep it warm for 20 minutes;

[0094] Step 3: After the insulation in step 2 is completed, the thick-sized zinc selenide plate is left to stand and cooled naturally to reduce the temperature of the thick-sized zinc selenide plate to 55°C;

[0095] Step 4: Heat to 75°C at a rate of 2°C / min and keep warm for 10 minutes. Keep warm for 10 minutes for every 5°C increase in temperature.

[0096] Step 5: Heat to 90°C at a rate of 1.5°C / min, then polish and bond the joints. Cool to room temperature naturally and let stand for 12 hours.

[0097] Step 6: The thick zinc selenide plate with the polished joint bonded in step 4 is subjected to fine grinding, rough polishing and fine polishing in a polishing machine in sequence to obtain a processed thick zinc selenide plate; wherein the spindle speed of the fine grinding is 30RPM and the swing shaft speed is 20RPM; the spindle speed of the rough polishing is 50RPM and the swing shaft speed is 30RPM; the spindle speed of the fine polishing is 30RPM and the swing shaft speed is 20RPM.

[0098] Comparative Example 1

[0099] A method for processing a thick zinc selenide plate comprises the following steps:

[0100] Step 1: The upper and lower surfaces of the thick zinc selenide plate are subjected to coarse grinding, fine grinding and polishing treatment in sequence, wherein the speed of coarse grinding is 20RPM, the feed speed is 0.8mm / min, the upper surface grinding area is 90%, and the lower surface grinding area is 95%, the speed of fine grinding is 20RPM, the feed speed is 0.8mm / min, the thickness is 0.3mm, and the speed of polishing is 18RPM and the time is 60s;

[0101] Step 2: Heat the thick zinc selenide plate after flat grinding to 90°C, then polish and bond the joints, cool naturally to room temperature, and then let stand for 12 hours;

[0102] Step 3: The thick zinc selenide plate bonded with the polishing joint in step 4 is subjected to fine grinding, rough polishing and fine polishing in a polishing machine in sequence to obtain a processed thick zinc selenide plate; wherein the spindle speed of the fine grinding is 30RPM and the swing shaft speed is 20RPM; the spindle speed of the rough polishing is 50RPM and the swing shaft speed is 30RPM; the spindle speed of the fine polishing is 30RPM and the swing shaft speed is 20RPM.

[0103] Comparative Example 2

[0104] The method is generally the same as Example 1, except that step 2 is changed to: heating the thick zinc selenide plate after flat grinding to 60° C. and then keeping the temperature for 20 minutes.

[0105] Comparative Example 3

[0106] It is generally the same as Example 1, except that step 3 is changed to: after the insulation in step 2 is completed, the temperature is increased to 75°C at a heating rate of 2°C / min and then kept warm for 10 minutes, without insulation during the process.

[0107] Comparative Example 4

[0108] It is generally the same as Example 1, except that step 3 is changed to: after the insulation in step 2 is completed, the temperature is increased to 75°C at a heating rate of 2°C / min and then kept warm for 10 minutes. During the process, the temperature is kept warm for 10 minutes every time the temperature is increased by 8°C.

[0109] Comparative Example 5

[0110] It is generally the same as Example 1, except that step 4 is changed to: heating to 90°C at a heating rate of 1.5°C / min, then polishing the joint for bonding, and naturally cooling to room temperature without standing.

[0111] Comparative Example 6

[0112] It is generally the same as Example 1, except that step 4 is changed to: heating to 90°C at a heating rate of 1.5°C / min, then polishing the joint for bonding, cooling naturally to room temperature, and then standing for 10 hours.

[0113] 1400 pieces of thick zinc selenide plates were taken out, and 100 pieces of thick zinc selenide plates were processed according to the methods of Examples 1-8 and Comparative Examples 1-6, and the internal cracks were visually observed. Since the processed zinc selenide plates were transparent, the internal cracks of the zinc selenide plates could be visually observed. The final results are shown in Table 1, where the internal crack ratio = the number of internal crack ratios greater than 30% / the number of processed pieces * 100%;

[0114] Table 1 Test results of products obtained by processing methods of Examples 1-8 and Comparative Examples 1-6

[0115]

[0116]

[0117] According to the results in Table 1, we can see that:

[0118] According to the data comparison of Examples 1-8 and Comparative Examples 1-6, the present invention can effectively ensure that the thick-sized zinc selenide plate is heated uniformly by controlling the heating rate, heating amplitude, insulation time and static treatment time in the heating process of the bonded and polished joint, thereby reducing the internal thermal stress difference of the thick-sized zinc selenide plate and eliminating part of the thermal stress to a certain extent, thereby reducing the probability of internal cracks in the thick-sized zinc selenide plate.

[0119] According to the data comparison between Example 1 and Example 2, it can be seen that the rotation speed of the rough grinding and fine grinding in step 1 will also affect the probability of internal cracks. The reason is that processing thick-sized zinc selenide plates at an excessively large rotation speed will cause the stress of the thick-sized zinc selenide plates to increase, thereby accumulating stress during the processing of subsequent steps and causing internal cracks in the thick-sized zinc selenide plates.

[0120] According to the data comparison between Example 1 and Example 3, it can be seen that the static state after the flat grinding treatment in step 1 can also reduce the probability of internal cracks to a certain extent. The reason is that static state for a certain period of time can effectively eliminate the internal stress of the thick zinc selenide plate.

[0121] According to the data comparison between Example 3 and Example 4 and Example 5, it can be known that in the process of controlling the temperature rise of the bonded and polished joint, heating to 75°C and then cooling within a certain temperature range can effectively eliminate the stress generated during the temperature rise process, thereby greatly avoiding internal cracks caused by the accumulation of stress during the entire processing process. The technical solutions of Example 4 and Example 5 can achieve an internal crack generation rate of 0%, greatly improving the product yield.

[0122] According to the data of Example 6, if the temperature is lowered after being heated to 75°C, the temperature is lowered too much, which will cause uneven heating of the thick zinc selenide sheet during the heating process in step 5, and increase the probability of internal cracks in the thick zinc selenide sheet during the processing; according to the data of Example 7, if the temperature is lowered after being heated to 75°C, the stress is not sufficiently eliminated. Although the probability of internal cracks in the thick zinc selenide sheet is effectively reduced, the internal crack generation rate does not reach 0% as in Examples 4 and 5.

[0123] Furthermore, it can be seen from the data of Example 9 that the selection of the temperature point for cooling to eliminate stress is critical for stress elimination of thick-sized zinc selenide plates. Example 9 did not effectively eliminate the internal stress accumulation of the thick-sized zinc selenide plates after the temperature was raised to 60°C. Therefore, compared with Example 3, the effect of reducing the probability of internal cracks in the thick-sized zinc selenide plates was not achieved.

[0124] According to the data comparison between Example 1 and Example 8, in the polishing process of step 5, processing the thick zinc selenide plate at an excessively high rotation speed will increase the stress of the thick zinc selenide plate, thereby increasing the probability of internal cracks in the thick zinc selenide plate to a certain extent.

[0125] According to the data comparison between Example 1 and Comparative Example 1, the technical solution of directly heating to 90° C. for polishing joint bonding in Comparative Example 1 will lead to excessive stress accumulation of the thick zinc selenide plate, and the probability of internal cracks in the thick zinc selenide plate reaches 100%.

[0126] According to the data comparison between Example 1 and Comparative Example 2, it is very necessary to heat up to 50°C before 60°C to ensure that the thick zinc selenide plate is heated evenly, which can greatly reduce the probability of internal cracks in the thick zinc selenide plate.

[0127] According to the data comparison between Example 1 and Comparative Examples 3 and 4, it can be seen that the heat preservation treatment step and the temperature increase amplitude control during the temperature increase from 60°C to 75°C can greatly reduce the probability of internal cracks in thick-sized zinc selenide plates.

[0128] According to the data comparison between Example 1, Example 5 and Example 6, the thick zinc selenide plate is subjected to a static treatment before bonding and polishing the joint, and the static treatment time must reach 12 hours, so as to effectively remove the stress accumulated in the thick zinc selenide plate during the entire processing process, and avoid excessive stress accumulated during the final polishing process, which may cause internal cracks in the thick zinc selenide plate.

[0129] The embodiments presented herein are only embodiments selected according to the combination of all possible embodiments. The appended claims should not be limited by the embodiments describing the present invention. Some numerical ranges used in the claims include sub-ranges therein, and the changes in these ranges should also be covered by the appended claims.

Claims

1. A method for processing a thick zinc selenide sheet, wherein the thickness of the thick zinc selenide sheet is 35-70 mm, characterized in that: The steps include: Step 1: Grind the upper and lower surfaces of the thick zinc selenide sheet; Step 2: Heat the thick zinc selenide plate after flat grinding to 50°C and keep it warm for 20-30 minutes, then heat it to 60°C at a heating rate of 1-2°C / min and keep it warm for 20-30 minutes; Step 3: After the end of step 2, heat the temperature to 75°C at a rate of 1-2°C / min and keep it for 10 minutes. During the process, keep it for 10 minutes for every 5°C increase in temperature. Step 4: Heat to 90°C at a rate of 1-1.5°C / min, then polish and bond the joints. Cool to room temperature naturally and let stand for 12-14 hours. Step 5: Polishing the thick zinc selenide plate obtained in step 4.

2. The method for processing a thick zinc selenide sheet according to claim 1, characterized in that: The step a is also included between step 3 and step 4: placing the thick zinc selenide plate after the heat preservation in step 3 at rest, and cooling it naturally to reduce the temperature of the thick zinc selenide plate to 68-71° C.

3. The method for processing a thick zinc selenide sheet according to claim 1, characterized in that: The specific operation of step 1 is: the upper and lower surfaces of the thick zinc selenide plate are subjected to coarse grinding, fine grinding and polishing treatment in sequence, and then left to stand for 12 hours, the thickness of the coarse grinding of the upper surface is 3-5 mm or the flattened area is ≥85%, the thickness of the fine grinding is 0.3 mm, the thickness of the coarse grinding of the lower surface is 0.5-1 mm or the flattened area is ≥95%, the thickness of the fine grinding is 0.3 mm, and the polishing time is 60 seconds.

4. The method for processing a thick zinc selenide sheet material according to claim 3, characterized in that: The speed of coarse grinding is 10-20RPM and the feed speed is 0.2-0.8mm / min; the speed of fine grinding is 10-20RPM and the feed speed is 0.2-0.8mm / min; the speed of light grinding is 10-20RPM.

5. The method for processing a thick zinc selenide sheet according to claim 1, characterized in that: The specific operation of step 5 is: the thick-sized zinc selenide plate bonded with the polishing joint in step 4 is subjected to fine grinding, rough polishing and fine polishing in a polishing machine in sequence to obtain a processed thick-sized zinc selenide plate; wherein the spindle speed of fine grinding is 30RPM and the swing shaft speed is 20RPM; the spindle speed of rough polishing is 50RPM and the swing shaft speed is 30RPM; the spindle speed of fine polishing is 30RPM and the swing shaft speed is 20RPM.

6. A thick zinc selenide sheet, obtained by processing the thick zinc selenide sheet according to any one of claims 1 to 5.

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