CN114538938B

CN114538938B - Shell, preparation method thereof and electronic equipment

Info

Publication number: CN114538938B
Application number: CN202210245231.3A
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: 2023-03-24
Anticipated expiration: 2042-03-11
Also published as: CN114538938A

Abstract

The application provides a preparation method of a shell, which comprises the steps of mixing a ceramic material and a mixed solution, and then sanding the mixed solution to obtain premixed slurry, wherein the mixed solution comprises a humectant and a coupling agent, the humectant accounts for 0.2-0.8% of the mass of the ceramic material, and the coupling agent accounts for 0.2-1% of the mass of the ceramic material; after the premixed slurry is defoamed, adding a catalyst and an initiator to obtain mixed slurry; the mixed slurry is subjected to gel casting and drying to obtain a ceramic green body; and removing the adhesive from the ceramic green body and sintering to obtain a ceramic substrate, thus obtaining the shell. The preparation method improves the surface quality of the ceramic green body, ensures that the ceramic material is not easy to agglomerate or settle in the process of preparing the ceramic green body, and improves the strength of the ceramic green body and the uniformity of volume density distribution, thereby improving the surface performance and the mechanical strength of the ceramic substrate and the shell. The application also provides a shell and an electronic device.

Description

Shell, preparation 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 of the shell and electronic equipment.

Background

The ceramic material has the advantages of high hardness, good toughness, wear resistance and the like, and is often applied to electronic equipment in recent years. Ceramic materials are often made into green bodies, and then the green bodies are dried and sintered to form ceramic products, the green bodies are easy to crack in the preparation process, and the strength of the green bodies needs to be improved, so that the preparation yield and the service performance of the ceramic products are influenced.

Disclosure of Invention

In view of this, the present application provides a housing, a method for manufacturing the same, and an electronic device.

In a first aspect, the present application provides a method for preparing a housing, comprising:

mixing a ceramic material and a mixed solution, and then sanding to obtain a premixed slurry, wherein the mixed solution comprises a humectant and a coupling agent, the humectant accounts for 0.2-0.8% of the mass of the ceramic material, and the coupling agent accounts for 0.2-1% of the mass of the ceramic material;

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

the mixed slurry is subjected to gel casting and drying to obtain a ceramic green body;

and carrying out glue discharging and sintering on the ceramic green body to obtain a ceramic substrate, and thus obtaining the shell.

In a second aspect, the present application provides a housing made by the method of the first aspect.

In a third aspect, the present application provides an electronic device comprising the housing of the second aspect.

According to the preparation method of the shell, the humectant and the coupling agent are added, the adding amount of the humectant and the coupling agent is controlled simultaneously, the surface quality of the ceramic green body is improved, the ceramic material is prevented from agglomerating or settling easily in the process of preparing the ceramic green body, the strength of the ceramic green body and the uniformity of volume density distribution are improved, the shell with good surface performance and excellent mechanical performance can be obtained, the production yield of the preparation method is high, the application of the shell in electronic equipment is facilitated, and the use performance and the product competitiveness of the electronic equipment are improved.

Drawings

In order to more clearly explain the technical solution in the embodiments of the present application, the drawings that are required to be 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 housing according to an embodiment of the present disclosure.

Fig. 2 is a schematic structural diagram of a housing according to an embodiment of the present application.

Fig. 3 is a schematic structural diagram of a housing according to another embodiment of the present application.

Fig. 4 is a schematic structural diagram of an electronic device according to an embodiment of the present application.

Fig. 5 is a schematic structural diagram of an electronic device according to an embodiment of the present application.

FIG. 6 is a microscopic topography of the ceramic green body made in example 1.

FIG. 7 is a microscopic topography of the ceramic green body made in example 2.

Fig. 8 is a microscopic morphology of the ceramic green body prepared in comparative example 1.

Fig. 9 is a microscopic morphology of the ceramic green body prepared in comparative example 2.

Fig. 10 is a microscopic topography of the ceramic green body prepared in comparative example 3.

Fig. 11 is a microscopic morphology of the ceramic green body prepared in comparative example 4.

Detailed Description

The following is a preferred embodiment of the present application, and it should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present application, and these improvements and modifications 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 disclosure of the present application, specific example components and arrangements are described below. Of course, they are merely examples and are not intended to limit the present application. Moreover, the present application may repeat reference numerals and/or letters in the various examples, such repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. In addition, examples of various specific processes and materials are provided herein, but one of ordinary skill in the art may recognize applications of other processes and/or use of other materials.

Referring to fig. 1, a schematic flow chart of a method for manufacturing a housing according to an embodiment of the present disclosure includes:

s101: and mixing the ceramic material and the mixed solution, and then sanding to obtain the premixed slurry, wherein the mixed solution comprises a humectant and a coupling agent, the mass of the humectant accounts for 0.2-0.8% of the mass of the ceramic material, and the mass of the coupling agent accounts for 0.2-1% of the mass of the ceramic material.

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

S103: and carrying out gel casting molding and drying on the mixed slurry to obtain a ceramic green body.

S104: and (4) carrying out glue discharging and sintering on the ceramic green body to obtain a ceramic substrate, thus obtaining the shell.

In the correlation technique, often need prepare ceramic green body earlier and obtain ceramic product through thermal treatment to also need drying process in the preparation process of ceramic green body, crack, peeling scheduling problem appear easily in drying process, heat treatment process etc. in-process product surface, influence ceramic substrate's processing, ceramic green body intensity is little simultaneously, thereby influences ceramic substrate mechanical properties and promotes. According to the method, a proper amount of the humectant and the coupling agent are added into the mixed solution, and the humectant can form a thin film layer on the surface of the ceramic material, so that water is slowly removed in the processes of drying, sintering and the like, the problems of cracking, peeling and the like on the surfaces of ceramic green bodies and ceramic substrates are avoided, and the deformation is reduced; the coupling agent can modify the surface of the ceramic materials and improve the compatibility among the ceramic materials, thereby avoiding the agglomeration among the ceramic materials, being beneficial to obtaining the premixed slurry with low viscosity and high stability and being beneficial to improving the strength of a ceramic green body and the uniformity of volume density distribution; the preparation method provided by the application is beneficial to the application of the shell 100 by improving the surface property and the mechanical strength of the ceramic green body, thereby improving the surface property and the mechanical strength of the shell 100.

In S101, a premixed slurry is obtained by mixing and sanding a ceramic material and the mixed liquid. In the present application, the ceramic material is an inorganic substance, and the mixed liquid is an aqueous solution containing an organic substance.

In the present application, the mixed solution includes a humectant and a coupling agent. The mass of the humectant accounts for 0.2-0.8% of the mass of the ceramic material. The moisture removal in the drying process is influenced by too much humectant content, and the improvement on the surface performance of the ceramic green body is limited due to too little humectant content; the humectant with the content can effectively promote the moisture to be slowly and uniformly removed in the drying process, avoids the occurrence of cracking and peeling, and improves the surface quality of ceramic green bodies, thereby being beneficial to the improvement of the surface performance and the mechanical strength of the shell 100. Specifically, the mass of the humectant may be, but is not limited to, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, or the like, based on the mass of the ceramic material. In one embodiment, the humectant is present in an amount of 0.2% to 0.4% by weight of the ceramic material. In another embodiment, the humectant comprises 0.4% to 0.6% by mass of the ceramic material. In yet another embodiment, the humectant comprises 0.6% to 0.8% by mass of the ceramic material. In an embodiment of the present application, the humectant includes at least one of glycerin, polyethylene glycol, aqueous acrylate, sodium carboxymethyl cellulose, and polyvinylpyrrolidone. Further, the humectant comprises at least one of glycerol and polyethylene glycol, so that the moisture is more favorably and uniformly and slowly removed in the drying process.

In the present application, the mass of the coupling agent is 0.2% to 1% of the mass of the ceramic material. The content of the coupling agent is excessive, and after the coupling agent completely modifies the surface of the ceramic material, the alkoxy is excessive in the solution, so that the property of the solution is changed, the ceramic material is changed from hydrophilicity to hydrophobicity, and the agglomeration of the ceramic material is increased; the content of the coupling agent is too low, so that the ceramic material is not enough to be completely modified, and the agglomeration among the ceramic materials cannot be effectively avoided; the ceramic material can be effectively modified by adopting the content, the solution performance is not influenced, and the agglomeration is avoided, so that the surface performance and the mechanical strength of the ceramic green body and the shell 100 are improved. Specifically, the mass of the coupling agent may be, but not limited to, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, or the like based on the mass of the ceramic material. In one embodiment, the mass of the coupling agent is 0.2-0.5% of the mass of the ceramic material. In another embodiment, the mass of the coupling agent is 0.4% -0.7% of the mass of the ceramic material. In yet another embodiment, the coupling agent is present in an amount of 0.5% to 1% by mass of the ceramic material. In embodiments of the present application, the coupling agent comprises a titanate-based coupling agent. The titanate coupling agent has wide application range and can better match a mixed solution system; and meanwhile, alkoxy on the surface of the coupling agent can react with hydroxide ions on the surface of the ceramic material, so that the surface of the ceramic material is modified, and the stability of the premixed slurry is improved. In one embodiment, the coupling agent comprises at least one of a monoalkoxy titanate coupling agent, a monoalkoxy pyrophosphate titanate coupling agent, a chelating titanate coupling agent, and a coordination titanate coupling agent. Specifically, the monoalkoxy titanate coupling agent comprises at least one of a monoalkoxy fatty acid titanate coupling agent, a monoalkoxy phosphoric acid titanate coupling agent and a monoalkoxy pyrophosphoric acid titanate coupling agent. Specifically, the coupling agent may further include an alkoxyfatty acid titanate, and the alkoxyfatty acid titanate includes at least one of isopropyltrioleate acyloxy titanate and isopropyltristearate acyloxy titanate.

In an embodiment of the present invention, the mixed solution further includes at least one of an organic monomer, a crosslinking agent, a dispersant, an antifoaming agent, a surfactant, and a pH adjuster.

In the application, an organic monomer and a cross-linking agent undergo in-situ polymerization under the action of an initiator and a catalyst to form a high-molecular three-dimensional network structure, so that liquid mixed slurry undergoes gel curing, ceramic materials undergo in-situ bonding, and the cross-linking agent can promote the monomer to form a three-dimensional network structure through cross-linking and influence the cross-linking degree; the dispersing agent, the defoaming agent, the surfactant, the pH regulator and the like can improve the performance of materials and solutions and facilitate the subsequent gel curing.

In an embodiment of the present application, the organic monomer includes at least one of acrylamide, methacrylamide, dimethylacrylamide and hydantoin epoxy resin. In the embodiment of the present application, the mass of the organic monomer accounts for 1.5% to 4% of the mass of the ceramic material, such as 1.5%, 2%, 2.5%, 3%, 3.5%, or 4%. The content of the organic monomer is too low, which is not beneficial to the formation of a three-dimensional network structure and the dispersion and fixation of the ceramic material; the content of the organic monomer is too much, and the formed three-dimensional network structure is too much, so that the removal of bubbles is not facilitated; the organic monomer with the content not only ensures the dispersion and fixation of the ceramic material, but also does not increase the porosity of the ceramic green body, and is beneficial to the improvement of the strength of the ceramic green body and the improvement of the volume density uniformity. In one embodiment, the organic monomer is present in an amount of 1.5% to 2.5% by weight of the ceramic material. In yet another embodiment, the organic monomer is present in an amount of 2.5% to 4% by mass of the ceramic material.

In embodiments herein, the crosslinking agent comprises at least one of methylene bisacrylamide and phosphonobutane tricarboxylic acid. In the embodiment of the present application, the mass of the cross-linking agent is 0.1% to 0.4% of the mass of the ceramic material, such as 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, or 0.4%. The content of the cross-linking agent is too large, the chain length of a polymer formed by the organic monomer is too short, the dispersion and fixation of the ceramic material are not facilitated, and the four-point bending strength of the ceramic green body is not improved; the content of the cross-linking agent is too small, the three-dimensional network structure formed by the organic monomer is incomplete, and the improvement of the strength of the ceramic green body is not facilitated; the cross-linking agent with the content can effectively promote the organic monomer to be cross-linked to form a proper three-dimensional network structure, and is beneficial to improving the strength of the ceramic green body. In one embodiment, the cross-linking agent is present in an amount of 0.1% to 0.2% by weight of the ceramic material. In yet another embodiment, the cross-linking agent is present in an amount of 0.2% to 0.4% by mass of the ceramic material.

In the examples of the present application, the mass ratio of the organic monomer to the crosslinking agent is (10-20): 1. thus, the formation of a three-dimensional network structure is facilitated, the ceramic material is uniformly dispersed in the three-dimensional network structure, and the strength of the ceramic green body is improved. 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 (13-17): 1, the strength of the ceramic green body is further improved.

In the application, the dispersing agent is used for promoting the ceramic material to be uniformly dispersed in the premixed slurry, the dispersing agent can be adsorbed on the surface of the ceramic material particles, so that a macromolecular layer is formed on the surface of the particles, and a macromolecular chain extends into the premixed slurry, thereby preventing the ceramic material particles from being contacted with each other, simultaneously changing the Zeta potential on the surface of the ceramic material, weakening the agglomeration effect among the ceramic materials, and further avoiding the occurrence of agglomeration. In one embodiment, the dispersant includes at least one of ammonium polyacrylate, polyacrylic acid, sodium polyacrylate, polyvinyl alcohol, and ammonium citrate. In one embodiment, the dispersant is present in an amount of 0.2% to 0.5% by mass, such as 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, or 0.5% by mass of the ceramic material. The dispersant with the content can effectively promote the dispersion of the ceramic material, 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 weight 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, the defoamer is used to suppress the formation of foam in the mixed liquor as well as in the premixed slurry. In one embodiment, the defoamer comprises at least one of n-octanol, glycerol, and glycerol polyoxyethylene ether. In one embodiment, the defoaming agent comprises 0.01% to 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% by mass. The defoaming agent with the content can ensure that the foam of the mixed solution and the premixed slurry can be effectively removed. In one embodiment, the mass of the defoaming agent is 0.01-0.025% of the mass of the ceramic material. In yet another embodiment, the mass of the defoamer is 0.03-0.05% of the 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 premixed slurry, contribute to increasing the solid content of the premixed slurry, reduce the viscosity of the premixed slurry and improve the stability of the premixed slurry. In one embodiment, the surfactant comprises at least one of triethanolamine, diethanolamine, and fatty alcohol polyoxyethylene ether. In one embodiment, the surfactant is present in an amount of 0.1% to 0.3% by mass, such as 0.1%, 0.15%, 0.2%, 0.25%, or 0.3% by mass of the ceramic material. The surfactant with the content can effectively improve the rheological property of the premixed slurry. In one embodiment, the surfactant is present in an amount of 0.1% to 0.2% by weight of the ceramic material. In yet another embodiment, the surfactant is present in an amount of 0.2% to 0.3% by mass of the ceramic material.

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

In the embodiment of the application, the mixed liquid contains water; the water is used as a solvent for dispersing other components in the mixed solution, and plays a role in dispersing the ceramic material in the premixed slurry, so that the solid content of the premixed slurry is ensured, and the addition amount of the water is added according to the solid content required by the premixed slurry. In the application, the mixing ratio of the ceramic material and the mixed solution can be selected according to the solid content required by the premixed slurry.

In the present embodiment, the ceramic material includes zirconia, and thus the ceramic substrate 10 is made of zirconia ceramic. The zirconia ceramic has excellent toughness, strength and hardness, improves the mechanical properties 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 or the ceramic material are not limited, and for example, the primary particle diameter D50 of the zirconia or the ceramic material is less than 0.2 μm, the secondary particle diameter D50 is less than 0.1 μm and the specific surface area is less than 20m ² (iv) g. Wherein, the grain diameter D50 is the corresponding grain diameter when the cumulative grain size distribution percentage of the material reaches 50 percent, and is also called as the median diameter or the median diameter.

In an embodiment of the present application, the ceramic material comprises zirconia and yttria. Wherein, the yttrium oxide is used as a stabilizer, which is beneficial to the formation of tetragonal phase zirconium oxide and improves the stability of the whole structure. In one embodiment, the mass content of yttrium oxide in the ceramic material is 2% -8%, which can ensure the formation and stable existence of tetragonal zirconia, and does not affect the structural performance. Specifically, the mass content of yttrium oxide in the ceramic material may be, but not limited to, 2%, 3%, 4%, 5%, 6%, 7%, 8%, or the like. In one embodiment, the mass content of yttria in the ceramic material is 2% to 4%. In another embodiment, the yttrium oxide content of the ceramic material is 4% to 8% by mass.

In embodiments of the present application, the ceramic material may further comprise hafnium oxide. Among them, hafnium oxide is a intergrowth of zirconia powder, and zirconia powder usually contains a small amount of hafnium oxide. Specifically, the mass content of hafnium oxide in the ceramic material may be, but is not limited to, less than or equal to 3%, such as 0.1%, 0.5%, 1%, 1.5%, 2%, or 3% by mass of hafnium oxide in the ceramic material.

In embodiments of the present application, the ceramic material may further include a reinforcing agent. The fracture toughness of the ceramic green body is further improved by adding the reinforcing agent. In one embodiment, the reinforcing agent may include at least one of titanium oxide, silicon oxide, germanium oxide, magnesium oxide, and zinc oxide. The inorganic material can be used as a reinforcing agent to effectively improve the fracture toughness of the ceramic green body. In one embodiment, the mass content of the reinforcing agent in the ceramic material is less than or equal to 5%, which not only can ensure that the fracture toughness of the ceramic green body is improved, but also can avoid the influence of excessive content on the hardness of the ceramic green body. 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 reinforcing agent is present in the ceramic material in an amount of 0.5% to 2% by weight. In another embodiment, the reinforcing agent is present in the ceramic material in an amount of 3% to 5% by mass.

In embodiments of the present application, the ceramic material may further include a coloring agent. The ceramic green body 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 colorant may be, but is not limited to, at least one selected from the group consisting of aluminum oxide, zinc oxide, cobalt oxide, iron trioxide, chromium trioxide, 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 above cations. For example, other compounds having the above cations 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 can be selected according to the color required by the product. In one embodiment, the mass content of the coloring agent in the ceramic material is less than or equal to 5%, which not only ensures that the ceramic green body has color appearance, but also avoids the influence of excessive content on the mechanical properties of the ceramic green body. Specifically, the mass content of the coloring agent in the ceramic material may be, but 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 coloring agent in the ceramic material is 2.5% -5%.

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

In the embodiment of the present application, the ceramic raw material is calcined to obtain a ceramic material. The ceramic raw material and the ceramic material are the same in material, and are different only in the primary particle size, the secondary particle size and the specific surface area of the particles. In one embodiment, the zirconia is calcined and then mixed with yttrium oxide, hafnium oxide, a reinforcing agent and a coloring agent to obtain a ceramic material; or mixing zirconium oxide, yttrium oxide, hafnium oxide, a reinforcing agent and a coloring agent, and then calcining to obtain the ceramic material. In the application, the particles are modified by calcination, so that the specific surface area of the particles is reduced, and the particle size of primary particles and the particle size of secondary particles of the particles are improved, so that a ceramic material is more easily and uniformly dispersed in a mixed solution, and the particles can be effectively prevented from being agglomerated, so that a premixed slurry with high solid content and low viscosity is formed, the internal defects of a ceramic green body are reduced, and the ceramic green body with excellent mechanical properties is formed; in addition, organic impurities on the surfaces of the particles can be removed through calcination, the influence of the organic impurities on the mixing of the ceramic material and the mixed liquid is avoided, and the premixed slurry is ensuredStability of (2). In the embodiment of the present application, the calcination temperature is 300 ℃ to 600 ℃ and the time is 1h to 2h. If the calcining temperature is too low and the time is too short, the calcining effect cannot be achieved, the specific surface area of the particles cannot be reduced, and organic impurities cannot be completely removed; if the calcining temperature is too high and the calcining time is too long, hard agglomeration is easily formed among particles, but the defects in the ceramic green body are increased, and the performance of the ceramic green body is not favorably improved; therefore, the calcining process can ensure that the ceramic material with the required size is formed, and simultaneously, the particles can be uniformly dispersed, thereby being beneficial to reducing the internal defects of the ceramic green body and improving the mechanical property of the ceramic green body. In the present application, the temperature of calcination may be, but is not limited to, 300 ℃, 350 ℃, 400 ℃, 450 ℃, 500 ℃, 550 ℃ or 600 ℃ and the like, and the time of calcination may be, but is not limited to, 60min, 70min, 80min, 90min, 100min, 110min or 120min and the like. In one embodiment, the calcination temperature is 300 ℃ to 400 ℃ and the calcination time is 1.5h to 2h. In another embodiment, the calcination is at a temperature of 500 ℃ to 600 ℃ for a time of 1h to 1.5h. In another embodiment, the zirconia is calcined and then mixed with yttrium oxide, hafnium oxide, a reinforcing agent and a coloring agent; or mixing zirconium oxide, yttrium oxide, hafnium oxide, a reinforcing agent and a coloring agent and then calcining to obtain the ceramic material, wherein the calcining temperature is 300-600 ℃, the time is 1-2 h, the grain diameter D50 of primary particles of the obtained ceramic material is less than 0.15 mu m, the grain diameter D50 of secondary particles is less than 0.5 mu m, and the specific surface area is less than 8m ² (iv) wherein the specific surface area of the zirconia is greater than the specific surface area of the ceramic material.

In this application, mix the back with ceramic material and mixed liquid, can obtain the slurry that mixes through the sanding. The physical properties of the ceramic material are improved by sanding while the properties of the pre-mixed slurry are improved. In an embodiment of the present application, the sanding includes mixing the ceramic material, the mixed liquid, and the sanding medium to perform the grinding. Specifically, the particle size of the sanding medium may be 0.1mm to 2mm, such as 0.1mm, 0.5mm, 1mm, 1.5mm, or 2mm, and the sanding medium may be, but is not limited to, zirconia beads, and the like. In one embodiment, the sanding temperature is 5-15 ℃ (e.g., 5 ℃, 8 ℃, 10 ℃, 13 ℃ or 15 ℃) and the sanding time is 4-12 h (e.g., 4h, 5h, 8h, 10h or 12 h). Through the temperature of control sanding in-process and long to guarantee can improve the performance of premixing thick liquids, be favorable to promoting the performance of ceramic unburned bricks. Specifically, the sanded slurry may be screened, wherein the mesh number of the screen may be, but is not limited to, 1500.

In this application, the solids content is the volume fraction of the solid matter in the slurry. In an embodiment, the solids content of the pre-mix slurry is 40% to 60%, such as 40%, 45%, 50%, 55%, or 60%. The solid content is too low, the content of the ceramic material is low, the combination among particles is loose, the number of air holes is large, and the improvement of the strength of a ceramic green body is not facilitated; the solid content is too high, the content of ceramic materials is high, agglomeration is easy to occur, the viscosity of the premixed slurry is high, injection molding is not facilitated, and the strength of a ceramic green body is still influenced. The solid content in the range ensures the combination and distribution of the ceramic materials, and is beneficial to the improvement of the volume density of the ceramic green body and the reduction of the drying shrinkage rate. In one embodiment, the solids content of the pre-mix slurry is 40% to 50%. In another embodiment, the solids content of the pre-mix slurry is 50% to 60%. In one embodiment, the pre-mix slurry has a viscosity of less than 1000 mPa-s. The premixed slurry has small viscosity and good fluidity, is beneficial to quickly and uniformly filling the slurry in a mould in the injection molding process, is beneficial to discharging air bubbles in the slurry, and improves the mechanical property of a ceramic green body.

In step S102, the premixed slurry is defoamed, so that the content of bubbles in the premixed slurry is reduced, the low porosity of the ceramic green body is ensured, and the strength of the ceramic green body is improved. In one embodiment, the debubbling includes debubbling at a vacuum level of less than or equal to-70 kPa for 10min to 60min (e.g., 10min, 15min, 20min, 30min, 45min, 60min, etc.). And the defoaming time is long under high vacuum degree, so that the bubbles in the premixed slurry can be quickly removed, and the content of the bubbles in the premixed slurry is greatly reduced.

In the present application, the catalyst is used to increase the rate of the cross-linking polymerization reaction and reduce the gel curing time. In one embodiment, the catalyst comprises at least one of tetramethylethylenediamine and dimethylaniline. In one embodiment, the mass of the catalyst is 0.1% to 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%. The catalyst content is too low, the gel curing time of the mixed slurry is too long, and the ceramic material can be settled, so that the density distribution of the ceramic green body is not uniform, and the ceramic green body is easy to deform during drying; 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 a ceramic green body is influenced; the catalyst with the content can ensure that the defects are avoided, and is favorable for improving the performance of the ceramic green body. 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 15min-20min, the injection molding time is ensured, the ceramic material can be prevented from being settled, and the performance of the ceramic green body is improved. In yet another embodiment, the catalyst comprises 0.6% to 1% by mass of the ceramic material.

In the present application, the initiator is used to generate free radicals, sufficient of which are capable of initiating the polymerization reaction of the organic monomer with the crosslinker to promote gel curing. In one embodiment, the initiator includes at least one of ammonium persulfate, diaminodipropylamine, and benzoyl peroxide. In one embodiment, the mass of the initiator is 0.3% to 1% of the mass of the ceramic material, such as 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, or the like. The content of the initiator 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 reaction is too fast in the initial stage of the polymerization reaction, the long-chain structure is not favorably formed, and the strength of the ceramic green body is influenced; the initiator with the content can ensure that the defects are avoided, and the performance of the ceramic green body is promoted. In one embodiment, the initiator is present in an amount of 0.5% to 0.8% by weight of the ceramic material. Therefore, the gel curing time can be ensured to be 15min-20min, the injection molding time is ensured, and the ceramic material can be prevented from settling. In yet another embodiment, the initiator is present in an amount of 0.3% to 0.4% by mass of the ceramic material.

In the application, the catalyst and the initiator are added after the pre-mixed slurry is defoamed, and the mixed slurry can be obtained after uniform stirring. The stirring time is not preferably too long, which may increase the viscosity of the mixed slurry and even start gel curing. Specifically, the stirring time may be less than 5min, such as 1min, 2min, 3min or 4 min. In the present application, the addition of the catalyst and initiator does not affect the solids content and viscosity of the premix slurry too much. In an embodiment, the solids content of the mixed slurry is 40% to 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 solids content of the mixed slurry is 50% to 60%. In one embodiment, the viscosity of the mixed slurry is less than 1000mPa · s.

And S103, carrying out gel casting on the mixed slurry to obtain a ceramic pre-blank, and drying the ceramic pre-blank to obtain a ceramic green body. In one embodiment, the gel-casting process includes injecting the mixed slurry into a mold, curing, and demolding to obtain a ceramic preform. It is understood that it is advantageous to obtain the ceramic substrate 10 of a desired shape by injecting the mixed slurry into a mold. In a specific embodiment, an automatic grouting machine can be used for injecting mixed slurry into a mold, the slurry is injected from a feed port of the mold, the slurry stops grouting after overflowing from an exhaust port, and the whole grouting process is short, so that the gel curing is prevented from being influenced. Specifically, the whole grouting process 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 die cavity can be less than 1 mu m, which is beneficial to reducing the surface roughness of the ceramic green body and improving the surface quality of the ceramic green body.

In one embodiment of the present application, the gel-casting temperature is 30-90 deg.C (e.g., 30 deg.C, 40 deg.C, 50 deg.C, 60 deg.C, 70 deg.C, 80 deg.C or 90 deg.C), and the time is 10-30 min (e.g., 10min, 15min, 20min, 25min or 30 min). The gel casting temperature is too low, the forming time is too long, and the ceramic material is easy to settle, so that the density distribution of the ceramic preform is not uniform, and the ceramic preform deforms in the drying and sintering processes, thereby influencing the use of the ceramic substrate 10; the gel injection molding temperature is too high, the molding time is too short, and the uniform distribution of the mixed slurry in the mold and the discharge of bubbles are not facilitated; the gel injection molding conditions are adopted, so that gel curing is facilitated, and the negative pressure is beneficial to discharging of air bubbles. In one embodiment, the ceramic preform can be prepared by injecting the mixed slurry into a mold at a temperature of 30 ℃ to 90 ℃ and a vacuum degree of a cavity of the mold at-100 kPa to-10 kPa (e.g., -100kPa, 80kPa, 60kPa, 50kPa, 30kPa, or-10 kPa). The vacuum degree of the mold cavity is favorable for injecting mixed slurry and discharging bubbles. Optionally, the temperature of the die is 30-50 ℃, and the vacuum degree of the die cavity of the die is-100 kPa-60 kPa; or the temperature of the die is 60-90 ℃, and the vacuum degree of the die cavity of the die is-60 kPa-10 kPa.

In the 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.), wherein the soaking temperature is 10 ℃ to 50 ℃ (e.g., 10 ℃, 20 ℃, 30 ℃, 40 ℃, or 50 ℃, etc.); treating at humidity of 70-90% (such as 70%, 75%, 80%, 85% or 90%), 30-50 deg.C (such as 30 deg.C, 35 deg.C, 40 deg.C, 45 deg.C or 50 deg.C) for 12-24 hr (such as 12 hr, 15 hr, 17 hr, 20 hr or 22 hr); then treating for 6h-12h (such as 6h, 7h, 8h, 10h or 11 h) at humidity of 20% -50% (such as 20%, 25%, 30%, 40% or 50%), 60 deg.C-120 deg.C (such as 60 deg.C, 70 deg.C, 80 deg.C, 90 deg.C, 100 deg.C, 110 deg.C or 120 deg.C). Soaking in a solution containing a hydrophilic organic solvent to replace water in the ceramic preform with the hydrophilic organic solvent, and removing part of free water on the surface of the ceramic preform, wherein the removed water accounts for 20-30% of the total water content of the ceramic preform; drying at a higher humidity and a lower temperature to remove part of free water and the adsorbed hydrophilic organic solvent on the surface layer of the ceramic preform, wherein the removed water accounts for 40-50% of the total water content of the ceramic preform; finally, drying at low humidity and higher temperature to remove free water and part of absorbed water in the ceramic preform, wherein the removed water accounts for 20-40% of the total water content of the ceramic preform, so that the whole ceramic preform is dried to obtain a ceramic green body; by adopting the drying method, the moisture in the ceramic pre-blank can be removed as far as possible, the problems of peeling and cracking of the surface of the ceramic pre-blank before and after drying are further ensured, the deformation of the ceramic pre-blank before and after drying is small, and the preparation yield is improved. In one embodiment, the hydrophilic organic solvent-containing solution contains 50% to 100% (e.g., 50%, 60%, 70%, 80%, 90%, or 100%) by mass of the hydrophilic organic solvent, thereby facilitating more displacement of free water from 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, thereby facilitating free water displacement without affecting the properties of the ceramic green body. In one embodiment, the drying process comprises soaking in a solution containing a hydrophilic organic solvent for 3h to 5h at a temperature of 30 ℃ to 50 ℃; then processing for 15h-24h at the humidity of 70% -80% and the temperature of 30 ℃ -50 ℃; then processing for 8-12 h at the humidity of 20-50% and the temperature of 60-100 ℃. In another embodiment, the drying process comprises soaking in a solution containing a hydrophilic organic solvent for 5h to 8h at a temperature of 20 ℃ to 35 ℃; then treating for 12-18 h at 40-50 ℃ and with the humidity of 70-90%; then processing for 8-9 h at the humidity of 20-40% and the temperature of 80-120 ℃. In another embodiment, the drying process comprises soaking in a solution containing a hydrophilic organic solvent for 8-12 h at 10-20 deg.C; then processing for 15h-24h at the humidity of 70% -90% and the temperature of 30 ℃ -40 ℃; then processing for 6-8 h at the humidity of 30-50% and the temperature of 80-120 ℃.

In the embodiment of the application, the deformation amount of the ceramic pre-blank before and after drying is less than 0.2mm, and the preparation yield and the product quality of the ceramic green blank are improved. In one embodiment, the ceramic preform has a deformation amount of less than 0.15mm before and after drying. In another embodiment, the ceramic preform has a deformation amount of less than 0.1mm before and after drying. Wherein, the ceramic pre-blank is placed on a flat plate with the flatness less than 0.05mm for drying, and the size of the dried ceramic green blank is about 200mm in length, 150mm in width and 1.5mm in thickness; and placing the ceramic green body on a marble platform, testing the warping degrees of four sides and four corners of the green body by using a feeler gauge, and recording the maximum warping value as a deformation.

In the present application, the drying may be performed in a constant humidity and temperature drying oven. In one embodiment, the water content of the ceramic green body is less than 3%, that is, the mass ratio of water in the ceramic green body is less than 3%, which is beneficial to improving the performance of the ceramic green body. Specifically, the water content of the ceramic green body is less than 2.5%, less than 2%, less than 1%, and the like.

In embodiments of the present application, the four-point bending strength of the ceramic green body is greater than 30MPa. It is understood that the four-point bending strength of the ceramic green body is an average of multiple measurements. Further, the four-point bending strength of the ceramic green body is more than 35MPa. Further, the four-point bending strength of the ceramic green body is greater than 40MPa. In this application, ceramic green compact has high bending strength, and mechanical properties is good, can satisfy the machining requirement, can carry out rough machining to it to reduce the processing degree of difficulty and the processing cost of casing 100. In the embodiment of the application, the internal particles of the ceramic green body are uniformly dispersed without obvious agglomeration, so that the ceramic green body has excellent mechanical properties.

In the embodiments of the present application, the ceramic green body has a work crack ratio of less than 5%. Milling holes (through holes) on ceramic green bodies with the length of 200mm, the width of 150mm and the thickness of 1.5mm by CNC (computerized numerical control), wherein the hole diameter is 10mm, continuously milling 5 holes, the centers of the 5 holes are on the same straight line, the distance between the centers of adjacent holes is 20mm, detecting whether the ceramic green bodies crack after all the 5 holes are milled, and calculating to obtain the machining crack proportion, wherein the diameter D8mm of a tool used by CNC is used, the type of the tool is a diamond grinding wheel rod, the mesh number is 200 meshes, the rotating speed of a main shaft is 20000rpm, the feeding rate is 3000mm/min, and the Z-direction feed amount is 0.10mm. In an embodiment, after the ceramic green body is obtained by drying with the above drying method, the processing cracking proportion of the ceramic green body is less than 4%, the bending strength of the ceramic green body is higher, the requirements of mechanical processing can be met, the processing yield is improved, and the preparation of the ceramic substrate 10 is facilitated. In this application, can be through processing ceramic green body to avoided processing ceramic substrate 10, reduced the processing degree of difficulty, improved the processing yield.

In embodiments of the present application, the ceramic green body has a bulk density greater than 3.78g/cm ³ The volume density difference is less than 0.3g/cm ³ (ii) a That is, the difference in bulk density at different locations in the ceramic green body is less than 0.3g/cm ³ . This applicationThe ceramic green body provided has the advantages of large volume density, close combination among internal particles, contribution to improvement of mechanical properties, small volume density difference, uniform density distribution and good overall performance consistency.

In the application, the four-point bending strength is detected according to GB/T6569-2006 Fine ceramic bending strength test method, the four-point bending strength in the application is an average value of multiple detections, and effective data are not less than 32; detecting the volume density according to GB/T25995-2010 'test method for fine ceramic density and apparent porosity'; obtaining the water content through a water content tester; the agglomeration of the particles in the ceramic green body is observed by a scanning electron microscope.

In S104, the ceramic green body is subjected to binder removal and sintering to obtain the ceramic substrate 10. In one embodiment, the discharging comprises treating at 400-600 ℃ for 2-4 h, and the sintering comprises treating at 1300-1500 ℃ for 1-2 h. Specifically, the glue discharging temperature can be but is not limited to 400 ℃, 450 ℃, 500 ℃, 550 ℃ or 600 ℃, and the glue discharging time can be but is 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 does not 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 compactness of the ceramic green body. By the binder removal and sintering, organic components in the ceramic green body are removed, and simultaneously, the internal compactness and bonding strength are enhanced, so that the performance of the ceramic substrate 10 is improved.

In the present embodiment, the ceramic substrate 10 may be subjected to CNC machining, sand blasting, polishing, or the like to obtain the ceramic substrate 10 of a desired shape and surface properties; the ceramic substrate 10 may also be subjected to laser etching, plating, and the like to change the appearance of the ceramic substrate 10. In the embodiment of the present application, a protective solution is coated on the surface of the ceramic substrate 10, and the protective layer 20 is formed after curing, thereby preparing the case 100. The housing 100 has an inner surface and an outer surface opposite to each other during use, and the protective layer 20 is disposed on the outer surface side so as to protect the housing 100 during use. 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, or 20 nm. 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 hardened layer may include at least one of urethane acrylate, silicone resin, and perfluoropolyether acrylate; the contact angle of the anti-fingerprint layer can be larger than 105 degrees, so that the surface of the anti-fingerprint layer is prevented from being polluted, and the anti-fingerprint layer has excellent anti-fingerprint performance; the anti-fingerprint layer can comprise fluorine-containing compounds such as fluorine-silicon resin, perfluoropolyether, fluorine-containing acrylate and the like, and the anti-fingerprint layer also comprises silicon dioxide, so that the friction resistance of the anti-fingerprint layer is further improved by adding the silicon dioxide.

In the present application, the thickness and shape of the ceramic green body and the ceramic substrate 10 may be selected according to the requirement of the casing 100, and the casing 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, an MP3, an MP4, a GPS navigator, a digital camera, etc. In the present application, the ceramic substrate 10 and the case 100 may be a 2D structure, a 2.5D structure, a 3D structure, or the like. In one embodiment, when the housing 100 is used as a mobile phone rear cover, the thickness of the ceramic substrate 10 may be 0.5mm to 1mm, such as 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, or 1mm.

The preparation method of the shell 100 provided by the application is simple to operate, the preparation yield is high, 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 favorably expanded.

Referring to fig. 2, which is a schematic structural diagram of a housing according to an embodiment of the present disclosure, the housing 100 is manufactured by the method for manufacturing the housing 100 according to any of the embodiments, the housing 100 includes the ceramic substrate 10, and the ceramic substrate 10 has good mechanical properties and good surface quality, so that the performance of the housing 100 is improved, and the application of the housing 100 is facilitated.

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

Referring to fig. 3, which is a schematic structural diagram of a housing according to another embodiment of the present disclosure, 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 present application further provides an electronic device 200 including the housing 100 in any of the above embodiments. It is understood that the electronic device 200 may be, but is not limited to, a mobile phone, a tablet computer, a notebook computer, a watch, an MP3, an MP4, a GPS navigator, a digital camera, etc. Please refer to fig. 4, which is a schematic structural diagram of an electronic device according to an embodiment of the present disclosure, wherein the electronic device 200 includes a housing 100. The housing 100 can improve the mechanical performance of the electronic device 200, and the electronic device 200 has an appearance with a ceramic texture and excellent product competitiveness. Referring to fig. 5, which is a schematic view illustrating a structure of an electronic device according to an embodiment of the present disclosure, a structure of 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 supply power to the entire electronic device 200. Specifically, the RF circuit 210 is used for transmitting and receiving signals; the memory 220 is used for storing data instruction information; the input unit 230 is used for inputting information, and may specifically include other input devices such as a touch panel and 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 approach signal, a distance signal, etc.; the speaker 261 and the microphone 262 are connected with the processor 280 through the audio circuit 260 and used for emitting and receiving sound signals; the WiFi module 270 is configured to receive and transmit WiFi signals; the processor 280 is used for processing data information of the electronic device 200.

The properties of the ceramic green body and the shell obtained by the present application are further described below by way of specific examples and comparative examples.

Example 1

Adding an organic monomer methacrylamide (the addition amount is 3% of the mass of the ceramic material), a cross-linking agent methylene bisacrylamide (the addition amount is 0.2% of the mass of the ceramic material), a dispersing agent ammonium polyacrylate (the addition amount is 0.4% of the mass of the ceramic material), a defoaming agent n-octanol (the addition amount is 0.02% of the mass of the ceramic material), a surfactant triethanolamine (the addition amount is 0.15% of the mass of the ceramic material), a humectant glycerol (the addition amount is 0.15% of the mass of the ceramic material), a humectant polyethylene glycol (the addition amount is 0.25% of the mass of the ceramic material), and a coupling agent monoalkoxy titanate (the addition amount is 0.55% of the mass of the ceramic material) into deionized water, and then adding a pH regulator ammonia water to regulate the pH value, so as to obtain a mixed solution, wherein the pH value of the mixed solution is 11.

The ceramic material comprises 87.8% of zirconium oxide, 5.2% of yttrium oxide, 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 3.5% of coloring agent (comprising 0.9% of aluminum oxide, 0.8% of zinc oxide, 1% of cobalt oxide and 0.8% of ferroferric oxide) by mass; the ceramic material has a primary particle diameter D50 of 0.08 μm, a secondary particle diameter D50 of 0.21 μm, and a specific surface area of 12m ² (ii) in terms of/g. Mixing the ceramic material and the mixed solution, and sanding to obtain premixed slurry, wherein the premixed slurry contains solidThe viscosity was 427 mPas at 45%.

Under the condition of vacuum degree of-75 kPa, defoaming the premixed slurry for 30min, then adding catalyst tetramethylethylenediamine (the addition amount is 0.4 percent of the mass of the ceramic material) and initiator ammonium persulfate (the addition amount is 0.6 percent of the mass of the ceramic material) into the premixed slurry, and stirring to obtain mixed slurry, wherein the solid content of the mixed slurry is 44 percent, and the viscosity of the mixed slurry is 610 mPas.

And 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, controlling the temperature of the mold to be 50 ℃ and the vacuum degree of a mold cavity to be-75 kPa, and standing for 25min after grouting is finished to solidify the mixed slurry. And then demoulding the cured mixed slurry to obtain the ceramic preform. Soaking the ceramic preform in an ethanol solution (the ethanol content is 50%) for 6 hours at the temperature of 20 ℃; and treating at 40 ℃ for 18h under the humidity of 85 percent, and treating at 110 ℃ for 8h under the humidity of 40 percent to obtain a ceramic green body. And (3) removing the glue from the ceramic green body and sintering to obtain a ceramic substrate, namely the shell.

The surface of the ceramic green body is complete, smooth and free of cracks; referring to fig. 6, which is a microscopic morphology of the ceramic green body, it can be seen that the ceramic particles are uniformly dispersed and do not agglomerate; and simultaneously detecting the performance of the ceramic green body, wherein the water content of the ceramic green body is 1.8 percent, the average value of the four-point bending strength is 43.7MPa, and the volume density is 3.78g/cm ³ The difference of the volume densities of different parts is less than 0.17g/cm ³ And the deformation amount of the ceramic pre-blank before and after drying is less than 0.1mm. And milling the green body by using CNC, wherein the machining cracking rate of the ceramic green body is less than 3%.

Example 2

Adding an organic monomer methacrylamide (the addition amount is 2% of the mass of the ceramic material), an organic monomer dimethylacrylamide (the addition amount is 1.5% of the mass of the ceramic material), a cross-linking agent methylene bisacrylamide (the addition amount is 0.1% of the mass of the ceramic material), a cross-linking agent phosphonobutane tricarboxylic acid (the addition amount is 0.05% of the mass of the ceramic material), a dispersing agent ammonium polyacrylate (the addition amount is 0.2% of the mass of the ceramic material), a dispersing agent polyvinyl alcohol (the addition amount is 0.1% of the mass of the ceramic material), a defoaming agent glycerol (the addition amount is 0.02% of the mass of the ceramic material), a surfactant fatty alcohol polyoxyethylene ether (the addition amount is 0.15% of the mass of the ceramic material), a humectant water-borne acrylate (the addition amount is 0.2% of the mass of the ceramic material), a humectant sodium carboxymethyl cellulose (the addition amount is 0.05% of the mass of the ceramic material), a coupling agent alkoxy fatty acid titanate (the addition amount is 0.2% of the mass of the ceramic material), a coupling agent monoalkoxy titanate (the addition amount is 0.2% of the mass of the ceramic material) into deionized water, then adding a pH regulator ammonia water to regulate the pH, and obtain a mixed solution, wherein the pH value is 10.

The ceramic material comprises 90.2% of zirconium oxide, 4.3% of yttrium oxide, 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 aluminum oxide coloring agent by mass; the ceramic material has a primary particle diameter D50 of 0.15 μm, a secondary particle diameter D50 of 0.62 μm, and a specific surface area of 5.1m ² (ii) in terms of/g. And mixing the ceramic material and the mixed solution, and sanding to obtain the premixed slurry, wherein the solid content of the premixed slurry is 55%, and the viscosity of the premixed slurry is 524mPa & s.

Under the condition that the vacuum degree is-75 kPa, defoaming the premixed slurry for 30min, then adding catalyst tetramethyl ethylene diamine (the addition amount is 0.4 percent of the mass of the ceramic material), initiator ammonium persulfate (the addition amount is 0.35 percent of the mass of the ceramic material) and initiator diamino dipropylamine (the addition amount is 0.15 percent of the mass of the ceramic material) into the premixed slurry, and stirring to obtain mixed slurry, wherein the solid content of the mixed slurry is 54 percent, and the viscosity of the mixed slurry is 730 mPas.

And 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, controlling the temperature of the mold to be 40 ℃ and the vacuum degree of a mold cavity to be-75 kPa, and standing for 30min after grouting is finished to solidify the mixed slurry. And then demoulding the cured mixed slurry to obtain the ceramic preform. Soaking the ceramic preform in an acetone solution (the content of acetone is 90%) for 4 hours at the temperature of 30 ℃; and treating at 45 ℃ for 24h under the humidity of 75 percent, and treating at 100 ℃ for 10h under the humidity of 30 percent to obtain a ceramic green body. And (3) removing the glue from the ceramic green body and sintering to obtain a ceramic substrate, namely the shell.

The surface of the ceramic green body is complete, smooth and free of cracks; referring to fig. 7, which is a microscopic image of the ceramic green body, it can be seen that the ceramic particles are uniformly dispersed and do not agglomerate; and simultaneously detecting the performance of the ceramic green body, wherein the water content of the ceramic green body is 2.3 percent, the average value of the four-point bending strength is 35MPa, and the volume density is 3.75g/cm ³ The difference of the volume densities of different parts is less than 0.15g/cm ³ And the deformation amount of the ceramic pre-blank before and after drying is less than 0.2mm. And milling the green body by using CNC, wherein the machining cracking rate of the ceramic green body is less than 5%.

Comparative example 1

Adding an organic monomer methacrylamide (the addition amount is 3% of the mass of the ceramic material), a cross-linking agent methylene bisacrylamide (the addition amount is 0.2% of the mass of the ceramic material), a dispersant ammonium polyacrylate (the addition amount is 0.4% of the mass of the ceramic material), a defoaming agent n-octanol (the addition amount is 0.02% of the mass of the ceramic material), and a surfactant triethanolamine (the addition amount is 0.15% of the mass of the ceramic material) into deionized water, and then adding a pH regulator ammonia water to regulate the pH, so as to obtain a mixed solution, wherein the pH value of the mixed solution is 11.

The ceramic material comprises 90.2% of zirconium oxide, 4.3% of yttrium oxide, 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 aluminum oxide coloring agent by mass; the ceramic material has a primary particle diameter D50 of 0.08 μm, a secondary particle diameter D50 of 0.21 μm, and a specific surface area of 12m ² (ii) in terms of/g. And mixing the ceramic material and the mixed solution, and sanding to obtain the premixed slurry, wherein the solid content of the premixed slurry is 45%, and the viscosity of the premixed slurry is 612mPa & s.

And (2) defoaming the premixed slurry for 30min under the condition of vacuum degree of-75 kPa, then adding catalyst tetramethylethylenediamine (the addition amount is 0.4 percent of the mass of the ceramic material) and initiator ammonium persulfate (the addition amount is 0.6 percent of the mass of the ceramic material) into the premixed slurry, and stirring to obtain mixed slurry, wherein the solid content of the mixed slurry is 44 percent, and the viscosity of the mixed slurry is 880mPa & s.

And 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, controlling the temperature of the mold to be 50 ℃ and the vacuum degree of a mold cavity to be-75 kPa, and standing for 25min after grouting is finished to solidify the mixed slurry. And then demoulding the cured mixed slurry to obtain the ceramic preform. Soaking the ceramic preform in an ethanol solution (the ethanol content is 50%) for 6 hours at the temperature of 20 ℃; and treating at 40 ℃ for 18h under the humidity of 85 percent, and treating at 75 ℃ for 8h under the humidity of 85 percent to obtain a ceramic green body. And (3) removing the glue from the ceramic green body and sintering to obtain a ceramic substrate, namely the shell.

Referring to FIG. 8, which is a microscopic image of the ceramic green body, it can be seen that the ceramic particles are not uniformly dispersed and have agglomerates; the ceramic green body has cracks, and the performance of the ceramic green body is detected, wherein the water content of the ceramic green body is 3.4%, the average value of four-point bending strength is 19.4MPa, and the bulk density is 3.74g/cm ³ The difference of the volume densities of different parts is less than 0.21g/cm ³ And the deformation amount of the ceramic pre-blank before and after drying is more than 0.3mm. The green body was milled using CNC and the machining crack rate of the ceramic green body was about 85%.

Comparative example 2

Adding an organic monomer methacrylamide (the addition amount is 2% of the mass of the ceramic material), an organic monomer dimethylacrylamide (the addition amount is 1.5% of the mass of the ceramic material), a cross-linking agent methylenebisacrylamide (the addition amount is 0.1% of the mass of the ceramic material), a cross-linking agent phosphonobutane tricarboxylic acid (the addition amount is 0.05% of the mass of the ceramic material), a dispersing agent ammonium polyacrylate (the addition amount is 0.2% of the mass of the ceramic material), a dispersing agent polyvinyl alcohol (the addition amount is 0.1% of the mass of the ceramic material), a defoaming agent glycerol (the addition amount is 0.02% of the mass of the ceramic material), a surfactant fatty alcohol polyoxyethylene ether (the addition amount is 0.15% of the mass of the ceramic material), a humectant water-borne acrylic ester (the addition amount is 0.05% of the mass of the ceramic material), a humectant carboxymethylcellulose sodium (the addition amount is 0.05% of the mass of the ceramic material), a coupling agent alkoxy fatty acid titanate (the addition amount is 0.7% of the mass of the ceramic material), a coupling agent monoalkoxytitanate (the addition amount is 0.5% of the mass of the ceramic material) into deionized water, and then adding a pH regulator ammonia water to adjust the pH to obtain a mixed solution, wherein the pH value is 10.

The ceramic material comprises 90.2% of zirconium oxide, 4.3% of yttrium oxide, 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 aluminum oxide coloring agent by mass; the ceramic material has a primary particle diameter D50 of 0.15 μm, a secondary particle diameter D50 of 0.62 μm, and a specific surface area of 5.1m ² (ii) in terms of/g. And mixing the ceramic material and the mixed solution, and sanding to obtain premixed slurry, wherein the solid content of the premixed slurry is 55%, and the viscosity of the premixed slurry is 1204mPa & s.

Under the condition that the vacuum degree is-75 kPa, defoaming the premixed slurry for 30min, then adding catalyst tetramethyl ethylene diamine (the addition amount is 0.4 percent of the mass of the ceramic material), initiator ammonium persulfate (the addition amount is 0.35 percent of the mass of the ceramic material) and initiator diamino dipropylamine (the addition amount is 0.15 percent of the mass of the ceramic material) into the premixed slurry, and stirring to obtain mixed slurry, wherein the solid content of the mixed slurry is 54 percent, and the viscosity is 1570 mPa.

And injecting the mixed slurry into a mold by using an automatic slurry injector, injecting the slurry from a feed inlet of the mold, stopping injecting the slurry after the slurry overflows from an exhaust port, controlling the temperature of the mold to be 40 ℃, controlling the vacuum degree of a mold cavity to be-75 kPa, and standing for 30min after injecting the slurry to solidify the mixed slurry. And then demoulding the cured mixed slurry to obtain the ceramic preform. And (3) treating the ceramic pre-blank for 24 hours at the humidity of 50% and the temperature of 80 ℃, and then treating for 10 hours at the humidity of 30% and the temperature of 120 ℃ to obtain a ceramic green body. And (3) removing the glue from the ceramic green body and sintering to obtain a ceramic substrate, namely the shell.

Referring to fig. 9, which is a microscopic morphology of the ceramic green body, it can be seen that the ceramic particles are not uniformly dispersed and have serious agglomeration problem; the surface of the ceramic green body is seriously cracked, and the performance of the ceramic green body is detected, wherein the water content of the ceramic green body is 3.2 percent, the average value of the four-point bending strength is 12MPa, and the volume density is 3.66g/cm ³ The difference of the volume densities of different parts is less than 0.37g/cm ³ And the deformation amount of the ceramic pre-blank before and after drying is more than 0.5mm. The green body was milled using CNC with a machining crack rate of 100% for the ceramic green body.

Comparative example 3

The same as example 1 except that no coupling agent was included. Referring to fig. 10, which is a microscopic morphology of the ceramic green body obtained in comparative example 3, it can be seen that the ceramic particles are not uniformly dispersed and the agglomeration problem is serious; the ceramic green body has a complete, smooth and crack-free surface, and the performance of the ceramic green body is detected, wherein the water content of the ceramic green body is 2%, the average value of four-point bending strength is 21.1MPa, and the bulk density is 3.61g/cm ³ The difference of the volume densities of different parts is less than 0.35g/cm ³ The amount of deformation of the ceramic preform before and after drying was about 0.15mm. The green body was milled using CNC and the machining crack rate of the ceramic green body was about 25%.

Comparative example 4

The same as example 1 except that the humectant was not included. Referring to fig. 11, which is a microscopic image of the ceramic green body obtained in comparative example 4, it can be seen that the ceramic particles are dispersed more uniformly; the surface of the ceramic green body is seriously cracked, and the performance of the ceramic green body is detected, wherein the water content of the ceramic green body is 1.4 percent, the average value of the four-point bending strength is 26.7MPa, and the volume density is 3.64g/cm ³ The difference of the volume densities of different parts is less than 0.2g/cm ³ The amount of deformation of the ceramic preform before and after drying was about 0.25mm. The green body is milled by CNC, and the machining cracking rate of the green ceramic body is about 20%.

As can be seen from the above, compared with the comparative example, the ceramic green body prepared by the method provided by the application has the advantages of high four-point bending strength, large volume density, uniform distribution, low water content, small deformation amount before and after drying, low mechanical processing cracking proportion and high processing yield; compared with the ceramic substrate obtained by the comparative example, the ceramic substrate obtained by the embodiment has the advantages of smooth surface, no peeling, cracking and other problems, better mechanical property, higher preparation yield and more contribution to the preparation and use of the ceramic substrate and the shell after the same glue discharging and sintering treatment.

The foregoing detailed description has provided for the embodiments of the present application, and the principles and embodiments of the present application have been presented herein for purposes of illustration and description only and to facilitate understanding of the methods and their core concepts; meanwhile, for a person skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.

Claims

1. A method of making a housing, comprising:

the mixed slurry is subjected to gel casting molding and drying to obtain a ceramic green body, and the drying process comprises the steps of soaking in a solution containing a hydrophilic organic solvent for 3-12 h at the temperature of 10-50 ℃; then treating for 12-24 h at 30-50 ℃ and with the humidity of 70-90%; then processing for 6h-12h at the humidity of 20% -50% and the temperature of 60 ℃ -120 ℃;

2. The preparation method according to claim 1, wherein the hydrophilic organic solvent-containing solution contains 50 to 100% by mass of the hydrophilic organic solvent;

the hydrophilic organic solvent includes at least one of methanol, ethanol, propanol, methyl ethyl ketone and acetone.

3. The method of claim 1, wherein said gel-casting provides a ceramic preform having a deformation amount of less than 0.2mm before and after said drying.

4. As claimed inThe preparation method of claim 1, wherein the green ceramic body has a water content of less than 3%, a four-point bending strength of greater than 30MPa, and a bulk density of greater than 3.7g/cm ³ The volume density difference is less than 0.3g/cm ³ 。

5. The preparation method according to claim 1, wherein the mass of the catalyst accounts for 0.1-1% of the 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 tetramethylethylenediamine and dimethylaniline;

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

6. The method according to claim 1, wherein the mixed solution further comprises at least one of an organic monomer, a crosslinking agent, a dispersant, an antifoaming agent, a surfactant, and a pH adjuster;

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 cross-linking agent is (10-20): 1;

the mass of the dispersant accounts for 0.2 to 0.5 percent 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 organic monomer comprises at least one of acrylamide, methacrylamide, dimethylacrylamide and hydantoin epoxy resin;

the cross-linking agent comprises at least one of methylene bisacrylamide and phosphonobutane tricarboxylic acid;

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

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

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

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

7. The method of claim 1, wherein the humectant comprises at least one of glycerin, polyethylene glycol, water-based acrylate, sodium carboxymethylcellulose, and polyvinylpyrrolidone;

the coupling agent includes at least one of a monoalkoxy titanate coupling agent, a monoalkoxy pyrophosphate titanate coupling agent, a chelating titanate coupling agent, and a coordination titanate coupling agent.

8. The method of claim 1, wherein the debubbling comprises debubbling 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 rubber discharging comprises the steps of processing for 2-4 h at 400-600 ℃;

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

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

10. A housing produced by the production method according to any one of claims 1 to 9.

11. The housing of claim 10, wherein the ceramic substrate is a zirconia ceramic, and wherein the zirconia ceramic has a zirconia content of 79% to 98% by mass.

12. The housing of claim 11, wherein the zirconia ceramic further comprises, by mass, 2% to 8% yttria, 0% to 3% hafnia, 0% to 5% strengthening agents, and 0% to 5% coloring agents.

13. An electronic device, characterized in that the electronic device comprises a housing according to any of claims 10-12.