CN112192716B - Water-absorbing lower punch of permanent magnetic ferrite magnetic shoe wet pressing forming die - Google Patents
Water-absorbing lower punch of permanent magnetic ferrite magnetic shoe wet pressing forming die Download PDFInfo
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- CN112192716B CN112192716B CN202011044226.3A CN202011044226A CN112192716B CN 112192716 B CN112192716 B CN 112192716B CN 202011044226 A CN202011044226 A CN 202011044226A CN 112192716 B CN112192716 B CN 112192716B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28B7/00—Moulds; Cores; Mandrels
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28B3/00—Producing shaped articles from the material by using presses; Presses specially adapted therefor
- B28B3/20—Producing shaped articles from the material by using presses; Presses specially adapted therefor wherein the material is extruded
- B28B3/26—Extrusion dies
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
- H01F41/0206—Manufacturing of magnetic cores by mechanical means
- H01F41/0246—Manufacturing of magnetic circuits by moulding or by pressing powder
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Abstract
The invention relates to the technical field of magnetic shoe forming dies, and discloses a water-absorbing lower punch of a permanent magnetic ferrite magnetic shoe wet pressing forming die, which comprises an upper end surface and a plurality of water-absorbing holes; the upper end surface comprises a convex cambered surface and two platform surfaces which are respectively arranged at two ends of the cambered surface; the upper end of the water suction hole is opened on the upper end surface; the water suction holes are vertical to the upper end face. In the water absorption female die, the water absorption holes are vertical to the upper end surface, so that water of slurry is extruded, the pressing time can be shortened, the low yield caused by unsmooth water drainage is prevented, and the density of a product is more uniform, so that the performance of the magnetic shoe is improved.
Description
Technical Field
The invention relates to the technical field of magnetic shoe forming dies, in particular to an underwater absorption male die of a permanent magnetic ferrite magnetic shoe wet pressing forming die.
Background
The permanent magnetic ferrite magnetic shoe is widely applied to various direct current motors due to the advantage of cost performance, and is used for replacing an excitation coil to generate a constant magnetic potential source. The wet pressing molding is a common magnetic tile molding method, the water content of slurry is generally 35-40%, during molding, the slurry is injected into a cavity, most of water is discharged through water suction holes by extrusion to form a green body, and then the green body is sintered at high temperature and ground to prepare a finished product. Compared with dry pressing, wet pressing can obtain higher orientation degree and better magnetic shoe performance because the forming slurry contains moisture and particles are easy to turn when forming in a magnetic field.
The drainage mode of the wet pressing forming die is generally single-sided water absorption, namely water in the slurry is pumped out through water absorption holes in the upper die water absorption plate. The single-side water absorption is suitable for producing magnetic tiles with small thickness, for products with blank thickness larger than 15mm, the single-side water absorption can prolong the pressing time, and the unsmooth water absorption can also cause the problems of dark cracking, ring cracking and the like of the products after sintering, thereby influencing the yield. For products with large thickness, the problems can be well solved by adopting double-sided water absorption, namely, the upper die water absorption plate is provided with water absorption holes, the lower male die is also provided with water absorption holes, and water in the slurry is simultaneously pumped out through the water absorption holes at two positions during compression molding.
The Chinese patent document with publication number CN201941073U discloses a permanent magnetic ferrite magnetic shoe wet-pressing magnetic field forming water absorption male die, which comprises a male die, wherein the lower matrix of the male die is made of pure iron, a rectangular groove is formed between the male die and the pure iron of the lower matrix, a plurality of horizontal water absorption channels are arranged in the rectangular groove, a main water absorption channel is arranged in the pure iron of the lower matrix, and the horizontal water absorption channels are communicated with the main water absorption channel; the top of the male die is arc-shaped, the upper end of the male die is provided with a vertical water suction hole, a water flowing groove is arranged in the direction perpendicular to the arc-shaped direction, the water flowing groove is communicated with the vertical water suction hole, and the vertical water suction hole is communicated with the horizontal water suction channel. The water absorption male die can realize double-sided water absorption, but the water absorption holes are vertically arranged, so that water drainage is not facilitated, and the density of each part of the magnetic shoe is not uniform.
Disclosure of Invention
In order to solve the technical problem, the invention provides an underwater absorption male die of a permanent magnetic ferrite magnetic shoe wet pressing forming die. The water absorption holes in the underwater male die are perpendicular to the upper end face, so that water of slurry can be extruded, the pressing time can be shortened, the problem that the finished product rate is low due to unsmooth water drainage is avoided, and meanwhile, the density of a product is more uniform, so that the performance of the magnetic shoe is improved.
The specific technical scheme of the invention is as follows:
a water absorption lower punch of a permanent magnetic ferrite magnetic shoe wet pressing forming die comprises an upper end face and a plurality of water absorption holes; the upper end surface comprises a convex cambered surface and two platform surfaces which are respectively arranged at two ends of the cambered surface; the upper end of the water suction hole is opened on the upper end surface; the water suction holes are vertical to the upper end face.
According to the water-absorbing lower punch disclosed by the invention, the water-absorbing holes are arranged to be vertical to the upper end surface (comprising the cambered surface and the flat table surface), so that the water pumping direction is consistent with the direction of the magnetic force line of the magnetic shoe, the water of the slurry is favorably extruded, the pressing time can be shortened, and the problems of dark cracking, ring cracking and the like of a product after sintering due to unsmooth water drainage are prevented; in addition, the structure can also make the density distribution of the product on the curved surface vertical to the magnetic force lines more uniform, so that the obtained magnetic tile has better performance.
Preferably, the water-saving device also comprises a water flowing groove, a water draining counter bore and a water draining opening; the lower end of the water suction hole is opened in the launder; the upper end of the drainage counter bore is opened at the bottom of the flowing water tank, and the lower end of the drainage counter bore is communicated with the drainage outlet; the water outlet is opened outside the water absorption lower convex die.
During compression molding, water in the slurry enters the water flowing groove through the water absorbing holes and is discharged from the water flowing groove through the water discharging port, and the water flowing groove and the upper die water absorbing plate in the wet-pressing molding die realize double-sided water absorption together, so that the compression time is shortened, and the problems of hidden cracking, ring cracking and the like of a product after sintering due to unsmooth water discharging are prevented. The water outlet can be connected with an air pump, so that low pressure is formed in the water flowing groove and the water suction holes, and drainage is accelerated.
Preferably, the water suction hole comprises a water inlet section and a water outlet section which are communicated with each other; the upper end of the water inlet section is opened on the upper end surface, and the lower end of the water outlet section is opened in the flume; the inner diameter of the water inlet section is smaller than that of the water outlet section.
The water suction hole is designed into a water inlet section with a smaller inner diameter and a water outlet section with a larger inner diameter, so that the trace of the water suction hole is not obvious when the green body is demoulded on the premise of ensuring the rapid flow of water in the water suction hole.
Preferably, the inner diameter of the water inlet section is 1.0-1.5 mm, and the length of the water inlet section is 6-12 mm; the inner diameter of the water outlet section is 3.0-3.5 mm.
Preferably, the density of the water suction holes is gradually increased from the top of the cambered surface to the lowest point.
During the press forming, the compression ratio from the highest point to the lowest point of the cambered surface in the magnetic tile green body is gradually reduced, and the cracking phenomenon is easy to occur after sintering due to the density difference. According to the invention, through the differentiated design of the density of the water absorption holes, the density of the product is more uniform, so that cracking during sintering is prevented.
Preferably, the head part and the base body are sequentially arranged from top to bottom; the head part is detachably connected with the base body; the launder is arranged between the head and the base body.
The water-absorbing lower convex die is designed into the detachable head and the detachable base body, which is beneficial to the arrangement of the launder and is convenient for processing and maintenance.
Preferably, the head and the base are detachably connected through bolts.
Preferably, the head comprises an upper insert made of a non-magnetic conductive material and a lower insert made of a magnetic conductive material in sequence from top to bottom.
Preferably, a hydrophobic coating is arranged on the upper end face; the hydrophobicity of the hydrophobic coating is gradually reduced from a position far away from the water absorption hole to the water absorption hole.
The hydrophobic surface has a larger static contact angle and a smaller rolling angle, so that the hydrophobic coating can accelerate the movement of water on the cambered surface; meanwhile, on the hydrophobic coating with the gradient change of hydrophobicity, water tends to flow from a position with a larger contact angle (with larger hydrophobicity) to a position with a smaller contact angle (with smaller hydrophobicity), so that the invention is beneficial to guiding water in the slurry to flow from a position far away from the water suction hole to the water suction hole by coating the hydrophobic coating with the gradient change of hydrophobicity on the upper end surface, can shorten the pressing time and enables the density of the product to be more uniform.
Compared with the prior art (such as patent CN 201941073U), the method of the invention does not leave water absorption groove marks on the surface of the finished magnetic tile product.
Preferably, the preparation method of the hydrophobic coating is as follows:
(1) carboxylation of the surface of diamond: dispersing nano diamond and micro diamond with the mass ratio of 1.5-2.5: 1 into a mixed solution of concentrated nitric acid and concentrated sulfuric acid, wherein the volume ratio of the concentrated nitric acid to the concentrated sulfuric acid is 1: 3-4, and performing reflux reaction at 75-80 ℃ for 40-45 hours after uniform ultrasonic dispersion; and after the reaction is finished, washing the diamond to be neutral, and drying to obtain the carboxylated modified diamond.
In the step (1), a large number of carboxyl groups are formed on the surface of the diamond through mixed acid oxidation, and grafting sites are not provided through subsequent hydrophobic modification.
(2) Hydrophobic modification of diamond: dispersing the carboxylated modified diamond into a mixed solution of allyl trimethoxy silane and water, adding concentrated sulfuric acid, and reacting at 90-95 ℃ for 2-3 h, wherein the mass ratio of the allyl trimethoxy silane to the water is 1: 8-10; and after the reaction is finished, filtering, washing with acetone, and drying to obtain the hydrophobic modified diamond.
In the step (2), methoxy in the allyl trimethoxy silane is hydrolyzed and converted into silicon hydroxyl, and the silicon hydroxyl reacts with carboxyl on the surface of the diamond and is grafted to the diamond, so that the diamond has better hydrophobicity.
(3) Preparing a coating A: and (2) uniformly dispersing the hydrophobic modified diamond into a volatile solvent, wherein the mass volume ratio of the hydrophobic modified diamond to the volatile solvent is 1g: 15-20 mL, so as to prepare the coating A.
(4) Preparing a coating B: uniformly dispersing 3-mercaptopropyltriethoxysilane and a photoinitiator into a volatile solvent, wherein the mass volume ratio of the 3-mercaptopropyltriethoxysilane to the photoinitiator to the volatile solvent is 8-10 g:1g: 100-130 mL, and thus obtaining the coating B.
(5) Coating: uniformly spraying the coating B on the upper end face, and drying; diluting the coating A to 1.5-2.5 times and 3-4 times of volume by using a volatile solvent, respectively spraying the coating A diluted to 1.5-2.5 times and 3-4 times to the positions 1-2 mm and 0-1 mm away from the nearest edge of a water absorption hole under the irradiation of ultraviolet light, and spraying the undiluted coating A to the rest positions; and after the spraying is finished, continuing to irradiate the paint for 5-8 min by using ultraviolet light, and drying to obtain the hydrophobic coating.
In the step (5), after the coating B is sprayed on the upper end surface, alkoxy in the 3-mercaptopropyltriethoxysilane is combined with the upper end surface; under the irradiation of ultraviolet light, the alkenyl (from allyl trimethoxy silane) on the surface of the hydrophobic modified diamond and the sulfydryl in the 3-mercaptopropyl triethoxy silane generate light-initiated grafting reaction, so that the hydrophobic modified diamond is grafted to the upper end face to form a raised micro-nano lattice structure, and the hydrophobicity of the upper end face can be improved by the hydrophobic modified diamond and the micro-nano lattice structure; by spraying the coating A with different concentrations at different distances from the edge of the water absorption hole, the distribution density of the bulges (hydrophobic modified diamond) in the micro-nano lattice structure can be controlled to be in a gradient descending trend from the position far away from the water absorption hole to the direction of the water absorption hole, so that the hydrophobicity is in a gradient reducing trend.
The gradient change of the hydrophobicity can promote the water in the slurry to flow to the water absorption holes; meanwhile, in the wet pressing and forming process of the permanent magnetic ferrite magnetic shoe, powder particles in the slurry are fine and have high hardness, so that the surface of the upper end face is abraded, and the diamond has high hardness, so that the abrasion resistance of the upper end face can be improved; in addition, the hydrophobic modified diamond is covalently connected to the upper end face through a photo-initiated grafting reaction, so that the bonding strength of the hydrophobic coating can be improved, and the damage to the hydrophobic coating caused by long-term water flow is avoided.
Preferably, in the step (1), the particle size of the nano-diamond is 30-50 nm, and the particle size of the micro-diamond is 10-30 μm.
Preferably, in the steps (3) to (5), the volatile solvent is at least one of methanol, acetone and ethanol.
Preferably, in the step (1), the ultrasonic temperature is 25-30 ℃, the power is 70-80 kHz, and the time is 3-4 h.
Preferably, in the step (1), the mass fraction of the concentrated nitric acid is 65-68%; in the step (1) and the step (2), the mass fraction of the concentrated sulfuric acid is 95-98%.
Preferably, in the step (1), the mass volume ratio of the diamond to the mixed solution of concentrated nitric acid and concentrated sulfuric acid is 1g: 120-150 mL.
Preferably, in the step (2), the volume ratio of the concentrated sulfuric acid to the mixed solution of allyltrimethoxysilane and water is 1: 70-80.
Preferably, in the step (2), the mass-to-volume ratio of the carboxylated modified diamond to the mixed solution of the allyltrimethoxysilane and the water is 1g: 70-90 mL.
Preferably, in step (4), the photoinitiator is TPO.
Compared with the prior art, the invention has the following advantages:
(1) the water absorption holes are vertical to the upper end surface, so that the water of the slurry can be extruded, the pressing time can be shortened, the low yield caused by unsmooth drainage can be prevented, and the product density can be more uniform, so that the performance of the magnetic shoe can be improved;
(2) the hydrophobic coating with gradient change of hydrophobicity is arranged on the upper end face, so that water in the slurry can be promoted to flow to the water suction holes, the pressing time is shortened, the density of the product is more uniform, and the wear resistance of the upper end face can be improved.
Drawings
FIG. 1 is a schematic diagram of an embodiment of the present invention.
The reference signs are: the water-saving device comprises an upper end face 1, an arc face 1-1, a platform face 1-2, a water suction hole 2, a water inlet section 2-1, a water outlet section 2-2, a water flowing groove 3, a water drainage counter bore 4, a water outlet 5, a head 6, an upper insert 6-1, a lower insert 6-2, a base 7 and a bolt 8.
Detailed Description
The present invention will be further described with reference to the following examples. The devices, connections, and methods referred to in this disclosure are those known in the art, unless otherwise indicated.
Example 1
As shown in fig. 1, the underwater suction male die of the permanent magnetic ferrite magnetic shoe wet pressing forming die sequentially comprises a head 6 and a base 7 from top to bottom; the head part 6 comprises an upper insert 6-1 made of a non-magnetic material and a lower insert 6-2 made of a magnetic material from top to bottom in sequence; the lower insert 6-2 is detachably connected with the base body 7 through a bolt 8.
The upper end surface 1 of the upper insert 6-1 comprises a convex cambered surface 1-1 and two platform surfaces 1-2 respectively arranged at two ends of the cambered surface 1-1.
The top of the base body 7 is provided with a launder 3; a drainage counter bore 4 and a drainage port are arranged in the base body 7; the upper end of the drainage counter bore 4 is opened at the bottom of the flowing water tank 3, and the lower end is communicated with the drainage port 5; the water outlet 5 is opened outside the water absorption lower convex die.
A plurality of water suction holes 2 which are vertical to the upper end surface 1 and penetrate through the head part 6 are arranged in the head part 6; the water suction hole 2 comprises a water inlet section 2-1 and a water outlet section 2-2 which are communicated with each other; the inner diameter of the water inlet section 2-1 is 1.0-1.5 mm, the length h is 6-12 mm, and the inner diameter of the water outlet section 2-2 is 3.0-3.5 mm; the upper end of the water inlet section 2-1 is opened on the upper end face 1, and the lower end of the water outlet section 2-2 is opened on the launder 3; the density of the water suction holes 2 is gradually increased from the top of the cambered surface 1-1 to the lowest point.
The underwater suction male die structure has the following advantages:
(1) during compression molding, water in the slurry enters the water flowing groove 3 through the water suction holes 2 and is discharged from the water flowing groove 3 through the water discharge port 5, and double-sided water absorption is realized together with the upper die water suction plate in the wet-pressing molding die, so that the compression time is shortened, the problems of hidden opening, ring cracking and the like of a product after sintering due to unsmooth water discharge are prevented, and the water discharge requirement during compression molding of the magnetic tile with larger thickness can be met. The water outlet 5 can be connected with an air pump to form low pressure in the water flowing groove 3 and the water suction hole 2 and accelerate water drainage.
(2) The water suction holes are arranged to be vertical to the upper end face 1 (comprising the cambered surface 1-1 and the flat table surface 1-2), so that the water pumping direction is consistent with the direction of the magnetic force line of the magnetic shoe, the extrusion of water of slurry is facilitated, the pressing time can be shortened, and the problems of dark opening, ring cracking and the like of a product after sintering due to unsmooth water drainage are prevented; in addition, the structure can also make the density distribution of the product on the curved surface vertical to the magnetic force lines more uniform, so that the obtained magnetic tile has better performance.
(3) Through the differentiated design of the density of the water suction holes 2 (the density of the water suction holes gradually increases from the top of the cambered surface 1-1 to the lowest point), the density of the product can be more uniform, and cracking during sintering is prevented.
(4) The water suction hole 2 is designed into a water inlet section 2-1 with smaller inner diameter and a water outlet section 2-2 with larger inner diameter, so that the trace of the water suction hole 2 is not obvious when a green body is demoulded on the premise of ensuring the rapid flow of water in the water suction hole 2.
(5) The water absorption lower convex die is designed into the detachable head part 6 and the detachable base body 7, which is beneficial to the arrangement of the launder 3 and is convenient for processing and maintenance.
Example 2
The difference between this embodiment and embodiment 1 is that a hydrophobic coating is provided on the upper end surface 1, and the preparation method of the hydrophobic coating is as follows:
(1) carboxylation of the surface of diamond: dispersing nano diamond (with the particle size of about 40 nm) and micro diamond (with the particle size of about 20 microns) in a mass ratio of 2:1 into a mixed solution of 65% by mass of concentrated nitric acid and 98% by mass of concentrated sulfuric acid, wherein the volume ratio of the concentrated nitric acid to the concentrated sulfuric acid is 1:3.5, the mass-volume ratio of the diamond to the mixed solution of the concentrated nitric acid and the concentrated sulfuric acid is 1g:130mL, dispersing the mixed solution at 30 ℃ for 3.5 hours by using 75kHz ultrasonic waves, and then carrying out reflux reaction at 80 ℃ for 40 hours; after the reaction is finished, washing the diamond to be neutral, and drying to obtain the carboxylated modified diamond;
(2) hydrophobic modification of diamond: dispersing the carboxylated modified diamond into a mixed solution of allyltrimethoxysilane and water, wherein the mass ratio of the allyltrimethoxysilane to the water is 1:9, adding 98% by mass of concentrated sulfuric acid, and reacting the concentrated sulfuric acid with the mixed solution of the allyltrimethoxysilane and the water at the temperature of 90 ℃ for 3 hours, wherein the volume ratio of the concentrated sulfuric acid to the mixed solution of the allyltrimethoxysilane and the water is 1: 75; after the reaction is finished, filtering, washing with acetone, and drying to obtain the hydrophobic modified diamond;
(3) preparing a coating A: uniformly dispersing the hydrophobic modified diamond into methanol, wherein the mass volume ratio of the hydrophobic modified diamond to the methanol is 1g:20mL, so as to prepare a coating A;
(4) preparing a coating B: uniformly dispersing 3-mercaptopropyltriethoxysilane (TPO) and TPO into methanol, wherein the mass volume ratio of the 3-mercaptopropyltriethoxysilane to the TPO to the methanol is 9g:1g:110mL, so as to prepare a coating B;
(5) coating: uniformly spraying the coating B on the upper end face, and drying; diluting the coating A to 2 times and 3.5 times of volume by using a volatile solvent, respectively spraying the coating A diluted to 2 times and 3.5 times to the positions 1-2 mm and 0-1 mm away from the edge of the nearest water absorption hole under the irradiation of ultraviolet light, and spraying the coating A which is not diluted to the rest positions; and after the spraying is finished, continuing to irradiate the paint for 6min by using ultraviolet light, and drying to obtain the hydrophobic coating.
In the upper water-suction plates of examples 1 and 2, points at distances of 0.5mm, 1.5mm, and 2.5mm from the water-suction holes were selected on the upper end surface, and the static contact angles were measured. The results are as follows: in example 1, the static contact angles at positions 0.5mm, 1.5mm and 2.5mm from the water-absorbing hole were 53 °, 49 ° and 54 °, respectively; in example 2, the static contact angles at 0.5mm, 1.5mm and 2.5mm from the water-absorbing hole were 145 °, 158 ° and 168 °, respectively. The above results show that a hydrophobic surface can be formed on the upper end face by the method of the present invention, and the hydrophobicity gradient increases from a position away from the water-absorbing hole to the water-absorbing hole.
Example 3
The difference between this embodiment and embodiment 1 is that a hydrophobic coating is provided on the upper end surface 1, and the preparation method of the hydrophobic coating is as follows:
(1) carboxylation of the surface of diamond: dispersing nano diamond (with the grain diameter of about 30 nm) and micro diamond (with the grain diameter of about 10 microns) in a mass ratio of 1.5:1 into a mixed solution of 65% by mass of concentrated nitric acid and 95% by mass of concentrated sulfuric acid, wherein the volume ratio of the concentrated nitric acid to the concentrated sulfuric acid is 1:3, the mass-volume ratio of the mixed solution of the diamond, the concentrated nitric acid and the concentrated sulfuric acid is 1g:120mL, dispersing for 4 hours at 28 ℃ by using 70kHz ultrasonic waves, and then carrying out reflux reaction for 40 hours at 80 ℃; after the reaction is finished, washing the diamond to be neutral, and drying to obtain the carboxylated modified diamond;
(2) hydrophobic modification of diamond: dispersing carboxylated modified diamond into a mixed solution of allyltrimethoxysilane and water, wherein the mass ratio of allyltrimethoxysilane to water is 1:8, the mass volume ratio of the carboxylated modified diamond to the mixed solution of allyltrimethoxysilane and water is 1g:70mL, adding concentrated sulfuric acid with the mass fraction of 95%, and the volume ratio of the concentrated sulfuric acid to the mixed solution of allyltrimethoxysilane and water is 1:70, and reacting for 2.5 hours at 93 ℃; after the reaction is finished, filtering, washing with acetone, and drying to obtain the hydrophobic modified diamond;
(3) preparing a coating A: uniformly dispersing the hydrophobic modified diamond into methanol, wherein the mass volume ratio of the hydrophobic modified diamond to the methanol is 1g:15mL, and preparing a coating A;
(4) preparing a coating B: uniformly dispersing 3-mercaptopropyltriethoxysilane (TPO) and TPO into methanol, wherein the mass volume ratio of the 3-mercaptopropyltriethoxysilane to the TPO to the methanol is 8g:1g:100mL, so as to prepare a coating B;
(5) coating: uniformly spraying the coating B on the upper end face, and drying; diluting the coating A to 1.5 times and 3 times of volume by using a volatile solvent, respectively spraying the coating A diluted to 1.5 times and 3 times to the positions 1-2 mm and 0-1 mm away from the edge of the nearest water absorption hole under the irradiation of ultraviolet light, and spraying the coating A which is not diluted to the rest positions; and after the spraying is finished, continuing to irradiate the paint for 5min by using ultraviolet light, and drying to obtain the hydrophobic coating.
Example 4
The difference between this embodiment and embodiment 1 is that a hydrophobic coating is provided on the upper end surface 1, and the preparation method of the hydrophobic coating is as follows:
(1) carboxylation of the surface of diamond: dispersing nano diamond (with the grain diameter of about 50 nm) and micro diamond (with the grain diameter of about 30 microns) in a mass ratio of 2.5:1 into a mixed solution of concentrated nitric acid with the mass fraction of 68% and concentrated sulfuric acid with the mass fraction of 98%, wherein the volume ratio of the concentrated nitric acid to the concentrated sulfuric acid is 1:4, the mass-volume ratio of the mixed solution of the diamond, the concentrated nitric acid and the concentrated sulfuric acid is 1g:150mL, dispersing for 3 hours at 25 ℃ by using ultrasonic of 80kHz, and then carrying out reflux reaction for 40 hours at 80 ℃; after the reaction is finished, washing the diamond to be neutral, and drying to obtain the carboxylated modified diamond;
(2) hydrophobic modification of diamond: dispersing carboxylated modified diamond into a mixed solution of allyltrimethoxysilane and water, wherein the mass ratio of allyltrimethoxysilane to water is 1:10, the mass volume ratio of the carboxylated modified diamond to the mixed solution of allyltrimethoxysilane and water is 1g:90mL, adding 98% by mass of concentrated sulfuric acid, and the volume ratio of the concentrated sulfuric acid to the mixed solution of allyltrimethoxysilane and water is 1:80, and reacting for 2 hours at 95 ℃; after the reaction is finished, filtering, washing with acetone, and drying to obtain the hydrophobic modified diamond;
(3) preparing a coating A: uniformly dispersing the hydrophobic modified diamond into methanol, wherein the mass volume ratio of the hydrophobic modified diamond to the methanol is 1g:18mL, so as to prepare a coating A;
(4) preparing a coating B: uniformly dispersing 3-mercaptopropyltriethoxysilane (TPO) and TPO into methanol, wherein the mass volume ratio of the 3-mercaptopropyltriethoxysilane to the TPO to the methanol is 10g:1g:130mL, so as to prepare a coating B;
(5) coating: uniformly spraying the coating B on the upper end face, and drying; diluting the coating A to 2.5 times and 4 times of volume by using a volatile solvent, respectively spraying the coating A diluted to 2.5 times and 4 times to the positions 1-2 mm and 0-1 mm away from the edge of the nearest water absorption hole under the irradiation of ultraviolet light, and spraying the coating A which is not diluted to the rest positions; and after the spraying is finished, continuing to irradiate the paint for 8min by using ultraviolet light, and drying to obtain the hydrophobic coating.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and all simple modifications, changes and equivalent structural changes made to the above embodiment according to the technical spirit of the present invention still belong to the protection scope of the technical solution of the present invention.
Claims (8)
1. An underwater suction male die of a permanent magnetic ferrite magnetic shoe wet pressing forming die is characterized by comprising an upper end surface (1) and a plurality of water suction holes (2); the upper end face (1) comprises a convex cambered surface (1-1) and two platform faces (1-2) respectively arranged at two ends of the cambered surface (1-1); the upper end of the water suction hole (2) is opened on the upper end surface (1); the water suction holes (2) are vertical to the upper end surface (1); the upper end face (1) is provided with a hydrophobic coating; the hydrophobicity of the hydrophobic coating is gradually reduced from a position far away from the water absorption hole (2) to the water absorption hole (2);
the preparation method of the hydrophobic coating comprises the following steps:
(1) carboxylation of the surface of diamond: dispersing nano diamond and micro diamond with the mass ratio of 1.5-2.5: 1 into a mixed solution of concentrated nitric acid and concentrated sulfuric acid, wherein the volume ratio of the concentrated nitric acid to the concentrated sulfuric acid is 1: 3-4, and performing reflux reaction at 75-80 ℃ for 40-45 hours after uniform ultrasonic dispersion; after the reaction is finished, washing the diamond to be neutral, and drying to obtain the carboxylated modified diamond;
(2) hydrophobic modification of diamond: dispersing the carboxylated modified diamond into a mixed solution of allyl trimethoxy silane and water, adding concentrated sulfuric acid, and reacting at 90-95 ℃ for 2-3 h, wherein the mass ratio of the allyl trimethoxy silane to the water is 1: 8-10; after the reaction is finished, filtering, washing with acetone, and drying to obtain the hydrophobic modified diamond;
(3) preparing a coating A: uniformly dispersing the hydrophobic modified diamond into a volatile solvent, wherein the mass volume ratio of the hydrophobic modified diamond to the volatile solvent is 1g: 15-20 mL, and thus obtaining a coating A;
(4) preparing a coating B: uniformly dispersing 3-mercaptopropyltriethoxysilane and a photoinitiator into a volatile solvent, wherein the mass volume ratio of the 3-mercaptopropyltriethoxysilane to the photoinitiator to the volatile solvent is 8-10 g:1g: 100-130 mL, so as to prepare a coating B;
(5) coating: uniformly spraying the coating B on the upper end face, and drying; diluting the coating A to 1.5-2.5 times and 3-4 times of volume by using a volatile solvent, respectively spraying the coating A diluted to 1.5-2.5 times and 3-4 times to the positions 1-2 mm and 0-1 mm away from the nearest edge of a water absorption hole under the irradiation of ultraviolet light, and spraying the undiluted coating A to the rest positions; and after the spraying is finished, continuing to irradiate the paint for 5-8 min by using ultraviolet light, and drying to obtain the hydrophobic coating.
2. The water-absorbing lower punch die as recited in claim 1, further comprising a water flowing groove (3), a water discharge counter bore (4) and a water discharge port (5); the lower end of the water suction hole (2) is opened in the water flowing groove (3); the upper end of the drainage counter bore (4) is opened at the bottom of the flowing water tank (3), and the lower end of the drainage counter bore is communicated with the drainage outlet (5); the water outlet (5) is opened outside the water absorption lower convex die.
3. The lower water-absorbing punch according to claim 2, wherein the water-absorbing hole (2) comprises a water inlet section (2-1) and a water outlet section (2-2) which are communicated with each other; the upper end of the water inlet section (2-1) is opened on the upper end surface (1), and the lower end of the water outlet section (2-2) is opened on the launder (3); the inner diameter of the water inlet section (2-1) is smaller than that of the water outlet section (2-2).
4. The underwater suction male die as claimed in claim 3, wherein the water inlet section (2-1) has an inner diameter of 1.0 to 1.5mm and a length of 6 to 12 mm; the inner diameter of the water outlet section (2-2) is 3.0-3.5 mm.
5. The water-absorbing lower punch according to claim 1, wherein the density of the water-absorbing holes (2) gradually increases from the top of the cambered surface (1-1) to the lowest point.
6. A water-absorbing lower punch according to claim 2, characterised by comprising, in order from top to bottom, a head (6) and a base (7); the head (6) is detachably connected with the base body (7); the launder (3) is arranged between the head (6) and the base body (7).
7. The water-absorbing lower punch according to claim 1, wherein in the step (1), the nano-diamond has a particle size of 30 to 50nm, and the micro-diamond has a particle size of 10 to 30 μm.
8. The water-absorbing lower punch according to claim 1, wherein in the steps (3) to (5), the volatile solvent is at least one of methanol, acetone and ethanol.
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| CN202011044226.3A CN112192716B (en) | 2020-09-28 | 2020-09-28 | Water-absorbing lower punch of permanent magnetic ferrite magnetic shoe wet pressing forming die |
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Denomination of invention: A water absorbing lower punch of the wet pressing mold for permanent magnet ferrite magnetic tile Effective date of registration: 20220622 Granted publication date: 20210713 Pledgee: Dongyang Branch of China Construction Bank Co.,Ltd. Pledgor: HENGDIAN GROUP DMEGC MAGNETICS Co.,Ltd. Registration number: Y2022330001028 |
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