sintered body

Abstract

To provide a sintered body that combines high strength and low Young's modulus at a high level. [Solution] A sintered body containing Al2O3, SiO2, and MnO includes a main crystalline phase composed of Al2O3, a first glass phase, and a second glass phase having a different composition from the first glass phase. Each of the first glass phase and the second glass phase is a phase containing SiO2 and MnO. The ratio of SiO2 to the total of SiO2 and MnO in the first glass phase is higher than the ratio of SiO2 to the total of SiO2 and MnO in the second glass phase.

Description

[Technical Field]

[0001] The present disclosure relates to a sintered body containing alumina. [Background technology]

[0002] Sintered bodies containing alumina (Al2O3) as the main component and sintering aids such as silica (SiO2), manganese oxide (MnO), and oxides of 2a group elements are known as materials for ceramic packages and circuit boards.

[0003] One such sintered body is known, for example, to have alumina as the primary crystalline phase, 12-25 mass% Mn and Si (as oxides), and 2 mass% or less of a Group 2a element (as oxides), with a ratio of MnO / SiO of 0.5-2 (see JP 2003-104772 A (Patent Document 1)). This sintered body is obtained by mixing and firing an alumina raw material powder as a first component, a specific ratio of MnO powder and SiO powder as a second component, and an oxide powder of a Group 2a element (as a third component). The resulting sintered body is described as having a relative density of 95% or higher, a strength of 400 MPa or higher, a Young's modulus of 300 GPa or lower, and a thermal conductivity of 10 W / mK or higher. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-104772 Summary of the Invention [Problem to be solved by the invention]

[0005] It is desirable that sintered bodies used as materials for ceramic packages and circuit boards have high strength and low Young's modulus. For example, Patent Document 1 discloses a sintered body having a strength of 400 MPa or more and a Young's modulus of 300 GPa or less. However, further improvements in the physical properties of the sintered body are desired.

[0006] In view of this situation, one of the objects of the present disclosure is to provide a sintered body that combines high strength and low Young's modulus at a high level. [Means for solving the problem]

[0007] The sintered body according to the present disclosure includes Al2O3, SiO2, and MnO, and includes a main crystalline phase composed of Al2O3, a first glass phase, and a second glass phase having a composition different from that of the first glass phase. The first glass phase is a phase containing SiO2 and MnO. The second glass phase is a phase containing SiO2 and MnO. The ratio of SiO2 to the total of SiO2 and MnO in the first glass phase is greater than the ratio of SiO2 to the total of SiO2 and MnO in the second glass phase. [Effects of the Invention]

[0008] The above sintered body can provide a sintered body that can simultaneously achieve high strength and low Young's modulus at a high level. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic cross-sectional view showing the structure of a ceramic package. [Figure 2] FIG. 2 is an example of an SEM image of a sintered body according to the present disclosure. [Figure 3] FIG. 3 is an image obtained by binarizing an SEM image of the sintered body according to the present disclosure. [Figure 4] FIG. 4 shows an SEM image of the sintered body of Comparative Example 2 and an image showing the positions where elemental analysis was performed. [Figure 5]FIG. 5 shows an SEM image of the sintered body of Comparative Example 4 and an image showing the positions where elemental analysis was performed. [Figure 6] FIG. 6 shows an SEM image of the sintered body of Example 2 and an image showing the positions where elemental analysis was performed. [Figure 7] FIG. 7 shows an SEM image of the sintered body of Example 4 and an image showing the positions where elemental analysis was performed. [Figure 8] FIG. 8 shows an SEM image of the sintered body of Example 6 and an image showing the positions where elemental analysis was performed. [Figure 9] FIG. 9 shows an SEM image of the sintered body of Example 8 and an image showing the positions where elemental analysis was performed. [Figure 10] FIG. 10 is a graph showing the distribution of Young's modulus and bending strength of the sintered bodies of Examples 1 to 8 and Comparative Examples 1 to 5. [Figure 11] FIG. 11 is a graph showing the content ratio of SiO2 to the total of SiO2 and MnO at each elemental analysis position of the sintered bodies of Comparative Examples 2 and 4 and Examples 2, 4, 6 and 8. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Outline of the embodiment] First, embodiments of the present disclosure will be listed and described. A sintered body according to a first aspect of the present disclosure includes Al2O3, SiO2, and MnO, and includes a main crystalline phase composed of Al2O3, a first glass phase, and a second glass phase having a different composition from the first glass phase. The first glass phase is a phase containing SiO2 and MnO. The second glass phase is a phase containing SiO2 and MnO. The content ratio of SiO2 relative to the total of SiO2 and MnO in the first glass phase is higher than the content ratio of SiO2 relative to the total of SiO2 and MnO in the second glass phase. Note that, in the present application, the glass phase may include a small amount of crystalline components of the ceramic components contained in the sintered body in addition to the glass components SiO2 and MnO.

[0011] Electronic devices such as smartphones and wearable devices are becoming increasingly miniaturized. This trend is driving demands for smaller components, such as ceramic packages, that are installed inside these devices. However, reducing the thickness and height of components to achieve miniaturization poses a challenge: a decrease in physical strength. For example, when a ceramic package is bonded to a lid for airtight sealing, the package can be damaged by thermal stress resulting from the difference in thermal expansion coefficients between the package and the lid. For this reason, efforts have been made to increase the strength of ceramics. Meanwhile, it has also been known that a lower Young's modulus of ceramic is preferable from the perspective of stress relaxation.

[0012] The inventors have conducted extensive research into sintered bodies containing a main crystalline phase composed of alumina and a glass phase. They have discovered that two types of glass phases may be formed in sintered bodies containing SiO2 and MnO in addition to alumina. They have also discovered that sintered bodies containing these two types of glass phases exhibit both high strength and a low Young's modulus at a higher level than conventional sintered bodies. Furthermore, they have discovered that the two types of glass phases differ in the SiO2 content relative to the total of SiO2 and MnO, and that the SiO2 content in the first glass phase is higher than the SiO2 content in the second glass phase. More specifically, they have discovered that the first glass phase is a phase in which the SiO2 content relative to the total of SiO2 and MnO is 65% by mass or more but less than 100% by mass (hereinafter referred to as the Si-rich phase), and the second glass phase is a phase in which the SiO2 content is 35% by mass or more but less than 65% by mass (hereinafter referred to as the Mn-rich phase).

[0013] Without being bound by any particular theory, it is believed that the presence of three phases with different toughnesses in the sintered body according to the present disclosure may be one of the factors that allows it to simultaneously achieve high strength and a low Young's modulus. In the sintered body according to the present disclosure, the main crystalline phase composed of alumina is relatively less tough than the glass phase, and the first glass phase, which has a high SiO2 content, is believed to have higher toughness than the second glass phase. When stress is applied to this sintered body, microcracks first occur in the alumina phase, which has the lowest toughness. If the cracks propagate through most of the sintered body, the sintered body will fracture. On the other hand, if the cracks propagate and reach the glass phase, which is tougher than alumina, their propagation may be inhibited. It is believed that the presence of two glass phases with different toughnesses effectively stops crack propagation, allowing it to simultaneously achieve high strength and a low Young's modulus.

[0014] The fact that the sintered body contains a main crystalline phase composed of alumina, a first glass phase, and a second glass phase can be confirmed, for example, by identifying the three types of phases in an SEM image of the cross section of the sintered body and performing elemental analysis on each phase. A detailed identification method will be described later.

[0015] In the sintered body according to the present disclosure, the total content of SiO2 and MnO relative to the total mass of the sintered body may be 11.0 mass% or more and 30.0 mass% or less. The SiO2 content relative to the total mass of SiO2 and MnO may be 54.0 mass% or more and 66.6 mass% or less. When the content of the glass phase in the sintered body is within the above-mentioned range, high strength and a low Young's modulus are both achieved, and the sintered body can be produced stably and efficiently.

[0016] The area ratio of the first glass phase, obtained from an image obtained by binarizing a scanning electron microscope image of the alumina sintered body, may be 0.1 area % or more and 10 area % or less with respect to the sintered body. The area ratio of the second glass phase, obtained from an image obtained by binarizing a scanning electron microscope image of the alumina sintered body, may be 10 area % or more and 30 area % or less with respect to the sintered body.

[0017] The content ratio of each phase contained in the sintered body is a value calculated from the area of ​​each phase in a binarized image by observing a cross section of the sintered body with a scanning electron microscope (SEM), identifying the main crystalline phase, the first glass phase, and the second glass phase as three types of phases with different shades in the SEM image.

[0018] In the sintered body according to the present disclosure, a first glass phase having a high SiO2 content is formed in addition to a second glass phase having an SiO2 content of 35% by mass or more but less than 65% by mass. By forming the first glass phase at 0.1% by area or more, the effect of the presence of the first glass phase is obtained, and a sintered body having both high strength and a low Young's modulus is obtained.

[0019] [Specific example of embodiment] Next, specific embodiments of the sintered body according to the present disclosure will be described.

[0020] (sintered body) The sintered body according to the present disclosure is a solid material obtained by sintering a ceramic material such as alumina powder. The sintered body is typically obtained by sintering a green sheet formed by molding ceramic material powder into a tape shape or a compact formed by compacting ceramic material powder.

[0021] (Configuration of sintered body) The sintered body according to the present disclosure contains a crystalline phase and two types of glass phases. In the sintered body according to the present disclosure, the alumina phase, the first glass phase, and the second glass phase are randomly mixed without any particular regularity. The alumina phase, the first glass phase, and the second glass phase are phases characterized by their compositions, and are identified as three types of regions with different shades in, for example, an image (SEM image) obtained by observing the cross section of the sintered body with a scanning electron microscope.

[0022] FIG. 2 shows an example of an SEM image of a sintered body according to the present disclosure. Referring to FIG. 2, the alumina phase 11 of the sintered body 100 is observed as an opaque gray portion in the SEM image. In the SEM image, the alumina phase 11 is observed mainly as a continuous form in which many particles are bonded at their interfaces. Some of the alumina phase 11 is observed as an independent granular form. The form of the alumina phase in the sintered body is not limited to the example shown in FIG. 2; the degree of bonding between particles may be greater, or a form in which many independent particles exist may also be used.

[0023] In the SEM image, the first glass phase 21 of the sintered body 100 is darker in color than the alumina phase 11. In the SEM image, the first glass phase 21 is typically observed as an irregular particulate form. The first glass phase 21 is not limited to a particulate form, and may have an irregular continuous shape. The size of the particles constituting the first glass phase 21 is not particularly limited. For example, when the smallest rectangle S surrounding the particles is assumed, the proportion of particles in the first glass phase in which the length of one side of the rectangle S does not exceed 5 μm is 50% or more, preferably 80% or more.

[0024] In the SEM image, the second glass phase 31 of the sintered body 100 is lighter in color than the alumina phase 11. In the SEM image, the second glass phase 31 typically has a form that is solidified after being cast to fill the gaps in the alumina phase 11. The second glass phase 31 is observed as an amorphous portion extending to surround the alumina phase 11 and the first glass phase 21. In the sintered body according to the present disclosure, two types of glass phases are present so as to fill the gaps between the alumina phase 11, which exists in the form of particles or joined particles. The second glass phase 31 exists as an amorphous network portion in the sintered body.

[0025] In the SEM image, the black areas are voids 51 .

[0026] The content ratios of the first glass phase and the second glass phase in the sintered body are expressed as values ​​(area %) obtained by binarizing an SEM image of the sintered body to black and white using image processing software and calculating the area ratios of the first glass phase 21 and the second glass phase 31 to the total area of ​​the image. A specific calculation method is as follows, for example. An SEM image of the sintered body to be calculated is prepared, and a histogram is displayed for the image, with the horizontal axis representing brightness (e.g., 0 to 255) and the vertical axis representing frequency of occurrence. Next, while referring to the image, brightness thresholds are determined to separate the voids, the first glass phase, the alumina phase, and the second glass phase. After determining the thresholds, the integral value of the frequency of occurrence in each region is calculated, and the proportion of the integral value of each region to the integral value of the frequency of occurrence in the total brightness value is determined. Known image processing software, such as "ImageJ," can be used. Figure 3 shows an image obtained by binarizing the SEM image of Figure 2 using the above-mentioned method and extracting the first glass phase 21 and the second glass phase 31. The left side of Figure 3 is a binary image of the first glass phase (black is the first glass phase, white is other phases), and the right side is a binary image of the second glass phase (black is the second glass phase, white is other phases).

[0027] The sintered body according to the present disclosure preferably has a first glass phase content of 0.1 area % or more and 10 area % or less, based on the content calculated by the above-mentioned binarization analysis. It is believed that the effect of the present disclosure, i.e., high strength and low Young's modulus, can be obtained by containing the first glass phase at 0.1 area % or more. Furthermore, when the content of the first glass phase is 10 area % or less, a sintered body with excellent stability during manufacturing and high production efficiency can be obtained.

[0028] The sintered body according to the present disclosure preferably has a second glass phase content of 10% by area or more and 30% by area or less, as calculated by the binarization analysis described above. When the second glass phase content is 10% by area or more, it is effective in forming a dense ceramic with excellent sinterability. When the second glass phase content is 30% by area or less, a sintered body with excellent stability during production and high production efficiency can be obtained.

[0029] The relative proportions of the first glass phase and the second glass phase are not particularly limited, but may be, for example, 0.3 area % or more and 50 area % or less of the sum of the contents of the first glass phase and the second glass phase. While conventional sintered bodies produce only the second glass phase, the sintered body according to the present disclosure contains a first glass phase with a high Si content in addition to the second glass phase. It is believed that the presence of 0.3 area % or more of the first glass phase in the glass phase provides the effects of the presence of the first glass phase.

[0030] (Composition of sintered body) As described above, the sintered body according to the present disclosure comprises at least three phases. The compositions of the crystalline phase and glass phase of the sintered body according to the present disclosure will be described below.

[0031] In the sintered body according to the present disclosure, the crystalline phase includes a main crystalline phase (hereinafter sometimes referred to as an alumina phase) composed of Al2O3. The crystalline phase may be an alumina phase alone, or may include other crystalline phases. For example, when the sintered body contains Mo as a colorant, it may include a Mo crystalline phase in addition to the alumina phase. It may also include one or more other crystalline phases. When the crystalline phase includes an alumina phase and other phases, the content of the alumina phase relative to the entire crystalline phase is not particularly limited, but is preferably, for example, 50% by volume or more.

[0032] The sintered body according to the present disclosure contains at least two glass phases with different compositions. Here, "different compositions" means that at least one of the types and content ratios of the components constituting the glass phases is different. The glass phases contain SiO2 and MnO as essential components. Next, each of the two glass phases will be described.

[0033] The first glass phase contains SiO2 and MnO, and the SiO2 content is 65% by mass or more but less than 100% by mass relative to the total of SiO2 and MnO. In the first glass phase, the SiO2 content is more preferably 75% by mass to 99% by mass relative to the total of SiO2 and MnO. The SiO2 and MnO contents are obtained by calculating the Si atom and Mn atom contents at an observation point from measurements obtained by elemental analysis of the glass phase and converting these contents into the masses of SiO2 and MnO. The first glass phase has a significantly higher SiO2 content than the second glass phase. For example, the SiO2 content in the first glass phase may be 1.2 times or more, and more preferably 1.5 times or more, the SiO2 content in the second glass phase.

[0034] The elemental analysis of the glass phase can be measured using known analytical methods such as scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX), X-ray fluorescence spectroscopy (XRF), and inductively coupled plasma atomic emission spectroscopy (ICP-AES).

[0035] The second glass phase contains SiO2 and MnO, and the SiO2 content is 35% by mass or more and less than 65% by mass relative to the total of SiO2 and MnO. In the second glass phase, the SiO2 content is more preferably 40% by mass to 60% by mass relative to the total of SiO2 and MnO.

[0036] The first glass phase and the second glass phase may be composed only of SiO2 and MnO, or may contain components other than SiO2 and MnO. The components other than SiO2 and MnO are not particularly limited as long as the effects according to the present disclosure can be obtained.

[0037] The content ratio of each component constituting the sintered body having the above-mentioned structure can be, for example, within the following ranges. Al2O3: 70.0% by mass or more and 89.0% by mass or less of the total mass of the sintered body SiO2: 5.7% by mass or more and 20.0% by mass or less of the total mass of the sintered body MnO: 3.7% by mass or more and 11.0% by mass or less based on the total mass of the sintered body

[0038] In the sintered body according to the present disclosure, the total mass of SiO2 and MnO (total mass) of the sintered body may be 11.0 mass% or more and 30.0 mass% or less, and more preferably 11.8 mass% or more and 24.4 mass% or less. If it is less than 11.0 mass%, two types of glass phases are not formed, and if it is more than 30 mass%, sticking to the setter during firing is likely to occur, making it difficult to obtain a sintered body with high production efficiency.

[0039] In the sintered body according to the present disclosure, the ratio of SiO2 to the total of SiO2 and MnO may be 54.0% by mass or more and 66.6% by mass or less, and more preferably 56.0% by mass or more and 62.9% by mass or less. It has been found that if the ratio is less than 54.0% by mass, two types of glass phases are not generated in the sintered body, and if the ratio is more than 66.6% by mass, it is difficult to form a dense sintered body.

[0040] The sintered body according to the present disclosure may be composed only of the above components and unavoidable impurities, and the unavoidable components may be, for example, 0.1 wt% or less in terms of oxides.

[0041] (Physical properties of sintered body) The strength of the sintered body according to the present disclosure can be set depending on the application, but may be 300 MPa or more, and more preferably 400 MPa or more. Note that, as used herein, "strength" refers to so-called flexural strength, which is the average value measured at room temperature in accordance with a three-point bending test method based on JIS R1601 (bending test method for fine ceramics). Higher strength is preferable, but as strength increases, Young's modulus also increases. In a graph (FIG. 10) with strength (unit: MPa) on the vertical axis, i.e., the y-axis, and Young's modulus (unit: GPa) on the horizontal axis, i.e., the x-axis, the coordinates of the strength and Young's modulus of the sintered body may lie between the lines y=1.7x+18 and y=1.7x+168. Therefore, the strength may be 660 MPa or less, and more preferably 600 MPa or less.

[0042] The Young's modulus of the sintered body according to the present disclosure can be set depending on the application, but may be 290 GPa or less, and more preferably 280 GPa or less. The Young's modulus is the average value of values ​​measured at room temperature in accordance with a three-point bending strain gauge measurement method based on JIS R1602. A lower Young's modulus is preferable, but the lower the Young's modulus, the lower the strength. In a graph with the y-axis representing strength (unit: MPa) and the x-axis representing Young's modulus (unit: GPa), the coordinates of the strength and Young's modulus of the sintered body may lie between the lines y=1.7x+18 and y=1.7x+168. Therefore, the Young's modulus may be 170 GPa or more, and more preferably 190 GPa or more.

[0043] The porosity of the sintered body is not particularly limited, but for example, when the sintered body is used in a ceramic package that seals a vibrator or semiconductor element, the porosity is preferably 3% by area or less. Furthermore, when the sintered body is used in a ceramic package that seals an optical semiconductor element, the porosity is preferably 3% by area or more and 8% by area or less. The porosity is measured by photographing a cross section of the sintered body with a scanning electron microscope, binarizing it with image processing software, and measuring the area ratio occupied by voids.

[0044] (Method of manufacturing sintered body) When a sintered body according to the present disclosure is used to form a ceramic package, it can be manufactured, for example, by the following method. First, a green sheet preparation step is carried out. Specifically, Al2O3 powder, which is the main component of the sintered body, SiO2 powder, which is a sintering aid, Mn compound powder, resin, solvent, etc. are mixed in a ball mill to obtain a slurry. Mn salt, specifically MnCO3, is preferably used as the Mn compound. This slurry is processed into a green sheet by a doctor blade method. The shape of the green sheet can be determined depending on the shape of the target component. For example, when forming the bottom wall or circuit board of a package, a green sheet with a rectangular planar shape is prepared. When forming the frame of a package, a ring-shaped green sheet is prepared with the portion corresponding to the cavity removed.

[0045] Next, the conductive portion printing process is carried out. In this process, a paste to become the conductive portion is printed on the green sheet prepared in the previous process. Specifically, first, a metal powder of at least one of W, Mo, and Cu is mixed with additives, resin, solvent, etc., and then ceramic powder is added as needed, and the mixture is kneaded to create a paste.

[0046] This paste is printed, for example, by screen printing, onto the green sheets prepared in the previous process. For example, if the green sheets will become the bottom wall of the ceramic package, the conductive paste is printed in the areas corresponding to the external terminals. Similarly, the conductive paste is printed in positions according to the final shape. After printing the conductive paste, the green sheets are dried. Drying can be performed, for example, by heating to 110°C and holding for 5 minutes. After drying, the green sheets are stacked to obtain a green sheet laminate.

[0047] Next, the firing step is carried out. In this step, the laminate of green sheets prepared in the previous step is fired. Firing can be carried out, for example, by heating to a temperature of 1150°C or higher and 1300°C or lower in an atmosphere containing a mixture of hydrogen, nitrogen, and water vapor. The firing temperature is more preferably 1200°C or higher and 1250°C or lower. When firing is carried out within this temperature range, it is believed that there is a high tendency for two glass phases with different compositions to be formed.

[0048] (Uses of sintered bodies) While the uses of the sintered body according to the present disclosure are not particularly limited, one specific use is as a component of a package that houses a chip such as a quartz crystal resonator. FIG. 1 is a cross-sectional view that schematically shows the configuration of a quartz crystal resonator that uses the sintered body according to the present disclosure. The quartz crystal resonator 1 includes a package 101, a quartz crystal blank 201, a brazing material 301, and a lid 401. The package 101 has a cavity CV. The quartz crystal blank 201 is housed within the cavity CV. The quartz crystal blank 201 is mounted on element electrode pads 111 of the package 101. Package electrode pads 112 and 113 are located on the base 100 outside the cavity CV.

[0049] The base 100 of the package 101 is made of a sintered body (ceramic) according to the present disclosure. The base 100 includes a substrate portion 110 and a frame portion 120. The substrate portion 110 forms the bottom surface of the cavity CV. The frame portion 120 is laminated on the substrate portion 110 in the thickness direction (the vertical direction in FIG. 1).

[0050] The lid 401 is bonded to the metallized layer 600 of the package 101 by the brazing material 301. The lid 401 and the package 101 are bonded via the brazing material 301, and the cavity CV is sealed. The brazing material 301 is typically preferably made of an alloy containing gold, and may be, for example, an alloy containing gold and tin (Au—Sn-based alloy). The lid 401 is made of a metal, for example, an alloy containing iron and nickel.

[0051] The metallization layer 600 is made of a metal containing at least one of molybdenum (Mo) and tungsten (W), for example. A plating layer, typically a gold plating layer, may be provided on the surface of the metallization layer 600 (the surface facing the brazing filler metal 301). A nickel plating layer may be provided as a base for the gold plating layer.

[0052] The sintered body according to the present disclosure is suitably used as a material for forming various ceramic packages, such as ceramic packages for sealing semiconductor elements such as CMOS image sensors and ceramic packages for sealing optical semiconductor elements, and circuit boards. The shape of the sintered body according to the present disclosure can be various depending on the application. The shape when used for a package is as described above. In addition, the sintered body according to the present disclosure can have various shapes, such as a plate shape, a rectangular parallelepiped shape, or a film shape.

[0053] [Example] Sintered bodies according to Examples 1 to 8 and Comparative Examples 1 to 5 were produced and their morphologies were observed. In addition, the strength and Young's modulus of the sintered bodies were measured. (Sample preparation) A mixed powder was obtained by mixing alumina powder with an average particle size of 1.8 μm, MnCO powder with an average particle size of 3.5 μm, and SiO powder with an average particle size of 1.2 μm in the ratios shown in Table 1. Table 1 shows the amount of each powder charged (mixing ratio) and the calculated value from the charged amount (value obtained by converting MnCO to MnO). In Example 7, MoO3 powder was added as an additive. The amount of MoO3 powder added was 0.5 mass% when the total of the three powders was 100 mass%. Table 1 also shows the value of MnCO3 converted to MnO, the total of SiO2 and MnO, and the SiO2 content relative to the total of SiO2 and MnO. The SiO2 content relative to the total of SiO2 and MnO is expressed as SiO2 / (SiO2+MnO).

[0054] The obtained mixed powder was mixed with polyvinyl butyral, tertiary amine, and phthalate ester (diisononyl phthalate: DINP) as organic components, and further mixed with IPA (isopropyl alcohol) and toluene as solvents to prepare a slurry.

[0055] Using the prepared slurry, ceramic tapes with thicknesses of 50 to 400 μm were produced by the doctor blade method. The obtained ceramic tapes were cut into 50 mm length x 50 mm width, arranged on a Mo firing setter, and fired in an atmosphere containing a mixture of hydrogen, nitrogen, and water vapor with a dew point of 35°C, at the firing temperature (maximum temperature) shown in Table 1 for 2 hours. 100 sintered bodies were produced for each of Examples 1 to 8 and Comparative Examples 1 to 5. The temperature variation inside the furnace when firing at the firing temperatures shown in Table 1 was within ±5°C. The proportions of Al, Si, Mn, and Mo were the same within the margin of error between the charged amount and after firing.

[0056] [Table 1]

[0057] (Morphological observation) The sintered bodies of Examples 1 to 8 and Comparative Examples 1 to 5 were polished using a cross-section polisher (CP) (IB-15000CP, manufactured by JEOL Ltd.), and the resulting cross sections were observed using a field emission scanning electron microscope (SEM) (JSM-7000F, manufactured by JEOL Ltd.) to obtain SEM images. A gold film was formed on the cross section of the sintered body by sputtering, and the cross section was observed in backscattered electron mode. The acceleration voltage was 15.0 kV and the magnification was 5000 times. The phases contained in each sintered body were confirmed from the images. Furthermore, a histogram was displayed for the SEM image of each sintered body, with the horizontal axis representing brightness value (0 to 255) and the vertical axis representing frequency of occurrence. Next, with reference to the SEM images, brightness thresholds were determined to distinguish between voids, the first glass phase, the alumina phase, and the second glass phase. After determining the thresholds, the integral values ​​of the frequencies in each of the first and second glass phase sections were calculated. The percentage of the integrated values ​​of the first and second glass phases relative to the integrated value of the frequency of occurrence in all brightness values ​​was taken as the content (area %) of the first and second glass phases. ImageJ was used as image processing software. The results are shown in Table 2.

[0058] (Measurement of strength and Young's modulus) The flexural strength of the sintered bodies of Examples 1 to 8 and Comparative Examples 1 to 5 was measured at room temperature in accordance with the three-point bending test of JIS R 1601. The Young's modulus was also measured in accordance with the measurement method using a three-point bending strain gauge of JIS R 1602. The results are shown in Table 2 and FIG.

[0059] [Table 2]

[0060] As shown in Table 2, the sintered bodies of Examples 1 to 8 were confirmed to contain two types of glass phases: a first glass phase and a second glass phase. The content of the first glass phase in the sintered bodies was 0.1 area % to 7.5 area %. The content of the second glass phase was 14.8 area % to 26.1 area %. In contrast, the sintered bodies of Comparative Examples 1 to 5 did not contain the first glass phase, and the content of the second glass phase was 12.3 area % to 33.3 area %. Furthermore, the sintered bodies of Examples 1 to 8 had strengths of 366 MPa or more and Young's moduli of 275 GPa or less.

[0061] FIG. 10 is a graph showing the distribution of Young's modulus and flexural strength of the sintered bodies of Examples 1 to 8 and Comparative Examples 1 to 5. In FIG. 10, the horizontal axis represents Young's modulus and the vertical axis represents flexural strength. As shown in FIG. 10, the sintered bodies of Examples 1 to 8 are distributed in the upper left corner of the graph (low Young's modulus, high flexural strength) compared to the sintered bodies of Comparative Examples 1 to 5. That is, when the Young's modulus is the same, the sintered bodies of the Examples have higher flexural strength than the sintered bodies of the Comparative Examples. Furthermore, when the flexural strength is the same, the sintered bodies of the Examples have lower Young's modulus than the sintered bodies of the Comparative Examples. As shown in FIG. 10, for all of the sintered bodies of Examples 1 to 8, in a graph with flexural strength (MPa) on the y-axis and Young's modulus (GPa) on the x-axis, the coordinates of the flexural strength and Young's modulus lie between the lines y=1.7x+18 and y=1.7x+168. In contrast, for all of the sintered bodies of Comparative Examples 1 to 5, the coordinates of the flexural strength and Young's modulus lie outside the range defined by these two lines. When the ratio of the bending strength (MPa) to the Young's modulus (GPa) was calculated, it was 1.92 to 2.26 in Examples 1 to 8, while it was 1.48 to 1.66 in Comparative Examples 1 to 5. These results confirmed that the sintered bodies of Examples 1 to 8 had both high strength and a low Young's modulus.

[0062] (Elemental analysis) For the sintered bodies of Comparative Examples 2 and 4 and Examples 2, 4, 6, and 8, multiple positions where a glass phase was present were selected in the obtained SEM images, and point analysis was performed using EDS (JEOL Ltd., JSM-7000F). The sintered bodies of Comparative Examples had one type of glass phase, and multiple positions where this glass phase was present were selected. The sintered bodies of Examples had two types of glass phase, and each of the two types of glass phase was selected.

[0063] SEM images and analytical images (images showing the positions of elemental analysis in the SEM images) of Comparative Example 2, Comparative Example 4, Example 2, Example 4, Example 6, and Example 8 are shown in Figure 4, Figure 5, Figure 6, Figure 7, Figure 8, and Figure 9, respectively. The positions of elemental analysis are indicated by cross marks. Two fields of view were analyzed for each example. Tables 3 to 5 show the SiO2 and MnO contents (mass%) calculated from the elemental analysis results at each position shown in Figures 4 to 9. Note that the SiO2 and MnO values ​​in the analytical values ​​in Tables 3 to 5 are converted values ​​obtained by converting the blending ratios of Si and Mn elements into SiO2 and MnO, and the total of SiO2 and MnO does not equal 100%.

[0064] [Table 3]

[0065] 4, one type of glass phase was observed in the SEM image in Comparative Example 2. Furthermore, as shown in Table 3, in Comparative Example 2, the content of SiO2 relative to the total of SiO2 and MnO at seven measurement positions in the glass phase was 42.2 mass% to 49.3 mass%.

[0066] 5, one type of glass phase was observed in the SEM image in Comparative Example 4. Furthermore, as shown in Table 3, in Comparative Example 4, the content of SiO2 relative to the total of SiO2 and MnO at 10 measurement positions in the glass phase was 43.7 mass% to 49.9 mass%.

[0067] [Table 4]

[0068] As shown in Figure 6, two types of glass phases were observed in the SEM image of Example 2. Furthermore, as shown in Table 4, in Example 2, of the ten measurement positions of the glass phase, the content ratio of SiO2 to the total of SiO2 and MnO at nine positions (measurement positions 1 to 4, 6 to 10) where the glass phase appeared light in color was 52.4 mass% to 57.0 mass%. At one position (measurement position 5) where the glass phase appeared dark in color, the content ratio of SiO2 to the total of SiO2 and MnO was 76.0 mass%.

[0069] As shown in Figure 7, two types of glass phases were observed in the SEM image of Example 4. Furthermore, as shown in Table 4, in Example 4, of the ten measurement positions of the glass phase, the content ratio of SiO2 to the total of SiO2 and MnO at nine positions (measurement positions 1 to 5, 7 to 10) where the glass phase appeared light in color was 54.4 mass% to 59.0 mass%. At one position (measurement position 6) where the glass phase appeared dark in color, the content ratio of SiO2 to the total of SiO2 and MnO was 89.0 mass%.

[0070] [Table 5]

[0071] As shown in Figure 8, two types of glass phases were observed in the SEM image of Example 6. Furthermore, as shown in Table 5, in Example 6, of the 11 measurement positions of the glass phase, the content ratio of SiO2 to the total of SiO2 and MnO at eight positions (measurement positions 1 to 4, 7 to 10) where the glass phase appeared light in color was 51.4 mass% to 56.6 mass%. The content ratio of SiO2 to the total of SiO2 and MnO at three positions (measurement positions 5, 6, 11) where the glass phase appeared dark in color was 77.5 mass% to 91.6 mass%.

[0072] As shown in Figure 9, two types of glass phases were observed in the SEM image of Example 8. Furthermore, as shown in Table 5, in Example 8, of the 12 measurement positions of the glass phase, the content ratio of SiO2 to the total of SiO2 and MnO at eight positions (measurement positions 1 to 4, 7 to 10) where the glass phase appeared light in color was 49.3 mass% to 57.3 mass%. The content ratio of SiO2 to the total of SiO2 and MnO at four positions (measurement positions 5, 6, 11, 12) where the glass phase appeared dark in color was 81.7 mass% to 93.8 mass%.

[0073] Fig. 11 shows a graph of the SiO2 content relative to the total of SiO2 and MnO at each measurement position in Comparative Examples 2 and 4 and Examples 2, 4, 6, and 8. As shown in Fig. 11, in Comparative Examples 2 and 4, the SiO2 content relative to the total of SiO2 and MnO was between 40% and 60% by mass at all measurement positions, and only a second glass phase was formed. On the other hand, in Examples 2, 4, 6, and 8, it was confirmed that the second glass phase, in which the SiO2 content relative to the total of SiO2 and MnO was between 40% and 60% by mass, and the first glass phase, in which the SiO2 content relative to the total of SiO2 and MnO exceeded 75% by mass, were clearly separated.

[0074] It should be understood that the embodiments and examples disclosed herein are illustrative in all respects and are not limiting in any respect. The scope of the present disclosure is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0075] 1 quartz crystal unit, 101 package, 100 base, 110 substrate portion, 112 frame portion, 600 metallized layer, 100 sintered body, 11 alumina phase, 21 first glass phase, 31 second glass phase, 51 void.

Claims

1. Al ２ O ３ , SiO ２ and MnO, Al ２ O ３ A main crystalline phase consisting of a first glass phase; a second glass phase having a composition different from that of the first glass phase; The first glass phase is SiO ２ and a phase comprising MnO, The second glass phase is SiO ２ and a phase comprising MnO, SiO in the first glass phase ２ and SiO relative to the total of MnO ２ The content ratio of SiO in the second glass phase ２ and SiO relative to the total of MnO ２ The content is higher than Sintered body.

2. The first glass phase is SiO ２ and SiO relative to the total of MnO ２ The content ratio of the phase is 65 mass% or more and less than 100 mass%, The second glass phase is SiO ２ and SiO relative to the total of MnO ２ The content ratio of the phase is 35% by mass or more and less than 65% by mass. The sintered body according to claim 1 .

3. In the sintered body, SiO relative to the total mass of the sintered body ２ and MnO, the total content of which is 11.0 mass% or more and 30.0 mass% or less, SiO ２ and SiO relative to the total of MnO ２ The content ratio is 54.0 mass% or more and 66.6 mass% or less, The sintered body according to claim 1 or 2.

4. the first glass phase has an area ratio of 0.1 area % or more and 10 area % or less, obtained from an image obtained by binarizing a scanning electron microscope image of the sintered body; the second glass phase has an area ratio of 10 area % or more and 30 area % or less, obtained from an image obtained by binarizing a scanning electron microscope image of the sintered body; The sintered body according to claim 1 or 2.

5. The strength of the sintered body is 300 MPa or more and 660 MPa or less, and the Young's modulus is 170 GPa or more and 290 GPa or less, In a graph in which the vertical axis, i.e., the y-axis, represents strength in units of MPa and the horizontal axis, i.e., the x-axis, represents Young's modulus in units of GPa, the coordinates of the strength and Young's modulus of the sintered body lie between the lines y = 1.7x + 18 and y = 1.7x + 168. The sintered body according to claim 1 or 2.

Images