Fine-grained beryllium oxide ceramic thin film substrate and method of making same

Abstract

The present application relates to a kind of fine grain beryllium oxide ceramic film substrate and its preparation method, belong to ceramic technical field, to solve the average grain size of beryllium oxide ceramic substrate prepared by existing method at least one of the problems such as high, high surface roughness, low thermal conductivity, low room temperature bending strength and so on.The fine grain beryllium oxide ceramic film substrate, according to weight part, the raw material of the substrate includes nano beryllium oxide:99~99.5 portion, magnesium aluminum silicate:0.2~0.5 portion, nano silicon dioxide 0.2~0.3 portion.The volume density, thermal conductivity and bending strength of beryllium oxide ceramic substrate are improved and the grain size is reduced by the synergistic effect of nano beryllium oxide, magnesium aluminum silicate and nano silicon dioxide, and specific ratio.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ceramics, in particular to a fine-grained beryllium oxide ceramic film substrate and a preparation method thereof. BACKGROUND

[0002] Beryllium oxide ceramic is an important part of electronic devices. Because beryllium oxide ceramic has high thermal conductivity, good insulation, thermal shock resistance, low loss and good chemical stability, it is widely used in aerospace and other high-power devices for heat dissipation. It has been widely used in electronic vacuum devices, high-power module thick film circuits, packaged devices and optoelectronic devices. Microwave thin film electronic materials are developing towards new, light, thin, high frequency and high power. Polished beryllium oxide ceramic substrates with low loss and stable dielectric constant are increasingly important in the field of microwave electronics and aerospace.

[0003] At present, most of the beryllium oxide polishing pieces are prepared by calcining beryllium oxide powder, then ball milling, spray granulating, dry pressing preforming, isostatic pressing, sintering, and then grinding and polishing. Because the powder is calcined, the crystal grains grow, the activity decreases, the sintering temperature of the ceramic is high, the holding time is long, the crystal grains of the ceramic are large, which is not conducive to the later polishing process, the yield is low, the surface roughness can only reach 0.08-0.1 μm, and the thermal conductivity is poor, the bending strength is low, and the grain size is large. SUMMARY

[0004] In view of the above analysis, the present application aims to provide a fine-grained beryllium oxide ceramic film substrate and a preparation method thereof, to solve at least one of the problems of the average grain size of the beryllium oxide ceramic substrate prepared by the existing method, the high surface roughness, the low thermal conductivity, and the low room temperature bending strength.

[0005] In a first aspect, the present application provides a fine-grained beryllium oxide ceramic film substrate. According to weight parts, the raw materials of the substrate include nano beryllium oxide 99-99.5 parts, magnesium aluminum silicate 0.2-0.5 parts, and nano silicon dioxide 0.2-0.3 parts.

[0006] Further, the raw materials further include nano yttrium oxide 0.1-0.2 parts.

[0007] Further, the particle size of the nano beryllium oxide is 20-100 nm, the particle size of the magnesium aluminum silicate is 0.5-1 μm, the particle size of the nano silicon dioxide is 10-30 nm, and the particle size of the nano yttrium oxide is 30-40 nm.

[0008] In a second aspect, the present application provides a preparation method of the fine-grained beryllium oxide ceramic film substrate, including the following steps:

[0009] (1) According to the weight parts of each raw material, the standby raw materials are weighed respectively;

[0010] (2) Polyvinyl alcohol is dissolved in water to obtain solution A;

[0011] (3) The standby raw materials are added to water, stirred, and ground to obtain a beryllium oxide slurry;

[0012] (4) The solution A is added to the beryllium oxide slurry, stirred, spray granulated and dried to obtain a granulated powder;

[0013] (5) The granulated powder is hot-pressed and sintered, cut into a substrate, and the substrate is sequentially subjected to thinning, grinding and polishing treatment on both sides to obtain the fine-grained beryllium oxide ceramic thin film substrate.

[0014] Further, in step (2), the mass ratio of polyvinyl alcohol to water is 10-20:100.

[0015] Further, in step (3), the mass ratio of the total mass of the standby raw materials to water is 20-54:46-50.

[0016] Further, in step (4), the mass ratio of the beryllium oxide slurry to solution A is 100:3-5.

[0017] Further, in step (4), the stirring time is greater than or equal to 2 hours, and the average particle size of the granulated powder is 50-80 microns.

[0018] Further, the sintering temperature of the hot-pressing sintering is 1600-1650℃, the pressure is 20-30MPa, and the holding time is 10-30min.

[0019] Further, in step (5), the thickness of the cut substrate is 0.5-1mm.

[0020] Compared with the prior art, the present application can achieve at least one of the following beneficial effects:

[0021] (1) The present application realizes the improvement of the bulk density, thermal conductivity and bending strength of the beryllium oxide ceramic substrate and the reduction of the grain size through the synergistic effect of nano-beryllium oxide, magnesium aluminum silicate and nano-silicon dioxide, and a specific ratio;

[0022] (2) The raw material of the present application also includes a small amount of nano yttrium oxide, the nano yttrium oxide particles can be uniformly dispersed in the beryllium oxide matrix, the grain boundary migration is inhibited by physical pinning effect, and the abnormal grain growth is prevented. Y2O3 and MgO, Al2O3 and SiO2 in magnesium aluminum silicate form a low melting point eutectic phase (such as Y-Si-Al-O glass phase) at high temperature, promote densification sintering, and at the same time, the grain coarsening driven by surface diffusion is inhibited by liquid phase wrapping grain. Y2O3 can react with nano SiO2 to generate Y2Si2O7 and other high-temperature-resistant silicates, further enhancing the grain boundary stability and delaying the grain growth kinetics. The performance of the beryllium oxide substrate prepared by adding nano yttrium oxide in the raw material of the present application is better;

[0023] (3) The bulk density of the fine-grained beryllium oxide ceramic thin film substrate is 2.913~2.929g / cm 3 , the thermal conductivity (25℃) is ≥282W / m·K, preferably 282~308W / m·K, the room temperature bending strength is ≥240MPa, preferably 243~263MP, the average grain size is ≤10μm, preferably 7.9~9.9μm, the surface roughness after polishing is ≤0.041μm, preferably 0.013~0.041μm;

[0024] (4) The method of the present application replaces the dry isostatic pressing forming and sintering in the prior art with direct hot pressing sintering, cooperates with the specific raw material and ratio of the present application, improves the densification of the fine-grained beryllium oxide ceramic thin film substrate, the grain size is smaller, and the sintering temperature is reduced by the method of the present application.

[0025] In the present application, the above-mentioned technical solutions can be combined with each other to realize more preferred combination solutions. Other features and advantages of the present application will be described in the subsequent specification, and some advantages will become apparent from the specification, or will be understood by implementing the present application. The purposes and other advantages of the present application can be realized and obtained from the contents specifically pointed out in the specification and the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0026] The accompanying drawings are included to provide a further understanding of the present application and are incorporated in and constitute a part of this specification, illustrate embodiments of the present application and serve to explain the principles of the present application, and are not considered as limiting the scope of the present application.

[0027] Figure 1 The grain size diagram of the fine-grained beryllium oxide ceramic thin film substrate prepared in Example 1 of the present application. DETAILED DESCRIPTION

[0028] The preferred embodiments of the present application will be specifically described below in combination with the drawings, wherein the drawings constitute a part of the present application, and are used together with the embodiments of the present application to explain the principles of the present application, and are not considered as limiting the scope of the present application.

[0029] In one embodiment of the present application, a fine-grained beryllium oxide ceramic thin film substrate is disclosed, the raw materials of the substrate include, by weight, nano beryllium oxide: 99-99.5 parts (for example, 99.1 parts, 99.2 parts, 99.3 parts, 99.4 parts), magnesium aluminum silicate: 0.2-0.5 parts (for example, 0.22 parts, 0.24 parts, 0.26 parts, 0.28 parts, 0.30 parts, 0.32 parts, 0.34 parts, 0.36 parts, 0.38 parts, 0.40 parts, 0.42 parts, 0.44 parts, 0.46 parts, 0.48 parts), nano silicon dioxide 0.2-0.3 parts (for example, 0.22 parts, 0.24 parts, 0.26 parts, 0.28 parts).

[0030] The beryllium oxide substrate of the present application uses the synergistic effect of nano beryllium oxide, magnesium aluminum silicate and nano silicon dioxide to improve the thermal conductivity and bending strength of the substrate and reduce the grain size. Among them, the nano beryllium oxide has high sintering activity, and through the surface energy driving rapid diffusion, a low porosity matrix is formed, the nano particle size is small, the grain boundary hinders the dislocation movement, and the bending strength is significantly improved, the interface reaction of nano beryllium oxide, magnesium aluminum silicate and nano silicon dioxide at high temperature is controllable, and brittle phase generation is avoided. The Mg, Al and Si atoms in the structure of magnesium aluminum silicate are bonded, which is gradually released at high temperature, and the magnesium aluminum silicate forms a low melting point glass phase to fill the gap between BeO particles, drive particle rearrangement through capillary force, reduce porosity, and improve thermal conductivity and strength synergistically with nano BeO. In addition, magnesium aluminum silicate and nano silicon dioxide can also reduce the sintering temperature, nano silicon dioxide can fill the micropores and microcracks at the grain boundary of nano beryllium oxide, reduce the phonon scattering site, and optimize the thermal conductivity synergistically with nano beryllium oxide. Magnesium aluminum silicate can also inhibit the abnormal growth of nano beryllium oxide grains and maintain a fine and uniform microstructure.

[0031] In summary, the synergistic effect of nano beryllium oxide, magnesium aluminum silicate and nano silicon dioxide, as well as the specific ratio, realizes the improvement of the bulk density, thermal conductivity, bending strength and the reduction of the grain size of the beryllium oxide ceramic substrate. The purity of the fine-grained beryllium oxide ceramic thin film substrate of the present application can reach more than 99%.

[0032] Specifically, the raw materials further include nano yttrium oxide 0.1-0.2 parts.

[0033] It should be noted that the raw material of the present application also includes a small amount of nano yttrium oxide (Y2O3), and the nano yttrium oxide particles can be uniformly dispersed in the beryllium oxide matrix, and the grain boundary migration is inhibited by physical pinning effect, and the abnormal grain growth is prevented. Y2O3 and MgO, Al2O3 and SiO2 in magnesium aluminum silicate form a low melting point eutectic phase (such as Y-Si-Al-O glass phase) at high temperature, promote densification sintering, and at the same time, the grain coarsening driven by surface diffusion is inhibited by liquid phase wrapping grain. Y2O3 can react with nano SiO2 to generate Y2Si2O7 and other high-temperature-resistant silicates, further enhancing the grain boundary stability and delaying the grain growth kinetics. The performance of the substrate prepared by adding nano yttrium oxide in the raw material of the present application is better.

[0034] Specifically, the particle size of the nano beryllium oxide is 20-100 nm (for example, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 95 nm), the particle size of the magnesium aluminum silicate is 0.5-1 μm (for example, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm), the particle size of the nano silicon dioxide is 10-30 nm (for example, 12 nm, 14 nm, 16 nm, 18 nm), and the particle size of the nano yttrium oxide is 30-40 nm (for example, 32 nm, 34 nm, 36 nm, 38 nm).

[0035] It should be noted that if the particle size of the nano beryllium oxide is too small, the porosity will decrease, and abnormal grain growth will occur during sintering; if the particle size is too large, the sintering activity will decrease, and pores will be easily left, the thermal conductivity will decrease, and the grain coarsening will reduce the bending strength.

[0036] If the particle size of the magnesium aluminum silicate is too small, the thermal conductivity will decrease, and cracks will easily occur; if the particle size is too large, pores or weak interface will be formed, which will easily lead to interface brittle phase.

[0037] If the particle size of the nano silicon dioxide is too small, agglomeration will occur due to high surface energy; if the particle size is too large, only micron-level defects can be repaired, and the surface smoothing effect will decrease.

[0038] If the particle size of the nano yttrium oxide is within the above range, grain refinement, smooth surface, controllable thermal conductivity reduction, and strength improvement can be achieved.

[0039] Specifically, the surface roughness of the fine-grained beryllium oxide ceramic thin film substrate is ≤0.05 μm.

[0040] Specifically, the bulk density of the fine-grained beryllium oxide ceramic thin film substrate is 2.913-2.929 g / cm 3, thermal conductivity (25℃) ≥282 W / m·K, preferably, 282~308 W / m·K, room temperature bending strength ≥240 MPa, preferably, 243~263 MP, average grain size ≤10 μm, preferably, 7.9~9.9 μm, surface roughness after polishing ≤0.041 μm, preferably, 0.013~0.041 μm.

[0041] Another specific embodiment of the present application discloses a preparation method of the fine-grained beryllium oxide ceramic thin film substrate as above, comprising the following steps:

[0042] (1) according to the weight parts of each raw material, respectively, take standby;

[0043] (2) polyvinyl alcohol is dissolved in water to obtain solution A;

[0044] (3) the standby raw materials are added to water, stirred, ground, and beryllium oxide slurry is obtained;

[0045] (4) the solution A is added to the beryllium oxide slurry, stirred, granulated and dried to obtain granulated powder;

[0046] (5) the granulated powder is hot-pressed and sintered, cut into a substrate, and the substrate is sequentially subjected to thinning, grinding and polishing treatment on both sides to obtain the fine-grained beryllium oxide ceramic thin film substrate.

[0047] Specifically, in step (2), the mass ratio of polyvinyl alcohol to water is 10~20:100 (for example, 11:100, 12:100, 13:100, 14:100, 15:100, 16:100, 17:100, 18:100, 19:100).

[0048] Specifically, in step (3), the mass ratio of the total mass of the standby raw materials to water is 20~54 (for example, 22, 24, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52): 46~50 (for example, 47, 48, 49).

[0049] Preferably, the grinding adopts a sand mill circulating mill for 30~60 min (for example, 35 min, 40 min, 45 min, 50 min, 55 min) to eliminate agglomerates. If the ball milling time is too short, the agglomerates in the slurry are difficult to eliminate, and the particle size distribution is wide. If the ball milling time is too long, the grinding medium wear increases, which enters the beryllium oxide slurry, affecting the purity and performance of the beryllium oxide.

[0050] Specifically, in step (4), the mass ratio of the beryllium oxide slurry to solution A is 100:3-5 (100:3.2, 100:3.4, 100:3.6, 100:3.8, 100:4.0, 100:4.2, 100:4.4, 100:4.6, 100:4.8).

[0051] It should be noted that if the polyvinyl alcohol solution is added too little, the granulation particles are too small, and the powder flowability is poor. If the polyvinyl alcohol solution is added too much, micropores are formed after volatilization during sintering, which affects the density of the ceramic.

[0052] Specifically, in step (4), the stirring time is greater than or equal to 2 hours.

[0053] Specifically, in step (4), the average particle size of the granulated powder is 50-80 microns, for example, 55 microns, 60 microns, 65 microns, 70 microns, or 75 microns.

[0054] It should be noted that if the particle size of the granulated powder is too small, the flowability is poor, it is difficult to uniformly fill the mold, and it is easy to cause voids and low density. If the particle size of the granulated powder is too large, the contact area between the particles during sintering is reduced, which affects the density and strength of the sintered body. Large particles are difficult to achieve ideal densification during sintering, which may cause a decrease in product performance.

[0055] Specifically, in step (5), the sintering temperature of the hot-pressing sintering is 1600-1650 degrees Celsius, for example, 1605 degrees Celsius, 1610 degrees Celsius, 1615 degrees Celsius, 1620 degrees Celsius, 1625 degrees Celsius, 1630 degrees Celsius, 1635 degrees Celsius, 1640 degrees Celsius, or 1645 degrees Celsius. The pressure is 20-30 MPa, for example, 22 MPa, 24 MPa, 26 MPa, or 28 MPa. The holding time is 10-30 minutes, for example, 12 minutes, 14 minutes, 16 minutes, 18 minutes, 20 minutes, 22 minutes, 24 minutes, 26 minutes, or 28 minutes.

[0056] The method of the present application replaces the dry isostatic pressing and sintering in the prior art with direct hot-pressing sintering, and cooperates with the specific raw materials and proportions of the present application to improve the density of the fine-grained beryllium oxide ceramic thin film substrate, the grain size is smaller, and the method of the present application reduces the sintering temperature.

[0057] It should be noted that due to the high sintering temperature, the grains grow significantly, the grain boundaries increase, heat conduction is hindered, the thermal conductivity is reduced, defects are generated inside the material, cracks are generated, the flexural strength is reduced, the grains grow unevenly, the surface is uneven, and the surface roughness is increased. Under the pressure range of the present invention, the particles of beryllium oxide powder can be made closer, the pores are reduced, the density is increased, and the thermal conductivity is improved. Excessive pressure can cause abnormal grain growth, reduce thermal conductivity, excessive pressure causes uneven force on the grains, defects are generated, and the flexural strength is reduced. Excessive pressure causes the particles to break and the surface is uneven, resulting in increased surface roughness. The sintering time is too long, the grains grow excessively, the grain boundary scattering increases, the thermal conductivity decreases, the grains are coarse, defects are generated, the flexural strength is reduced, and the surface may also be uneven due to grain growth.

[0058] In summary, only by adopting the present invention's sintering temperature of 1600-1650°C, pressure of 20-30 MPa, and holding time of 10-30 minutes can fine-grained beryllium oxide ceramic thin film substrates achieve high density and high flexural strength. Furthermore, the present invention employs a hot-pressing rapid sintering method, which reduces the sintering temperature and shortens the holding time, effectively reducing grain size.

[0059] Specifically, in step (5), a diamond wire cutting machine is used to cut the substrate. Preferably, the thickness of the substrate is 0.5-1 mm, for example, 0.6 mm, 0.7 mm, 0.8 mm, or 0.9 mm.

[0060] Grinding is performed using a double-sided grinder equipped with a W20 diamond grinding pad and W10 diamond grinding fluid. The use of multi-wire cutting on thick plates significantly reduces machining allowance compared to single-piece machining, saving material and reducing costs.

[0061] It should be noted that in step (5), a polishing machine is used with a polishing liquid for polishing, and rough polishing and fine polishing are performed in sequence. After polishing, the surface roughness is ≤0.05μm.

[0062] The rough polishing is carried out on a rough polishing disc, and the rough polishing processing amount is 0.01mm~0.015mm, for example, 0.011mm, 0.012mm, 0.013mm, 0.014mm. The rough polishing is carried out using JX0750 polishing liquid, the polishing disc speed is 60~70rpm, for example, 62rpm, 64rpm, 66rpm, 68rpm, and the rough polishing time is 1~5min, for example, 2min, 3min, 4min.

[0063] The fine polishing is carried out on a fine polishing disc, the fine polishing allowance is 0.001mm~0.002mm, for example, 0.0012mm, 0.0014mm, 0.0016mm, 0.0018mm, the fine polishing adopts JX2000 polishing liquid to polish, the polishing disc rotation speed is 60~70rpm, for example, 62rpm, 64rpm, 66rpm, 68rpm, the fine polishing time is 60~70min, for example, 62min, 64min, 66min, 68min.

[0064] The manufacturer of JX0750 polishing liquid and JX2000 polishing liquid in the application is Guizhou Jintai Grinding Science and Technology Development Co., Ltd.

[0065] The application uses polyvinyl alcohol as a binder, grinding slurry, granulation drying, etc., improves the uniformity and density of the material, thereby significantly improving the thermal conductivity, bending strength and surface roughness; adopts a hot-pressing sintering process, promotes the diffusion and combination between particles through the joint action of high temperature and high pressure, and further improves the performance of the material. The optimization of the process significantly improves the density and strength of the material, while inhibiting the excessive growth of the crystal grains and avoiding the performance decline caused by the coarse crystal grains.

[0066] The preparation method of the application significantly improves the thermal conductivity, bending strength and reduces the surface roughness of the fine-grained beryllium oxide ceramic thin film substrate by optimizing the raw material ratio, processing steps and sintering process.

[0067] The thickness of the fine-grained beryllium oxide ceramic thin film substrate obtained by the method of the application is 0.381±0.005mm~0.762±0.005mm.

[0068] It should be noted that all the raw materials in the application are commercially available, and the technical solutions of the application will be further explained in combination with specific examples.

[0069] Example 1

[0070] The fine-grained beryllium oxide ceramic thin film substrate of the embodiment comprises, by weight, nano beryllium oxide: 99.5 parts, magnesium aluminum silicate: 0.2 parts, and nano silicon dioxide 0.3 parts.

[0071] The particle size of the nano beryllium oxide is 60nm, the particle size of the magnesium aluminum silicate is 0.75μm, and the particle size of the nano silicon dioxide is 30nm.

[0072] The preparation method of the fine-grained beryllium oxide ceramic thin film substrate of the embodiment comprises the following steps:

[0073] (1) According to the weight parts of each raw material, respectively, take the standby;

[0074] (2) Dissolve polyvinyl alcohol in water, the mass ratio of polyvinyl alcohol to water is 20:100, to obtain solution A;

[0075] (3) Add the standby nano beryllium oxide, magnesium aluminum silicate and nano silicon dioxide into water, the mass ratio of the total mass of nano beryllium oxide, magnesium aluminum silicate and nano silicon dioxide to water is 50:50, stir, and grind by using a sand mill circulating mill for 30 min to eliminate agglomerates, to obtain beryllium oxide slurry;

[0076] (4) Add the solution A into the beryllium oxide slurry, the volume ratio of the beryllium oxide slurry to solution A is 100:5, stir for ≥2 h, granulate and dry, to obtain granulated powder, the particle size of the granulated powder is 65 μm;

[0077] (5) Hot-press sinter the granulated powder, the hot-press sintering temperature is 1625℃, the pressure is 25 Mpa, and the holding time is 20 min, to obtain beryllium oxide 10~15 mm thick plate, cut the thick plate into thin substrate by using a diamond wire cutting machine, the thickness of the thin substrate is 0.75 mm, and then thin the thickness by using a double-sided grinding machine, the grinding machine is equipped with W20 diamond grinding pad and W10 diamond grinding liquid, to obtain fine-grained beryllium oxide ceramic substrate, the thickness is 0.65 mm, further polish by using a polishing machine matched with polishing liquid, sequentially perform coarse polishing and fine polishing, the surface roughness after polishing is ≤0.05 μm, the coarse polishing is performed on a coarse polishing disc, the coarse polishing processing amount is 0.013 mm, the coarse polishing is performed by using JX0750 polishing liquid, the polishing disc rotation speed is 65 rpm, and the coarse polishing time is 3.5 min, the fine polishing is performed on a fine polishing disc, the fine polishing processing amount is 0.0015 mm, the fine polishing is performed by using JX2000 polishing liquid, the polishing disc rotation speed is 65 rpm, and the fine polishing time is 65 min, to obtain the fine-grained beryllium oxide ceramic thin film substrate, the thickness is 0.635±0.005 mm.

[0078] The grain size of the fine-grained beryllium oxide ceramic thin film substrate prepared in this embodiment is shown in Figure 1 .

[0079] Example 2

[0080] The fine-grained beryllium oxide ceramic thin film substrate of this embodiment, according to the weight parts, the raw materials of the fine-grained beryllium oxide ceramic thin film substrate include nano beryllium oxide: 99.25 parts, magnesium aluminum silicate: 0.5 parts, and nano silicon dioxide 0.25 parts.

[0081] The particle size of the nano beryllium oxide is 20 nm, the particle size of the magnesium aluminum silicate is 1 μm, and the particle size of the nano silicon dioxide is 20 nm. The preparation method of the fine-grain beryllium oxide ceramic film substrate of the embodiment comprises the following steps:

[0082] (1) The raw materials are weighed according to the weight parts;

[0083] (2) Polyvinyl alcohol is dissolved in water, and the mass ratio of polyvinyl alcohol to water is 15:100, to obtain solution A;

[0084] (3) The prepared nano beryllium oxide, magnesium aluminum silicate and nano silicon dioxide are added to water, and the mass ratio of the total mass of the nano beryllium oxide, magnesium aluminum silicate and nano silicon dioxide to water is 20:46, stirred, and ground by a sand mill circulating mill for 45 min to eliminate agglomerates, to obtain a beryllium oxide slurry;

[0085] (4) The solution A is added to the beryllium oxide slurry, and the volume ratio of the beryllium oxide slurry to solution A is 100:4, and the stirring time is ≥2 h, granulation and drying are performed, to obtain a granulation powder, and the particle size of the granulation powder is 65 μm;

[0086] (5) The granulation powder is subjected to hot-pressing sintering, the hot-pressing sintering temperature is 1600℃, the pressure is 20 Mpa, and the holding time is 30 min, to obtain a beryllium oxide 10~15 mm thick plate, the thick plate is cut into a thin substrate by using a diamond wire cutting machine, the thickness of the thin substrate is 0.62 mm, and the thickness is thinned by using a double-sided grinding machine, the grinding machine is matched with a W20 diamond grinding pad and a W10 diamond grinding liquid, to obtain a fine-grain beryllium oxide ceramic substrate, the thickness of which is 0.52 mm, further polishing treatment is performed by using a polishing machine matched with a polishing liquid, coarse polishing and fine polishing are sequentially performed, the surface roughness after the polishing treatment is ≤0.05 μm, the coarse polishing is performed on a coarse polishing disc, the coarse polishing processing amount is 0.01 mm, the coarse polishing is performed by using JX0750 polishing liquid, the polishing disc rotates at 60 rpm, and the coarse polishing time is 1 min, the fine polishing is performed on a fine polishing disc, the fine polishing processing amount is 0.001 mm, the fine polishing is performed by using JX2000 polishing liquid, the polishing disc rotates at 60 rpm, and the fine polishing time is 70 min, to obtain the fine-grain beryllium oxide ceramic film substrate, the thickness of which is 0.508±0.005 mm.

[0087] Example 3

[0088] The fine-grain beryllium oxide ceramic film substrate of the embodiment comprises, according to weight parts, nano beryllium oxide: 99 parts, magnesium aluminum silicate: 0.3 parts, and nano silicon dioxide: 0.3 parts.

[0089] The particle size of the nano beryllium oxide is 100 nm, the particle size of the magnesium aluminum silicate is 0.5 μm, and the particle size of the nano silicon dioxide is 10 nm.

[0090] The preparation method of the fine-grained beryllium oxide ceramic film substrate of the embodiment comprises the following steps:

[0091] (1) According to the weight parts of each raw material, the standby materials are weighed respectively;

[0092] (2) Polyvinyl alcohol is dissolved in water, and the mass ratio of polyvinyl alcohol to water is 10:100, to obtain solution A;

[0093] (3) The standby nano beryllium oxide, magnesium aluminum silicate and nano silicon dioxide are added to water, and the mass ratio of the total mass of nano beryllium oxide, magnesium aluminum silicate and nano silicon dioxide to water is 37:48, stirring, grinding and circulating grinding for 60 min by using a sand mill to eliminate agglomerates, to obtain a beryllium oxide slurry;

[0094] (4) The solution A is added to the beryllium oxide slurry, and the volume ratio of the beryllium oxide slurry to solution A is 100:3, stirring for ≥2 h, granulating and drying, to obtain a granulated powder, and the particle size of the granulated powder is 65 μm;

[0095] (5) The granulated powder is subjected to hot-pressing sintering, the hot-pressing sintering temperature is 1650℃, the pressure is 30 Mpa, and the holding time is 10 min, to obtain a beryllium oxide 10~15 mm thick plate, the thick plate is cut into a thin substrate by using a diamond wire cutting machine, the thickness of the thin substrate is 0.88 mm, and the thickness is thinned by using a double-sided grinding machine, the grinding machine is matched with a W20 diamond grinding pad and a W10 diamond grinding liquid, to obtain a fine-grained beryllium oxide ceramic substrate, and the thickness is 0.78 mm. Further, polishing treatment is performed by using a polishing machine matched with a polishing liquid, coarse polishing and fine polishing are sequentially performed, the surface roughness after the polishing treatment is ≤0.05 μm, the coarse polishing is performed on a coarse polishing disc, the coarse polishing processing amount is 0.015 mm, the coarse polishing is performed by using JX0750 polishing liquid, the polishing disc rotation speed is 70 rpm, and the coarse polishing time is 5 min, the fine polishing is performed on a fine polishing disc, the fine polishing processing amount is 0.002 mm, the fine polishing is performed by using JX2000 polishing liquid, the polishing disc rotation speed is 70 rpm, and the fine polishing time is 60 min, to obtain the fine-grained beryllium oxide ceramic film substrate, and the thickness is 0.762±0.005 mm.

[0096] Example 4

[0097] The fine-grained beryllium oxide ceramic film substrate of the embodiment comprises, according to weight parts, nano beryllium oxide: 99.2 parts, magnesium aluminum silicate: 0.5 parts, and nano silicon dioxide: 0.3 parts.

[0098] The particle size of the nano beryllium oxide is 35 nm, the particle size of the magnesium aluminum silicate is 0.85 μm, and the particle size of the nano silicon dioxide is 25 nm.

[0099] The preparation method of the fine-grained beryllium oxide ceramic thin film substrate of the embodiment comprises the following steps:

[0100] (1) The raw materials are weighed according to the weight parts;

[0101] (2) Polyvinyl alcohol is dissolved in water, and the mass ratio of polyvinyl alcohol to water is 13:100, to obtain solution A;

[0102] (3) The prepared nano beryllium oxide, magnesium aluminum silicate and nano silicon dioxide are added to water, and the mass ratio of the total mass of nano beryllium oxide, magnesium aluminum silicate and nano silicon dioxide to water is 54:46, stirred, and ground by a sand mill for 50 min to eliminate agglomerates, to obtain a beryllium oxide slurry;

[0103] (4) The solution A is added to the beryllium oxide slurry, and the volume ratio of the beryllium oxide slurry to solution A is 100:3.5, the stirring time is ≥2 h, granulation and drying are performed, to obtain a granulated powder, and the particle size of the granulated powder is 65 μm;

[0104] (5) The granulated powder is subjected to hot-pressing sintering, the hot-pressing sintering temperature is 1610℃, the pressure is 28 Mpa, and the holding time is 15 min, to obtain a beryllium oxide 10~15 mm thick plate, the thick plate is cut into a thin substrate by using a diamond wire cutting machine, the thickness of the thin substrate is 0.5 mm, and the thickness is thinned by using a double-sided grinding machine, the grinding machine is matched with a W20 diamond grinding pad and a W10 diamond grinding liquid, to obtain a fine-grained beryllium oxide ceramic substrate, and the thickness is 0.4 mm. Further, polishing treatment is performed by using a polishing machine matched with a polishing liquid, coarse polishing and fine polishing are sequentially performed, the surface roughness after the polishing treatment is ≤0.05 μm, the coarse polishing is performed on a coarse polishing disc, the coarse polishing processing amount is 0.012 mm, the coarse polishing is performed by using JX0750 polishing liquid, the polishing disc rotation speed is 63 rpm, and the coarse polishing time is 2.5 min, the fine polishing is performed on a fine polishing disc, the fine polishing processing amount is 0.0018 mm, the fine polishing is performed by using JX2000 polishing liquid, the polishing disc rotation speed is 63 rpm, and the fine polishing time is 67 min, to obtain the fine-grained beryllium oxide ceramic thin film substrate, and the thickness is 0.381±0.005 mm.

[0105] Example 5

[0106] The raw material and the preparation method of the fine-grained beryllium oxide ceramic thin film substrate of the embodiment are the same as those of embodiment 1, except that the raw material further comprises 0.15 parts of nano yttrium oxide, the particle size of the nano yttrium oxide is 35 nm, and the nano yttrium oxide is added in step (3) of the preparation method.

[0107] Embodiment 6

[0108] The raw material and the preparation method of the fine-grained beryllium oxide ceramic thin film substrate of the embodiment are the same as those of embodiment 1, except that the raw material further comprises 0.1 parts of nano yttrium oxide, the particle size of the nano yttrium oxide is 30 nm, and the nano yttrium oxide is added in step (3) of the preparation method.

[0109] Embodiment 7

[0110] The raw material and the preparation method of the fine-grained beryllium oxide ceramic thin film substrate of the embodiment are the same as those of embodiment 1, except that the raw material further comprises 0.2 parts of nano yttrium oxide, the particle size of the nano yttrium oxide is 40 nm, and the nano yttrium oxide is added in step (3) of the preparation method.

[0111] Comparative Example 1

[0112] The raw material and the preparation method of the beryllium oxide ceramic substrate of the comparative example are the same as those of embodiment 1, except that the magnesium aluminum silicate in the raw material is replaced by magnesium silicate.

[0113] Comparative Example 2

[0114] The raw material and the preparation method of the beryllium oxide ceramic substrate of the comparative example are the same as those of embodiment 1, except that the magnesium aluminum silicate in the raw material is replaced by aluminum oxide.

[0115] Comparative Example 3

[0116] The raw material and the preparation method of the beryllium oxide ceramic substrate of the comparative example are the same as those of embodiment 1, except that the magnesium aluminum silicate in the raw material is replaced by magnesium oxide.

[0117] Comparative Example 4

[0118] The raw material and the preparation method of the beryllium oxide ceramic substrate of the comparative example are the same as those of embodiment 1, except that the weight parts of the magnesium aluminum silicate is 0.2 parts.

[0119] Comparative Example 5

[0120] The raw material and the preparation method of the beryllium oxide ceramic substrate of the comparative example are the same as those of embodiment 1, except that in step (5) of the preparation method, the hot-pressing sintering is replaced by directly placing the granulated powder into a mold, pressing into a shape under a pressure of 25 MPa, and sintering for 20 min at a sintering temperature of 1625 ℃.

[0121] Comparative Example 6

[0122] The raw material and the preparation method of the beryllium oxide ceramic substrate of the present comparative example are the same as those of Example 1, except that in step (5) of the preparation method, the sintering temperature is 1700℃ and the pressure is 35MPa.

[0123] Comparative Example 7

[0124] The raw material and the preparation method of the beryllium oxide ceramic substrate of the present comparative example are the same as those of Example 1, except that the particle size of the nano beryllium oxide in the raw material is replaced by 15nm.

[0125] Comparative Example 8

[0126] The raw material and the preparation method of the beryllium oxide ceramic substrate of the present comparative example are the same as those of Example 1, except that the particle size of the magnesium aluminum silicate in the raw material is replaced by 1.2μm.

[0127] Comparative Example 9

[0128] The raw material and the preparation method of the beryllium oxide ceramic substrate of the present comparative example are the same as those of Example 1, except that the magnesium aluminum silicate in the raw material is replaced by SiO2, MgO and Al2O3, and the molar ratio of silicon, magnesium and aluminum remains unchanged.

[0129] Test Example 1

[0130] The volume density of the substrates prepared in Examples 1-7 and Comparative Examples 1-9 is tested respectively, and the thermal conductivity at 25℃, the room temperature bending strength and the average grain size are tested according to the requirements of GJB 3522A-2011 standard, and the surface roughness after polishing is tested, and the results are shown in Table 1.

[0131] ;

[0132] From the above table, compared with Examples 1-4, the performance of the substrate prepared by adding nano yttrium oxide in the raw material of Examples 5-7 is obviously better than that of the substrate without adding nano yttrium oxide, and compared with Example 1, the performance of Comparative Examples 1-9 is poorer, which shows that the performance of the substrate prepared under the conditions of the present application is better.

[0133] The above description is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any changes or replacements within the technical range disclosed by the present application can be easily thought by those skilled in the art, which should be covered in the protection scope of the present application.

Claims

1. A fine-grained beryllium oxide ceramic thin film substrate, characterized in that: According to weight parts, the raw materials of the substrate are composed of 99-99.5 parts of nano-beryllium oxide, 0.2-0.5 parts of magnesium aluminum silicate, 0.2-0.3 parts of nano-silicon dioxide, and 0.1-0.2 parts of nano-yttrium oxide; The particle size of the nano-beryllium oxide is 20-100 nm, the particle size of the magnesium aluminum silicate is 0.5-1 μm, the particle size of the nano-silicon dioxide is 10-30 nm, and the particle size of the nano-yttrium oxide is 30-40 nm. The fine-grained beryllium oxide ceramic thin film substrate is formed by hot pressing and sintering, wherein the sintering temperature of the hot pressing and sintering is 1600-1650° C., the pressure is 20-30 MPa, and the holding time is 10-30 minutes; The volume density of the fine-grained beryllium oxide ceramic thin film substrate is 2.913~2.929g / cm 3 , thermal conductivity ≥282W / m·K at 25℃, flexural strength ≥240MPa at room temperature, average grain size ≤10μm, and surface roughness after polishing ≤0.041μm.

2. A method for preparing the fine-grained beryllium oxide ceramic thin film substrate according to claim 1, characterized in that: The steps include: (1) Weigh each raw material according to its weight and set aside; (2) dissolving polyvinyl alcohol in water to obtain solution A; (3) Adding the prepared raw materials into water, stirring, and grinding to obtain beryllium oxide slurry; (4) adding the solution A to the beryllium oxide slurry, stirring, spray granulating and drying to obtain granulated powder; (5) hot-pressing and sintering the granulated powder, cutting it into substrates, and thinning, grinding, and polishing the substrates on both sides to obtain the fine-grained beryllium oxide ceramic thin film substrate; Wherein, in step (5), the sintering temperature of the hot pressing sintering is 1600-1650°C, the pressure is 20-30 MPa, and the holding time is 10-30 min.

3. The preparation method according to claim 2, characterized in that In step (2), the mass ratio of polyvinyl alcohol to water is 10-20:

100.

4. The preparation method according to claim 2, characterized in that In step (3), the mass ratio of the total mass of the reserved raw materials to the mass of water is 20~54:46~50.

5. The preparation method according to claim 2, characterized in that In step (4), the mass ratio of the beryllium oxide slurry to solution A is 100:3~5.

6. The preparation method according to claim 2, characterized in that In step (4), the stirring time is ≥2h, and the average particle size of the granulated powder is 50~80μm.

7. The preparation method according to claim 2, characterized in that In step (5), the substrate is cut into a thickness of 0.5 to 1 mm.

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