Composite material and component

Abstract

To provide a composite material and a component in which volume change with respect to temperature change is suppressed by using a new material exhibiting negative thermal expansion.SOLUTION: The composite material is represented by general formula (1) Cu2-xRxV2-yPyO7 (R includes at least one element selected from Mg, Al, Si, Ti, Cr, Mn, Fe, Co, Ni, Zn, and Sn, and satisfies 0 <x <2 and 0 <y <2). And exhibits negative heat expansion in a temperature range of 100 to 500K, and a positive heat expansion material having a positive linear expansion coefficient.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] This application is based on and claims the benefit of priority from Japanese Patent Application No. 2020-198758 filed on November 30, 2020 and Japanese Patent Application No. 2021-113729 filed on July 8, 2021, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to composite materials and components. [Background technology]

[0003] It is generally known that materials expand with increasing temperature. However, the recent advances in industrial technology have made it necessary to control even the thermal expansion that is the fate of solid materials. -5 ), which is considered a small change by ordinary standards, is a major problem in fields such as semiconductor device manufacturing, which requires nanometer-level precision, and precision equipment, where even the slightest distortion in a component can have a significant impact on its functionality. Furthermore, in devices made from multiple materials, differences in the thermal expansion of the constituent materials can cause other problems, such as interfacial peeling and wire breakage.

[0004] On the other hand, negative thermal expansion materials are also known, whose lattice volume decreases with increasing temperature (having a negative thermal expansion coefficient). For example, β-Cu, which has a monoclinic crystal structure, exhibits large negative thermal expansion over a wide temperature range. 1.8 Zn 0.2 V2O7 is known (see Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-210198 Summary of the Invention [Problem to be solved by the invention]

[0006] The present disclosure has been made in view of such circumstances, and one of its objectives is to realize a composite material and a component in which volume change with respect to temperature change is suppressed, using a new material exhibiting negative thermal expansion.

Means for Solving the Problems

[0007] In order to solve the above problems, a composite material according to an aspect of the present disclosure has an oxide represented by the general formula (1) Cu 2-x R[[ID=​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​FIG. 1 is a diagram showing the thermal expansion characteristics of Cu1.5Zn0.5V1.4P0.6O7. [Figure 5] FIG. 1 is a diagram showing the thermal expansion characteristics of Cu2V2-yPyO7 (x=0.2, 0.6). [Figure 6] FIG. 1 shows the X-ray diffraction pattern of Cu1.8Zn0.2V1.8P0.2O7 (line L9) produced by a spray-drying method. [Figure 7] FIG. 1 is a diagram showing the thermal expansion characteristics of a composite material according to an embodiment. [Figure 8] FIG. 1 is a diagram showing the thermal expansion characteristics of a composite material according to an embodiment. [Figure 9] FIG. 1 shows the X-ray diffraction pattern of Zn2-xMgxP2O7. [Figure 10] FIG. 1 shows the X-ray diffraction pattern of Zn2P2-yAyO7 (A is any of Sn, Ge, Si, and V). [Figure 11] FIG. 1 is a diagram showing the thermal expansion properties of Zn2-xMgxP2O7 (x=0, 0.2, 0.4, 0.6, 0.8, 2). [Figure 12] FIG. 1 is a diagram showing the thermal expansion characteristics of Zn1.64Mg0.3Al0.06P2O7. [Figure 13] FIG. 1 is a diagram showing the thermal expansion characteristics of Zn2P2-yAyO7 (x=0.1, A is either Sn or Si). [Figure 14] FIG. 1 is a diagram showing an X-ray diffraction pattern of Ti2-xMxO3 (M is any of Mn, Cr, V, Si, Ta, Nb, and Zr). [Figure 15] FIG. 1 is a diagram showing the thermal expansion characteristics of Ti2-xMxO3 (M is either Cr or Nb). [Figure 16] FIG. 1 is a diagram showing the thermal expansion characteristics of Ti2-xMxO3 (M is either Si or Al). [Figure 17] FIG. 1 shows the color of Cu1.8Zn0.2V2-yPyO7. DETAILED DESCRIPTION OF THE INVENTION

[0011] The inventors focused on the Cu2V2O7 system as a candidate material exhibiting negative thermal expansion. α-Cu2V2O7, which has an orthorhombic crystal structure, has attracted attention as a multiferroic material in which ferroelectricity and weak paramagnetism coexist. However, over a relatively wide temperature range, including room temperature, anisotropic thermal deformation of the crystal lattice is observed, which is thought to be due to dielectric instability. As a result, negative thermal expansion, in which the unit cell volume contracts with increasing temperature, appears over a wide temperature range.

[0012] By substituting various elements, Cu2V2O7 can assume an orthorhombic α phase, a monoclinic β phase, and a triclinic γ phase. The inventors discovered that substituting a portion of the Cu site or V site with other elements results in the development of negative thermal expansion properties that could not be achieved with conventional α-Cu2V2O7 systems, and have devised the negative thermal expansion materials exemplified below.

[0013] The inventors also focused on the Zn2P2O7 system as a further candidate for a material that exhibits negative thermal expansion. Zn2P2O7 is stable in the monoclinic I2 / c α phase at low temperatures and the monoclinic C2 / m β phase at high temperatures, and as the temperature rises, it undergoes a transition accompanied by a large contraction of 1.68% (calculated from the lattice constant) at approximately 405 K. The inventors discovered that negative thermal expansion properties are exhibited when part of the Zn site or P site is substituted with other elements, and have devised the negative thermal expansion materials shown below.

[0014] The present inventors also focused on Ti2O3-based materials as a further candidate for materials exhibiting negative thermal expansion. Corundum-type Ti2O3 is stable at room temperature and normal pressure, has a hexagonal R-3c crystal structure (the "-" is on top of the 3), and is composed of honeycomb lattice layers. Ti2O3 is also a Mott-Hubbard insulator that exhibits a metal-insulator transition at 400-600K, and the unit cell exhibits anisotropic positive thermal expansion during the transition. The present inventors discovered that negative thermal expansion properties are exhibited when part of the Ti site is replaced with other elements, and devised the negative thermal expansion materials shown below.

[0015] The negative thermal expansion material according to an embodiment of the present disclosure has the general formula (1): 2-x R x V2-y P y It contains an oxide represented by O7 (R contains at least one element selected from Mg, Al, Si, Ti, Cr, Mn, Fe, Co, Ni, Zn, Sn, and satisfies 0 ≦ x ≦ 2, 0 < y < 2).

[0016] According to this aspect, by substituting relatively expensive V with relatively inexpensive P, it is possible to provide a new and less expensive negative thermal expansion material while maintaining the characteristics of negative thermal expansion to a certain extent.

[0017] The oxide may have a linear expansion coefficient of -10 ppm / K or less at 400 K.

[0018] In the general formula (1), x may be 0.1 to 1.6. More preferably, x is 0.1 to 1.0. Thereby, a negative linear expansion coefficient with an absolute value larger than that of α-Cu2V2O7 in which Cu is not substituted by R can be realized.

[0019] In the general formula (1), y may be 0.1 to 1.8. More preferably, y is 0.1 to 1.2. Thereby, it is possible to provide a negative thermal expansion material that is less expensive than Cu 2-x R x V2O7 is provided.

[0020] The oxide may contain a monoclinic β-phase.

[0021] It may contain at least one of an oxide with a monoclinic crystal system and an oxide with an orthorhombic crystal system. Further, the oxide may have a crystal structure selected from any of the space groups C2 / c, C2 / m, and Fdd2.

[0022] The negative thermal expansion material may exhibit negative thermal expansion in the temperature range of 100 to 500 K.

[0023] The negative thermal expansion material may have a linear expansion coefficient of -10 ppm / K or less in the temperature range of 100 to 500 K.

[0024] The negative thermal expansion material may change color by changing y in the general formula (1). According to this aspect, it can be used for thermal expansion control of paints and the like.

[0025] The negative thermal expansion material of another aspect of the present disclosure is represented by the general formula (2) Zn 2-x T x P 2-y A y O7 (T contains at least one element selected from Mg, Al, Si, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ga, Ge, Zr, Nb, Mo, Ag, In, Sn, Sb, La, Ta, W, Bi, and A contains at least one element selected from Al, Si, V, Ge, Sn, and 0 ≤ x < 2, 0 ≤ y ≤ 2 are satisfied. However, (x, y) = (0, 0) and (0, 2) are excluded.)

[0026] According to this aspect, a new inexpensive negative thermal expansion material with large negative thermal expansion near room temperature can be provided.

[0027] In the general formula (2), oxides where x = 0, 0 < y < 2, and A = V may be excluded.

[0028] In the general formula (2), x may be 0.1 to 1.6.

[0029] In the general formula (2), y may be 0.1 to 1.6.

[0030] The negative thermal expansion material may exhibit negative thermal expansion in the temperature range of 200 to 400 K.

[0031] The negative thermal expansion material may have a linear expansion coefficient of -10 ppm / K or less in the temperature range of 200 to 400 K.

[0032] The negative thermal expansion material of still another aspect of the present disclosure is represented by the general formula (3) Ti 2-x M xIt contains an oxide represented by O3 (M contains at least one element selected from Mg, Al, Si, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ag, In, Sn, Sb, La, Ta, W, Bi, and satisfies 0≦x<2).

[0033] According to this aspect, an inexpensive new negative thermal expansion material can be provided.

[0034] In the general formula (3), x may satisfy 0<x≦1.6. More preferably, x is 0.05 to 1.6, and still more preferably, 0.1 to 1.0.

[0035] The negative thermal expansion material may exhibit negative thermal expansion in the temperature range of 100 to 500K.

[0036] The negative thermal expansion material may have a linear expansion coefficient of -10 ppm / K or less in the temperature range of 100 to 500K.

[0037] Still another aspect of the present disclosure is a composite material. This composite material includes a negative thermal expansion material and a positive thermal expansion material having a positive linear expansion coefficient. Thereby, a composite material with suppressed volume change against temperature change can be realized.

[0038] Still another aspect of the present disclosure is a method for manufacturing a negative thermal expansion material. This manufacturing method includes a step of preparing an aqueous solution containing a raw material of a compound represented by the general formula (1) Cu 2-x R x V 2-y P y O7 (R contains at least one element selected from Mg, Al, Si, Ti, Cr, Mn, Fe, Co, Ni, Zn, Sn, and satisfies 0≦x≦2, 0<y<2).

[0039] Still another aspect of the present disclosure is also a method for manufacturing a negative thermal expansion material. This manufacturing method includes a step of preparing an aqueous solution containing a raw material of a compound represented by the general formula (2) Zn 2-x T x P 2-y A yThe method includes a step of preparing an aqueous solution containing a raw material for a compound represented by the formula (I) O7 (T includes at least one element selected from Mg, Al, Si, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ga, Ge, Zr, Nb, Mo, Ag, In, Sn, Sb, La, Ta, W, and Bi, and A includes at least one element selected from Al, Si, V, Ge, and Sn, and satisfies 0≦x<2 and 0≦y≦2, excluding (x,y)=(0,0) and (0,2)).

[0040] Yet another aspect of the present disclosure is a component that includes a negative thermal expansion material or a composite material that includes a negative thermal expansion material and a positive thermal expansion material having a positive linear expansion coefficient, thereby realizing a component that exhibits reduced volumetric change in response to temperature changes.

[0041] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0042] [First embodiment] Cu using solid-state reaction method 2-x R x V 2-y P y A polycrystalline sintered (ceramic) sample of O7 (R is Zn) was prepared. Specifically, CuO, ZnO, V2O3 or V2O5, (NH4)2HPO4 or (NH4)H2PO4, weighed in stoichiometric ratios, were mixed in an agate mortar and pestle in air for 1 hour. The mixed powder was then pressed into a pellet and heated at temperatures of 873 to 953 K in air for 10 hours. The resulting powder was sintered using a spark plasma sintering (SPS) furnace (manufactured by SPS Syntex Co., Ltd.) to obtain an oxide sintered body. Sintering was performed in a vacuum (<10 -1 The process was carried out at 723 K for 5 minutes under a pressure of 100 Pa using a graphite die. The starting materials are not limited to those mentioned above, and P2O5, Zn2P2O7, Cu2P2O7, etc. can also be used. The sintered body is obtained by sintering the raw materials, and can take any form, such as powder or powder agglomerated and processed into a predetermined shape.

[0043] The crystal structure of each sample was then evaluated using powder X-ray diffraction (XRD) (measurement temperature 295 K, CuKα characteristic X-ray: wavelength λ = 0.15418 nm) and synchrotron radiation temperature-dependent X-ray diffraction (wavelength λ = 0.06521 nm). Figure 1 shows the crystal structure of β-Cu2P2O7 and β-Cu2V2O7, and Cu 1.8 Zn 0.2 V 2-y P y Figure 2 shows the X-ray diffraction patterns of β-Cu2P2O7 and β-Cu2V2O7, and Cu 1.8 Zn 0.2 V 2-y P y 2 shows the X-ray diffraction patterns of β-Cu2P2O7 and β-Cu2V2O7 (y = 1.8, 1.5). Note that the X-ray diffraction patterns of β-Cu2P2O7 and β-Cu2V2O7 are calculated values.

[0044] As shown in Figures 1 and 2, β-Cu2P2O7 (line L1) is an oxide sintered body that corresponds to the high-temperature phase and has a monoclinic crystal structure with a space group of C2 / m. On the other hand, β-Cu2V2O7 (line L8) is also an oxide sintered body that corresponds to the high-temperature phase, but has a monoclinic crystal structure with a space group of C2 / c. Note that any of the oxide sintered bodies may have a crystal structure with a space group of C2 / c, C2 / m, or Fdd2 by substituting some elements or by using a different manufacturing method.

[0045] As shown in Figures 1 and 2, Cu is partially substituted with Zn. 1.8 Zn 0.2 V 2-y P y O7 (lines L2 to L7, L9, and L10) also have a β-phase (monoclinic) crystal structure. 2-x R x V 2-y P yIn O7, R contains an element that substitutes for Cu, and by substituting a portion of the V with P, it is presumed that the β phase, which does not stably exist unless at high temperatures (977 K or higher) in the composition Cu2V2O7, can exist stably over a wide temperature range including room temperature. Note that the oxide contained in the negative thermal expansion material according to this embodiment is not necessarily limited to monoclinic, and may contain at least one of an oxide whose crystal system is monoclinic and an oxide whose crystal system is orthorhombic.

[0046] Figure 3 shows the β-Cu 1.8 Zn 0.2 V 2-y P y This figure shows the thermal expansion characteristics of O7. The vertical axis represents the change in length ΔL / L, with the length L at 100 K as the reference. The change in length was calculated using the linear expansion coefficient α calculated using a laser thermal dilatometer (LIX-2, manufactured by ULVAC, Inc.) (measurement temperature range: 100 to 500 K).

[0047] As shown in Figure 3, β-Cu 1.8 Zn 0.2 V 2-y P y When the value of y, the proportion of P substituting V in O7, is 0.1, 0.4, or 0.6, negative thermal expansion is exhibited in the temperature range of 100 to 500 K, and the linear expansion coefficient is -10 ppm / K or less at least at 400 K. In particular, when the value of y is 0.1 or 0.4, the linear expansion coefficient is -10 ppm / K or less in the temperature range of 100 to 500 K, and it is clear that large negative thermal expansion is exhibited in a wide temperature range including room temperature.

[0048] In this embodiment, Zn is used as an example of a substitution element for Cu. However, it is presumed that negative thermal expansion will also be exhibited if part of Cu is substituted with an element such as Mg, Al, Si, Ti, Cr, Mn, Fe, Co, Ni, or Sn.

[0049] Next, we will explain the effect of the ratio of Zn substituting for Cu. 1.5 Zn 0.5 V 1.4 P 0.6It is a diagram showing the thermal expansion characteristics of O7. As shown in Fig. 4, even when the ratio x of Zn substituting for Cu is 0.5, it shows negative thermal expansion in the temperature range of 100 to 500 K, and the linear expansion coefficient at least at 400 K is -10 ppm / K or less. Note that the ratio x of the element R substituting for Cu may be 0.1 to 1.6. More preferably, x is 0.1 to 1.0. Thereby, a negative linear expansion coefficient having an absolute value larger than that of α-Cu2V2O7 in which Cu is not substituted with the element R can be realized.

[0050] Fig. 5 is Cu2V 1.8 P 0.2 O7 and Cu2V 1.4 P 0.6 It is a diagram showing the thermal expansion characteristics of O7. As shown in Fig. 5, even when Cu is not substituted and V is substituted with P. It shows negative thermal expansion in the temperature range of 100 to 500 K, and the linear expansion coefficient at least at 400 K is -10 ppm / K or less. [[ID=*13]]

[0051] As described above, the negative thermal expansion material according to the present embodiment has the general formula (1) Cu 2-x R x V 2-y P y O7 (R contains at least one element selected from Mg, Al, Si, Ti, Cr, Mn, Fe, Co, Ni, Zn, Sn, and satisfies 0 ≤ x ≤ 2, 0 < y < 2.) It is a sintered oxide body represented by. Thereby, by substituting relatively expensive V with relatively inexpensive P, a new and less expensive negative thermal expansion material can be provided while maintaining the characteristics of negative thermal expansion to some extent. Also, y in the general formula (1) may be 0.1 to 1.8. More preferably, y is 0.1 to 1.2. Thereby, a negative thermal expansion material less expensive than Cu 2-x R x R2O7 can be provided.

[0052] [Second Embodiment] Using the spray drying method, β-Cu 1.8 Zn 0.2 V 2-y P yPolycrystalline sintered ceramic samples of O7 were prepared. Specifically, Cu was obtained by solid-state reaction. 2-x Zn x V 2-y P y To 1 g of O7 sample powder, add 3 g of anhydrous citric acid and approximately 100 ml of pure water, and stir using a magnetic stirrer until all the sample powder is dissolved.

[0053] The resulting aqueous solution is then spray-dried using a Yamato Scientific ADL-311SA spray dryer at a spray rate of 2 ml / min and a temperature of 150°C to obtain a citrate powder. This powder is placed in an alumina crucible and heated in air at 673 K for 5 to 10 hours to decompose the citric acid. The resulting powder is then crushed thoroughly in a mortar, formed into pellets, placed in an alumina crucible, and fired in an electric furnace in air at 873 to 953 K for 2 to 10 hours.

[0054] An organic acid such as acetic acid may be used instead of the citric acid described above. Furthermore, the raw materials may be mixed in a molar ratio and then directly mixed with citric acid to form an aqueous solution. The concentration of the citric acid aqueous solution and the conditions for spray drying are not limited to those described above. The decomposition process of citric acid and the chemical reaction process may be carried out continuously. Furthermore, the processes from spray drying to the final chemical reaction may be carried out in a continuous process.

[0055] Figure 6 shows Cu prepared by spray drying. 1.8 Zn 0.2 V 1.8 P 0.2 1 shows the X-ray diffraction pattern of O7 (line L11). From the pattern shown in line L11, it is clear that Cu prepared by the solid-state reaction method 1.8 Zn 0.2 V 1.8 P 0.2 It can be seen that the crystal structure is the same as that of O7 (line L6).

[0056] Thus, the β-Cu produced by the spray drying method 1.8 Zn 0.2 V 1.8 P 0.2O7 can obtain a linear expansion coefficient as large as that of β-Cu manufactured by the solid-phase reaction method by optimizing the firing conditions. 1.8 Zn 0.2 V 1.8 P 0.2 O7, and can also obtain a linear expansion coefficient at least equal to or greater than that of conventionally known α-Cu2V2O7.

[0057] As described above, the method for manufacturing a negative thermal expansion material by the spray drying method includes the step of preparing an aqueous solution containing a raw material of a compound represented by the general formula (1) Cu 2-x R x V 2-y P y O7 (R contains at least one element selected from Mg, Al, Si, Ti, Cr, Mn, Fe, Co, Ni, Zn, Sn, and satisfies 0 ≦ x ≦ 2, 0 < y < ). According to this manufacturing method, a negative thermal expansion material having a negative linear expansion coefficient with an absolute value larger than that of α-Cu2V2O7 in which Cu is not substituted with Zn can be manufactured relatively inexpensively by using an aqueous solution that is easy to handle at low temperatures. In addition, since a part of V can be substituted with P, a more inexpensive negative thermal expansion material can be provided.

[0058] In addition, the above manufacturing method includes the step of drying and granulating the aqueous solution by the spray drying method to produce a powder of an organic acid salt. Thereby, a powder of an organic acid salt can be manufactured without requiring excessive energy such as granulation and pulverization at high temperatures or expensive equipment.

[0059] In addition, the above manufacturing method includes the step of heating the powder of the organic acid salt to decompose the organic acid, and the step of firing the powder from which the organic acid has been decomposed to produce an oxide sintered body. Thereby, an oxide sintered body having a desired shape can be produced with relatively low energy.

[0060] As described above, the negative thermal expansion material manufactured by the manufacturing method according to the embodiment of the present disclosure has a substantially constant linear expansion coefficient with respect to temperature change in a wide temperature range up to about 100 to 500 K, and material function design is easy. In addition, it is mainly composed of inexpensive elements such as Cu, Zn, and P, has a low synthesis temperature with oxides, is easy to manufacture, and has industrial merits such as being able to obtain fine particles.

[0061] [Third Embodiment] General formula (1) Cu 2-x R x V 2-y P y A composite material containing a negative thermal expansion material represented by O7 (R contains at least one element selected from Mg, Al, Si, Ti, Cr, Mn, Fe, Co, Ni, Zn, Sn, and satisfies 0 ≦ x ≦ 2, 0 < y < 2) and a positive thermal expansion material having a positive linear expansion coefficient such as resin or metal will be described.

[0062] FIG. 7 is a diagram showing the thermal expansion characteristics of the composite material according to the present embodiment. The composite material shown in FIG. 7 is a mixture of 30 vol% of Cu 1.8 Zn 0.2 V 1.6 P 0.4 O7 having a linear expansion coefficient α of -10 ppm / K or more and 70 vol% of an epoxy resin having a linear expansion coefficient α of 60 ppm / K. As shown in FIG. 7, the composite material according to the present embodiment greatly suppresses thermal expansion (volume change) with respect to temperature change compared to the case of epoxy resin alone. Instead of epoxy resin, it may contain resin materials such as engineering plastics, polyvinyl butyral resin, and phenolic resin, or metal materials such as aluminum.

[0063] FIG. 8 is also a diagram showing the thermal expansion characteristics of the composite material according to the present embodiment. One of the three composite materials shown in FIG. 8 is the composite material shown in FIG. 7. Another one is Cu having a linear expansion coefficient α of -10 ppm / K or more 1.8 Zn 0.2 V 1.0 P 1.0The remaining one is a mixture of 30 vol% O and 70 vol% epoxy resin with a linear expansion coefficient α of 60 ppm / K. 1.8 Zn 0.2 It is a mixture of 30 vol% VO and 70 vol% epoxy resin with a linear expansion coefficient α of 60 ppm / K. The composite material according to this embodiment shown in Fig. 8 also shows a greater suppression of thermal expansion (volume change) with temperature changes than epoxy resin alone.

[0064] [Fourth embodiment] Zn using solid-state reaction method 2-x T x Polycrystalline sintered (ceramic) samples of P2O7 (T is Mg) were prepared. Specifically, ZnO, MgO, (NH4)2HPO4, or (NH4)H2PO4, weighed in stoichiometric ratios, were mixed in an agate mortar and pestle in air for 1 hour. The mixed powder was then pressed into pellets and heated in air at temperatures between 1023 and 1173 K for 2 to 10 hours. If the sinterability was insufficient, the obtained sample was crushed into powder in air using an agate mortar and pestle, and then fired again as described above, or sintered using a spark plasma sintering (SPS) furnace (manufactured by SPS Syntex Co., Ltd.). SPS sintering was performed in a vacuum (<10 -1 The reaction was carried out at 823-1023K for 5 minutes under a pressure of 1000 Pa using a graphite die. The starting materials are not limited to those mentioned above, and P2O5, Zn2P2O7, Mg2P2O7, etc. can also be used. When replacing part of the P with T (for example, V), powder of T alone or an oxide of T such as V2O5 can be used as the starting material.

[0065] The crystal structure of each sample was then evaluated using powder X-ray diffraction (XRD) (measurement temperature 295 K, CuKα characteristic X-ray: wavelength λ = 0.15418 nm) and synchrotron radiation temperature-dependent X-ray diffraction (wavelength λ = 0.06521 nm). 2-x Mg x 10 shows the X-ray diffraction pattern of Zn2P 2-y A y FIG. 1 shows an X-ray diffraction pattern of O7 (A is any of Sn, Ge, Si, and V).

[0066] As shown in Figure 9, Zn 2-x T x It has been confirmed that P2O7 (T is Mg) can be obtained as a single-phase sample in the entire composition range where x is from 0 to 2. At room temperature, the crystal structure has the space group I2 / c for x = 0, 0.2, 0.4, and 0.6, the space group C2 / m for x = 0.8 and 1.2, and the space group B21 / c for x = 1.6 and 2.

[0067] As shown in Figure 10, Zn2P 2-y A y O7 (A is Sn, Ge, Si, or V) indicates that its main component has a crystal structure in the same space group as Zn2P2O7, and it can be seen that A can take on various elements.

[0068] Figure 11 shows the Zn 2-x Mg x 12 is a diagram showing the thermal expansion characteristics of P2O7 (x = 0, 0.2, 0.4, 0.6, 0.8, 2). 1.64 Mg 0.3 Al 0.06 13 is a diagram showing the thermal expansion characteristics of Zn2P 2-y A y These figures show the thermal expansion characteristics of O7 (x=0.1, A is either Sn or Si). In both Figures 11 to 13, the vertical axis represents the change in length ΔL / L, with the length L at 100 K as the reference. The change in length is calculated using the linear expansion coefficient α calculated using a laser thermal dilatometer (LIX-2, manufactured by ULVAC, Inc.) (measurement temperature range: 100 to 500 K).

[0069] As shown in Figure 11, Zn 2-x Mg x When the value of x, the ratio of Mg substituting Zn in P2O7, is 0.2, 0.4, 0.6, or 0.8, negative thermal expansion is observed in the temperature range of 200 to 400 K. In particular, when the value of x is 0.6 or 0.8, large negative thermal expansion is observed in a wide temperature range, including room temperature.

[0070] In this embodiment, Mg is used as an example of a substitution element for Zn, but it is presumed that negative thermal expansion will also be exhibited when a portion of Zn is substituted with elements such as Al, Si, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ga, Ge, Zr, Nb, Mo, Ag, In, Sn, Sb, La, Ta, W, and Bi. For example, Zn in which a portion of Zn is substituted with Mg and Al 1.64 Mg 0.3 Al 0.06 P2O7 also exhibits negative thermal expansion, as shown in Figure 12.

[0071] As shown in Figure 13, Zn2P 2-y A y O7 (A is either Sn or Si) exhibits negative thermal expansion around 400K.

[0072] As described above, the negative thermal expansion material according to the present embodiment is a material represented by the general formula (2) Zn 2-x T x P 2-y A y The oxide sintered body is represented by the formula (2) as follows: O7 (T contains at least one element selected from Mg, Al, Si, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ga, Ge, Zr, Nb, Mo, Ag, In, Sn, Sb, La, Ta, W, and Bi, and A contains at least one element selected from Al, Si, V, Ge, and Sn, and satisfies 0≦x<2 and 0≦y≦2, excluding (x, y)=(0,0) and (0,2)). This makes it possible to provide a new, inexpensive negative thermal expansion material that has a large negative thermal expansion near room temperature. Furthermore, x in the general formula (2) may be 0.1 to 1.6. More preferably, y is 0.5 to 1.0. This makes it possible to provide a more inexpensive negative thermal expansion material.

[0073] [Fifth embodiment] In the same manner as in the second embodiment, Zn was also extracted by spray drying. 2-x T x A polycrystalline sintered body (ceramic) sample of P2O7 (T is Mg) was prepared. That is, the method for producing a negative thermal expansion material according to this embodiment is to prepare a polycrystalline sintered body (ceramic) sample of P2O7 (T is Mg). 2-x T x P 2-yA y The method includes preparing an aqueous solution containing an organic acid and a raw material for a compound represented by the formula: O7 (T includes at least one element selected from Mg, Al, Si, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ga, Ge, Zr, Nb, Mo, Ag, In, Sn, Sb, La, Ta, W, and Bi, and A includes at least one element selected from Al, Si, V, Ge, and Sn, and satisfies 0≦x<2 and 0≦y≦2, excluding (x,y)=(0,0) and (0,2)). This manufacturing method allows a negative thermal expansion material with a large absolute negative linear expansion coefficient to be manufactured relatively inexpensively by utilizing the aqueous solution form, which is easy to handle at low temperatures.

[0074] [Sixth embodiment] Ti by solid-state reaction 2-x M x We prepared polycrystalline sintered (ceramic) samples of TiO3 (where M is Al, Mn, Cr, V, Si, Ta, Nb, or Zr). Specifically, powders of TiO2, Ti, and M, weighed in stoichiometric ratios, were mixed in an agate mortar and pestle in air or in a glove box for 1 hour. Next, the mixed powder was pressed into a pellet and placed in a quartz tube in a vacuum sealed tube (<10 -3 The samples were heated at a temperature of 1223 to 1323 K for 20 to 50 hours. If the sinterability was insufficient, the samples were crushed into powder using an agate mortar and pestle in the air or in a glove box, and sintered using a spark plasma sintering (SPS) furnace (manufactured by SPS Syntex Co., Ltd.). Sintering was carried out in a vacuum (<10 -1 The reaction was carried out using a graphite die at 1173 K for 2 to 5 minutes under 1000 kJ / cm2 (Pa). The starting materials are not limited to those mentioned above, and Cr2O3, etc. can also be used.

[0075] The crystal structure of each sample was then evaluated using powder X-ray diffraction (XRD) (measurement temperature 295 K, CuKα characteristic X-ray: wavelength λ = 0.15418 nm) and synchrotron radiation temperature-dependent X-ray diffraction (wavelength λ = 0.06521 nm). 2-x M xFIG. 1 shows an X-ray diffraction pattern of O3 (M is any of Mn, Cr, V, Si, Ta, Nb, and Zr).

[0076] As shown in Figure 14, Ti 2-x M x O3 (where M is any of Mn, Cr, V, Si, Ta, Nb, and Zr) indicates that its main component has a crystal structure in the same space group as Ti2O3, indicating that M can be a variety of elements.

[0077] Figure 15 shows the Ti 2-x M x Fig. 16 shows the thermal expansion characteristics of TiO3 (M is either Cr or Nb). 2-x M x These figures show the thermal expansion characteristics of O3 (M is either Si or Al). In both Figures 15 and 16, the vertical axis represents the change in length ΔL / L, with the length L at 300 K as the reference. The change in length was calculated using the linear expansion coefficient α calculated using a laser thermal dilatometer (LIX-2, manufactured by ULVAC, Inc.) (measurement temperature range: 100 to 700 K).

[0078] As shown in Figs. 15 and 16, Ti 2-x M x O3 (M is any of Cr, Nb, Si and Al) exhibits negative thermal expansion in the temperature range of 400 to 600K.

[0079] In this embodiment, Cr, Nb, Si, and Al are used as examples of elements that substitute for Ti. However, it is presumed that negative thermal expansion will also be exhibited if part of the Ti is replaced with an element such as Mg, V, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, Mo, Ag, In, Sn, Sb, La, Ta, W, or Bi.

[0080] As described above, the negative thermal expansion material according to the present embodiment is a material represented by the general formula (3) Ti 2-x M xIt is an oxide sintered body represented by O3 (M contains at least one element selected from Mg, Al, Si, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ag, In, Sn, Sb, La, Ta, W, Bi, and satisfies 0 ≦ x < 2). Thereby, an inexpensive new negative thermal expansion material can be provided.

[0081] [Seventh Embodiment] General formula (1) Cu 2-x R x V 2-y P y The color of the negative thermal expansion material represented by O7 (R contains at least one element selected from Mg, Al, Si, Ti, Cr, Mn, Fe, Co, Ni, Zn, Sn, and satisfies 0 ≦ x ≦ 2, 0 < y < 2) will be described. [[ID=]15]

[0082] FIG. 17 is a diagram showing the color of Cu 1.8 Zn 0.2 V 2-y P y O7 which is a negative thermal expansion material. In the general formula (1), when R = Zn and x = 0.2, the negative thermal expansion material Cu 1.8 Zn 0.2 V 2-y P y O7 can change its color such as reddish brown (y = 0), orange (y = 0.6), yellow (y = 1.0), yellowish green (y = 1.5), light green (y = 1.8), light blue (y = 2.0) by changing y from 0 to 2.0. Since the solid solution ratio (y) of vanadium and phosphorus can be arbitrarily changed, a negative thermal expansion material of any color between the examples shown in this figure can be manufactured. Thus, the negative thermal expansion material represented by the general formula (1) Cu 2-x R x V 2-y P y O7 (R contains at least one element selected from Mg, Al, Si, Ti, Cr, Mn, Fe, Co, Ni, Zn, Sn, and satisfies 0 ≦ x ≦ 2, 0 < y < 2) can change its color by changing y, and thus can be used for thermal expansion control of paints and the like.

[0083] The above has been described based on the embodiments. It is understood by those skilled in the art that these embodiments are illustrative, and various modifications are possible for each of the constituent elements and combinations of each processing process, and such modifications are also within the scope of the present disclosure.

[0084] Generalizing the invention embodied by the above embodiments leads to the following technical ideas.

[0085] (First Aspect) A negative thermal expansion material containing an oxide represented by the general formula (1) Cu 2-x R x V 2-y P y O7 (R contains at least one element selected from Mg, Al, Si, Ti, Cr, Mn, Fe, Co, Ni, Zn, Sn, and satisfies 0 ≦ x ≦ 2, 0 < y < 2).)

[0086] (Second Aspect) The negative thermal expansion material according to the first aspect, wherein the oxide has a linear expansion coefficient of -10 ppm / K or less at 400 K.

[0087] (Third Aspect) The negative thermal expansion material according to the first or second aspect, wherein x in the general formula (1) is 0.1 to 1.6.

[0088] (Fourth Aspect) The negative thermal expansion material according to any one of the first to third aspects, wherein y in the general formula (1) is 0.1 to 1.8.

[0089] (Fifth Aspect) The negative thermal expansion material according to any one of the first to fourth aspects, wherein the oxide contains a monoclinic β phase.

[0090] (Sixth Aspect) The negative thermal expansion material according to any one of the first to fourth aspects, containing at least one of an oxide having a monoclinic crystal system and an oxide having an orthorhombic crystal system.

[0091] (Seventh Aspect) The negative thermal expansion material according to the sixth aspect, wherein the oxide has a crystal structure selected from the space groups C2 / c, C2 / m, Fdd2.

[0092] (8th Aspect) A negative thermal expansion material according to any one of the 1st to 7th aspects, characterized by exhibiting negative thermal expansion in a temperature range of 100 to 500K.

[0093] (9th Aspect) A negative thermal expansion material according to any one of the 1st to 8th aspects, characterized in that the linear expansion coefficient is -10 ppm / K or less in a temperature range of 100 to 500K.

[0094] (10th Aspect) A negative thermal expansion material containing an oxide represented by the general formula (2) Zn 2-x T x P 2-y A y O7 (T contains at least one element selected from Mg, Al, Si, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ga, Ge, Zr, Nb, Mo, Ag, In, Sn, Sb, La, Ta, W, Bi, and A contains at least one element selected from Al, Si, V, Ge, Sn, satisfying 0≦x<2 and 0≦y≦2. However, (x,y)=(0,0) and (0,2) are excluded.)

[0095] (11th Aspect) The negative thermal expansion material according to the 10th aspect, characterized in that x in the general formula (2) satisfies 0<x≦1.6.

[0096] (12th Aspect) The negative thermal expansion material according to the 10th or 11th aspect, characterized in that y in the general formula (2) is 0.1 to 1.6.

[0097] (13th Aspect) A negative thermal expansion material according to any one of the 10th to 12th aspects, characterized by exhibiting negative thermal expansion in a temperature range of 200 to 400K.

[0098] (14th Aspect) A negative thermal expansion material according to any one of the 10th to 13th aspects, characterized in that the linear expansion coefficient is -10 ppm / K or less in a temperature range of 200 to 400K.

[0099] (15th Aspect) The general formula (3) Ti 2-x M xA negative thermal expansion material containing an oxide represented by O3 (M contains at least one element selected from Mg, Al, Si, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ag, In, Sn, Sb, La, Ta, W, Bi, and satisfies 0 ≦ x < 2).

[0100] (The 16th aspect) The negative thermal expansion material according to the 15th aspect, wherein x in the general formula (3) is 0.1 to 1.6.

[0101] (The 17th aspect) The negative thermal expansion material according to the 15th or 16th aspect, which exhibits negative thermal expansion in the temperature range of 100 to 500K.

[0102] (The 18th aspect) The negative thermal expansion material according to any one of the 15th to 17th aspects, wherein the linear expansion coefficient is -10 ppm / K or less in the temperature range of 100 to 500K.

[0103] (The 19th aspect) A composite material including the negative thermal expansion material according to any one of the 1st to 18th aspects and a positive thermal expansion material having a positive linear expansion coefficient.

[0104] (The 20th aspect) General formula (1) Cu 2-x R x V 2-y P y (The 21st aspect) A method for producing a negative thermal expansion material, including the step of preparing an aqueous solution containing a raw material of a compound represented by O7 (R contains at least one element selected from Mg, Al, Si, Ti, Cr, Mn, Fe, Co, Ni, Zn, Sn, and satisfies 0 ≦ x ≦ 2, 0 < y < 2) and an organic acid.

[0105] (The 21st aspect) General formula (2) Zn 2-x T x P 2-y A yA method for manufacturing a negative thermal expansion material, comprising the step of preparing an aqueous solution containing a raw material of a compound represented by O7 (where T contains at least one element selected from Mg, Al, Si, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ga, Ge, Zr, Nb, Mo, Ag, In, Sn, Sb, La, Ta, W, Bi, A contains at least one element selected from Al, Si, V, Ge, Sn, and 0 ≦ x < 2, 0 ≦ y ≦ 2 are satisfied. However, (x, y) = (0, 0) and (0, 2) are excluded.) and an organic acid.

[0106] (22nd Aspect) A component including a negative thermal expansion material according to any one of the 1st to 18th aspects, or a composite material including a negative thermal expansion material according to any one of the 1st to 18th aspects and a positive thermal expansion material having a positive linear expansion coefficient.

[0107] (23rd Aspect) A negative thermal expansion material according to any one of the 1st to 9th aspects, the color of which changes by changing y in the general formula (1).

Industrial Applicability

[0108] Cu in the general formula (1) of the present disclosure 2-x R x V 2-y P y O7 (R contains at least one element selected from Mg, Al, Si, Ti, Cr, Mn, Fe, Co, Ni, Zn, Sn, and 0 ≦ x ≦ 2, 0 < y < 2 are satisfied.), Zn in the general formula (2) 2-x T x P 2-y A y O7 (T contains at least one element selected from Mg, Al, Si, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ga, Ge, Zr, Nb, Mo, Ag, In, Sn, Sb, La, Ta, W, Bi, A contains at least one element selected from Al, Si, V, Ge, Sn, and 0 ≦ x < 2, 0 ≦ y ≦ 2 are satisfied. However, (x, y) = (0, 0) and (0, 2) are excluded.), and Ti in the general formula (3) 2-x M xOxides represented by any of the formulas O3 (M is at least one element selected from Mg, Al, Si, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ag, In, Sn, Sb, La, Ta, W, and Bi, and 0≦x<2 is satisfied) can be used as thermal expansion inhibitors that offset and suppress the thermal expansion of ordinary materials. Furthermore, it is possible to create zero thermal expansion materials that do not expand positively or negatively within a specific temperature range.

[0109] Specifically, it can be used in precision optical and mechanical components that are sensitive to changes in shape and dimensions due to temperature, process equipment and tools, temperature compensation materials for fiber gratings, printed circuit boards, encapsulants for electronic components, thermal switches, refrigerator parts, satellite parts, etc. In particular, by creating a composite material in which a negative thermal expansion material is dispersed in a matrix phase of a resin with a large positive thermal expansion coefficient, it becomes possible to suppress and control the thermal expansion of the resin material as well, enabling use in a variety of applications.

Claims

1. General formula (1) Cu ２－ｘ R ｘ V ２－ｙ P ｙ O ７ (R is at least one element selected from Mg, Al, Si, Ti, Cr, Mn, Fe, Co, Ni, Zn, and Sn, and satisfies 0<x<2 and 0<y<2), and a negative thermal expansion material that exhibits negative thermal expansion in a temperature range of 100 to 500 K; a positive thermal expansion material having a positive linear expansion coefficient; Composite material including:

2. The linear expansion coefficient of the negative thermal expansion material at 400K is −10 ppm / K or less. The composite material of claim 1.

3. In the general formula (1), x is 0.1 to 1.

6.

3. The composite material according to claim 1 or 2.

4. In the general formula (1), y is 0.1 to 1.

8. A composite material according to any one of claims 1 to 3.

5. The oxide contains a monoclinic β phase A composite material according to any one of claims 1 to 4.

6. The negative thermal expansion material contains an oxide having a monoclinic crystal system. A composite material according to any one of claims 1 to 5.

7. The oxide has a crystal structure with a space group of C2 / c. The composite material of claim 6.

8. The negative thermal expansion material has a linear expansion coefficient of −10 ppm / K or less in the temperature range of 100 to 500 K. A composite material according to any one of claims 1 to 7.

9. A component comprising the composite material of any one of claims 1 to 8.

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