Inorganic composition with high thermal expansion coefficient

Abstract

To provide an inorganic composition, which is an inorganic composition used in a composite material used in a variety of applications including metal coating, package for crystal oscillator, semiconductor support substrate, HDD substrate, magnetic head and the like, and the inorganic composition having a thermal expansion coefficient that is adaptive to the volume change caused by the thermal change of the material.SOLUTION: Provided is an inorganic composition that is characterized by containing, in terms of oxide conversion mass%, SiO2 component by 35.0% to 60.0%, K2O component by 10.0% to 30.0%, Al2O3 component by 5.0% to 25.0%, ZrO2 component by 0% to 10.0%, TiO2 component by 0% to 15.0%, ZrO2 component and TiO2 component total amount over 0% to 15.0%, and having a thermal expansion coefficient at -30 to 70°C of 125 to 155(×10-7 / °C).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to inorganic compositions with high thermal expansion coefficients. [Background technology]

[0002] In recent years, composite materials consisting of inorganic compositions, metal-inorganic compositions, or organic-inorganic compositions have been used in a variety of applications, such as metal coating materials, packages for quartz oscillators, semiconductor support substrates, HDD substrates, magnetic heads, and optical filters. However, there is a demand for materials with a high thermal expansion coefficient that can accommodate the stress associated with thermal volume changes in the material.

[0003] Patent Document 1 describes a glass substrate for a magnetic recording medium, a magnetic recording medium, and a glass substrate blank for a magnetic recording medium, which has a thermal expansion coefficient of 70×10 at 100°C to 300°C. -7 / ℃~98×10 -7 / °C has been disclosed, but the problem of the inorganic composition having a thermal expansion coefficient smaller than that of the metal material used as the spindle material of the magnetic recording medium has not been solved. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. WO2012 / 057338 Summary of the Invention [Problem to be solved by the invention]

[0005] Therefore, the present invention aims to obtain an inorganic composition having a thermal expansion coefficient that can accommodate the thermal volume change of composite materials used in various fields, such as metal coating materials, packages for quartz oscillators, semiconductor support substrates, HDD substrates, and magnetic heads. [Means for solving the problem]

[0006] In order to solve the above problems, the inventors of the present invention have conducted extensive testing and research, and as a result have discovered a formulation of an inorganic composition having a high thermal expansion coefficient by adjusting the alkali metal oxide component, alkaline earth oxide component, and glass network former component and by crystallizing the glass, thereby completing the present invention. Specifically, the present invention provides the following:

[0007] (1) Mass % of oxide equivalent SiO2 content: 35.0% to 60.0% K2O component 10.0% to 30.0%, Al2O3 component 5.0% to 25.0%, ZrO2 content: 0% to 10.0% TiO2 content: 0% to 15.0% The total amount of ZrO2 and TiO2 components is more than 0% to 15.0%. Thermal expansion coefficient at -30 to 70°C is 125 to 155 (×10 -7 / °C).

[0008] (2) In terms of oxide, mass % Li2O content: 0% to 7.0% Na2O content: 0% to 7.0% P2O5 component 0% to 5.0%, B2O3 content: 0% to 5.0% MgO content: 0% to 15.0% ZnO content: 0% to 25.0%, SrO content: 0% to 7.0% The inorganic composition according to (1), characterized by containing:

[0009] (3) As a crystalline phase, The inorganic composition according to (1) or (2), characterized in that it contains KAlSiO4 or a KAlSiO4 solid solution. [Effects of the Invention]

[0010] According to the present invention, an inorganic composition having a thermal expansion coefficient that can accommodate volume changes caused by thermal changes in the material can be obtained. DETAILED DESCRIPTION OF THE INVENTION

[0011] The composition ranges of each component constituting the inorganic composition of the present invention are described below. In this specification, unless otherwise specified, the content of each component is expressed as mass % relative to the total mass of the composition converted into oxides. Here, "composition converted into oxides" refers to a composition in which each component contained in glass is expressed, assuming that the oxides, composite salts, metal fluorides, etc. used as raw materials for the glass components of the present invention are all decomposed and converted into oxides during melting, with the total mass of the oxides produced being 100 mass %.

[0012] [Glass components] In terms of oxides, the material contains 35.0% to 60.0% SiO2, 10.0% to 30.0% K2O, 5.0% to 25.0% Al2O3, 0% to 10.0% ZrO2, 0% to 15.0% TiO2, and the total amount of ZrO2 and TiO2 is over 0% to 15.0%.

[0013] [Required and optional ingredients] The SiO2 component is a glass framework component and is also an essential component for forming the crystals that precipitate when the base glass is heat-treated. In particular, by increasing the SiO2 content to 35.0% or more, base glass can be produced stably. Therefore, the lower limit of the SiO2 component content is preferably 35.0% or more, more preferably 35.5% or more, and even more preferably 36.0% or more. On the other hand, by keeping the content of the SiO2 component at 60.0% or less, excessive increases in viscosity and deterioration of meltability can be suppressed, so the upper limit of the content of the SiO2 component is preferably set at 60.0% or less, more preferably at 57.0% or less, and even more preferably at 55.0% or less.

[0014] When the LiO content exceeds 0%, it promotes the melting reaction of the raw materials, lowers the melting temperature of the glass, and is an effective component for improving meltability. However, an increased content can cause a deterioration in chemical durability and a change in the precipitated crystalline phase. Therefore, the lower limit of the content of the Li2O component is preferably more than 0%, more preferably 0.5% or more, and even more preferably 1.0% or more. On the other hand, by keeping the content of the Li2O component at 7.0% or less, it is possible to suppress the deterioration of devitrification, changes in the precipitated crystal phase, and deterioration of chemical durability that are caused by an excessive content. Therefore, the upper limit of the content of the Li2O component is preferably 7.0% or less, more preferably 6.0% or less, and even more preferably 5.0% or less.

[0015] When the Na2O content exceeds 0%, it adjusts the meltability of the glass and is also a component that forms crystals that precipitate when the base glass is heat-treated. Therefore, the lower limit of the content of the Na2O component is preferably more than 0%, and more preferably 0.5% or more. On the other hand, by keeping the content of the Na2O component at 7.0% or less, it is possible to suppress deterioration of chemical durability and changes in the precipitated crystal phase. Therefore, the upper limit of the Na2O content is preferably 7.0% or less, more preferably 5.0% or less, and even more preferably 4.0% or less.

[0016] When the K2O content exceeds 0%, it is one of the components that constitute the crystals that precipitate upon heat treatment of the raw glass, and is also an essential component that contributes to improving the meltability of the glass. The lower limit of the K2O content is preferably 10.0% or more, more preferably 14.0% or more, and even more preferably 18.0% or more. On the other hand, by keeping the content of the K2O component at 30.0% or less, deterioration of chemical durability is suppressed, so the upper limit of the content of the K2O component is preferably set to 30.0% or less, more preferably 28.0% or less, and even more preferably 26.0% or less.

[0017] When the Al2O3 component is contained in an amount exceeding 0%, it is one of the components that constitute the crystals that precipitate upon heat treatment of the base glass, and at the same time, it is a component that is effective in increasing the chemical durability and mechanical strength of the glass and improving the devitrification resistance of the glass melt, and is therefore an essential component of the inorganic composition of the present invention. Therefore, the lower limit of the content of the Al2O3 component is preferably 5.0% or more, more preferably 5.5% or more, and even more preferably 6.0% or more. On the other hand, by keeping the content of the Al2O3 component at 25.0% or less, it is possible to reduce the deterioration of meltability and devitrification caused by excessive content, so the upper limit of the content of the Al2O3 component is preferably set at 25.0% or less, more preferably at 22.0% or less, and even more preferably at 19.0% or less.

[0018] The P2O5 component is an optional component that, when contained in excess of 0%, serves as a nucleating agent for precipitated crystals, lowers the viscosity of the melt, and contributes to improving the stability of the glass. However, if contained in excess, the precipitated crystal phase may change, the glass may become more susceptible to devitrification, and vitrification may become difficult. Therefore, the lower limit of the P2O5 component is preferably set to more than 0%, and more preferably to 0.5% or more. The upper limit is preferably 5.0% or less, more preferably 3.0% or less, more preferably 2.5% or less, and even more preferably 2.0% or less.

[0019] The B2O3 component is an optional component that, when contained in an amount greater than 0%, contributes to lowering the viscosity of the melt and forming a glass network structure, thereby contributing to the stability of the glass. However, as the content increases, the precipitated crystal phase changes and chemical durability decreases, so the lower limit of the B2O3 component content is preferably greater than 0%, and more preferably 0.1% or more. The upper limit is preferably 5.0% or less, more preferably 3.0% or less, more preferably 2.5% or less, and even more preferably 2.0% or less.

[0020] When the MgO content exceeds 0%, it is an optional component that not only improves the meltability of the glass but also prevents the precipitated crystals from becoming coarse, but also contributes to improving the meltability of the glass. Therefore, the lower limit of the content of the MgO component is preferably more than 0%, and more preferably 1.0% or more. On the other hand, by keeping the content of the MgO component at 15.0% or less, it is possible to reduce devitrification caused by an excessive content. Therefore, the upper limit of the content of the MgO component is preferably 15.0% or less, more preferably 12.0% or less, and even more preferably 10.0% or less.

[0021] ZnO is an optional component that, when contained in an amount exceeding 0%, improves the meltability of the glass and at the same time prevents the precipitated crystals from becoming coarse, thereby contributing to improving the meltability of the glass. Therefore, the lower limit of the ZnO content is preferably more than 0%, and more preferably 1.0% or more. On the other hand, by keeping the ZnO content at 25.0% or less, it is possible to reduce devitrification caused by an excessive content. Therefore, the upper limit of the ZnO content is preferably 25.0% or less, more preferably 23.0% or less, and even more preferably 20.0% or less.

[0022] The SrO component is an optional component that contributes to improving the meltability and stability of the glass when contained in an amount exceeding 0%. However, since devitrification tends to occur as the content increases, the upper limit of the SrO component content is preferably set to 7.0% or less, more preferably 5.0% or less, and even more preferably 4.0% or less. Furthermore, since the inclusion of the SrO component improves the stability of the glass, the lower limit of the SrO content is preferably more than 0%, more preferably 1.0% or more, and even more preferably 1.5% or more.

[0023] When the ZrO2 content is more than 0%, it functions as a nucleating agent for precipitated crystals and also contributes to the refinement of precipitated crystals and the improvement of the mechanical strength of the material. In particular, in the present invention, it is a component that can adjust the grain size of the crystals. Therefore, the lower limit of the content of the ZrO2 component is preferably more than 0%, and more preferably 1.0% or more. On the other hand, by keeping the content of the ZrO2 component at 10.0% or less, it is possible to reduce devitrification and deterioration of meltability caused by an excessive content of the ZrO2 component. Therefore, the upper limit of the content of the ZrO2 component is preferably 10.0% or less, more preferably 8.0% or less, and even more preferably 6.0% or less.

[0024] When the TiO2 component is contained in an amount exceeding 0%, it functions as a nucleating agent for precipitated crystals and also contributes to the refinement of precipitated crystals and the improvement of the mechanical strength of the material. In particular, in the present invention, it is a component that can adjust the grain size of the crystals. Therefore, the lower limit of the content of the TiO2 component is preferably more than 0%, and more preferably 1.0% or more. On the other hand, by keeping the content of the TiO2 component at 15.0% or less, the decrease in transmittance can be suppressed. Therefore, the upper limit of the content of the TiO2 component is preferably 15.0% or less, more preferably 12.0% or less, and even more preferably 9.0% or less.

[0025] The Sb2O3 component is an optional component that can degas the glass melt when its content exceeds 0%. Therefore, the lower limit of the content of the Sb2O3 component may be preferably set to more than 0%, and more preferably to 0.03% or more. On the other hand, by keeping the content of the Sb2O3 component at 1.0% or less, the decrease in transmittance can be suppressed. Therefore, the upper limit of the content of the Sb2O3 component may be preferably set to 1.0% or less, more preferably 0.5% or less, and even more preferably 0.2% or less.

[0026] The Gd2O3 component is a component that reduces the formability and devitrification of the glass melt when contained in an amount of 3.0% or more. Therefore, the upper limit of the Gd2O3 content is preferably set to less than 3.0%, and it may not be contained at all.

[0027] In addition, La2O3 component, Y2O3 component, Yb2O3 component, Eu2O3 component, Dy2O3 component, Er2O3 component, Tb2O3 component, Pr6O 11 The composition may or may not contain any of the following components: Nd2O3, Tm2O3, Sm2O3, Ho2O3, CeO2, CaO, BaO, CoO, Co2O3, Ta2O5, Nb2O5, WO3, TeO2, Bi2O3, FeO, Fe2O3, MnO2, Cr2O3, GeO2, Ga2O3, CuO, NiO, V2O5, and SnO2. The content of each component may be 0% to less than 3.0%.

[0028] When the total content of the ZrO2 component and the TiO2 component exceeds 0%, they function as nucleating agents for precipitated crystals and also contribute to the refinement of precipitated crystals and the improvement of the mechanical strength of the material. In particular, in the present invention, they are components that can adjust the grain size of the crystals. Therefore, the lower limit of the total content of the ZrO2 component and the TiO2 component is preferably more than 0%, more preferably 1.0% or more, more preferably 1.5% or more, and more preferably 3.5% or more. On the other hand, by keeping the total content of ZrO2 and TiO2 at 15.0% or less, it is possible to suppress the decrease in the thermal expansion coefficient that accompanies changes in the precipitated crystal phase and the sudden change in physical properties during crystallization. Therefore, the upper limit of the total content of the ZrO2 component and the TiO2 component is preferably 15.0% or less, and more preferably 12.0% or less.

[0029] By setting the ratio of the total content of the Na2O component, the K2O component, and the MgO component to the content of the SiO2 component [(Na2O+K2O+MgO) / SiO2] to be 0.40 or more, the thermal expansion characteristics of the crystallized glass can be improved. Therefore, the upper limit of the ratio of the total content of Na2O, K2O, and MgO to the content of SiO2 [(Na2O + K2O + MgO) / SiO2] is preferably 1.20 or less, more preferably 1.00 or less, and even more preferably 0.95 or less, while the lower limit is preferably 0.40 or more, and even more preferably 0.45 or more.

[0030] By setting the ratio of the total content of the Na2O component and the K2O component to the content of the SiO2 component [(Na2O+K2O) / SiO2] to be 0.30 or more, the thermal expansion characteristics of the crystallized glass can be improved. Therefore, the upper limit of the ratio of the total content of Na2O and K2O to the content of SiO2 [(Na2O + K2O) / SiO2] is preferably 0.80 or less, more preferably 0.78 or less, and even more preferably 0.75 or less, while the lower limit is preferably 0.30 or more, more preferably 0.32 or more, and even more preferably 0.35 or more.

[0031] By setting the ratio of the total content of the Na2O component and the K2O component to the content of the Al2O3 component [(Na2O+K2O) / Al2O3] to be 1.00 or more, the thermal expansion characteristics of the crystallized glass can be improved. Therefore, the upper limit of the ratio of the total content of Na2O and K2O to the content of Al2O3 [(Na2O + K2O) / Al2O3] is preferably 3.80 or less, more preferably 3.75 or less, and even more preferably 3.70 or less, while the lower limit is preferably 1.00 or more, more preferably 1.05 or more, and even more preferably 1.10 or more.

[0032] [Manufacturing method] The inorganic composition of the present invention is prepared, for example, as follows: Raw materials such as oxides, hydroxides, carbonates, nitrates, fluorides, chlorides, and metaphosphate compounds are uniformly mixed so that each component falls within a predetermined content range, the mixture is placed in a platinum crucible, and melted in an electric furnace at a temperature ranging from 1300 to 1600°C depending on the melting difficulty of the glass composition. After stirring and homogenization, the mixture is cooled to an appropriate temperature, poured into a mold, and slowly cooled to prepare a glass base material.

[0033] The crystallization process is not particularly limited, but for example, the glass base material was heated at a temperature range of 500°C to 560°C for 5 hours to form crystal nuclei, and then heated at a temperature range of 570°C to 800°C for 3 hours to crystallize. The precipitated crystalline phase was analyzed and identified using a Bruker D8 DISCOVER X-ray diffractometer.

[0034] The precipitated crystalline phase of the inorganic composition of the present invention is preferably KAlSiO4 or a KAlSiO4 solid solution in order to improve the thermal expansion coefficient.Other precipitated crystalline phases may or may not include Rn2MgSiO4 (where Rn is one or more selected from Li, Na, and K), Rn2ZnSiO4 (where Rn is one or more selected from Li, Na, and K), Rn2SiO3 (where Rn is one or more selected from Li, Na, and K), MgSiO3, R2SiO4 (where R is one or more selected from Mg and Zn), Li2TiO3, K2ZrSiO7, etc.

[0035] This crystallized glass was lapped and then polished to obtain an inorganic composition substrate. It was also crushed to obtain an inorganic composition powder for compounding with metals, inorganic compounds, or organic compounds. These inorganic composition substrates and powders can be used in fields such as metal coating materials, packages for quartz crystal oscillators, semiconductor support substrates, HDD substrates, magnetic heads, and optical filters for DWDM.

[0036] [Coefficient of thermal expansion] The linear expansion coefficient was measured in the temperature range of -30°C to 70°C using a Mac Science TD5000S, based on the Japan Optical Glass Industry Association standard JOGIS-16 (2019), "Method for measuring the average linear expansion coefficient of optical glass near room temperature." In each case, the samples were processed into cylindrical shapes with a diameter of 4 mm and a length of 20 mm, and the linear expansion coefficient was calculated from the slope of the expansion curve, which shows the relationship between temperature and material elongation, in the temperature range of -30°C to 70°C. The lower limit of the thermal expansion coefficient of the inorganic composition of the present invention at -30°C to 70°C is preferably 125 (×10 -7 / ℃), more preferably 126(×10 -7 / ℃), and most preferably 127(×10 -7 / °C) or more. The upper limit is preferably 155 (×10 -7 / ℃), more preferably 154(×10 -7 / °C), and more preferably 153 (× 10 -7 / °C) or less.

[0037] [specific gravity] The specific gravity of the inorganic composition was measured in accordance with Japanese Industrial Standard JIS Z 8807 (2012) "Method for measuring density and specific gravity of solids." The specific gravity of the inorganic composition of the present invention is preferably 4.0 or less, more preferably 3.8 or less, and even more preferably 3.5 or less.

[0038] [Internal transmittance] Using the Japan Optical Glass Industry Association standard JOGIS-17 (2019) "Method for measuring the internal transmittance of optical glass," the spectral transmittance, including reflection loss, of 10 mm and 1 mm thick, parallel-polished, face-to-face samples was measured, and the internal transmittance of the 1 mm thickness (spectral transmittance excluding reflection loss) was calculated from these spectral transmittances. The internal transmittance of the present invention is preferably 60.0% or more, more preferably 65.0% or more, and even more preferably 70.0% or more at 1550 nm.

[0039] [Transmittance] Based on the Japan Optical Glass Industry Association standard JOGIS-02 (2019) "Method for measuring color intensity of optical glass," the spectral transmittance of a 1 mm thick, parallel-polished specimen was measured using a Hitachi Measurement was carried out using a spectrophotometer U-4100. The transmittance of the present invention is preferably 5.0% or more, more preferably 10.0% or more, and even more preferably 20.0% or more, in terms of spectral transmittance at 1550 nm. [Example]

[0040] The following examples are provided to illustrate the present invention in detail for illustrative purposes, but it should be noted that these examples are for illustrative purposes only and that many modifications may be made by those skilled in the art without departing from the spirit and scope of the present invention.

[0041] Glass-ceramics of various compositions, as listed in Tables 1 to 4, were prepared as Examples (Nos. 1 to 33) and Comparative Examples 1 and 2. High-purity raw materials typically used in glass-ceramics, such as oxides, hydroxides, carbonates, nitrates, fluorides, chlorides, and metaphosphate compounds, were selected as the raw materials for each component. These were weighed and mixed to achieve the compositional ratios shown in Tables 1 to 4 for each example. The mixture was then placed in a platinum crucible and melted in an electric furnace at a temperature ranging from 1300 to 1600°C, depending on the melting difficulty of the glass composition. The mixture was then stirred and homogenized, cooled to an appropriate temperature, poured into a mold, and slowly cooled. The resulting glass was then crystallized at a predetermined temperature. The thermal expansion coefficient, transmittance, internal transmittance, and specific gravity of each glass-ceramic were measured, and the results are shown in Tables 1 to 4.

[0042] [Table 1]

[0043] [Table 2]

[0044] [Table 3]

[0045] [Table 4]

[0046] It has been revealed that the inorganic compositions of the examples of the present invention are suitable for use in a variety of applications, such as in composites with metals, organic compounds, or inorganic compounds in fields such as metal coating materials, packages for quartz oscillators, semiconductor support substrates, HDD substrates, and magnetic heads, as inorganic compositions having a thermal expansion coefficient that can accommodate volume changes caused by thermal changes in the material.

Claims

1. In terms of oxide, mass % SiO ２ The content of ingredients is 35.0% to 60.0%, K ２ The content of O component is 23.07% to 30.0%. Al ２ O ３ The content of the ingredients is 5.0% to 25.0%, ZrO ２ The content of the ingredients is 0% to 10.0%, TiO ２ The content of the ingredients is 0% to 15.0%, ZrO ２ Ingredients and TiO ２ The total amount of the components is greater than 0% to 15.0%; Thermal expansion coefficient at -30 to 70°C is 136 to 155 (x10 －７ / °C).

2. In terms of oxide, mass % Li ２ The content of O component is 0% to 7.0%, Na ２ The content of O component is 0% to 7.0%, P ２ O ５ The content of the ingredients is 0% to 5.0%, B ２ O ３ The content of the ingredients is 0% to 5.0%, The content of MgO component is 0% to 15.0%, The content of ZnO component is 0% to 25.0%, SrO content is 0% to 7.0% 2. The inorganic composition according to claim 1, wherein

3. As a crystalline phase, KAlSiO ４ or KAlSiO ４ 3. The inorganic composition according to claim 1, further comprising a solid solution.

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