Zirconium-based composite ceramic material, method for producing same, and ceramic structural component

Abstract

This invention discloses a zirconium-based composite ceramic material, its preparation method, and ceramic structural components. The zirconium-based composite ceramic material comprises: a zirconium oxide matrix; and LaAl dispersed in the zirconium oxide matrix. 11 O 18 Phases and Zn2SiO4 phases. LaAl dispersed in a zirconia matrix. 11 O 18 The Zn₂SiO₄ phase dispersed in the zirconia matrix reduces the transmittance, density, and dielectric constant of the zirconium-based composite ceramic material, while improving its toughness and impact resistance. Simultaneously, the Zn₂SiO₄ phase reduces the sintering temperature during the preparation of the zirconium-based composite ceramic material and improves its strength and impact resistance. Therefore, the zirconium-based composite ceramic material of this invention simultaneously possesses high hardness, toughness, and impact resistance, as well as low density, dielectric constant, and transmittance.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of ceramic materials, and particularly relates to a zirconium-based composite ceramic material, a preparation method thereof and a ceramic structural part. BACKGROUND

[0002] Zirconia ceramic has a wide range of applications due to its good corrosion resistance, high hardness and high strength as conventional ceramic. Its toughness reaches 5-6 MPa.m 1 / 2 , which is higher than that of other conventional ceramics, but it has the disadvantage of weak impact resistance when made into large-area appearance parts. In addition, when made into a mobile phone back cover product, the semi-transparency of zirconia ceramic itself is amplified due to the very thin thickness of the product, so a process of coating ink on the back is needed to prevent the internal components from being seen, thereby increasing the cost. At the same time, with the advent of the 5G era, customers have higher and higher requirements for the dielectric constant and density, and reducing the dielectric constant and density has become an urgent problem to be solved. In view of these problems, some manufacturers reduce the density and dielectric constant by adding more alumina, but the high hardness and high brittleness of alumina will greatly increase the processing difficulty of the product, thereby leading to low yield and high cost. Therefore, it is very important to develop a ceramic with low density, low dielectric constant, high impact resistance and good processability for the application of ceramic back cover in the 5G era. SUMMARY

[0003] The present application aims to at least partially solve one of the problems in the related art. To this end, one object of the present application is to propose a zirconium-based composite ceramic material, a preparation method thereof and a ceramic structural part. The zirconium-based composite ceramic material of the present application simultaneously has high hardness, toughness and impact resistance, and low density, dielectric constant and light transmittance.

[0004] In one aspect of the present application, a zirconium-based composite ceramic material is proposed. According to an embodiment of the present application, the zirconium-based composite ceramic material comprises:

[0005] a zirconia matrix;

[0006] and LaAl 11 O 18 phases and Zn2SiO4 phases dispersed in the zirconia matrix.

[0007] The zirconium-based composite ceramic material according to the embodiment of the present application has LaAl 11 O 18The phase has the effects of reducing the light transmittance, density and dielectric constant of the zirconium-based composite ceramic material and improving the toughness and impact resistance of the zirconium-based composite ceramic material; meanwhile, the Zn2SiO4 phase dispersed in the zirconia matrix has the effects of reducing the sintering temperature in the preparation process of the zirconium-based composite ceramic material and improving the strength and impact resistance of the zirconium-based composite ceramic material. Thus, the zirconium-based composite ceramic material of the application simultaneously has higher hardness, toughness and impact resistance and lower density, dielectric constant and light transmittance.

[0008] In addition, the zirconium-based composite ceramic material according to the above-mentioned embodiments of the application can also have the following additional technical features:

[0009] In some embodiments of the application, the zirconium-based composite ceramic material comprises: 27.5-59.8wt% of a zirconia matrix, 40-70wt% of LaAl 11 O 18 a phase and 0.2-2.5wt% of a Zn2SiO4 phase; preferably, the zirconium-based composite ceramic material comprises: 38-49.5wt% of a zirconia matrix, 50-60wt% of LaAl 11 O 18 a phase and 0.5-2wt% of a Zn2SiO4 phase.

[0010] In some embodiments of the application, the zirconium-based composite ceramic material comprises, in terms of elements: 18.94-43.11wt% of Zr, 7.67-13.43wt% of La, 0.56-3.26wt% of Y, 16.43-28.75wt% of Al, 0.11-1.46wt% of Zn and 0.02-0.31wt% of Si, and the molar ratio of La to Al is 1:11 and the molar ratio of Zn to Si is 2:1; preferably, the zirconium-based composite ceramic material comprises: 26.17-35.68wt% of Zr, 9.58-11.52wt% of La, 0.77-2.71wt% of Y, 20.53-24.65wt% of Al, 0.27-1.09wt% of Zn and 0.05-0.2wt% of Si, and the molar ratio of La to Al is 1:11 and the molar ratio of Zn to Si is 2:1.

[0011] In some embodiments of the application, the zirconia matrix is 1.5-4mol% yttrium-stabilized tetragonal phase zirconia.

[0012] In some embodiments of the application, at least one of the following conditions is met:

[0013] The hardness of the zirconium-based composite ceramic material is 1330-1390Hv;

[0014] The toughness of the zirconium-based composite ceramic material is 4.4-6.0 Mpa·m 0.5 ;

[0015] The dielectric constant of the zirconium-based composite ceramic material is 16.0-18.5;

[0016] The density of the zirconium-based composite ceramic material is 4.6-4.9 g / cm 3 .

[0017] In still another aspect of the present application, the present application provides a method for preparing the above-mentioned zirconium-based composite ceramic material. According to an embodiment of the present application, the method comprises:

[0018] (1) mixing zirconia powder, LaAl 11 O 18 powder, Zn2SiO4 powder, water and a dispersing agent, and grinding to obtain a mixed slurry;

[0019] or, mixing zirconia powder, LaAl 11 O 18 powder, zinc oxide powder, silicon dioxide powder, water and a dispersing agent, and grinding to obtain a mixed slurry;

[0020] or, mixing zirconia powder, lanthanum oxide powder, aluminum oxide powder, Zn2SiO4 powder, water and a dispersing agent, and grinding to obtain a mixed slurry;

[0021] or, mixing zirconia powder, lanthanum oxide powder, aluminum oxide powder, zinc oxide powder, silicon dioxide powder, water and a dispersing agent, and grinding to obtain a mixed slurry;

[0022] (2) mixing the mixed slurry with a binder and stirring to form a slurry for spray drying;

[0023] (3) spray drying the slurry for spray drying to form spherical powder, and dry pressing the spherical powder to obtain a shaped powder;

[0024] (4) high-temperature sintering the shaped powder to obtain a zirconium-based composite ceramic material.

[0025] According to the method for preparing the above-mentioned zirconium-based composite ceramic material according to the embodiment of the present application, the zirconium-based composite ceramic material prepared by the method has high hardness, toughness and impact resistance, and low density, dielectric constant and light transmittance. Moreover, the Zn2SiO4 added or formed in the preparation process has the effect of reducing the sintering temperature, greatly reducing the cost required for purchasing sintering equipment.

[0026] In addition, the method according to the above-mentioned embodiment of the present application can also have the following additional technical features:

[0027] In some embodiments of the present application, the mass ratio of the zirconium oxide powder, the lanthanum aluminate powder and the zinc silicate powder is (27.5-59.8):(40-70):(0.2-2.5), preferably, the mass ratio of the zirconium oxide powder, the lanthanum aluminate powder and the zinc silicate powder is (38-49.5):(50-60):(0.5-2). 11 O 18 In some embodiments of the present application, the mass ratio of the zirconium oxide powder, the lanthanum aluminate powder and the zinc silicate powder is (27.5-59.8):(40-70):(0.2-2.5), preferably, the mass ratio of the zirconium oxide powder, the lanthanum aluminate powder and the zinc silicate powder is (38-49.5):(50-60):(0.5-2). 11 O 18 In some embodiments of the present application, the mass ratio of the zirconium oxide powder, the lanthanum aluminate powder and the zinc silicate powder is (27.5-59.8):(40-70):(0.2-2.5), preferably, the mass ratio of the zirconium oxide powder, the lanthanum aluminate powder and the zinc silicate powder is (38-49.5):(50-60):(0.5-2).

[0028] In some embodiments of the present application, the molar ratio of the silicon dioxide powder and the zinc oxide powder is 1:(1.9-2.1).

[0029] In some embodiments of the present application, the molar ratio of the lanthanum oxide powder and the aluminum oxide powder is 1:(10.8-11.2).

[0030] In some embodiments of the present application, in step (1), the particle size of the powder is ground to nanoscale.

[0031] In some embodiments of the present application, in step (1), the amount of the dispersant is 0.01-0.03wt% based on the total mass of the mixed powder.

[0032] In some embodiments of the present application, in step (2), the amount of the binder is 3-5wt% based on the total mass of the mixed powder.

[0033] In some embodiments of the present application, in step (4), the temperature of the high-temperature sintering is 1400-1500 degrees Celsius, and the time of the high-temperature sintering is 1-2 hours.

[0034] In a third aspect, the present application provides a ceramic structural member. According to embodiments of the present application, the ceramic structural member has the zirconium-based composite ceramic material described in the above embodiments or is made of the zirconium-based composite ceramic material made by the method described in the above embodiments. Thus, the ceramic structural member has all the advantages of the zirconium-based composite ceramic material described in the above embodiments, specifically, the hardness and toughness of the ceramic structural member are significantly improved, and the density, dielectric constant and light transmittance of the ceramic structural member are significantly reduced.

[0035] Additional aspects and advantages of the present application will be made apparent from the following description. DETAILED DESCRIPTION

[0036] The embodiments described below are exemplary and are intended to be illustrative of the present application, and are not to be construed as limiting the present application.

[0037] In one aspect of the present application, the present application provides a zirconium-based composite ceramic material. According to an embodiment of the present application, the above-mentioned zirconium-based composite ceramic material comprises: a zirconia matrix; and LaAl 11 O 18 phase and a Zn2SiO4 phase. Specifically, the LaAl 11 O 18 phase dispersed in the zirconia matrix has the effect of reducing the light transmittance, density and dielectric constant of the zirconium-based composite ceramic material, and improving the toughness and impact resistance of the zirconium-based composite ceramic material; meanwhile, the Zn2SiO4 phase dispersed in the zirconia matrix has the effect of reducing the sintering temperature in the preparation process of the zirconium-based composite ceramic material, and improving the strength and impact resistance of the zirconium-based composite ceramic material. Thus, the zirconium-based composite ceramic material of the present application simultaneously has higher hardness, toughness and impact resistance, and lower density, dielectric constant and light transmittance. The zirconium-based composite ceramic material according to the embodiment of the present application is described in further detail below.

[0038] The zirconia ceramic has the disadvantages of weak impact resistance, high light transmittance, high dielectric constant and high density. In the prior art, alumina is added to reduce the density, dielectric constant and light transmittance. However, the inventors have found that the more alumina is added, the higher the hardness and strength of the zirconia ceramic, but the toughness is often worse, which leads to a significant increase in processing difficulty, thereby leading to a low yield and high cost. Therefore, to significantly reduce the dielectric constant, alumina alone cannot be added, and other oxides also need to be added. In view of this, the idea of the present application is to replace the addition of alumina alone with the addition of LaAl 11 O 18 to reduce the light transmittance of the zirconia ceramic, thereby reducing the preparation process of the zirconia ceramic and reducing the cost. Moreover, the LaAl 11 O 18 phase dispersed in the zirconia matrix will form a whisker structure at high temperature, thereby improving the toughness of the zirconium-based composite ceramic material and improving the impact resistance of the zirconium-based composite ceramic material. The LaAl 11 O 18The phase also has the effect of reducing the density and dielectric constant of the zirconium-based composite ceramic material. Meanwhile, the addition of a certain amount of Zn2SiO4 on the basis of the present application has the effect of inhibiting grain growth, so that the grain growth is better and the internal structure is more uniform, thereby further improving the strength and further improving the impact resistance. Moreover, Zn2SiO4 can also reduce the sintering temperature in the preparation process. Specifically, the sintering temperature of the zirconium-based composite ceramic material without the addition of Zn2SiO4 in the prior art is about 1550-1600 degrees Celsius, while the sintering temperature of the zirconium-based composite ceramic material after the addition of Zn2SiO4 in the present application is about 1400-1500 degrees Celsius. Thus, the sintering temperature and processing difficulty in the preparation process are reduced, the processability is improved, and energy consumption is also reduced. It should be noted that the push plate furnace used for mass production of sintered zirconium-based composite ceramic materials in China is below 1500 degrees Celsius, and there is no mature push plate furnace above 1500 degrees Celsius. The cost of the mature push plate furnace above 1500 degrees Celsius imported from abroad is relatively high. Therefore, the dispersed Zn2SiO4 phase in the zirconia matrix not only reduces the sintering temperature and processing difficulty in the preparation process of the zirconium-based composite ceramic material, but also greatly reduces the equipment cost required for sintering.

[0039] In addition, the dispersed LaAl 11 O 18 The phase and the Zn2SiO4 phase also have a mutual effect. Specifically, the Zn2SiO4 phase has the effect of controlling the grain growth of the LaAl 11 O 18 phase, so as to avoid the formation of a too long whisker structure of the LaAl 11 O 18 phase at high temperatures. If the whisker structure of the LaAl 11 O 18 phase is too long, the internal structure will be loose, thereby reducing the strength of the zirconium-based composite ceramic material.

[0040] According to some specific embodiments of the present application, the above-mentioned zirconium-based composite ceramic material comprises: 27.5-59.8wt% of a zirconia matrix, 40-70wt% of LaAl 11 O 18 phase, and 0.2-2.5wt% of a Zn2SiO4 phase. Preferably, the zirconium-based composite ceramic material comprises: 38-49.5wt% of a zirconia matrix, 50-60wt% of LaAl 11 O 18 phase, and 0.5-2wt% of a Zn2SiO4 phase. Thus, the zirconium-based composite ceramic material further simultaneously has high hardness and toughness, and low density, dielectric constant and light transmittance. The inventors have found that if the LaAl 11 O 18The content of the phase is too low, which will cause the density and dielectric constant of the zirconium-based composite ceramic material to be high, and if the content of LaAl 11 O 18 The content of the phase is too high, which will cause the content of zirconia to be relatively low, thereby causing the tetragonal phase toughening effect to be weak, and causing the strength of the zirconium-based composite ceramic material to be low; if the content of the Zn2SiO4 phase is too low, the effect of the sintering aid will not be enough, thereby causing the sintering temperature to be high, and if the content of the Zn2SiO4 phase is too high, the strength of the zirconium-based composite ceramic material will decrease, because zinc silicate itself is a substance with weak strength and hardness.

[0041] According to still some specific embodiments of the present application, the zirconium-based composite ceramic material comprises, in terms of elements, 18.94-43.11wt% of Zr, 7.67-13.43wt% of La, 0.56-3.26wt% of Y, 16.43-28.75wt% of Al, 0.11-1.46wt% of Zn and 0.02-0.31wt% of Si, and the molar ratio of La to Al is 1:11, and the molar ratio of Zn to Si is 2:1; preferably, the zirconium-based composite ceramic material comprises 26.17-35.68wt% of Zr, 9.58-11.52wt% of La, 0.77-2.71wt% of Y, 20.53-24.65wt% of Al, 0.27-1.09wt% of Zn and 0.05-0.2wt% of Si, and the molar ratio of La to Al is 1:11, and the molar ratio of Zn to Si is 2:1. In this way, the zirconium-based composite ceramic material is further made to simultaneously have high hardness and toughness, and low density, dielectric constant and light transmittance.

[0042] According to still some specific embodiments of the present application, the zirconia matrix is 1.5-4mol% yttrium stabilized tetragonal zirconia, thereby making the zirconium-based composite ceramic material formed therefrom have excellent hardness and toughness.

[0043] The zirconium-based composite ceramic material of the present application simultaneously has high hardness and toughness, and low density, dielectric constant and light transmittance, and specifically, at least one of the following conditions is met: the hardness of the zirconium-based composite ceramic material is 1330-1390Hv; the toughness of the zirconium-based composite ceramic material is 4.4-6.0Mpa·m 0.5 ; the dielectric constant of the zirconium-based composite ceramic material is 16.0-18.5; and the density of the zirconium-based composite ceramic material is 4.6-4.9g / cm 3 .

[0044] In still another aspect of the present application, the present application proposes a method for preparing the above-mentioned zirconium-based composite ceramic material. According to embodiments of the present application, the above-mentioned method comprises:

[0045] S100: mixing and grinding the raw materials

[0046] In this step, zirconia powder, LaAl 11 O 18 powder, Zn2SiO4 powder, water and dispersant are mixed and ground to obtain a mixed slurry. In the present application, zirconia powder, LaAl 11 O 18 powder and Zn2SiO4 powder can be mixed to prepare the zirconium-based composite ceramic material. Alternatively, LaAl 11 O 18 powder can be replaced by lanthanum oxide powder and aluminum oxide powder, and / or Zn2SiO4 powder can be replaced by zinc oxide powder and silicon dioxide powder. Preferably, the above-mentioned zirconia powder is 1.5-4 mol% yttrium stabilized tetragonal zirconia powder with a median particle size of 0.3-0.6 μm and a specific surface area of 7-13 m 2 / g. Preferably, the lanthanum oxide powder has a median particle size of 9-11 μm. Preferably, the aluminum oxide powder has a median particle size of 0.15-0.6 μm. Preferably, the zinc oxide powder has a median particle size of 0.1-0.3 μm. Preferably, the silicon dioxide powder has a median particle size of 0.2-0.5 μm.

[0047] The specific process of the above-mentioned step is not particularly limited. As a specific example, the powders (e.g., zirconia powder, LaAl 11 O 18 powder and Zn2SiO4 powder) are ball-milled in a ball mill tank with water for 7-9 hours, and then a dispersant and water are added to a sand mill for 9-11 hours to obtain a mixed slurry. In order to prevent the introduction of impurities, the ball mill tank and the sand mill are lined with zirconia ceramic and zirconia grinding balls.

[0048] According to some specific embodiments of the present application, the mass ratio of zirconia powder, LaAl 11 O 18 powder and Zn2SiO4 powder is (27.5-59.8):(40-70):(0.2-2.5). Preferably, the mass ratio of zirconia powder, LaAl 11 O 18 powder and Zn2SiO4 powder is (38-49.5):(50-60):(0.5-2), so that the zirconium-based composite ceramic material prepared has high hardness, toughness and impact resistance, and low density, dielectric constant and light transmittance. The inventors have found that if the content of LaAl 11 O 18 powder is too low, the density and dielectric constant of the zirconium-based composite ceramic material formed will be high. If the content of LaAl 11 O 18If the content of the Zn2SiO4 powder is too high, the content of the zirconia is relatively low, which results in weak tetragonal phase transformation toughening effect and low strength of the finally formed zirconium-based composite ceramic material; if the content of the Zn2SiO4 powder is too low, the sintering effect is not enough, which results in high sintering temperature; if the content of the Zn2SiO4 powder is too high, the strength of the finally formed zirconium-based composite ceramic material is reduced, because the zinc silicate itself is a material with weak strength and hardness.

[0049] It should be noted that if the LaAl 11 O 18 If the LaAl 11 O 18 powder is replaced by lanthanum oxide powder and aluminum oxide powder, it is necessary to ensure that the lanthanum oxide powder and the aluminum oxide powder react to generate LaAl 11 O 18 powder, and the mass fraction of the LaAl 11 O 18 powder is still 40-70 parts, preferably 50-60 parts. Among them, the molar ratio of the lanthanum oxide powder and the aluminum oxide powder is 1:(10.8-11.2), thereby ensuring that the lanthanum oxide powder and the aluminum oxide powder react to generate LaAl 11 O 18 powder.

[0050] According to still some specific embodiments of the present application, the particle size of the mixed powder is ground to nanoscale. If the particle size of the mixed powder is larger, the sintering difficulty is greater, which results in poor density and thus poor strength of the finally formed zirconium-based composite ceramic material. If the particle size of the mixed powder is smaller, the dry pressing forming difficulty is greater, thereby increasing the processing difficulty.

[0051] In the embodiments of the present application, the dispersant promotes the mixing and dispersion of the raw material powders, and makes the dispersion more uniform. As some specific embodiments, the amount of the dispersant is 0.01-0.03wt% based on the total mass of the mixed powder, which further promotes the mixing and dispersion of the raw material powders, and makes the dispersion more uniform.

[0052] In the embodiments of the present application, the specific type of the dispersant is not particularly limited, and hydroxypropyl methyl cellulose is preferred.

[0053] S200: mixing the mixed slurry with a binder and stirring

[0054] In this step, the mixed slurry is mixed with a binder and stirred for 2-4 hours to form a slurry for spraying.

[0055] In the embodiment of the present application, the binder is used to facilitate the dry-pressing in the subsequent step. As some specific embodiments, the binder is used in an amount of 3-5wt% based on the total mass of the mixed powder, thereby further facilitating the dry-pressing in the subsequent step.

[0056] In the embodiment of the present application, the specific type of the binder is not particularly limited, and preferably a mixture of polyethylene glycol 4000 and PVA in a mass ratio of 1:1.

[0057] S300: spray drying the slurry for spraying to form spherical powder, and dry-pressing the spherical powder

[0058] In this step, the slurry for spraying is spray dried to form spherical powder, and the spherical powder is dry-pressed to obtain the shaped powder. It should be noted that the spherical powder has good fluidity, thereby making the density uniformity of the green body good.

[0059] As some specific embodiments, the inlet air temperature of the spray drying is 240-260 degrees Celsius (preferably 250 degrees Celsius), the outlet air temperature is 105-115 degrees Celsius (preferably 110 degrees Celsius), and the centrifugal rotation speed is 13-17 revolutions per second (preferably 15 revolutions per second).

[0060] S400: high-temperature sintering of the shaped powder

[0061] In this step, the shaped powder is high-temperature sintered to obtain the zirconium-based composite ceramic material. In the sintering process, the LaAl 11 O 18 The LaAl 11 O 18 phase is formed by sintering the LaAl 11 O 18 powder and the Al2O3 powder at high temperature, thereby improving the toughness of the zirconium-based composite ceramic material and improving the impact resistance of the zirconium-based composite ceramic material. The dispersed LaAl 11 O 18 phase in the zirconia matrix also has the effect of reducing the density and dielectric constant of the zirconium-based composite ceramic material. At the same time, the Zn2SiO4 phase is formed by sintering the Zn2SiO4 powder or zinc oxide powder and the SiO2 powder at high temperature, and the Zn2SiO4 phase has the effect of inhibiting grain growth, making the grain growth good and the internal structure uniform, thereby further improving the strength and further improving the impact resistance. Moreover, the Zn2SiO4 phase can also reduce the sintering temperature and processing difficulty in the preparation process, and greatly reduce the equipment cost required for sintering.

[0062] According to still some specific embodiments of the present application, the temperature of high-temperature sintering is 1400-1500 degrees Celsius, and the time of high-temperature sintering is 1-2 hours, thereby, by limiting the temperature and time of high-temperature sintering within the above ranges, the sintering density is ensured while abnormal grain growth is avoided, thus being beneficial to the improvement of the strength and impact resistance of the zirconium-based composite ceramic material. The inventors have found that if the temperature of high-temperature sintering is too low or the time of high-temperature sintering is too short, the sintering density is not ensured, thus being not beneficial to the improvement of the strength and impact resistance of the zirconium-based composite ceramic material; if the temperature of high-temperature sintering is too high or the time of high-temperature sintering is too long, the abnormal grain growth is caused, thus being not beneficial to the improvement of the strength and impact resistance of the zirconium-based composite ceramic material.

[0063] As a specific example, the sintering procedure is as follows: rising from room temperature to 600 degrees Celsius for 400 minutes, keeping the temperature for 2 hours, rising from 600 degrees Celsius to 1150 degrees Celsius for 300 minutes, keeping the temperature for 2 hours, rising from 1150 degrees Celsius to 1300 degrees Celsius for 150 minutes, keeping the temperature for 2 hours, rising from 1300 degrees Celsius to 1400-1500 degrees Celsius for 50 minutes, keeping the temperature for 1-2 hours, then falling to 900 degrees Celsius for 150 minutes, and finally naturally cooling to room temperature. After sintering, the sample is ground and polished, and then cut into a final sample by using a laser.

[0064] According to the method for preparing the above zirconium-based composite ceramic material according to the embodiments of the present application, the zirconium-based composite ceramic material prepared by the method has high hardness, toughness and impact resistance, and low density, dielectric constant and light transmittance. Moreover, the Zn2SiO4 added or formed in the preparation process has the effect of reducing the sintering temperature, thus greatly reducing the cost required for purchasing a sintering device.

[0065] In a third aspect of the present application, a ceramic structural member is provided. According to the embodiments of the present application, the ceramic structural member has the zirconium-based composite ceramic material according to the above embodiments or the zirconium-based composite ceramic material prepared by the method according to the above embodiments. Thus, the ceramic structural member has all the advantages of the zirconium-based composite ceramic material according to the above embodiments, specifically, the hardness and toughness of the ceramic structural member are significantly improved, and the density, dielectric constant and light transmittance of the ceramic structural member are significantly reduced. Specifically, the above ceramic structural member can be applied in the fields of mobile phones, computers and the like, for example, applied in mobile phone back cover products.

[0066] The embodiments of the present application are described in detail below, and it should be noted that the embodiments described below are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application. In addition, if not specifically stated, all reagents used in the following embodiments are commercially available or can be synthesized according to the methods described herein or known methods, and the reaction conditions not listed are also easily obtained by those skilled in the art.

[0067] Example 1

[0068] The present embodiment provides a preparation method of a zirconium-based composite ceramic material, comprising the following steps:

[0069] Raw materials: composite powder 200 g, containing lanthanum oxide (La2O3) 12.38 wt%, aluminum oxide (Al2O3) 42.62 wt%, 44 wt% of zirconium oxide powder containing 3 mol% yttrium oxide, and 1 wt% of zinc silicate (Zn2SiO4).

[0070] The raw materials were ball milled in a ball mill tank with water for 8 h, then 0.02 wt% of hydroxypropyl methyl cellulose and water were added to a sand mill for sand milling for 10 h, and finally 4 wt% of a binder (mass ratio of PEG4000 and PVA of 1:1) of the composite powder was added and stirred for 0.5 h to form a slurry for spraying, with a solid content of 25 wt%.

[0071] The slurry was sent to a spray tower for spray drying (inlet air temperature of 250°C, outlet air temperature of 110°C, and centrifugal rotation speed of 15 revolutions per second) to form a spherical powder with strong fluidity for dry pressing, and then dry pressing (8 MPa oil pressure was used for a 200-ton press).

[0072] The molded powder was sintered by heating from room temperature to 600°C for 400 min and holding for 2 h, heating from 600°C to 1150°C for 300 min and holding for 2 h, and heating from 1150°C to 1450°C for 150 min and holding for 2 h, and then cooling from 1450°C to 900°C for 150 min, and finally naturally cooling to room temperature. The whole process was carried out in air.

[0073] The sintered product was polished and laser cut to form the final sample, which had a size of 150*75*0.6 mm in the shape and size of a mobile phone back cover.

[0074] The prepared sample was detected by high-energy XRF, and the composition elements contained Zr 31.2 wt%, Y 2.1 wt%, La 10.7 wt%, Al 22.7 wt%, Zn 0.7 wt%, and Si 0.3 wt%.

[0075] The XRD detected phase included: tetragonal zirconia 43.3 wt%, LaAl 11 O 18 55.2 wt%, Zn2SiO4 1.2 wt%, and monoclinic zirconia 0.3 wt%. Among them, the tetragonal zirconia was a solid solution formed by yttrium oxide and zirconium oxide.

[0076] Example 2

[0077] The present embodiment provides a preparation method of a zirconium-based composite ceramic material, comprising the following steps:

[0078] Raw materials: composite powder 200g, containing lanthanum oxide (La2O3) 11.25wt%, aluminum oxide (Al2O3) 38.75wt%, 49wt% of zirconium oxide powder containing 3mol% yttrium oxide and 1wt% of zinc silicate (Zn2SiO4).

[0079] The raw materials were ball milled in a ball mill tank for 8h, then 0.02wt% of hydroxypropyl methyl cellulose and water were added in a sand mill for 10h, and finally 4wt% of the powder binder (mass ratio of PEG4000 and PVA is 1:1) was added and stirred for 0.5h to form a slurry for spraying, with a solid content of 25wt%.

[0080] The slurry was sent to a spray tower for spray drying (the inlet air temperature was 250℃, the outlet air temperature was 110℃, and the centrifugal speed was 15 revolutions per second) to form a spherical powder with good fluidity for dry pressing, and then dry pressing (8MPa oil pressure was used in a 200-ton press).

[0081] The molded powder was sintered by heating from room temperature to 600℃ for 400min and holding for 2h, heating from 600℃ to 1150℃ for 300min and holding for 2h, and heating from 1150℃ to 1450℃ for 150min and holding for 2h, and then cooling from 1450℃ to 900℃ for 150min, and finally naturally cooling to room temperature. The whole process was carried out in air.

[0082] The sintered product was polished and laser cut to form the final sample, which was in the shape and size of a mobile phone back cover, 150*75*0.6mm.

[0083] The prepared sample was detected by high-energy XRF, and the composition elements contained: Zr 34.7wt%, Y 2.2wt%, La 9.7wt%, Al 20.7wt%, Zn 0.8wt%, and Si 0.3wt%.

[0084] The XRD detected phase included: tetragonal zirconia 48.5wt%, LaAl 11 O 18 50.2wt%, Zn2SiO4 1.1wt%, and monoclinic zirconia 0.2wt%. Among them, the tetragonal zirconia was a solid solution formed by yttrium oxide and zirconium oxide.

[0085] Example 3

[0086] The embodiment provides a preparation method of a zirconium-based composite ceramic material, comprising the following steps:

[0087] Raw materials: 200g of composite powder containing 13.5wt% of lanthanum oxide (La2O3), 46.5wt% of aluminum oxide (Al2O3), 39wt% of zirconium oxide powder containing 3mol% yttrium oxide, and 1wt% of zinc silicate (Zn2SiO4).

[0088] The raw materials were ball-milled in a ball mill tank for 8h with water, then 0.02wt% of hydroxypropyl methyl cellulose and water were added to the raw materials and sand-milled for 10h, and finally 4wt% of a binder (mass ratio of 1:1 of PEG4000 and PVA) was added to the powder and stirred for 0.5h to form a slurry for spraying, with a solid content of 25wt%.

[0089] The slurry was sent to a spray tower for spray drying (inlet temperature of 250℃, outlet temperature of 110℃, and centrifugal speed of 15 revolutions per second) to form a spherical powder with good fluidity for dry pressing, and then dry pressing (8MPa of oil pressure was used for a press with a tonnage of 200 tons).

[0090] The molded powder was sintered by heating from room temperature to 600℃ for 400min and maintaining for 2h, heating from 600℃ to 1150℃ for 300min and maintaining for 2h, and heating from 1150℃ to 1450℃ for 150min and maintaining for 2h, and then cooling from 1450℃ to 900℃ for 150min, and finally naturally cooling to room temperature. The whole process was carried out in air.

[0091] The sintered product was polished and laser cut to form the final sample, which had a size of a mobile phone back cover, 150*75*0.6mm.

[0092] The prepared sample was detected by high-energy XRF, and the composition elements contained Zr of 27.6wt%, Y of 1.7wt%, La of 11.7wt%, Al of 24.9wt%, Zn of 0.8wt%, and Si of 0.2wt%.

[0093] The XRD detected phases included: 38.4wt% of tetragonal zirconia, 60.1wt% of LaAl 11 O 18 1.1wt% of Zn2SiO4, and 0.4wt% of monoclinic zirconia. Among them, the tetragonal zirconia was a solid solution formed by yttrium oxide and zirconia.

[0094] Example 4

[0095] The embodiment provides a preparation method of a zirconium-based composite ceramic material, which comprises the following steps:

[0096] Raw materials: 200g of composite powder containing 12.38wt% of lanthanum oxide (La2O3), 42.62wt% of aluminum oxide (Al2O3), 44.5wt% of zirconium oxide powder containing 3mol% yttrium oxide, and 0.5wt% of zinc silicate (Zn2SiO4).

[0097] The raw materials were ball-milled in a ball mill tank for 8h with water, then 0.02wt% of hydroxypropyl methyl cellulose and water were added to the raw materials and sand-milled for 10h, and finally 4wt% of a binder (mass ratio of 1:1 of PEG4000 and PVA) was added to the powder and stirred for 0.5h to form a slurry for spraying, with a solid content of 25wt%.

[0098] The slurry was sent to a spray tower for spray drying (inlet temperature of 250℃, outlet temperature of 110℃, and centrifugal speed of 15 revolutions per second) to form a spherical powder with good fluidity for dry pressing, and then dry pressing (8MPa of oil pressure was used for a press with a tonnage of 200 tons).

[0099] The molded powder was sintered by heating from room temperature to 600℃ for 400min and holding for 2h, heating from 600℃ to 1150℃ for 300min and holding for 2h, and heating from 1150℃ to 1470℃ for 150min and holding for 2h, and then cooling from 1470℃ to 900℃ for 150min, and finally naturally cooling to room temperature. The whole process was carried out in air.

[0100] The sintered product was polished and laser cut to form the final sample, which had a size of 150*75*0.6mm in the shape and size of a mobile phone back cover.

[0101] The prepared sample was detected by high-energy XRF, and the composition elements contained Zr of 31.6wt%, Y of 2.2wt%, La of 10.8wt%, Al of 22.8wt%, Zn of 0.4wt%, and Si of 0.2wt%.

[0102] The XRD detected phases included: tetragonal zirconia of 44.1wt%, LaAl 11 O 18 of 55.3wt%, Zn2SiO4 of 0.5wt%, and monoclinic zirconia of 0.1wt%. Among them, the tetragonal zirconia was a solid solution formed by yttrium oxide and zirconium oxide.

[0103] Example 5

[0104] The embodiment provides a preparation method of a zirconium-based composite ceramic material, which comprises the following steps:

[0105] Raw material: composite powder 200 g, containing lanthanum oxide (La2O3) 12.38 wt%, aluminum oxide (Al2O3) 42.62 wt%, 43 wt% of 3 mol% yttria-stabilized zirconia powder and 2 wt% of zinc silicate (Zn2SiO4).

[0106] The raw material was ball milled in a ball mill tank for 8 h, then 0.02 wt% of hydroxypropyl methyl cellulose and water were added to the raw material in a sand mill for 10 h, and finally 4 wt% of a binder (mass ratio of PEG4000 and PVA of 1:1) was added to the powder and stirred for 0.5 h to form a slurry for spraying, with a solid content of 25 wt%.

[0107] The slurry was fed into a spray tower for spray drying (inlet temperature of 250°C, outlet temperature of 110°C, and centrifugal speed of 15 revolutions per second) to form a spherical powder with good fluidity for dry pressing, and then dry pressing (8 MPa oil pressure was used for a 200-ton press).

[0108] The molded powder was sintered by heating from room temperature to 600°C for 400 min and holding for 2 h, heating from 600°C to 1150°C for 300 min and holding for 2 h, and heating from 1150°C to 1430°C for 150 min and holding for 2 h, and then cooling from 1430°C to 900°C for 150 min, and finally naturally cooling to room temperature. The entire process was carried out in air.

[0109] The sintered product was polished and laser cut to form the final sample, which had a size of 150*75*0.6 mm in the shape and size of a mobile phone back cover.

[0110] The prepared sample was subjected to high-energy XRF detection, and the composition elements included: Zr 30.6 wt%, Y 2.1 wt%, La 10.7 wt%, Al 22.6 wt%, Zn 1.5 wt%, and Si 0.6 wt%.

[0111] The XRD detected phases included: tetragonal zirconia 42.4 wt%, LaAl 11 O 18 55.2 wt%, Zn2SiO4 2.1 wt%, and monoclinic zirconia 0.3 wt%. Among them, the tetragonal zirconia was a solid solution formed by yttria and zirconia.

[0112] Comparative Example 1

[0113] Raw material: composite powder 200 g, containing aluminum oxide (Al2O3) 50 wt%, and 50 wt% of 3 mol% yttria-stabilized zirconia powder.

[0114] The raw material was ball-milled in a ball mill tank with water for 8 h, then 0.02 wt% of hydroxypropyl methyl cellulose and water were added to a sand mill for sand milling for 10 h, and finally 4 wt% of a binder (PEG4000 and PVA in a mass ratio of 1:1) was added to the powder and stirred for 0.5 h to form a slurry for spraying, with a solid content of 25 wt%.

[0115] The slurry was sent to a spray tower for spray drying (an inlet air temperature of 250°C, an outlet air temperature of 110°C, and a centrifugal rotation speed of 15 revolutions per second) to form a spherical powder with good fluidity for dry pressing, and then dry pressing (an oil pressure of 8 MPa was used for a press with a tonnage of 200 tons).

[0116] The molded powder was sintered by heating from room temperature to 600°C for 400 min and maintaining the temperature for 2 h, heating from 600°C to 1150°C for 300 min and maintaining the temperature for 2 h, and heating from 1150°C to 1550°C for 150 min and maintaining the temperature for 2 h, and then cooling from 1550°C to 900°C for 150 min, and finally naturally cooling to room temperature. The entire process was carried out in air.

[0117] After polishing, polishing and laser cutting of the sintered product, the final sample was prepared, with a size of a mobile phone back cover shape and size, 150*75*0.6mm.

[0118] The prepared sample was detected by high-energy XRF, and the composition elements contained: Zr was 35.3wt%, Y was 2.4wt%, and Al was 26.6wt%.

[0119] The XRD detected phase included: tetragonal zirconia was 49.6wt%, Al2O3 was 50.1wt%, and monoclinic zirconia was 0.3wt%. Among them, the tetragonal zirconia was a solid solution formed by yttrium oxide and zirconia.

[0120] Comparative Example 2

[0121] Raw material: composite powder 200g, 100wt% containing 3mol% yttria stabilized zirconia powder.

[0122] The raw material was ball-milled in a ball mill tank with water for 8 h, then 0.02 wt% of hydroxypropyl methyl cellulose and water were added to a sand mill for sand milling for 10 h, and finally 4 wt% of a binder (PEG4000 and PVA in a mass ratio of 1:1) was added to the powder and stirred for 0.5 h to form a slurry for spraying, with a solid content of 25 wt%.

[0123] The slurry was sent to a spray tower for spray drying (an inlet air temperature of 250°C, an outlet air temperature of 110°C, and a centrifugal rotation speed of 15 revolutions per second) to form a spherical powder with good fluidity for dry pressing, and then dry pressing (an oil pressure of 8 MPa was used for a press with a tonnage of 200 tons).

[0124] The molding powder was sintered by heating from room temperature to 600°C for 400 min and holding for 2 h, heating from 600°C to 1150°C for 300 min and holding for 2 h, and heating from 1150°C to 1450°C for 150 min and holding for 2 h, and then cooling to 900°C for 150 min, and finally naturally cooling to room temperature. The whole process was carried out in air.

[0125] The sintered product was polished and laser cut to form the final sample, which had the shape and size of a mobile phone back cover, 150*75*0.6 mm.

[0126] The sample was subjected to high-energy XRF detection, and the composition elements included Zr 70.3 wt%, Y 4.3 wt%.

[0127] The XRD detection included tetragonal zirconia 99.6 wt%, and monoclinic zirconia 0.4 wt%. Among them, the tetragonal zirconia was a solid solution formed by yttrium oxide and zirconium oxide.

[0128] Comparative Example 3

[0129] Raw materials: 200 g of composite powder, including 12.38 wt% of lanthanum oxide (La2O3), 42.62 wt% of aluminum oxide (Al2O3), and 45 wt% of 3 mol% yttrium oxide stabilized zirconia powder.

[0130] The raw materials were ball milled in a ball mill tank for 8 h, and then 0.02 wt% of hydroxypropyl methyl cellulose and water were added to a sand mill for sand milling for 10 h. Finally, 4 wt% of a binder (mass ratio of PEG4000 to PVA was 1:1) was added to the powder and stirred for 0.5 h to form a slurry for spraying, and the solid content was 25 wt%.

[0131] The slurry was sent to a spray tower for spray drying (the inlet air temperature was 250°C, the outlet air temperature was 110°C, and the centrifugal speed was 15 revolutions per second) to form a spherical powder with good fluidity for dry pressing. Then, dry pressing was performed (8 MPa oil pressure was used for a 200-ton press).

[0132] The molding powder was sintered by heating from room temperature to 600°C for 400 min and holding for 2 h, heating from 600°C to 1150°C for 300 min and holding for 2 h, and heating from 1150°C to 1550°C for 150 min and holding for 2 h, and then cooling to 900°C for 150 min, and finally naturally cooling to room temperature. The whole process was carried out in air.

[0133] The sintered product was polished and laser cut to form the final sample, which had the shape and size of a mobile phone back cover, 150*75*0.6 mm.

[0134] The prepared sample was subjected to high-energy XRF detection, and the composition elements contained: Zr was 31.9wt%, Y was 2.2wt%, La was 10.8wt%, and Al was 22.6wt%.

[0135] The phase detected by XRD included: tetragonal zirconium oxide was 44.5wt%, LaAl 11 O 18 was 55.3wt%, and monoclinic zirconium oxide was 0.2wt%. Among them, the tetragonal zirconium oxide was a solid solution formed by yttrium oxide and zirconium oxide.

[0136] Test

[0137] The following tests were respectively carried out on examples 1-5 and comparative examples 1-3:

[0138] Fracture toughness Kic: hardness tester indentation method (diamond indenter, force 10 kg, test pressure time 15 s);

[0139] Hardness Hv: hardness tester and indentation method (diamond indenter, force 10 kg, test pressure time 15 s);

[0140] Processability: copper grinding plate size speed, such as fixed time 1 hour, test the thickness difference before and after copper grinding;

[0141] Density: take the average pit number (greater than 20um) in the range of 10*10mm on the large surface of the polished sample;

[0142] Drop hammer impact: using a drop hammer impact testing machine, the sample is placed on the platform, a 60g drop hammer is used to hit the sample at a new position, starting from a height of 5cm, if it does not crack, increase the height by 5cm each time until the sample appears visible cracks, stop and record the height value;

[0143] Dielectric constant: using a network analyzer to test the dielectric constant of the material at 2GHz.

[0144] The test results of examples 1-5 and comparative examples 1-3 are shown in table 1 and table 2.

[0145] Table 1

[0146] Experiment No. Hardness (Hv) Toughness (Mpa-m 0.5 )]]> Pit Count (number) Example 1 1357 5.2 0 Example 2 1346 5.4 0 Example 3 1371 5.1 0 Example 4 1381 4.4 0 Example 5 1333 5.6 0 Comparative Example 1 1605 4.1 0 Comparative Example 2 1311 5.9 0 Comparative Example 3 1393 3.9 0

[0147] Table 2

[0148]

[0149] As can be seen from table 1, although the hardness of comparative example 1 and comparative example 3 is good, the toughness of comparative example 1 and comparative example 3 is poor, although the toughness of comparative example 2 is good, the hardness of comparative example 2 is poor, and the hardness, toughness and density of examples 1-5 are all good.

[0150] To meet the mass production requirements, it is required to simultaneously meet the requirements of thinning speed greater than 28 filaments / hour, drop hammer greater than 28 cm, dielectric constant less than 20 and sintering temperature lower than 1500°C. As can be seen from Table 2, Examples 1-5 all simultaneously meet the performance requirements of thinning speed greater than 28, drop hammer greater than 28 cm, dielectric constant less than 20 and sintering temperature lower than 1500°C. The thinning speed of Comparative Examples 1 and 3 is less than 28 filaments / hour, the drop hammer of Comparative Examples 1 and 3 is less than 28 cm, the sintering temperature of Comparative Examples 1 and 3 is greater than 1500°C, the dielectric constant of Comparative Example 2 is greater than 20, and the density of Comparative Example 2 is greater.

[0151] As can be seen from Tables 1 and 2, the zirconium-based composite ceramic materials prepared in Examples 1-5 simultaneously have high hardness, toughness and impact resistance, and low density and dielectric constant, and the sintering temperature is lower than 1500°C. The comprehensive performance of Comparative Examples 1-3 cannot meet the mass production requirements.

[0152] In the description of the present specification, the description referring to the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific feature, structure, material or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. The illustrative expressions of the above terms in the present specification do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples, without contradiction.

[0153] Although the embodiments of the present application have been shown and described above, it is to be understood that the above-described embodiments are exemplary, and are not to be construed as limiting the present application, and the person skilled in the art can make changes, modifications, replacements and variations to the above-described embodiments within the scope of the present application.

Claims

1. A composite ceramic material, characterized by, comprising: zirconia; and LaAl dispersed in the zirconia 11 O 18 phases and Zn2SiO4 phases; The content of the zirconium oxide is 27.5-59.8 wt%, the content of the LaAl 11 O 18 The content of the phase is 40-70 wt%, the content of the Zn2SiO4 phase is 0.2-2.5 wt%.

2. The composite ceramic material of claim 1, wherein, The content of the zirconium oxide is 38-49.5 wt%, the content of the LaAl 11 O 18 The content of the phase is 50-60 wt%, the content of the Zn2SiO4 phase is 0.5-2 wt%.

3. The composite ceramic material of claim 1, wherein, comprising, in terms of elements: 18.94-43.11 wt% of Zr, 7.67-13.43 wt% of La, 0.56-3.26 wt% of Y, 16.43-28.75 wt% of Al, 0.11-1.46 wt% of Zn and 0.02-0.31 wt% of Si, and the molar ratio of La to Al is 1:11, and the molar ratio of Zn and Si is 2:

1.

4. The composite ceramic material of claim 1, wherein, comprising, in terms of elements: 26.17-35.68 wt% of Zr, 9.58-11.52 wt% of La, 0.77-2.71 wt% of Y, 20.53-24.65 wt% Al, 0.27-1.09 wt% of Zn and 0.05-0.2 wt% of Si, and the molar ratio of La to Al is 1:11, and the molar ratio of Zn and Si is 2:

1.

5. The composite ceramic material according to any one of claims 1 to 4, characterized in that, the zirconia is 1.5-4 mol% yttrium stabilized tetragonal phase zirconia.

6. The composite ceramic material according to any one of claims 1 to 4, characterized in that, at least one of the following conditions is met: the hardness of the composite ceramic material is 1330-1390 Hv; The toughness of the composite ceramic material is 4.4-6.0 Mpa•m 0.5 ; the dielectric constant of the composite ceramic material is 16.0-18.5; The density of the composite ceramic material is 4.6-4.9 g / cm 3 .

7. A method of preparing the composite ceramic material according to any one of claims 1 to 6, characterized in that, comprising: (1) mixing zirconia powder, LaAl 11 O 18 powder, Zn2SiO4 powder, water and dispersant, and grinding to obtain a mixed slurry; or, zirconia powder, LaAl 11 O 18 powder, zinc oxide powder, silica powder, water, and a dispersant are mixed and ground to obtain a mixed slurry; or, mixing zirconia powder, lanthana powder, alumina powder, Zn2SiO4 powder, water and dispersant, grinding, so as to obtain a mixed slurry; or, mixing zirconia powder, lanthana powder, alumina powder, Zn2SiO4 powder, water and dispersant, grinding, so as to obtain a mixed slurry; (2) mixing the mixed slurry with a binder, stirring, so as to form a slurry for spraying; (3) spray drying the slurry for spraying, so as to form a spherical powder, dry pressing the spherical powder, so as to obtain a shaped powder; (4) high temperature sintering the shaped powder, so as to obtain a composite ceramic material.

8. The method of claim 7, wherein, the molar ratio of the silica powder to the zinc oxide powder is 1:(1.9-2.1).

9. The method of claim 7, wherein, the molar ratio of the lanthana powder to the alumina powder is 1:(10.8-11.2).

10. The method of claim 7, wherein, in step (1), the particle size of the powder is ground to nanoscale.

11. The method of claim 7, wherein, in step (1), the amount of the dispersant is 0.01-0.03 wt% based on the total mass of the mixed powder.

12. The method of claim 7, wherein, in step (2), the amount of the binder is 3-5 wt% based on the total mass of the mixed powder.

13. The method according to any one of claims 7-12, characterized in that, in step (4), the temperature of the high temperature sintering is 1400-1500 degrees Celsius, and the time of the high temperature sintering is 1-2 hours.

14. A ceramic structural member, characterized by, the composite ceramic material of any one of claims 1-6 or the composite ceramic material prepared by the method of any one of claims 7-13.

Images