CN114554766B

CN114554766B - Shell, manufacturing method thereof and electronic equipment

Info

Publication number: CN114554766B
Application number: CN202210244363.4A
Authority: CN
Inventors: 张文宇
Original assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Current assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Priority date: 2022-03-11
Filing date: 2022-03-11
Publication date: 2023-11-07
Anticipated expiration: 2042-03-11
Also published as: CN114554766A

Abstract

The application provides a shell, which comprises a ceramic substrate, wherein the porosity of the ceramic substrate is less than 0.3%, and the Weber modulus is greater than 10. The ceramic substrate in the shell has low porosity and high strength consistency, has excellent performance and is beneficial to the application of the shell. The application also provides a preparation method of the shell and electronic equipment.

Description

Shell, manufacturing method thereof and electronic equipment

Technical Field

The application belongs to the technical field of electronic products, and particularly relates to a shell, a preparation method thereof and electronic equipment.

Background

Ceramic materials have the advantages of high hardness, good toughness, wear resistance and the like, and are often applied to electronic equipment in recent years. At present, the internal defects of products made of ceramic materials are serious, and the application requirements are difficult to meet. Therefore, the performance of ceramic products is still further improved.

Disclosure of Invention

In view of the above, the application provides a housing, a manufacturing method thereof and an electronic device.

In a first aspect, the application provides a housing comprising a ceramic substrate having a porosity of less than 0.3% and a weber modulus of greater than 10.

In a second aspect, the present application provides a method for manufacturing a housing, comprising:

Mixing ceramic material and mixed solution, and sanding to obtain premixed slurry, wherein the primary particle size D50 of the ceramic material is smaller than 0.15 mu m, the secondary particle size D50 is smaller than 0.5 mu m, and the specific surface area is smaller than 8m ² The mixed solution comprises a gel agent and auxiliary agent water;

after the pre-mixed slurry is defoamed, adding a catalyst and an initiator to obtain mixed slurry;

and (3) performing gel casting, drying, glue discharging and sintering on the mixed slurry to obtain a ceramic substrate, wherein the porosity of the ceramic substrate is less than 0.3%, and the Weber modulus is greater than 10, so as to obtain the shell.

In a third aspect, the present application provides an electronic device comprising a housing comprising a ceramic substrate having a porosity of less than 0.3% and a weber modulus of greater than 10.

The ceramic substrate in the shell provided by the application has low porosity, high strength consistency and excellent performance, and is beneficial to the application of the shell; the preparation method of the shell is simple to operate, and a ceramic substrate with excellent performance can be obtained, so that the performance of the shell is improved; the electronic equipment with the shell not only has excellent mechanical properties, but also has ceramic texture appearance, and improves the product competitiveness of the electronic equipment.

Drawings

In order to more clearly explain the technical solutions in the embodiments of the present application, the drawings that are used in the embodiments of the present application will be described below.

Fig. 1 is a schematic flow chart of a method for manufacturing a shell according to an embodiment of the application.

Fig. 2 is a schematic flow chart of a method for manufacturing a shell according to another embodiment of the present application.

Fig. 3 is a schematic flow chart of a method for manufacturing a shell according to another embodiment of the present application.

Fig. 4 is a schematic structural diagram of a housing according to an embodiment of the application.

Fig. 5 is a schematic structural diagram of a housing according to another embodiment of the present application.

Fig. 6 is a schematic structural diagram of an electronic device according to an embodiment of the present application.

Fig. 7 is a schematic structural diagram of an electronic device according to an embodiment of the present application.

FIG. 8 is a microscopic morphology of the ceramic substrate grains produced in example 1.

FIG. 9 is a microscopic morphology of the ceramic substrate grains produced in example 2.

FIG. 10 is a microscopic morphology of the ceramic substrate grains produced in example 3.

FIG. 11 is a microscopic morphology of the ceramic substrate grains produced in comparative example 1.

FIG. 12 is a microscopic topography of the ceramic substrate grains produced in comparative example 2.

Detailed Description

The following are preferred embodiments of the present application, and it should be noted that modifications and variations can be made by those skilled in the art without departing from the principle of the present application, and these modifications and variations are also considered as the protection scope of the present application.

The following disclosure provides many different embodiments, or examples, for implementing different features of the application. In order to simplify the present disclosure, components and arrangements of specific examples are described below. They are, of course, merely examples and are not intended to limit the application. Furthermore, the present application may repeat reference numerals and/or letters in the various examples, which are for the purpose of brevity and clarity, and which do not themselves indicate the relationship between the various embodiments and/or arrangements discussed. In addition, the present application provides examples of various specific processes and materials, but one of ordinary skill in the art will recognize the application of other processes and/or the use of other materials.

Referring to fig. 1, a flow chart of a method for manufacturing a shell according to an embodiment of the application includes:

s101: mixing ceramic material and mixed solution, and sand grinding to obtain premixed slurry, wherein the primary particle diameter D50 of the ceramic material is less than 0.15 μm, the secondary particle diameter D50 is less than 0.5 μm, and the specific surface area is less than 8m ² And/g, the mixed solution comprises a gel and an auxiliary agent.

S102: and (3) after defoaming the premixed slurry, adding a catalyst and an initiator to obtain the mixed slurry.

S103: and (3) performing gel casting, drying, glue discharging and sintering on the mixed slurry to obtain a ceramic substrate, wherein the porosity of the ceramic substrate is less than 0.3%, and the Weber modulus is greater than 10, so as to obtain the shell.

The present application prepares the ceramic substrate 10 through a gel casting process to obtain the housing 100; by providing a proper primary particle size D50, a proper secondary particle size D50 and a ceramic material with a low specific surface area, the uniform dispersion of the ceramic material in the mixed slurry is ensured, the occurrence of agglomeration is avoided, the internal defects caused by the agglomeration are avoided, the porosity of the ceramic substrate 10 is reduced, and the strength consistency of the ceramic substrate 10 is improved. It can be understood that the smaller the porosity, the fewer pores inside the ceramic substrate 10, the fewer internal defects, and the better the air tightness of the ceramic substrate 10; the weber modulus (Weibull modulus), which may also be referred to as the Weibull modulus, reflects the dispersion of the four-point flexural strength values of the ceramic substrate 10, with the greater the data, the less the dispersion, the fewer defects in product strength, and the more stable the performance. The ceramic plate formed by dry pressing has a plurality of holes, the injection molding needs a special injection machine, the casting molding is only suitable for preparing the planar ceramic plate, the application can greatly reduce the holes in the ceramic substrate 10 by a gel casting molding process, the performance of the ceramic substrate 10 is improved, meanwhile, large equipment is not required, the preparation cost is reduced, the ceramic substrates 10 with different shapes can be manufactured by changing the shape of the mold, the variability of the appearance shape is high, and the application is suitable for various application scenes, thereby being beneficial to the use of the shell 100.

In S101, a ceramic material and a mixed solution are mixed and sanded to obtain a premix slurry. In the present application, the ceramic material is an inorganic substance, and the mixed solution is a solution containing an organic substance.

In an embodiment of the present application, the ceramic material comprises zirconia, such that the resulting ceramic substrate 10 is a zirconia ceramic. The zirconia ceramic has excellent toughness, strength and hardness, improves the mechanical properties and resistance of the shell 100, and is beneficial to the application thereof. In the present application, the primary particle diameter D50, the secondary particle diameter D50 and the specific surface area of the zirconia are not limited as long as the primary particle diameter D50 of the ceramic material is less than 0.15 μm, the secondary particle diameter D50 is less than 0.5 μm and the specific surface area is less than 8m ² And/g. For example, the primary particle diameter D50 of zirconia is less than 0.1 μm, the secondary particle diameter D50 is less than 0.25 μm, and the specific surface area is less than 20m ² And/g. The particle diameter D50 is a particle diameter corresponding to a cumulative particle size distribution percentage of the material reaching 50%, and is also called a median diameter or a median particle diameter.

In an embodiment of the application, the ceramic material comprises zirconia and yttria. Wherein, yttrium oxide is used as a stabilizer, which is favorable for forming stable and compact tetragonal zirconia in the ceramic substrate 10, thereby improving the structural stability of the ceramic substrate 10 and ensuring that the ceramic substrate 10 is not easy to crack in the preparation and processing processes. In one embodiment, the ceramic material has a yttria content of 2-8% by mass, which ensures the formation and stable presence of tetragonal zirconia without affecting the performance of the ceramic substrate 10. Specifically, the mass content of yttrium oxide in the ceramic material may be, but is not limited to, 2%, 3%, 4%, 5%, 6%, 7%, 8%, etc. In one embodiment, the ceramic material has a yttria content of 2% to 4% by mass. In another embodiment, the ceramic material has a yttria content of 4% to 8% by mass.

In embodiments of the present application, the ceramic material may further include hafnium oxide. Hafnium oxide is a co-product of zirconia powder, and a small amount of hafnium oxide is usually contained in zirconia powder. Specifically, the mass content of hafnium oxide in the ceramic material may be, but is not limited to, less than or equal to 3%, for example, 0.1%, 0.5%, 1%, 1.5%, 2% or 3% by mass of hafnium oxide in the ceramic material, etc.

In embodiments of the present application, the ceramic material may further include a reinforcing agent. By adding the reinforcing agent, sintering is further promoted and fracture toughness of the ceramic is improved, thereby improving performance of the housing 100. In an embodiment, the reinforcing agent may include at least one of titanium oxide, silicon oxide, germanium oxide, magnesium oxide, and zinc oxide. The above inorganic material can effectively improve fracture toughness of the ceramic substrate 10 as a reinforcing agent. In one embodiment, the mass content of the reinforcing agent in the ceramic material is less than or equal to 5%, so that the fracture toughness of the ceramic substrate 10 can be improved, and the influence of excessive content on the hardness of the ceramic substrate 10 can be avoided. Specifically, the mass content of the reinforcing agent in the ceramic material may be, but is not limited to, 1%, 2%, 3%, 4%, 5%, or the like. In one embodiment, the ceramic material has a reinforcing agent content of 0.5% to 2% by mass. In another embodiment, the ceramic material has a reinforcing agent content of 3% to 5% by mass.

In embodiments of the present application, the ceramic material may also include a colorant. The ceramic substrate 10 is made to present different colors by adding the coloring agent, and the appearance of the ceramic substrate 10 is changed, thereby expanding the application scene of the housing 100. In one embodiment, the coloring agent may be, but is not limited to, at least one selected from the group consisting of aluminum oxide, zinc oxide, cobalt oxide, ferric oxide, chromium oxide, nickel oxide, manganese oxide, erbium oxide, neodymium oxide, praseodymium oxide, copper oxide, titanium oxide, niobium pentoxide, calcium oxide, silicon oxide, cerium oxide, barium oxide, lanthanum oxide, cesium oxide, bismuth oxide, strontium oxide, gallium oxide, magnesium oxide, vanadium oxide, tin oxide, and other compounds having the cations described above. For example, other compounds having the cations described above may be, but are not limited to, nickel silicate, vanadium zirconium yellow, chromite, cobalt aluminate, and the like. Specifically, the material of the coloring agent may be selected according to the desired color of the ceramic substrate 10. In one embodiment, the mass content of the coloring agent in the ceramic material is less than or equal to 5%, which can ensure that the ceramic substrate 10 has a color appearance, and can avoid the influence of excessive content on the mechanical properties of the ceramic substrate 10. Specifically, the mass content of the coloring agent in the ceramic material may be, but is not limited to, 0.5%, 1%, 2%, 2.5%, 3%, 4%, 5%, or the like. In one embodiment, the mass content of the coloring agent in the ceramic material is 0.5% -2%. In another embodiment, the mass content of the colorant in the ceramic material is 2.5% -5%.

In one embodiment, the ceramic material comprises 79% -98% zirconia, 2% -8% yttria, 0% -3% hafnium oxide, 0% -5% reinforcing agent, and 0% -5% coloring agent by mass. By mixing the above substances, a ceramic material is obtained. Further, the ceramic material comprises 79% -94.4% of zirconia, 2% -8% of yttria, 0.1% -3% of hafnium oxide, 3% -5% of reinforcing agent and 0.5% -5% of coloring agent by mass.

In the present application, the mixed solution includes a gelling agent for generating gel curing under the action of a catalyst and an initiator during gel casting to obtain the ceramic substrate 10, and an auxiliary agent for improving the properties of materials and solutions to facilitate the subsequent gel curing.

In an embodiment of the application, the gelling agent comprises at least one of an organic monomer and a cross-linking agent. It will be appreciated that if the organic monomer is capable of producing gel cure under the action of the catalyst and initiator, no cross-linking agent is required to be added to the gelling agent, and if the organic monomer is capable of producing gel cure under the action of the cross-linking agent, catalyst and initiator, the organic monomer and cross-linking agent are required to be added to the gelling agent.

In the application, the organic monomer can be polymerized in situ under the action of the initiator and the catalyst to form a high molecular three-dimensional network structure, so that the liquid mixed slurry is gel-cured, and the ceramic material is bonded in situ. In one embodiment, the organic monomer includes at least one of acrylamide, methacrylamide, dimethylacrylamide, hydantoin epoxy resin, and an isobutylene-maleic anhydride copolymer. Wherein, if the isobutylene-maleic anhydride copolymer is used, the gelling agent may not be added with a crosslinking agent. In one embodiment, the mass of the organic monomer is 1.5% -4% of the mass of the ceramic material, such as 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, etc. The organic monomer content is too small, which is not beneficial to the formation of a three-dimensional network structure and the dispersion and fixation of ceramic materials; the organic monomer content is excessive, the formed three-dimensional network structure is excessive, and the porosity of the ceramic substrate 10 is easy to improve; the organic monomer with the content ensures the dispersion and fixation of the ceramic material, does not increase the porosity of the ceramic substrate 10, and is beneficial to the improvement of the strength consistency of the ceramic substrate 10. In one embodiment, the mass of the organic monomer is 1.5% -2.5% of the mass of the ceramic material. In yet another embodiment, the mass of the organic monomer is 2.5% -4% of the mass of the ceramic material.

In the present application, the crosslinking agent can promote crosslinking of the monomer to form a three-dimensional network structure and influence the degree of crosslinking. In one embodiment, the crosslinking agent includes at least one of methylene bisacrylamide and phosphonobutane tricarboxylic acid. In one embodiment, the cross-linking agent comprises 0.1% -0.4% by mass of the ceramic material, such as 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, or 0.4% by mass, etc. The chain length of the polymer formed by the organic monomer is too short, which is not beneficial to the dispersion and fixation of the ceramic material; the content of the cross-linking agent is too small, and the three-dimensional network structure formed by the organic monomer is incomplete, which is not beneficial to the improvement of the strength of the ceramic green body; the cross-linking agent with the content can effectively promote the cross-linking of the organic monomer to form a proper three-dimensional network structure, which is beneficial to the improvement of the green strength of the ceramic. In one embodiment, the cross-linking agent comprises 0.1% -0.2% by mass of the ceramic material. In yet another embodiment, the cross-linking agent comprises 0.2% to 0.4% by mass of the ceramic material.

In the embodiment of the application, the mass ratio of the organic monomer to the cross-linking agent is (10-20): 1. thus, the formation of the three-dimensional network structure is facilitated, the ceramic material is uniformly dispersed therein, the strength of the ceramic green body is improved, and the improvement of the consistency of the strength of the ceramic substrate 10 is facilitated. Specifically, the mass ratio of the organic monomer to the crosslinking agent may be, but is not limited to, 10, 12, 15, 17, 19, 20, or the like. In one embodiment, the mass ratio of the organic monomer to the crosslinking agent may be (10-15): 1. in one embodiment, the mass ratio of the organic monomer to the crosslinking agent may be (15-20): 1.

In an embodiment of the present application, the auxiliary agent includes at least one of a dispersant, an antifoaming agent, a surfactant, and a pH adjuster.

In the application, the dispersing agent is used for promoting the ceramic materials to be uniformly dispersed in the premix slurry, the dispersing agent can be adsorbed on the surfaces of ceramic material particles, so that a polymer layer is formed on the surfaces of the particles, and polymer chains extend into the premix slurry, thereby preventing the ceramic material particles from contacting with each other, and simultaneously reducing the aggregation effect between the ceramic materials due to the Zeta potential change on the surfaces of the ceramic materials, and further avoiding the occurrence of aggregation. In one embodiment, the dispersant comprises at least one of ammonium polyacrylate, polyacrylic acid, sodium polyacrylate, polyvinyl alcohol, and ammonium citrate. In one embodiment, the dispersant comprises 0.2% -0.5% by mass of the ceramic material, such as 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, or 0.5% by mass, etc. The dispersing agent with the content can effectively promote the dispersion of ceramic materials, prevent agglomeration and ensure the viscosity of the premixed slurry. In one embodiment, the dispersant is present in an amount of 0.2% to 0.3% by mass of the ceramic material. In yet another embodiment, the dispersant comprises 0.4% to 0.5% by mass of the ceramic material.

In the present application, an antifoaming agent is used to inhibit the formation of foam in the mixed liquor as well as the premix slurry. In one embodiment, the defoamer comprises at least one of n-octanol, glycerol, and glycerol polyoxyethylene ether. In one embodiment, the defoamer comprises 0.01% -0.05% by mass of the ceramic material, such as 0.01%, 0.015%, 0.02%, 0.025%, 0.03%, 0.04%, or 0.05%, etc. The foam of the mixed liquid and the premixed slurry can be effectively removed by adopting the defoaming agent with the content. In a specific embodiment, the defoamer comprises 0.01% -0.025% of the ceramic material by mass. In yet another embodiment, the defoamer comprises 0.03% to 0.05% by mass of the ceramic material.

In the application, the surfactant can reduce the surface energy of the ceramic material, improve the rheological property of the premix slurry, help to improve the solid content of the premix slurry, reduce the viscosity of the premix slurry and improve the stability of the premix slurry. In one embodiment, the surfactant includes at least one of triethanolamine, diethanolamine, polyethylene glycol, ethylene glycol, and fatty alcohol-polyoxyethylene ether. In one embodiment, the surfactant comprises 0.1% -0.3% by mass of the ceramic material, such as 0.1%, 0.15%, 0.2%, 0.25% or 0.3% by mass, etc. The rheological property of the premixed slurry can be effectively improved by adopting the surfactant with the content. In one embodiment, the mass of the surfactant is 0.1% -0.2% of the mass of the ceramic material. In yet another embodiment, the surfactant comprises 0.2% to 0.3% by mass of the ceramic material.

In the present application, a pH adjuster is used to adjust the pH of the mixed liquid. In an embodiment, the pH of the mixed solution is alkaline, which is favorable for adsorbing hydroxyl ions on the surface of the ceramic material when the mixed solution is mixed with the ceramic material, so that the surface of the ceramic material is electronegative, the absolute value of Zeta potential is increased, the ceramic material is better dispersed in the mixed solution, agglomeration is prevented, and the strength and strength consistency of the ceramic substrate 10 are improved. Specifically, the pH adjuster may be an alkaline solution such as ammonia water, sodium hydroxide solution, or the like. In one embodiment, the pH of the mixture is 9-12. In this way, agglomeration of the ceramic material can be effectively prevented. Specifically, the pH of the mixture may be, but is not limited to, 9, 10, 11 or 12.

In the embodiment of the application, the mixed solution contains water; the water is used as a solvent for dispersing the gel and the auxiliary agent, plays a role in dispersing the ceramic material in the premix slurry, ensures the solid content of the premix slurry, and is added according to the solid content required by the premix slurry. In the present application, the mixing ratio of the ceramic material and the mixed liquid may be selected according to the solid content required for the premix slurry.

In the application, after the ceramic material and the mixed solution are mixed, the premixed slurry can be obtained through sanding. The physical properties of the ceramic material are improved by sanding while the properties of the premix slurry are improved. In an embodiment of the present application, sanding includes mixing the ceramic material, the mixed liquor, and the sanding medium for grinding. In particular, the particle size of the sanding medium may be in the range of 0.1mm to 2mm, such as 0.1mm, 0.5mm, 1mm, 1.5mm, 2mm, etc., and the sanding medium may be, but is not limited to, zirconia beads, etc. In one embodiment, the temperature of the sanding is 5-15 ℃ (e.g., 5 ℃, 8 ℃, 10 ℃, 13 ℃, or 15 ℃, etc.), and the time of the sanding is 4-12 hours (e.g., 4 hours, 5 hours, 8 hours, 10 hours, or 12 hours, etc.). By controlling the temperature in the sanding process to be long in time, the performance of the premixed slurry can be improved, and the performance of the ceramic substrate 10 can be improved. Specifically, the sanded slurry may also be screened, where the mesh size of the screen may be, but is not limited to, 1500 mesh.

In the present application, the solid content is the volume ratio of the solid matter in the slurry. In one embodiment, the premix slurry has a solids content of 40% to 60%, such as 40%, 45%, 50%, 55% or 60%. The solid content is too low, the ceramic material content is low, the strength of the ceramic substrate 10 is not improved, and meanwhile, the water and organic matters are more, so that the ceramic substrate is easy to use A large number of air holes remain in the ceramic substrate 10, so that the internal defects of the ceramic substrate 10 are improved; the solid content is too high, the ceramic material content is too high, agglomeration is easy to occur, internal defects of the ceramic substrate 10 are improved, and the strength of the ceramic substrate 10 is still affected. In one embodiment, the premix slurry has a solids content of 40% to 50%. In another embodiment, the premix slurry has a solids content of 50% to 60%. In one embodiment, the viscosity of the premix slurry is less than 1000 mPa-s. The premixed slurry has small viscosity and good fluidity, is beneficial to the slurry to be rapidly and uniformly filled in a die in the injection molding process, is beneficial to the discharge of bubbles in the slurry, reduces the defects in the ceramic substrate 10, and improves the mechanical properties of the ceramic substrate 10. In one embodiment, the primary particle size D50 of the solids in the premix slurry is less than 0.15 μm, the secondary particle size D50 is less than 0.4 μm, and the specific surface area is less than 5m ² And/g. It can be understood that the primary particle size D50, the secondary particle size D50 and the specific surface area of the solid, i.e., the ceramic material, are measured by drying the liquid in the premix slurry.

In S102, the pre-mixed slurry is defoamed, so that the content of bubbles in the pre-mixed slurry is reduced, the low porosity of the ceramic substrate 10 is ensured, and the strength consistency of the ceramic substrate 10 are improved. In one embodiment, the defoaming includes defoaming for 10min to 60min (e.g., 10min, 15min, 20min, 30min, 45min, 60min, etc.) at a vacuum level of less than or equal to-70 kPa. The foam is removed for a long time under high vacuum, so that the air bubbles in the premixed slurry can be removed rapidly, and the air bubble content in the premixed slurry is reduced greatly.

In the present application, the catalyst is used to increase the rate of the cross-linking polymerization reaction and shorten the gel curing time. In one embodiment, the catalyst comprises at least one of tetramethyl ethylenediamine and dimethyl aniline. In one embodiment, the mass of the catalyst is 0.1% -1% of the mass of the ceramic material, such as 0.1%, 0.25%, 0.3%, 0.5%, 0.6%, 0.7%, 0.8%, or 1%, etc. The catalyst content is too low, the gel curing time of the mixed slurry is too long, and ceramic materials can be settled, so that the ceramic green density distribution is uneven, deformation can occur in the drying and sintering processes, and the use of the ceramic substrate 10 is affected; the catalyst content is too high, the gel curing time of the mixed slurry is too short, and bubbles cannot be discharged in the injection molding process, so that the performance of the ceramic substrate 10 is affected; the catalyst with the content can ensure that the defects are avoided, and is beneficial to the improvement of the performance of the ceramic substrate 10. In one embodiment, the mass of the catalyst is 0.3% to 0.5% of the mass of the ceramic material. Therefore, the gel curing time can be ensured to be 15-20 min, the injection molding time can be ensured, and the ceramic material can be prevented from sedimentation. In yet another embodiment, the mass of the catalyst is 0.6% -1% of the mass of the ceramic material.

In the present application, the initiator is used to generate free radicals, and sufficient free radicals can initiate the polymerization reaction of the organic monomer and the crosslinking agent to promote the gel curing. In one embodiment, the initiator comprises at least one of ammonium persulfate, diaminodipropylamine, and benzoyl peroxide. In one embodiment, the initiator comprises 0.3% -1% by mass of the ceramic material, such as 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1% by mass, etc. The initiator content is too low, the organic monomer cannot completely participate in the gel curing reaction, and the formed three-dimensional network structure skeleton is incomplete; the initiator content is too high, the initial reaction of the polymerization reaction is too fast, which is unfavorable for forming a long-chain structure, influencing the strength of the ceramic green compact, and easily generating cracks in the drying and sintering processes, influencing the performance of the ceramic substrate 10; the initiator with the content can ensure that the defects are avoided, and the performance of the ceramic substrate 10 is improved. In a specific embodiment, the mass of the initiator is 0.5% -0.8% of the mass of the ceramic material. Therefore, the gel curing time can be ensured to be 15-20 min, the injection molding time can be ensured, and the ceramic material can be prevented from sedimentation. In yet another embodiment, the mass of the initiator is 0.3% to 0.4% of the mass of the ceramic material.

In the application, after the pre-mixed slurry is defoamed, a catalyst and an initiator are added, and the mixed slurry is obtained after uniform stirring. The stirring time should not be too long, otherwise the viscosity of the mixed slurry increases and gel curing even begins to occur. Specifically, the stirring time may be less than 5 minutes, such as stirring for 1, 2, 3, or 4 minutes. In the present application, the addition of catalyst and initiator does not affect the solids content and viscosity of the premix slurry too much. In one embodiment, the solids content of the mixed slurry is 40% -60%, such as 40%, 45%, 50%, 55% or 60%. In one embodiment, the solids content of the mixed slurry is 40% to 50%. In another embodiment, the mixed slurry has a solids content of 50% to 60%. In one embodiment, the viscosity of the mixed slurry is less than 1000 mPa-s. In one embodiment, the primary particle size D50 of the solids in the mixed slurry is less than 0.15 μm and the secondary particle size D50 is less than 0.5 μm. It can be understood that the primary particle size D50 and the secondary particle size D50 of the solid, i.e., the ceramic material, are measured by drying the liquid in the mixed slurry.

In S103, the mixed slurry is gel-molded to obtain a ceramic preform, and the ceramic preform is dried to obtain a ceramic green body, and the ceramic green body is discharged and sintered to obtain the ceramic substrate 10. In one embodiment, the gel casting process includes injecting the mixed slurry into a mold, curing, and demolding to obtain a ceramic preform. It will be appreciated that the ceramic substrate 10 is advantageously obtained in the desired shape by injecting the mixed slurry into a mold. In a specific embodiment, the mixed slurry can be injected into the mold by using an automatic slurry injector, the slurry is injected from a feed inlet of the mold, the slurry stops being injected after overflowing from an exhaust port, and the whole time of the slurry injection is avoided to influence the gel solidification. Specifically, the whole grouting duration can be less than 3min; the material of the mold can be at least one of glass, metal and plastic, for example, a glass mold can be selected; the surface roughness of the cavity may be less than 1 μm, which is advantageous for reducing the surface roughness of the ceramic substrate 10 and improving the surface quality of the ceramic substrate 10.

In one embodiment of the present application, the temperature of the gel casting is 30-90 ℃ (e.g. 30 ℃, 40 ℃, 50 ℃, 60 ℃, 70 ℃, 80 ℃ or 90 ℃ etc.), and the time is 10min-30min (e.g. 10min, 15min, 20min, 25min or 30min etc.). The temperature of gel casting is too low, the molding time is too long, ceramic materials are easy to subside, the density distribution of ceramic preforms is uneven, deformation can occur in the drying and sintering processes, and the use of the ceramic substrate 10 is affected; the gel casting molding temperature is too high, the molding time is too short, and the uniform distribution of mixed slurry in a mold and the discharge of bubbles are not facilitated; the gel injection molding condition is favorable for gel solidification, and negative pressure is favorable for discharging bubbles. In one embodiment, the mixed slurry may be injected into a mold at a temperature of 30-90 ℃ and a vacuum degree of a cavity of the mold of-100 kPa to-10 kPa (e.g., -100kPa, -80kPa, -60kPa, -50kPa, -30kPa, or-10 kPa, etc.), and the mixed slurry is left to stand and solidify in the mold for 10-30 minutes to prepare a ceramic preform. The vacuum degree of the die cavity is adopted, so that the injection of mixed slurry and the discharge of bubbles are facilitated. Optionally, the temperature of the die is 30-50 ℃, and the vacuum degree of a die cavity of the die is-100 kPa to-60 kPa; or the temperature of the die is 60-90 ℃, and the vacuum degree of the die cavity of the die is minus 60kPa to minus 10kPa.

In one embodiment of the application, the drying process comprises treating at a humidity of 70% -90% (e.g., 70%, 75%, 80%, 85%, or 90%, etc.), 30 ℃ -50 ℃ (e.g., 30 ℃, 35 ℃, 40 ℃, 45 ℃, or 50 ℃, etc.) for 12h-24h (e.g., 12h, 15h, 17h, 20h, or 22h, etc.), and then treating at a humidity of 20% -50% (e.g., 20%, 25%, 30%, 40%, or 50%, etc.), 80 ℃ -120 ℃ (e.g., 80 ℃, 90 ℃, 100 ℃, 110 ℃, or 120 ℃, etc.) for 6h-12h (e.g., 6h, 7h, 8h, 10h, or 11h, etc.). Drying at a higher humidity and a lower temperature to slowly and uniformly remove water on the surface layer of the ceramic preform, thereby removing free water on the surface layer; drying at low humidity and higher temperature to remove free water and part of adsorbed water in the ceramic preform, so that the ceramic preform is dried to obtain a ceramic green body; the ceramic green body has low water content, no obvious cracking, peeling and other problems on the surface, and good surface quality. In one embodiment, the drying process comprises treating at a humidity of 80% -90% at 30-40 ℃ for 15-20 hours, and then treating at a humidity of 20% -30% at 100-120 ℃ for 6-10 hours. In another embodiment, the drying process comprises treating at a humidity of 70% -80% at 40-50deg.C for 12-15 h, and then treating at a humidity of 30% -50% at 80-100deg.C for 10-12 h.

In another embodiment of the present application, the drying process comprises soaking in a solution containing a hydrophilic organic solvent for 3h to 12h (e.g., 3h, 5h, 8h, 10h, or 12h, etc.) at a temperature of 10 ℃ -50 ℃ (e.g., 10 ℃, 20 ℃, 30 ℃, 40 ℃, 50 ℃, etc.); then the mixture is treated for 12h to 24h (such as 12h, 15h, 17h, 20h or 22h, etc.) under the conditions that the humidity is 70 percent to 90 percent (such as 70 percent, 75 percent, 80 percent, 85 percent or 90 percent, etc.), 30 ℃ -50 ℃ (such as 30 ℃, 35 ℃, 40 ℃, 45 ℃ or 50 ℃, etc.); then treating at a humidity of 20% -50% (e.g. 20%, 25%, 30%, 40% or 50%, etc.), 60-120deg.C (e.g. 60 deg.C, 70 deg.C, 80 deg.C, 90 deg.C, 100 deg.C, 110 deg.C or 120 deg.C, etc.) for 6-12 h (e.g. 6h, 7h, 8h, 10h or 11h, etc.). The method comprises the steps of immersing the ceramic preform in a solution containing a hydrophilic organic solvent to enable water in the ceramic preform to be replaced by the hydrophilic organic solvent, and removing part of free water on the surface of the ceramic preform; drying at a higher humidity and a lower temperature to remove part of free water and adsorbed hydrophilic organic solvent on the surface layer of the ceramic preform; finally drying at low humidity and higher temperature, and removing free water and part of adsorbed water in the ceramic preform, so that the ceramic preform is dried integrally to obtain a ceramic green body; the ceramic green body has low water content, no cracking, peeling and other problems on the surface, and good surface quality. In one embodiment, the hydrophilic organic solvent-containing solution has a hydrophilic organic solvent content of 50% -100% (e.g., 50%, 60%, 70%, 80%, 90% or 100% by mass, etc.), so as to facilitate more replacement of free water on the surface of the ceramic preform. In one embodiment, the hydrophilic organic solvent may include at least one of methanol, ethanol, propanol, methyl ethyl ketone, and acetone to facilitate the displacement of free water without affecting the properties of the ceramic green body.

In the present application, the drying may be performed in a constant humidity and constant temperature drying oven. In one embodiment, the water content of the ceramic green body is less than 3%, i.e., the mass ratio of water in the ceramic green body is less than 3%, which is advantageous for improving the performance of the ceramic substrate 10. Specifically, the water content of the ceramic green body is less than 2.5%, less than 2% or less than 1%, etc.

In one embodiment, the discharging includes treating at 400-600 ℃ for 2-4 hours, and the sintering includes treating at 1300-1500 ℃ for 1-2 hours. Specifically, the temperature of the glue discharging can be but not limited to 400 ℃, 450 ℃, 500 ℃, 550 ℃ or 600 ℃, and the time of the glue discharging can be but not limited to 2 hours, 2.5 hours, 3 hours, 3.5 hours or 4 hours, so as to ensure that the ceramic green body cannot crack in the glue discharging process; the sintering temperature can be, but is not limited to 1300 ℃, 1350 ℃, 1380 ℃, 1400 ℃, 1450 ℃, 1470 ℃ or 1500 ℃, and the sintering time can be, but is not limited to, 1h, 1.5h or 2h, so as to ensure the improvement of the internal bonding strength and compactability of the ceramic green body. Organic components in the ceramic green body are removed by discharging glue and sintering, and simultaneously, the compactness and the bonding strength of the inside are enhanced to improve the performance of the ceramic substrate 10.

In an embodiment of the present application, the ceramic raw material is calcined to obtain a ceramic material. Wherein, the ceramic raw material and the ceramic material are the same in material quality, and only the primary particle size, the secondary particle size and the specific surface area of the particles are different.

Referring to fig. 2, a flow chart of a method for manufacturing a shell according to another embodiment of the application includes:

s201: the zirconia is calcined and then mixed with yttrium oxide, hafnium oxide, reinforcing agent and coloring agent to obtain ceramic material, the primary particle size D50 of the ceramic material is smaller than 0.15 mu m, the secondary particle size D50 is smaller than 0.5 mu m, and the specific surface area is smaller than 8 mu m ² /g。

S202: and (3) mixing the ceramic material with a mixed solution, and then performing sand grinding to obtain premixed slurry, wherein the mixed solution comprises a gelling agent and an auxiliary agent.

S203: and (3) after defoaming the premixed slurry, adding a catalyst and an initiator to obtain the mixed slurry.

S204: the mixed slurry is subjected to gel casting, drying, glue discharging and sintering to obtain the ceramic substrate, wherein the porosity of the ceramic substrate is less than 0.3%, and the Weber modulus is greater than 10, so that the shell is prepared.

The descriptions of S202, S203, S204 with reference to S101, S102, S103 are not repeated here.

Referring to fig. 3, a flow chart of a method for manufacturing a shell according to another embodiment of the present application includes:

s301: oxidationZirconium, yttrium oxide, hafnium oxide, reinforcing agent and coloring agent are mixed and then calcined to obtain ceramic material, wherein the primary particle size D50 of the ceramic material is smaller than 0.15 mu m, the secondary particle size D50 is smaller than 0.5 mu m, and the specific surface area is smaller than 8 mu m ² /g。

S302: and (3) mixing the ceramic material with a mixed solution, and then performing sand grinding to obtain premixed slurry, wherein the mixed solution comprises a gelling agent and an auxiliary agent.

S303: and (3) after defoaming the premixed slurry, adding a catalyst and an initiator to obtain the mixed slurry.

S304: the mixed slurry is subjected to gel casting, drying, glue discharging and sintering to obtain the ceramic substrate, wherein the porosity of the ceramic substrate is less than 0.3%, and the Weber modulus is greater than 10, so that the shell is prepared.

The descriptions of S302, S303, S304 with reference to S101, S102, S103 are not repeated here.

In the application, the particles are modified by calcining, so that the specific surface area of the particles is reduced, and the primary particle size and the secondary particle size of the particles are improved, so that the ceramic material is easier to uniformly disperse in the mixed liquid, agglomeration of the particles can be effectively avoided, a premixed slurry with high solid content and low viscosity is formed, and the internal defects of the ceramic substrate 10 are reduced, and the ceramic substrate 10 with excellent mechanical properties is formed; in addition, calcination can remove organic impurities on the surface of the particles, so that the influence of the organic impurities on the mixing of the ceramic material and the mixed liquid is avoided, and the stability of the premixed slurry is ensured. In an embodiment of the application, the calcination temperature is 300-600 ℃ and the time is 1-2 h. Too low calcination temperature and too short calcination time cannot achieve the calcination effect, the specific surface area of the particles cannot be reduced, and organic impurities cannot be completely removed; too high calcination temperature and too long calcination time can easily form hard agglomeration among particles, but increase defects in the ceramic substrate 10, and are not beneficial to the improvement of the performance of the ceramic substrate 10; therefore, the sintering process can ensure the formation of ceramic materials with required sizes, can uniformly disperse particles, is beneficial to reducing internal defects of the ceramic substrate 10 and improves the mechanical properties of the ceramic substrate 10. In the present application, the temperature of calcination may be, but is not limited to The calcination time may be, but not limited to, 60, 70, 80, 90, 100, 110, 120, etc., at 300, 350, 400, 450, 500, 550, 600, etc. In one embodiment, the calcination temperature is 300 ℃ to 400 ℃ for 1.5h to 2h. In another embodiment, the calcination temperature is 500 ℃ to 600 ℃ for a time of 1h to 1.5h. In yet another embodiment, the zirconia is calcined and mixed with yttria, hafnia, a reinforcing agent, a colorant; or mixing zirconia, yttria, hafnium oxide, a reinforcing agent and a coloring agent, and calcining to obtain the ceramic material, wherein the calcining temperature is 300-600 ℃ and the calcining time is 1-2 h, the primary particle size D50 of the obtained ceramic material is less than 0.15 mu m, the secondary particle size D50 is less than 0.5 mu m, and the specific surface area is less than 8m ² And/g, wherein the specific surface area of the zirconia is greater than the specific surface area of the ceramic material.

In the embodiment of the present application, the ceramic substrate 10 may be subjected to CNC processing, sand blasting, polishing, etc. to obtain a ceramic substrate 10 of a desired shape, surface properties; the ceramic substrate 10 may be subjected to laser etching, plating, etc. to change the appearance effect of the ceramic substrate 10. In the embodiment of the present application, the protective liquid is coated on the surface of the ceramic substrate 10, and the protective layer 20 is formed after curing, so as to prepare the housing 100. The housing 100 has oppositely disposed inner and outer surfaces during use, and the protective layer 20 is located on one side of the outer surface to provide protection during use of the housing 100. The protective layer 20 protects the ceramic substrate 10. Specifically, the thickness of the protective layer 20 may be, but is not limited to, 5nm to 20nm, such as 5nm, 8nm, 10nm, 13nm, 15nm, 18nm, 20nm, or the like. In an embodiment, the protective liquid may include at least one of an anti-fingerprint agent and a hardening liquid to form at least one of an anti-fingerprint layer and a hardening layer. Specifically, the material of the hardening layer can comprise at least one of polyurethane acrylic ester, organic silicon resin and perfluoropolyether acrylic ester; the contact angle of the fingerprint-resistant layer can be larger than 105 degrees, so that the surface of the fingerprint-resistant layer is prevented from being polluted, and the fingerprint-resistant layer has excellent fingerprint-resistant performance; the fingerprint-resistant layer can comprise fluorine-containing compounds such as fluorosilicone resin, perfluoropolyether, fluorine-containing acrylate and the like, and further comprises silicon dioxide, and the friction resistance of the fingerprint-resistant layer is further improved by adding the silicon dioxide.

In the present application, the porosity of the ceramic substrate 10 is less than 0.3% and the weber modulus is greater than 10. The ceramic substrate 10 prepared by the method has low porosity, reduces internal defects, has large Weber modulus, and has the advantages of small strength discreteness, high strength consistency and excellent performance. Further, the porosity of the ceramic substrate 10 is 0.15% or less, and the weber modulus is greater than 10.5. Further, the ceramic substrate 10 has a porosity of 0.12% or less and a weber modulus of greater than 12. In one embodiment, the four-point flexural strength of the ceramic substrate 10 is greater than 1100MPa. It will be appreciated that the four-point flexural strength of the ceramic substrate 10 is the average of multiple measurements. Further, the four-point bending strength of the ceramic substrate 10 is greater than 1150MPa. In one embodiment, the ceramic substrate 10 has a characteristic strength of greater than 1150MPa, indicating that the ceramic substrate 10 has excellent mechanical properties and high strength uniformity. Further, the ceramic substrate 10 has a characteristic strength of more than 1200MPa. In one embodiment, the grain size in the ceramic substrate 10 is less than 400nm. It is understood that the grain size is the average of the measurements. The grain size in the ceramic substrate 10 is small, which is beneficial to improving the compactness of the internal structure, thereby improving the performance of the ceramic substrate 10. Further, the grain size of the ceramic substrate 10 is less than 350nm. Further, the grain size of the ceramic substrate 10 is less than 340nm.

In the application, four-point bending strength is detected according to GB/T6569-2006 fine ceramic bending strength test method, wherein the four-point bending strength is the average value of multiple detections, and the effective data is not less than 32; according to the effective data of the four-point bending strength which is not less than 32, adopting software such as Minitab, weibull ++ modules and the like to carry out statistical analysis, wherein the four-point bending strength corresponds to the ceramic substrate 10 when the failure probability is 63.2%; the Weber modulus is obtained according to GB/T40005-2021 Weber statistical analysis method of Fine ceramic intensity data, wherein the sample capacity is not less than 32, and the confidence interval is 90%; photographing by a scanning electron microscope and counting to obtain the primary particle size D50 of the particles, wherein the number of the counted particles is not less than 100; obtaining a secondary particle diameter D50 of the particles by a laser particle size distribution instrument; obtaining the specific surface area of the particles by a specific surface area tester; photographing the section of the ceramic substrate 10 by a scanning electron microscope and counting to obtain grain sizes, wherein the number of the counted grains is not less than 100; detecting the porosity according to GB/T25995-2010 fine ceramic Density and apparent porosity test method; the water content was obtained by a water content meter.

In the present application, the thickness and shape of the ceramic substrate 10 may be selected according to the requirements of the housing 100, and the housing 100 may be used as a casing, a middle frame, a key cap, etc. of the electronic device 200, such as a casing of a mobile phone, a tablet computer, a notebook computer, a watch, MP3, MP4, a GPS navigator, a digital camera, etc. In the present application, the ceramic substrate 10 and the case 100 may have a 2D structure, a 2.5D structure, a 3D structure, or the like. In an embodiment, when the housing 100 is used as a rear cover of a mobile phone, the thickness of the ceramic substrate 10 may be 0.5mm-1mm, such as 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, or 1 mm.

The preparation method of the shell 100 provided by the application is simple to operate, and the ceramic substrate 10 with excellent performance can be obtained, so that the performance of the shell 100 is improved, and the application range of the shell 100 is enlarged.

Referring to fig. 4, a schematic structural diagram of a housing according to an embodiment of the application is shown, the housing 100 includes a ceramic substrate 10, wherein the porosity of the ceramic substrate 10 is less than 0.3%, and the weber modulus is greater than 10. The ceramic substrate 10 has low porosity, high strength uniformity, and excellent performance.

In an embodiment of the present application, the case 100 may be manufactured by the manufacturing method of the case 100 described in any of the above embodiments.

In the embodiment of the present application, the ceramic substrate 10 is zirconia ceramic. Zirconia ceramics are advantageous for improving the mechanical properties of the housing 100. In one embodiment, the zirconia ceramic has a zirconia mass content of 79% to 98%. Specifically, the mass content of zirconia in the zirconia ceramic may be, but is not limited to, 79%, 80%, 82%, 85%, 88%, 90%, 92%, 95%, 98%, or the like. In one embodiment, the tetragonal zirconia in the ceramic substrate 10 accounts for more than 70% of the zirconia mass, which is beneficial to improve the structural stability and mechanical properties of the ceramic substrate 10. In one embodiment, the zirconia ceramic further comprises at least one of yttria, hafnia, a reinforcing agent, and a colorant. The content of yttrium oxide, hafnium oxide, reinforcing agent and coloring agent, and the selection of the reinforcing agent and coloring agent materials are described in the above section S101, and are not described herein. In a specific embodiment, the zirconia ceramic further comprises, by mass, 2% -8% yttria, 0% -3% hafnium oxide, 0% -5% reinforcing agent, and 0% -5% coloring agent.

Referring to fig. 5, a schematic structural diagram of a housing according to another embodiment of the application is shown, the housing 100 further includes a protection layer 20, and the protection layer 20 is disposed on a surface of the ceramic substrate 10. In one embodiment, the protective layer 20 includes at least one of an anti-fingerprint layer and a hardened layer.

The application also provides an electronic device 200 comprising the housing 100 of any of the above embodiments. It is understood that the electronic device 200 may be, but is not limited to, a cell phone, tablet, notebook, watch, MP3, MP4, GPS navigator, digital camera, etc. Referring to fig. 6, a schematic structural diagram of an electronic device according to an embodiment of the application is shown, wherein an electronic device 200 includes a housing 100. The housing 100 can enhance the mechanical properties of the electronic device 200, and the electronic device 200 has a ceramic-textured appearance with excellent product competitiveness. Referring to fig. 7, a schematic structural diagram of an electronic device according to an embodiment of the application is shown, and the electronic device 200 may include an RF circuit 210, a memory 220, an input unit 230, a display unit 240, a sensor 250, an audio circuit 260, a WiFi module 270, a processor 280, a power supply 290, and the like. The RF circuit 210, the memory 220, the input unit 230, the display unit 240, the sensor 250, the audio circuit 260, and the WiFi module 270 are respectively connected to the processor 280; the power supply 290 is used to provide power to the entire electronic device 200. Specifically, RF circuit 210 is used to send and receive signals; memory 220 is used to store data instruction information; the input unit 230 is used for inputting information, and may specifically include a touch panel and other input devices such as operation keys; the display unit 240 may include a display screen or the like; the sensor 250 includes an infrared sensor, a laser sensor, etc., for detecting a user proximity signal, a distance signal, etc.; the speaker 261 and the microphone 262 are connected with the processor 280 through the audio circuit 260 for receiving and transmitting sound signals; the WiFi module 270 is configured to receive and transmit WiFi signals; the processor 280 is used to process data information of the electronic device 200.

The performance of the housing provided by the present application is further illustrated by the following specific examples and comparative examples.

Example 1

The ceramic material comprises, by mass, 87.8% of zirconia, 5.2% of yttria, 2% of hafnium oxide, 1.5% of a reinforcing agent (comprising 0.5% of titania, 0.4% of silica and 0.6% of germanium oxide), and 3.5% of a coloring agent (comprising 0.9% of alumina, 0.8% of zinc oxide, 1% of cobalt oxide and 0.8% of ferric oxide), wherein the primary particle size D50 of the zirconia is 0.08 mu m, the secondary particle size D50 of the zirconia is 0.21 mu m, and the specific surface area of the zirconia is 12m ² And/g. Calcining the ceramic material at 400 ℃ for 2 hours, wherein the primary particle size D50 of the calcined ceramic material is 0.11 mu m, the secondary particle size D50 is 0.28 mu m, and the specific surface area is 6.5m ² /g。

The preparation method comprises the steps of adding organic monomer methacrylamide (the addition amount is 1.5% of the mass of the ceramic material), organic monomer dimethylacrylamide (the addition amount is 1% of the mass of the ceramic material), cross-linking agent methylenebisacrylamide (the addition amount is 0.2% of the mass of the ceramic material), dispersant ammonium polyacrylate (the addition amount is 0.4% of the mass of the ceramic material), defoamer n-octanol (the addition amount is 0.02% of the mass of the ceramic material), surfactant triethanolamine (the addition amount is 0.1% of the mass of the ceramic material) and surfactant fatty alcohol polyoxyethylene ether (the addition amount is 0.1% of the mass of the ceramic material) into deionized water, and then adding pH regulator ammonia water to regulate pH to obtain a mixed solution, wherein the pH value of the mixed solution is 11.

Mixing the calcined ceramic material with the mixed solution, and sand grinding to obtain premixed slurry, wherein the solid content of the premixed slurry is 55%, the viscosity of the premixed slurry is 467 mPa.s, the primary particle size D50 is 0.11 mu m, the secondary particle size D50 is 0.32 mu m, and the ratio isSurface area of 4.5m ² /g。

The premixed slurry was defoamed for 30 minutes under the vacuum degree of-75 kPa, then, a catalyst tetramethyl ethylenediamine (the addition amount of which is 0.4% of the mass of the ceramic material) and an initiator ammonium persulfate (the addition amount of which is 0.6% of the mass of the ceramic material) were added to the premixed slurry, and the mixed slurry was obtained by stirring, wherein the solid content of the mixed slurry was 54%, the viscosity was 687 mPa.s, the primary particle diameter D50 was 0.11. Mu.m, and the secondary particle diameter D50 was 0.34. Mu.m.

And (3) injecting the mixed slurry into a mold by using an automatic grouting machine, injecting the slurry from a feed inlet of the mold, stopping grouting after the slurry overflows from an exhaust port, wherein the temperature of the mold is 50 ℃, the vacuum degree of a mold cavity is minus 75kPa, and standing and curing for 20 minutes after grouting is finished to cure the mixed slurry. And demolding the cured mixed slurry to obtain the ceramic preform. And (3) placing the ceramic preform at the humidity of 85% and the temperature of 40 ℃ for 24 hours, and then placing the ceramic preform at the humidity of 40% and the temperature of 115 ℃ for 10 hours to obtain a ceramic green body, wherein the water content of the ceramic green body is 2.5%. And (3) discharging glue for 2 hours at 600 ℃, and sintering for 1.5 hours at 1450 ℃ to obtain the ceramic substrate, namely the shell.

Referring to fig. 8, a microscopic morphology of the ceramic substrate grains shows that the grains have uniform and fine particle size, compact overall structure, and no defects such as pores, cracks, etc.; meanwhile, the performance of the ceramic substrate is detected, wherein the porosity of the ceramic substrate is 0.12%, the average grain size is 342nm, the four-point bending strength is 1147MPa, the characteristic strength is 1186MPa, and the Weber modulus is 13.2.

Example 2

The ceramic material comprises, by mass, 87.8% of zirconia, 5.2% of yttria, 2% of hafnium oxide, 1.5% of a reinforcing agent (comprising 0.5% of titania, 0.4% of silica and 0.6% of germanium oxide), and 3.5% of a coloring agent (comprising 0.9% of alumina, 0.8% of zinc oxide, 1% of cobalt oxide and 0.8% of ferric oxide), wherein the primary particle size D50 of the zirconia is 0.08 mu m, the secondary particle size D50 of the zirconia is 0.21 mu m, and the specific surface area of the zirconia is 12m ² And/g. Calcining the ceramic material at 400 ℃ for 2 hours, wherein the primary particle size D50 of the calcined ceramic material is 0.11 mu m, and the secondary is carried outThe particle diameter D50 of the particles is 0.28 mu m, and the specific surface area is 6.5m ² /g。

Organic monomer dimethyl acrylamide (the addition amount is 1% of the mass of the ceramic material), cross-linking agent methylene bisacrylamide (the addition amount is 0.2% of the mass of the ceramic material), dispersant ammonium polyacrylate (the addition amount is 0.4% of the mass of the ceramic material), defoamer n-octanol (the addition amount is 0.02% of the mass of the ceramic material), surfactant triethanolamine (the addition amount is 0.1% of the mass of the ceramic material) and surfactant fatty alcohol polyoxyethylene ether (the addition amount is 0.1% of the mass of the ceramic material) are added into deionized water, then pH regulator ammonia water is added to regulate pH, and mixed liquid is obtained, wherein the pH value of the mixed liquid is 11.

Mixing the calcined ceramic material with the mixed solution, and sand grinding to obtain premixed slurry, wherein the solid content of the premixed slurry is 55%, the viscosity of the premixed slurry is 467 mPa.s, the primary particle size D50 is 0.11 mu m, the secondary particle size D50 is 0.32 mu m, and the specific surface area is 4.5m ² /g。

And (3) injecting the mixed slurry into a mold by using an automatic grouting machine, injecting the slurry from a feed inlet of the mold, stopping grouting after the slurry overflows from an exhaust port, wherein the temperature of the mold is 50 ℃, the vacuum degree of a mold cavity is minus 75kPa, and standing and curing for 20 minutes after grouting is finished to cure the mixed slurry. And demolding the cured mixed slurry to obtain the ceramic preform. And (3) placing the ceramic preform at the humidity of 85% and the temperature of 40 ℃ for 24 hours, and then placing the ceramic preform at the humidity of 40% and the temperature of 115 ℃ for 10 hours to obtain a ceramic green body, wherein the water content of the ceramic green body is 2.4%. And (3) discharging glue for 2 hours at 600 ℃, and sintering for 1.5 hours at 1450 ℃ to obtain the ceramic substrate, namely the shell.

Referring to fig. 9, a microscopic morphology of the ceramic substrate grains shows that the grains have uniform and fine particle size, compact overall structure, and no obvious defects such as pores and cracks; meanwhile, the performance of the ceramic substrate is detected, wherein the porosity of the ceramic substrate is 0.18%, the average grain size is 348nm, the four-point bending strength is 1025MPa, the characteristic strength is 1062MPa, and the Weber modulus is 10.2.

Example 3

The ceramic material comprises 90.2% of zirconia, 4.3% of yttria, 2% of hafnium oxide, 1.5% of reinforcing agent (comprising 0.5% of titanium oxide, 0.4% of silicon oxide and 0.6% of germanium oxide) and 2% of alumina coloring agent by mass, wherein the primary particle diameter D50 of the zirconia is 0.06 mu m, the secondary particle diameter D50 is 0.2 mu m, and the specific surface area is 15m ² And/g. Calcining the ceramic material at 500 ℃ for 1h, wherein the primary particle size D50 of the calcined ceramic material is 0.09 mu m, the secondary particle size D50 is 0.32 mu m, and the specific surface area is 7.4m ² /g。

Organic monomer dimethyl acrylamide (the addition amount is 2% of the mass of the ceramic material), cross-linking agent methylene bisacrylamide (the addition amount is 0.1% of the mass of the ceramic material), cross-linking agent phosphonobutane tricarboxylic acid (the addition amount is 0.05% of the mass of the ceramic material), dispersing agent ammonium polyacrylate (the addition amount is 0.2% of the mass of the ceramic material), dispersing agent polyvinyl alcohol (the addition amount is 0.2% of the mass of the ceramic material), defoaming agent glycerol polyoxyethylene ether (the addition amount is 0.02% of the mass of the ceramic material) and surfactant diethanolamine (the addition amount is 0.2% of the mass of the ceramic material) are added into deionized water, and then pH is adjusted by adding pH regulator ammonia water to obtain a mixed solution, wherein the pH value of the mixed solution is 12.

Mixing the calcined ceramic material with the mixed solution, and sand grinding to obtain premixed slurry, wherein the solid content of the premixed slurry is 50%, the viscosity of the premixed slurry is 724 mPa.s, the primary particle size D50 is 0.09 mu m, the secondary particle size D50 is 0.37 mu m, and the specific surface area is 4.5m ² /g。

The premixed slurry is defoamed for 30min under the vacuum degree of 75kPa, then a catalyst tetramethyl ethylenediamine (the addition amount is 0.5 percent of the mass of the ceramic material), an initiator ammonium persulfate (the addition amount is 0.4 percent of the mass of the ceramic material) and an initiator diaminodipropylamine (the addition amount is 0.2 percent of the mass of the ceramic material) are added into the premixed slurry, and the mixed slurry is obtained after stirring, wherein the solid content of the mixed slurry is 49 percent, the viscosity is 904 mPa.s, the primary particle size D50 is 0.09 mu m, and the secondary particle size D50 is 0.42 mu m.

And (3) injecting the mixed slurry into a mold by using an automatic grouting machine, injecting the slurry from a feed inlet of the mold, stopping grouting after the slurry overflows from an exhaust port, wherein the mold temperature is 60 ℃, the vacuum degree of a mold cavity is minus 75kPa, and standing and curing for 20 minutes after grouting is finished to cure the mixed slurry. And demolding the cured mixed slurry to obtain the ceramic preform. And (3) placing the ceramic preform at the humidity of 85% and the temperature of 40 ℃ for 24 hours, and then placing the ceramic preform at the humidity of 40% and the temperature of 115 ℃ for 10 hours to obtain a ceramic green body, wherein the water content of the ceramic green body is 2.1%. And (3) discharging glue for 2 hours at 600 ℃, and sintering for 1.5 hours at 1420 ℃ to obtain the ceramic substrate, namely the shell.

Referring to fig. 10, a microscopic morphology of the ceramic substrate grains shows that the grains have uniform and fine particle size, compact overall structure, and no obvious defects such as pores and cracks; meanwhile, the performance of the ceramic substrate is detected, wherein the porosity of the ceramic substrate is 0.15%, the average grain size is 320nm, the four-point bending strength is 1171MPa, the characteristic strength is 1224MPa, and the Weber modulus is 10.7.

Comparative example 1

The ceramic material comprises, by mass, 87.8% of zirconia, 5.2% of yttria, 2% of hafnium oxide, 1.5% of a reinforcing agent (comprising 0.5% of titania, 0.4% of silica and 0.6% of germanium oxide), and 3.5% of a coloring agent (comprising 0.9% of alumina, 0.8% of zinc oxide, 1% of cobalt oxide and 0.8% of ferric oxide), wherein the primary particle size D50 of the zirconia is 0.08 mu m, the secondary particle size D50 of the zirconia is 0.21 mu m, and the specific surface area of the zirconia is 12m ² /g。

Mixing ceramic material and mixed solution, and sand grinding to obtain premixed slurry with solid content of 55%, viscosity of 1480 mPa.s, primary particle diameter D50 of 0.07 μm, secondary particle diameter D50 of 0.19 μm and specific surface area of 10.8m ² /g。

The premixed slurry was defoamed for 30 minutes under the vacuum degree of-75 kPa, then a catalyst tetramethyl ethylenediamine (the addition amount of which is 0.4% of the mass of the ceramic material) and an initiator ammonium persulfate (the addition amount of which is 0.6% of the mass of the ceramic material) were added to the premixed slurry, and the mixed slurry was obtained by stirring, the solid content of the mixed slurry was 54%, the viscosity was 1650 mPa.s, the primary particle diameter D50 was 0.07. Mu.m, and the secondary particle diameter D50 was 0.28. Mu.m.

Referring to FIG. 11, a microscopic morphology of the ceramic substrate grains is shown, in which the overall structure is not uniform, and the grains with abnormal growth and more pores are formed; meanwhile, the performance of the ceramic substrate is detected, wherein the porosity of the ceramic substrate is 0.37%, the average grain size is 307nm, the maximum grain size exceeds 1 mu m, the four-point bending strength is 740MPa, the characteristic strength is 810MPa, the Weber modulus is 5.4, and the strength data discreteness is large.

Comparative example 2

The ceramic material comprises 90.2% of zirconia, 4.3% of yttria, 2% of hafnium oxide, 1.5% of reinforcing agent (comprising 0.5% of titanium oxide, 0.4% of silicon oxide and 0.6% of germanium oxide) and 2% of alumina coloring agent by mass, wherein the primary particle diameter D50 of the zirconia is 0.06 mu m, the secondary particle diameter D50 is 0.2 mu m, and the specific surface area is 15m ² And/g. Calcining the ceramic material at 800 ℃ for 2 hours, wherein the primary particle size D50 of the calcined ceramic material is 0.18 mu m, the secondary particle size D50 is 0.91 mu m, and the specific surface area is 3.4m ² /g。

Mixing the calcined ceramic material with the mixed solution, and sand grinding to obtain premixed slurry, wherein the solid content of the premixed slurry is 50%, the viscosity of the premixed slurry is 210 mPa.s, the primary particle size D50 is 0.1 mu m, the secondary particle size D50 is 1.1 mu m, and the specific surface area is 3.1m ² /g。

The premixed slurry is defoamed for 30min under the vacuum degree of 75kPa, then a catalyst tetramethyl ethylenediamine (the addition amount is 0.5 percent of the mass of the ceramic material), an initiator ammonium persulfate (the addition amount is 0.4 percent of the mass of the ceramic material) and an initiator diaminodipropylamine (the addition amount is 0.2 percent of the mass of the ceramic material) are added into the premixed slurry, and the mixed slurry is obtained after stirring, wherein the solid content of the mixed slurry is 49 percent, the viscosity is 410 mPa.s, the primary particle size D50 is 0.18 mu m, and the secondary particle size D50 is 1.28 mu m.

And (3) injecting the mixed slurry into a mold by using an automatic grouting machine, injecting the slurry from a feed inlet of the mold, stopping grouting after the slurry overflows from an exhaust port, wherein the mold temperature is 60 ℃, the vacuum degree of a mold cavity is minus 75kPa, and standing and curing for 20 minutes after grouting is finished to cure the mixed slurry. And demolding the cured mixed slurry to obtain the ceramic preform. And (3) placing the ceramic preform at the humidity of 85% and the temperature of 40 ℃ for 24 hours, and then placing the ceramic preform at the humidity of 40% and the temperature of 115 ℃ for 10 hours to obtain a ceramic green body, wherein the water content of the ceramic green body is 2%. And (3) discharging glue for 2 hours at 600 ℃, and sintering for 1.5 hours at 1420 ℃ to obtain the ceramic substrate, namely the shell.

Referring to FIG. 12, a microscopic topography of a ceramic substrate grain can be seen to have a non-uniform overall structure with abnormally grown grains and defects in the pores; meanwhile, the performance of the ceramic substrate is detected, wherein the porosity of the ceramic substrate is 0.57%, the average grain size is 370nm, the maximum grain size exceeds 1 mu m, the four-point bending strength is 817MPa, the characteristic strength is 840MPa, the Weber modulus is 4.1, and the strength data discreteness is large. As can be seen from the above, compared with the comparative example, the ceramic substrate prepared by the method provided by the application has the advantages of low porosity, high Wei Shimo, good strength and consistency, excellent performance and more favorability for the application of the shell.

The foregoing has outlined rather broadly the more detailed description of embodiments of the application in order that the principles and embodiments of the application may be better understood, and in order that the present application may be better understood; meanwhile, as those skilled in the art will have variations in the specific embodiments and application scope in accordance with the ideas of the present application, the present description should not be construed as limiting the present application in view of the above.

Claims

1. A method of manufacturing a housing, comprising:

calcining the ceramic raw material to obtain a ceramic material, wherein the calcining temperature is 300-600 ℃ and the calcining time is 1-2 h, the primary particle size D50 of the ceramic material is less than 0.15 mu m, the secondary particle size D50 is less than 0.5 mu m, and the specific surface area is less than 8 mu m ² /g；

Mixing the ceramic material with a mixed solution, and then sanding to obtain premixed slurry, wherein the mixed solution comprises a gel agent and an auxiliary agent, and the ceramic material is an inorganic substance;

the mixed slurry is subjected to gel casting, drying, glue discharging and sintering to obtain a ceramic substrate, wherein the porosity of the ceramic substrate is smaller than 0.3%, the Weber modulus is larger than 10, the ceramic substrate is made of ceramic materials, and the ceramic materials are inorganic matters, so that the shell is prepared.

2. The method of claim 1, wherein the ceramic material comprises 79% -98% zirconia, 2% -8% yttria, 0% -3% hafnium oxide, 0% -5% reinforcing agent, and 0% -5% coloring agent by mass.

3. The method of manufacturing according to claim 2, wherein the preparation of the ceramic material comprises:

Mixing the calcined zirconia with the yttrium oxide, the hafnium oxide, the reinforcing agent and the coloring agent to obtain the ceramic material; or (b)

And mixing the zirconium oxide, the yttrium oxide, the hafnium oxide, the reinforcing agent and the coloring agent, and then calcining to obtain the ceramic material.

4. The method of claim 1, wherein the gelling agent comprises at least one of an organic monomer and a cross-linking agent;

the mass of the organic monomer accounts for 1.5% -4% of the mass of the ceramic material;

the mass of the cross-linking agent accounts for 0.1-0.4% of the mass of the ceramic material;

the mass ratio of the organic monomer to the crosslinking agent is (10-20): 1, a step of;

the organic monomer comprises at least one of acrylamide, methacrylamide, dimethylacrylamide, hydantoin epoxy resin and isobutene-maleic anhydride copolymer;

the crosslinking agent comprises at least one of methylene bisacrylamide and phosphonobutane tricarboxylic acid.

5. The method of claim 1, wherein the catalyst comprises 0.1% -1% by mass of the ceramic material;

the mass of the initiator accounts for 0.3% -1% of the mass of the ceramic material;

The catalyst comprises at least one of tetramethyl ethylenediamine and dimethyl aniline;

the initiator comprises at least one of ammonium persulfate, diaminodipropylamine and benzoyl peroxide.

6. The method of claim 1, wherein the adjuvant comprises at least one of a dispersant, an antifoaming agent, a surfactant, and a pH adjuster;

the mass of the dispersing agent accounts for 0.2-0.5% of the mass of the ceramic material;

the mass of the defoaming agent accounts for 0.01% -0.05% of the mass of the ceramic material;

the mass of the surfactant accounts for 0.1-0.3% of the mass of the ceramic material;

the dispersing agent comprises at least one of ammonium polyacrylate, polyacrylic acid, sodium polyacrylate, polyvinyl alcohol and ammonium citrate;

the defoamer comprises at least one of n-octanol, glycerol and glycerol polyoxyethylene ether;

the surfactant comprises at least one of triethanolamine, diethanolamine, polyethylene glycol, ethylene glycol and fatty alcohol polyoxyethylene ether;

the pH value of the mixed solution is 9-12.

7. The method of claim 1, wherein the premix slurry has a solids content of 40% to 60% and a viscosity of less than 1000 mPa-s;

The solid content of the mixed slurry is 40% -60%, and the viscosity is less than 1000 mPa.s.

8. The method according to claim 1, wherein the drying process comprises treating at a humidity of 70% -90%, 30 ℃ -50 ℃ for 12h-24h, and then treating at a humidity of 20% -50%, 80 ℃ -120 ℃ for 6h-12h; or (b)

The drying process comprises soaking in a solution containing a hydrophilic organic solvent for 3-12 h at a temperature of 10-50 ℃; then the mixture is treated for 12 to 24 hours at the humidity of 70 to 90 percent and the temperature of 30 to 50 ℃; then the mixture is treated for 6 to 12 hours at the humidity of 20 to 50 percent and the temperature of 60 to 120 ℃.

9. The method of manufacturing according to claim 1, wherein the ceramic green body is produced after drying, and the water content of the ceramic green body is less than 3%.

10. The method of claim 1, wherein the deaerating comprises deaerating at a vacuum of less than or equal to-70 kPa for 10min to 60min;

the temperature of the gel injection molding is 30-90 ℃ and the time is 10-30 min;

the glue discharging comprises the steps of treating for 2-4 hours at 400-600 ℃;

the sintering comprises treating at 1300-1500 ℃ for 1-2 h.

11. A casing prepared by the preparation method of any one of claims 1 to 10, wherein the casing comprises a ceramic substrate, the porosity of the ceramic substrate is less than 0.3%, the weber modulus is greater than 10, the ceramic substrate is made of a ceramic material, and the ceramic material is an inorganic substance.

12. The housing of claim 11, wherein the ceramic substrate has a four-point flexural strength of greater than 1100MPa and a grain size of less than 400nm.

13. The housing of claim 11, wherein the ceramic substrate is a zirconia ceramic having a zirconia content of 79% to 98% by mass.

14. The housing of claim 13, wherein the zirconia ceramic further comprises, by mass, 2% -8% yttria, 0% -3% hafnium oxide, 0% -5% reinforcing agent, and 0% -5% coloring agent.

15. The housing of claim 11, further comprising a protective layer disposed on a surface of the ceramic substrate, the protective layer comprising at least one of an anti-fingerprint layer and a hardened layer.

16. An electronic device comprising the housing of any one of claims 11-15.