JP2023050225A - Sintered body and manufacturing method thereof - Google Patents

Abstract

To provide at least one of a sintered body having zirconia as a matrix and exhibiting a color tone visually recognized as a bright yellow not tinged with green or orange and a manufacturing method thereof.SOLUTION: A sintered body according to the present invention contains vanadium and terbium and has zirconia as a matrix, with a mass ratio of vanadium to terbium being 0.12 or more.SELECTED DRAWING: None

Description

The present disclosure relates to a sintered body containing vanadium and terbium and having yellow zirconia as a matrix (base material). In particular, the present invention relates to a sintered body having a yellow-colored zirconia matrix and having strength suitable for an exterior member such as a decorative member.

A sintered body having a zirconia matrix exhibits arbitrary coloration by containing a lanthanoid-based rare earth element or a transition metal element as a coloring element. A zirconia sintered body with a zirconia matrix that contains a coloring element enhances designability in addition to the high-class feeling and mechanical strength inherent in zirconia, and exhibits a yellowish color tone. For example, Patent Documents 1 to 4).

For example, as a sintered body having a yellow zirconia matrix, a zirconia matrix containing a Zr—Si—V composite oxide, a Zr—Si—Pr composite oxide, or holmium oxide as a coloring agent. has been reported (Patent Document 1). The sintered body disclosed in Patent Document 1 was greenish yellow and pale yellow.

Moreover, it is disclosed that a sintered body having a matrix of zirconia containing an iron compound exhibits a yellow color (Patent Documents 2 and 3). The sintered bodies disclosed in Patent Documents 2 and 3 were orange-yellow.

Furthermore, a sintered body containing praseodymium oxide and having a matrix of translucent cubic zirconia has been reported (Patent Document 4). The sintered body disclosed in Patent Document 4 was greenish yellow.

All of the sintered bodies with zirconia as a matrix that have been reported in patent documents exhibit a yellowish color tone. However, these color tones were green or orange-tinged yellow, and were color tones in which colors other than yellow and yellow were mixed.

JP 2011-020873 A JP 2013-049616 A JP 2008-050246 A JP 2012-096977 A

An object of the present disclosure is to provide at least one of a sintered body having a zirconia matrix and exhibiting a bright yellow color that is not tinged with green or orange, and a method for producing the same.

In the present disclosure, in a sintered body having a matrix of zirconia exhibiting yellow color, suppression of coloration other than yellow was examined. As a result, it was found that a sintered body exhibiting a color tone visually recognized as bright yellow without being tinged with green or orange can be obtained by containing a specific element among countless coloring elements in a specific ratio.

That is, the present invention is as set forth in the claims, and the gist of the present disclosure is as follows.
[1] A sintered body containing vanadium and terbium and having zirconia as a matrix, wherein the mass ratio of vanadium to terbium is 0.12 or more.
[2] The sintered body according to [1] above, wherein the vanadium content is 0.010% by mass or more and 0.20% by mass or less with respect to the mass of the sintered body.
[3] The sintered body according to [1] or [2] above, wherein the terbium content is 0.050% by mass or more and 0.60% by mass or less with respect to the mass of the sintered body.
[4] The sintered body according to any one of [1] to [3] above, containing aluminum.
[5] The sintered body according to [4] above, wherein the aluminum content is 0.10% by mass or more and 15% by mass or less with respect to the mass of the sintered body.
[6] The sintered body according to any one of [1] to [5] above, wherein the zirconia is zirconia containing a stabilizing element.
[7] The sintered body according to [6] above, wherein the stabilizing element is one or more selected from the group consisting of yttrium, magnesium, and calcium.
[8] The sintered body according to [6] or [7] above, wherein the content of the zirconia stabilizing element is 1.0 mol % or more and 6.0 mol % or less.
[9] The sintered body according to any one of [1] to [8] above, wherein lightness L ^* , hue a ^* , and hue b ^* in the L ^* a ^* b ^* color system satisfy the following.
Lightness L ^* : 80≤L ^* ≤100
Hue a ^* : -3≤a ^* ≤4, and
Hue b ^* : 30<b ^* ≤50
[10] The sintered body according to any one of [1] to [9] above, wherein the chroma C ^* in the L ^* a ^* b ^* color system and the hue angle h satisfy the following.
Chroma C ^* : 28≤C ^* ≤44, and hue angle h: 83°<h≤96°
[11] The sintered body according to any one of [1] to [10] above, which has an average crystal grain size of 0.2 μm or more and 2 μm or less.
[12] The sintered body according to any one of [1] to [11] above, which has a three-point bending strength of 900 MPa or more.
[13] Contains 0.010% by mass or more and 0.20% by mass or less of vanadium, 0.050% by mass or more and 0.60% by mass or less of terbium, and the mass ratio of vanadium to terbium is 0.12% or more A method for producing a sintered body according to any one of the above [1] to [12], wherein a composition having zirconia as a matrix is used.
[14] The method for producing a sintered body according to [13] above, wherein the composition contains 0.10% by mass or more and 15% by mass or less of aluminum.
[15] Contains 0.010% by mass or more and 0.20% by mass or less of vanadium, 0.050% by mass or more and 0.60% by mass or less of terbium, and the mass ratio of vanadium to terbium is 0.12% or more , a composition with a zirconia matrix.
[16] The composition according to [15] above, containing 0.10% by mass or more and 15% by mass or less of aluminum.
[17] A member containing the sintered body according to any one of [1] to [12] above.

According to the present disclosure, it is possible to provide at least one of a sintered body having a zirconia matrix and exhibiting a bright yellow color tone that is not tinged with green or orange, and a method for producing the same.

A sintered body of the present disclosure will be described by showing an example of an embodiment. The terms used in this embodiment are as follows.

A “sintered body” is a composition having a certain shape composed of crystal grains, and is a composition in a state of being heat-treated at a temperature equal to or higher than the sintering temperature. "Zirconia sintered body" means a sintered body essentially made of zirconia, or a sintered body with zirconia as a matrix (base material), and "colored zirconia sintered body" contains a coloring element. It is a zirconia sintered body.

The “stabilizing element” is an element that has a function of stabilizing the crystal phase of zirconia by forming a solid solution in zirconia.

A “coloring element” is an element having a function of coloring zirconia.

A "composition" is a substance having a certain composition, and examples thereof include one or more selected from the group consisting of powder, granules, compacts, calcined bodies and sintered bodies. A "zirconia composition" is a composition consisting essentially of zirconia, or a composition having zirconia as a matrix (base material).

A “powder” is an aggregate of a plurality of powder particles and is a fluid composition. "Zirconia powder" means a powder consisting essentially of zirconia, or a powder having zirconia as a matrix (base material). In addition, the “powder composition” is a composition composed of a plurality of powders, and in particular, a composition in which a compound that is a precursor of a coloring element and zirconia powder are uniformly mixed, and has fluidity. composition.

A "molded body" is a composition having a certain shape composed of powder particles agglomerated by physical force, and in particular, a state in which heat treatment is not performed after imparting the shape (for example, after molding). is the composition of A "zirconia molded body" is a molded body essentially composed of zirconia, or a molded body having zirconia as a matrix (base material). Compact is also used interchangeably with "green compact".

"Color tone" refers to a spectrophotometer equipped with an illumination and light receiving optical system that conforms to JIS Z 8722 geometric condition c for a measurement sample with a thickness of 1 mm and a surface roughness (Ra) ≤ 0.02 µm (e.g., CM -700d, manufactured by Konica Minolta), the lightness L in the CIE L ^* a ^* b ^* color system (CIE 1976 (L ^* a ^* b ^* ) color space) measured by black background measurement under the following conditions ^* , color tone represented by chromaticities a ^* and b ^* .
Light source: D65 light source Viewing angle: 10°
Measurement diameter: 8mm
Measurement method: SCI
Measurement background: Black board

"Saturation" is one of the indices indicating vividness of color tone, and is a value obtained by the following formula from chromaticities a ^* and b ^* .
C ^* = (a ^*2 +b ^*2 ) ^0.5

where C ^* is the chroma and a ^* and b ^* are the chromaticities a ^* and b ^* respectively.

The “hue angle” is one of the indices indicating hue, and is a value obtained by the following formula from chromaticity a ^* and b ^* , excluding lightness L ^* .
h=tan ⁻¹ (b ^* /a ^* )

where h is the hue angle and a ^* and b ^* are the chromaticities a ^* and b ^* , respectively. When the hue angle is 0°, red coloration is exhibited, when the hue angle is 90°, yellow coloration is exhibited, when the hue angle is 180°, green coloration is exhibited, and when the hue angle is 270°, blue coloration is exhibited. show.

"Three-point bending strength" is a value determined by a three-point bending test according to JIS R1601. The three-point bending strength is measured using a columnar sample with a distance between fulcrums of 30 mm, a width of 4 mm and a thickness of 3 mm, and the average value of 10 measurements is taken as the three-point bending strength.

"Average crystal grain size" is determined by a planimetric method using SEM observation diagrams. That is, a circle with a known area is drawn on the SEM observation diagram, the number of crystal grains in the circle (Nc) and the number of crystal grains on the circumference of the circle (Ni) are measured, and the total number of crystal grains (Nc + Ni) is 125±25, the average grain size can be obtained using the following formula.
Average grain size = (Nc + (1/2) x Ni)/(A/M ² )

In the above formula, Nc is the number of crystal grains in the circle, Ni is the number of crystal grains on the circumference of the circle, A is the area of the circle, and M is the magnification of scanning electron microscope observation (for example, 5,000 to 10 , 000 times). When the number of crystal grains (Nc+Ni) in one SEM observation diagram is less than 100, (Nc+Ni) may be set to 125±25 using a plurality of SEM observation diagrams.

The sintered body to be subjected to SEM observation may be a sintered body having a surface roughness of Ra≦0.02 μm and subjected to thermal etching (for example, in air at 1300° C. to 1500° C.).

"Measured density" is the ratio of the volume measured by the Archimedes method to the mass measured by gravimetry (g/cm ³ ).

The "BET specific surface area" may be measured according to JIS R 1626 by the BET multipoint method (5 points) using nitrogen as the adsorption gas. The following conditions can be exemplified as specific measurement conditions for the BET specific surface area.
Adsorption medium: _N2
Adsorption temperature: -196°C
Pretreatment conditions: Air atmosphere, degassing treatment at 250°C for 1 hour or longer

The BET specific surface area can be measured using a common device (eg Tristar II 3020, manufactured by Shimadzu Corporation).

"Average particle size" is D50 in the volume particle size distribution of the powder or powder composition measured by a wet method, and is measured using a common device (e.g., MT3300EXII, manufactured by Microtrac Bell). be able to. As a measurement sample, a slurry obtained by dispersing powder, from which slow aggregation has been removed by a dispersion treatment such as ultrasonic treatment, in pure water, may be used. The measurement of the volume particle size distribution by the wet method is preferably carried out with the slurry having a pH of 3.0 to 6.0.

"Atmospheric pressure sintering" is a method of sintering by heating an object to be sintered (a molded body, a calcined body, etc.) during sintering without applying an external force. The "sintering temperature" is the highest temperature reached during sintering, and the "sintering time" is the time during which the sintering temperature is maintained.

This embodiment is a sintered body containing vanadium and terbium and having zirconia as a matrix, wherein the mass ratio of vanadium to terbium is 0.12 or more.

The sintered body of the present embodiment is a sintered body having a matrix of zirconia, preferably zirconia containing a stabilizing element, and is a sintered body mainly composed of crystal grains of zirconia.

The stabilizing element is preferably one or more selected from the group consisting of yttrium, magnesium and calcium, more preferably yttrium. Yttrium, magnesium, and calcium function as stabilizing elements with little effect on the color tone of zirconia.

The content of the stabilizing element (hereinafter, the content of the stabilizing element is also referred to as the "stabilizing element amount", and when the stabilizing element is yttrium or the like, is also referred to as the "yttrium amount" or the like). It is preferably 0 mol % or more, or 1.5 mol % or more, and 6.0 mol % or less, or 5.0 mol % or less.

When the stabilizing element is yttrium, the amount of yttrium is 2.0 mol% or more, 2.3 mol% or more, or 2.6 mol% or more, and 6.0 mol% or less, 5.0 mol% or less, or 3.4 mol%. % or less.

The stabilizing element amount [mol %] is the molar ratio of the stabilizing element converted to oxide with respect to the total of zirconium converted to ZrO ₂ and the stabilizing element converted to oxide in the sintered body. For example, when _the stabilizing _element is yttrium, _the yttrium amount [mol%] is _the molar ratio [ _mol %] and is obtained from {Y ₂ O ₃ [mol]/(ZrO ₂ +Y ₂ O ₃ ) [mol]}×100. Yttrium is Y ₂ O ₃ , magnesium is MgO, and calcium is CaO in terms of oxide conversion of the stabilizing elements.

The sintered body of the present embodiment contains vanadium and terbium, and the mass ratio of vanadium to terbium (hereinafter also referred to as "V/Tb ratio") is 0.12 or more. The mass ratio of vanadium to terbium is _the mass of vanadium converted to V ₂ O ₅ with respect to the mass of terbium converted to Tb _{4 O 7 , and is obtained from V 2 O 5} [g]/Tb ₄ O ₇ [g].

The V/Tb ratio is 0.12 or more, more preferably 0.15 or more, and preferably 0.80 or less, 0.70 or less, or 0.60 or less. When the V/Tb ratio satisfies this range, it is possible to obtain a sintered body exhibiting a bright yellow color that is not tinged with green or orange. If the V/Tb ratio is less than 0.12, the resulting sintered body tends to have an orange-tinged color tone. On the other hand, if the V/Tb ratio is 0.80 or less, the resulting sintered body exhibits a color tone visually recognized as yellow.

The sintered body of the present embodiment has a V ₂ O ₅ conversion of 0.010 mass % or more or 0.020 mass % or more and 0.20 mass % or less or 0.20 mass % or less with respect to the mass of the sintered body. It preferably contains 15% by mass or less of vanadium.

In the present embodiment, the mass of the sintered body is the total mass [g] of the metal elements contained in the sintered body converted to oxides. For example, zirconia containing vanadium, terbium and aluminum and containing yttrium The mass of the sintered body in _the matrix sintered body is _the mass of zirconium converted to _ZrO2 [g], the mass of yttrium converted to _Y2O3 [g], and the mass of vanadium converted to _V2O5 [g]. , the mass [g] of terbium converted to Tb ₄ O ₇ and the mass [g] of aluminum converted to Al ₂ O ₃ [g].

The sintered body of the present embodiment contains 0.050 mass % or more or 0.070 mass % or more in terms of Tb ₄ O ₇ and 0.60 mass % or less or 0.070 mass % or less with respect to the mass of the sintered body. It preferably contains 50% by mass or less of terbium.

The sintered body of the present embodiment is 0.10% by mass or more or 0.20% by mass or more in terms of Al ₂ O ₃ with respect to the mass of the sintered body, and 15% by mass or less and 12% by mass or less Alternatively, it preferably contains 10% by mass or less of aluminum. Since the content of aluminum is within the above range, the sintered body contains crystal grains of alumina.

Each element of vanadium, terbium and aluminum in the sintered body of the present embodiment functions as a coloring element. These elements may exist in any state in the sintered body, but oxides containing one or more selected from the group consisting of vanadium, terbium and aluminum can be mentioned. Examples of vanadium oxides include vanadium oxide (V ₂ O ₅ ), terbium oxides of terbium oxide (Tb ₄ O ₇ ), and aluminum oxides of alumina (Al ₂ O ₃ ). Furthermore, vanadium, terbium and aluminum may each be in a solid solution state in zirconia containing at least a part of the stabilizing element.

The sintered body of the present embodiment comprises zirconia crystal particles containing a stabilizing element, alumina (Al ₂ O ₃ ) crystal particles, and oxide crystal particles containing at least one of vanadium and terbium. preferably configured.

The sintered body of the present embodiment may contain impurities as long as they do not affect the color tone, and examples of impurities include hafnia (HfO ₂ ). The content of hafnia as an unavoidable impurity varies greatly depending on the raw material ore and the manufacturing method, but for example, it is 2.0% by mass or less. In the present embodiment, the calculation of values related to the composition, such as the calculation of the mass of the sintered body, may be calculated by regarding hafnia as zirconia (ZrO ₂ ).

However, it is preferable not to contain impurities that affect the color tone of the sintered body. Examples of impurities that affect the color tone include at least one selected from the group consisting of tin, zinc, lead, chromium and cadmium. The content is respectively 500 mass ppm or less, preferably 100 mass ppm or less.

The average crystal grain size of the sintered body of the present embodiment is 0.2 μm or more or 0.5 μm or more and is 2 μm or less or 1 μm or less. When the average crystal grain size is 2 μm or less, the sintered body has sufficient strength to be used as a member such as an ornament.

It is preferable that the zirconia crystal structure of the sintered body of the present embodiment includes a tetragonal crystal, and the main phase of the crystal structure is a tetragonal crystal. Moreover, the zirconia crystal structure of the sintered body of the present embodiment may be a mixed crystal of tetragonal and cubic. A tetragonal crystal is an optically anisotropic crystal structure. The inclusion of tetragonal crystals makes it easier for light to be reflected, so that the color tone of the sintered body lacks transparency. Furthermore, since the main phase of the zirconia crystal structure is tetragonal, the sintered body of the present embodiment has high strength.

The measured density of the sintered body of the present embodiment is 5.70 g/cm ³ or more or 6.00 g/cm ³ or more, and is 6.10 g/cm ³ or less or 6.07 g/cm ³ or less. I can give an example.

The sintered body of the present embodiment has a three-point bending strength of 800 MPa or more, 900 MPa or more, or 1000 MPa or more, and is 1600 MPa or less, 1500 MPa or less, or 1400 MPa or less. When the three-point bending strength is within the above range, it has a strength that can be processed appropriately, and also has a strength that can be used for main applications that require aesthetics, such as exterior members and decorative members.

The color tone of the sintered body of the present embodiment preferably satisfies the following as lightness L ^* , chromaticity a ^* , and chromaticity b ^* in the L ^* a ^* b ^* color system.
Lightness L ^* : 80≦L ^* ≦100, preferably 83≦L ^* ≦95
Chromaticity a ^* : -3≤a ^* ≤4, preferably -2≤a ^* ≤3, and
Chromaticity b ^* : 30<b ^* ≤50, preferably 35≤b ^* ≤45
The sintered body of the present embodiment does not satisfy any of the lightness L ^* , the chromaticity a ^*, or the chromaticity b ^* , but the lightness L ^* , the chromaticity a ^* , and the chromaticity b ^* . As a result, it exhibits a bright yellow color tone that is not tinged with green or orange.

The chroma (C ^* ) of the sintered body of the present embodiment can be exemplified to be 28 or more, 29 or more, or 30 or more, and 44 or less, 43 or less, or 42 or less.

The hue angle (h) of the sintered body of the present embodiment is preferably more than 83°, 84° or more, or 85° or more and 96° or less, less than 96°, or 95° or less. When the hue angle satisfies this range, a color tone visually recognized as yellow without being tinged with green or orange is exhibited.

A preferred sintered body of the present embodiment has a chroma (C ^* ) of 28 or more, 29 or more, or 30 or more and 44 or less, 43 or less, or 42 or less, and a hue angle (h) of more than 83°. , 84° or more, or 85° or more, and 96° or less, less than 96°, or 95° or less, with a zirconia matrix.

The sintered body of the present embodiment can be applied not only to various decorative members such as jewelry, watch parts, and exterior parts of portable electronic devices, but also to structural materials, optical materials, dental materials, etc. Conventional zirconia sintered bodies It can also be applied to the use of

Next, a method for manufacturing a sintered body according to this embodiment will be described.

The sintered body of the present embodiment contains 0.010% by mass or more and 0.20% by mass or less of vanadium and 0.050% by mass or more and 0.60% by mass or less of terbium, and the mass ratio of vanadium to terbium is A method for producing a sintered body, characterized by using a composition having a zirconia matrix of 0.12 or more.

The composition is preferably one or more selected from the group consisting of a powder composition, a molded body, and a calcined body, preferably at least one of a powder composition and a molded body, and preferably a powder composition. More preferred.

Examples of the powder composition include a composition in which powders containing a vanadium compound, a terbium compound and zirconia as a matrix are uniformly mixed.

The vanadium compound may be a compound or salt containing vanadium (V), and is one or more selected from the group consisting of vanadium oxide (V ₂ O ₅ ), ammonium vanadate, vanadium hydroxide, vanadium nitrate, and vanadium chloride. is preferred, and vanadium oxide is more preferred.

The terbium compound may be a compound or salt containing terbium (Tb), and be one or more selected from the group consisting of terbium oxide (Tb ₄ O ₇ ), terbium acetate, terbium hydroxide, terbium nitrate, and terbium chloride. is preferred, and terbium oxide is more preferred.

In the present embodiment, the mass of the composition is the total mass [g] of the metal elements contained in the composition in terms of oxides, for example, zirconia containing vanadium, terbium and aluminum and containing yttrium as a matrix The mass of the composition in the sintered body is the mass of zirconium converted to _ZrO2 [g], _the mass of yttrium converted to _Y2O3 [g] _, the mass of vanadium converted to _V2O5 [g], _Tb4 It is the _total mass [g] of the mass [g] of terbium converted to _O7 and the mass [g] of aluminum converted to _Al2O3 .

The content of the vanadium compound is 0.010% by mass or more or 0.020% by mass or more in terms of vanadium oxide (V ₂ O ₅ ) with respect to the mass of the composition, and 0.20% by mass or less or It may be 0.15% by mass or less.

The content of the terbium compound is 0.050% by mass or more or 0.070% by mass or more in terms of terbium oxide (Tb ₄ O ₇ ) with respect to the mass of the composition, and 0.60% by mass or less or It may be 0.50% by mass or less.

The mass ratio of vanadium to terbium in the composition is the mass of vanadium converted to V ₂ O ₅ with respect to the mass of terbium converted to Tb ₄ O ₇ . The mass ratio of vanadium to terbium in the composition is preferably 0.12 or more, or 0.15 or more, and 0.80 or less, 0.70 or less, or 0.60 or less.

The composition may contain an aluminum compound. The aluminum compound may be a compound or salt containing aluminum (Al), and is preferably alumina (Al ₂ O ₃ ) or an aluminum compound that is a precursor thereof, such as alumina, aluminum hydroxide, aluminum nitrate and aluminum chloride. It is preferably one or more selected from the group of, more preferably alumina, and even more preferably α-alumina.

The content of the aluminum compound is 0.10% by mass or more or 0.20% by mass or more in terms of aluminum oxide (Al ₂ O ₃ ) with respect to the mass of the composition, and is 15% by mass or less, 12% by mass. % or less or 10% by mass or less.

The powder having zirconia as a matrix is preferably zirconia containing a stabilizing element, more preferably zirconia containing yttrium as a stabilizing element, and zirconia containing yttrium obtained by heat-treating a zirconia sol containing yttria. is more preferable. In the present embodiment, the "zirconia sol" is a sol obtained by hydrating and cross-linking zirconium dioxide, and is preferably a zirconia sol obtained by at least one of a hydrothermal synthesis method and a hydrolysis method. The obtained zirconia sol is more preferable.

The yttrium-containing zirconia matrix powder is a mixed powder containing two or more selected from the group consisting of yttria powder, yttrium-containing zirconia matrix powder, and zirconia matrix powder containing no stabilizing element. There may be. Moreover, a mixed powder containing two or more powders having a matrix of zirconia containing yttrium with different yttrium concentrations may be used.

The stabilizing element content is preferably 1.0 mol % or more or 1.5 mol % or more and 6.0 mol % or less or 5.0 mol % or less.

When the stabilizing element is yttrium, the amount of yttrium is 2.0 mol% or more, 2.3 mol% or more, or 2.6 mol% or more, and 6.0 mol% or less, 5.0 mol% or less, or 3.4 mol%. % or less.

The composition is obtained, for example, by mixing powders containing an aluminum compound, a vanadium compound, a terbium compound and zirconia as a matrix by any method (hereinafter also referred to as a "mixing step"). Alternatively, it may be a composition in which powders having a zirconia matrix containing an aluminum compound, a vanadium compound, a terbium compound and an yttrium are mixed by any method, and a zirconia containing an aluminum compound, a vanadium compound and a terbium compound is used as the matrix. It may be a composition in which the powder and the zirconia matrix powder containing yttrium are mixed by any method, and the composition includes an aluminum compound, a zirconia matrix powder containing vanadium, and a zirconia matrix containing a terbium compound and yttrium. It may be a composition in which powders are mixed by any method, and may be any of aluminum compound, vanadium-containing zirconia matrix powder, terbium-containing zirconia matrix powder, and yttrium-containing zirconia matrix powder. may be a composition obtained by mixing an aluminum compound, a zirconia matrix powder containing vanadium and yttrium, and a terbium compound by any method, wherein the aluminum compound, A composition in which a vanadium compound and a zirconia matrix powder containing terbium and yttrium are mixed in any manner, and an aluminum compound, a zirconia matrix powder containing vanadium and yttrium, and A zirconia matrix powder containing terbium and yttrium may be mixed in any manner. A preferred manufacturing method includes mixing zirconia matrix powders containing aluminum compounds, vanadium compounds, terbium compounds and yttrium by any method.

In the production method of the present embodiment, the mixing method may be any method as long as the compound that is the precursor of the coloring element and the zirconia powder are uniformly mixed, and at least one of dry mixing and wet mixing can be exemplified. Preferably.

The BET specific surface area of the powder having zirconia as a matrix is preferably 5 m ² /g or more and 20 m ² /g or less. When the BET specific surface area satisfies this range in terms of the amount of stabilizing elements in the composition, the sintered body obtained from the composition tends to have sufficient strength to be used for main applications such as exterior members and decorative members.

The powder composition of the present embodiment preferably has an average particle size of 0.3 μm or more and 0.7 μm or less.

A compact is a state in which the powder composition is shaped. The compact may have any shape, taking into account shrinkage due to sintering. The shape of the molded body may be any shape according to the application, and can be exemplified by at least one selected from the group of disk-like, columnar, polyhedral, columnar, plate-like, spherical and substantially spherical.

A molded body is obtained by molding the composition by a known method, for example, at least one selected from the group of uniaxial pressing, cold isostatic pressing, slip casting and injection molding.

A sintered body is obtained by sintering the compact. Any sintering method may be used, and known sintering methods such as normal pressure sintering and hot pressing may be used. The sintering method is preferably pressureless sintering, more preferably pressureless sintering in an air atmosphere, because it is simple. Incidentally, the pressureless sintering in this embodiment is a method of sintering by simply heating the object to be sintered without applying an external force.

In the case of normal pressure sintering, the holding temperature is higher than 1300 ° C. and 1600 ° C. or lower, preferably 1400 ° C. or higher and 1550 ° C. or lower, and the holding time is 1 hour or more and 5 hours or less, preferably 2 hours or more and 4 hours or less. can be exemplified. It is preferable not to hold the temperature within the temperature range of 1300° C. or less during the temperature rise.

The manufacturing method of the present embodiment may include at least one of a polishing step of polishing the sintered body and a processing step of processing the shape. The polishing step polishes the surface of the sintered body after sintering. By polishing, the sintered body can be made into a sintered body having a surface state suitable for the intended use, such as imparting glossiness to the surface. In the processing step, the sintered body is processed into an arbitrary shape. Thereby, the sintered body can be made into a shape according to the application. Either the polishing step or the processing step may be performed first.

EXAMPLES The present embodiment will be described below with reference to examples. However, this embodiment is not limited to these examples.

(Average particle size)
The average particle size was measured by particle size distribution measurement by a laser diffraction/scattering method using a Microtrac particle size distribution meter (device name: MT3300EXII, manufactured by Microtrac Bell). Measurement conditions are shown below.
Light source: semiconductor laser (wavelength: 780 nm)
Voltage: 3mW
Measurement sample: pulverized slurry
Refractive index of zirconia: 2.17
Refractive index of solvent (water): 1.333
Calculation mode: HRA

As a pretreatment, the sample powder was suspended in pure water to form a slurry, which was dispersed for 3 minutes using an ultrasonic homogenizer (device name: US-150T, manufactured by Nippon Seiki Seisakusho). The slurry was measured at pH=3.0-6.0.

(BET specific surface area)
The BET specific surface area was measured by the BET multipoint method (5 points) using an automatic specific surface area measuring device (device name: Tristar II 3020, manufactured by Shimadzu Corporation) according to JIS R 1626 under the following conditions. .
Adsorption medium: _N2
Adsorption temperature: -196°C
Pretreatment conditions: Air atmosphere, degassing treatment at 250°C for 1 hour or longer

(measured density)
The density of the sintered body was measured by a method according to JISR1634 to obtain the measured density.

(color tone)
The color tone of the sintered sample was measured according to JISZ8722. A general spectrophotometer (apparatus name: CM-700d, manufactured by Konica Minolta) was used for the measurement. Measurement conditions include the following conditions.
Light source: D65 light source
Viewing angle: 10°
Measurement diameter: 8mm
Measurement method: SCI
Measurement background: Black board

A disk-shaped sintered sample having a diameter of 20 mm and a thickness of 2.7 mm was used. After the surface of the sintered body sample was ground and mirror-polished until the surface roughness (Ra) ≤ 0.02 µm, the polished surface was used as an evaluation surface to evaluate the color tone. A diameter of 8 mm was adopted as an effective area for color tone evaluation.

(three-point bending strength)
The bending strength of the sintered body sample was measured by a three-point bending test according to JIS R1601. The measurement was carried out using a pillar-shaped sintered body sample having a distance between fulcrums of 30 mm, a width of 4 mm and a thickness of 3 mm, and the average value of 10 measurements was taken as the bending strength.

(Average grain size)
The average crystal grain size is determined by a planimetric method using an SEM observation diagram of a sintered body sample obtained by observation using a field emission scanning electron microscope (device name: JSM-IT500, manufactured by JEOL Ltd.). obtained by Prior to the measurement, the sintered sample was mirror-polished until the surface roughness (Ra) ≤ 0.02 µm, and then subjected to thermal etching for pretreatment. The conditions for SEM observation are as follows.
Accelerating voltage: 15 kV
Observation magnification: 10000 times

Draw a circle on the SEM observation diagram so that the sum of the number of crystal grains in the circle (Nc) and the number of crystal grains on the circumference of the circle (Ni) is 125±25, and use the following formula to determine the average crystal grain size. asked for
Average grain size = (Nc + (1/2) x Ni)/(A/M ² )

In the above formula, Nc is the number of crystal grains in the circle, Ni is the number of crystal grains on the circumference of the circle, A is the area of the circle, and M is the scanning electron microscope observation magnification (10000 times). When the number of crystal grains (Nc+Ni) in one SEM observation diagram is less than 100, (Nc+Ni) was set to 125±25 using a plurality of SEM observation diagrams.

Example 1
Pure water was added to 3 mol% yttrium-containing zirconia powder (BET specific surface area: 6.8 m ² /g, manufactured by Tosoh), high-purity alumina powder (manufactured by Sumitomo Chemical), vanadium oxide (manufactured by Wako), and terbium oxide (manufactured by Nippon Yttrium). Mixed and wet blended into a slurry using a ball mill. The obtained slurry was dried at 110° C. in an air atmosphere to obtain a mixed powder having the following composition.

_Al2O3 : _3.0 % by mass
_V2O5 : _0.045 % by mass
_Tb4O7 : _0.075 % by mass
Zirconia containing 3 mol% yttrium: Balance The mixed powder after drying was filled in a mold, homogenized by tapping, and then molded at a uniaxial molding pressure of 1000 kg/cm ² to obtain a molded body (green compact). sintered at normal pressure.

Sintering atmosphere: Under air atmosphere
Sintering temperature: 1500°C
Heating rate: 100°C/hour
Sintering time: 2 hours The obtained sintered body had an aluminum content of 3.0% by mass, a vanadium content of 0.045% by mass, and a terbium content of 0.075% by mass. A sintered body made of zirconia containing yttrium with a Tb ratio of 0.60 and a balance of 3 mol% yttrium. As a result, it exhibited a vivid yellow color without being tinged with green or orange.

Further, when the surface of the zirconia sintered body was polished to a sample surface roughness of ≦0.02 μm, it was visually confirmed that the polished surface of the sintered body exhibited a yellow color. The sintered body of this example had a three-point bending strength of 1030 MPa and an average particle size of 0.83 μm. By SEM observation, zirconia crystal grains and alumina grains were confirmed on the polished surface and cross section of the sintered body.

Example 2
A sintered body of this example was obtained in the same manner as in Example 1, except that the components were mixed so as to have the following composition.
_Al2O3 : 10% _by mass
_V2O5 : _0.035 % by mass
_Tb4O7 : _0.075 % by mass
Zirconia containing 3 mol% yttrium: balance The obtained sintered body has an aluminum content of 10% by mass, a vanadium content of 0.035% by mass, and a terbium content of 0.075% by mass, and V/Tb A sintered body made of zirconia containing yttrium with a ratio of 0.47 and a balance of yttrium content of 3 mol%, and when the baked surface and the polished surface were visually observed, it was bright yellow without being tinged with green or orange. was presenting.

Example 3
A sintered body of this example was obtained in the same manner as in Example 1, except that the components were mixed so as to have the following composition.

_Al2O3 : 0.25% _by mass
_V2O5 : _0.085 % by mass
_Tb4O7 : _0.50 % by mass
Zirconia containing 3 mol% yttrium: balance The obtained sintered body has an aluminum content of 0.25 mass%, a vanadium content of 0.085 mass%, and a terbium content of 0.50 mass%, and V /Tb ratio is 0.17, the balance is a zirconia containing 3 mol% yttrium, and when the baked surface and the polished surface were visually observed, it was clear without being tinged with green or orange. It had a bright yellow color.

Example 4
A sintered body of this example was obtained in the same manner as in Example 1, except that the components were mixed so as to have the following composition.

_Al2O3 : 0.25% _by mass
_V2O5 : _0.045 % by mass
_Tb4O7 : 0.30% _by mass
Zirconia containing 3 mol% yttrium: balance The obtained sintered body has an aluminum content of 0.25% by mass, a vanadium content of 0.045% by mass, and a terbium content of 0.30% by mass, and V It is a zirconia sintered body containing yttrium with a /Tb ratio of 0.15 and the balance being yttrium content of 3 mol%. It had a bright yellow color.

Example 5
A sintered body of this example was obtained in the same manner as in Example 1, except that the components were mixed so as to have the following composition.

_Al2O3 : 0.25% _by mass
_{V2O5 :} 0.10% by mass
_Tb4O7 : 0.30% _by mass
Zirconia containing 3 mol% yttrium: balance The obtained sintered body has an aluminum content of 0.25 mass%, a vanadium content of 0.10 mass%, and a terbium content of 0.30 mass%, and V /Tb ratio is 0.33, the balance is yttrium content of 3 mol% yttrium sintered body made of zirconia, and when the baked surface and the polished surface were visually observed, it was clear without being tinged with green or orange. It had a bright yellow color.

Example 6
A sintered body of this example was obtained in the same manner as in Example 1, except that the components were mixed so as to have the following composition.

_{Al2O3 :} 5.0% by mass
_V2O5 : _0.045 % by mass
_Tb4O7 : _0.075 % by mass
Zirconia containing 3 mol% yttrium: balance The obtained sintered body has an aluminum content of 5.0% by mass, a vanadium content of 0.045% by mass, and a terbium content of 0.075% by mass, and V /Tb ratio is 0.60, the balance is yttrium content of 3 mol% yttrium sintered body made of zirconia, and when the baked surface and the polished surface were visually observed, it was clear without being tinged with green or orange. It had a bright yellow color.

Example 7
A sintered body of this example was obtained in the same manner as in Example 1, except that the components were mixed so as to have the following composition.

_Al2O3 : 0.50% _by mass
_{V2O5 :} 0.010% by mass
_Tb4O7 : _0.075 % by mass
Zirconia containing 3 mol% yttrium: balance The obtained sintered body has an aluminum content of 0.50% by mass, a vanadium content of 0.010% by mass, and a terbium content of 0.075% by mass, and V It is a zirconia sintered body containing yttrium with a /Tb ratio of 0.13 and the balance being yttrium content of 3 mol%. It had a bright yellow color.

Example 8
A sintered body of this example was obtained in the same manner as in Example 1, except that the components were mixed so as to have the following composition.

_Al2O3 : 0.50% _by mass
_{V2O5 :} 0.020% by mass
_Tb4O7 : _0.075 % by mass
Zirconia containing 3 mol% yttrium: balance The obtained sintered body has an aluminum content of 0.50% by mass, a vanadium content of 0.020% by mass, and a terbium content of 0.075% by mass, and V /Tb ratio is 0.27, the balance is a zirconia containing 3 mol% yttrium, and when the baked surface and the polished surface were visually observed, it was bright without being tinged with green or orange. It had a bright yellow color.

Example 9
A sintered body of this example was obtained in the same manner as in Example 1, except that the components were mixed so as to have the following composition.

_Al2O3 : 0.50% _by mass
_V2O5 : _0.030 % by mass
_Tb4O7 : _0.075 % by mass
Zirconia containing 3 mol% yttrium: balance The obtained sintered body has an aluminum content of 0.50% by mass, a vanadium content of 0.030% by mass, and a terbium content of 0.075% by mass, and V /Tb ratio is 0.40, the balance is yttrium content of 3 mol% yttrium sintered body made of zirconia, and when the baked surface and the polished surface were visually observed, it was clear without being tinged with green or orange. It had a bright yellow color.

Example 10
A sintered body of this example was obtained in the same manner as in Example 1, except that the components were mixed so as to have the following composition.

_Al2O3 : 0.50% _by mass
_V2O5 : _0.035 % by mass
_Tb4O7 : _0.080 % by mass
Zirconia containing 3 mol% yttrium: balance The obtained sintered body has an aluminum content of 0.50 mass%, a vanadium content of 0.035 mass%, and a terbium content of 0.080 mass%, and V It is a sintered body made of zirconia containing yttrium with a /Tb ratio of 0.44 and the balance being yttrium content of 3 mol%. It had a bright yellow color.

Example 11
A sintered body of this example was obtained in the same manner as in Example 1, except that the components were mixed so as to have the following composition.

_Al2O3 : 0.50% _by mass
_V2O5 : _0.035 % by mass
_Tb4O7 : 0.095% _by mass
Zirconia containing 3 mol% yttrium: balance The obtained sintered body has an aluminum content of 0.50% by mass, a vanadium content of 0.035% by mass, and a terbium content of 0.095% by mass, and V /Tb ratio is 0.37, the balance is yttrium content of 3 mol% yttrium sintered body made of zirconia, and when the baked surface and the polished surface were visually observed, it was clear without being tinged with green or orange. It had a bright yellow color.

Example 12
A sintered body of this example was obtained in the same manner as in Example 1, except that the components were mixed so as to have the following composition.

_Al2O3 : 0.50% _by mass
_V2O5 : _0.035 % by mass
_Tb4O7 : 0.10% _by mass
Zirconia containing 3 mol% yttrium: balance The obtained sintered body has an aluminum content of 0.50% by mass, a vanadium content of 0.035% by mass, and a terbium content of 0.10% by mass, and V It is a zirconia sintered body containing yttrium with a /Tb ratio of 0.35 and the balance being yttrium content of 3 mol%. It had a bright yellow color.

Example 13
A sintered body of this example was obtained in the same manner as in Example 1, except that the components were mixed so as to have the following composition.

_Al2O3 : 0.25% _by mass
_V2O5 : _0.035 % by mass
_Tb4O7 : _0.075 % by mass
Zirconia containing 3 mol% yttrium: balance The obtained sintered body has an aluminum content of 0.25% by mass, a vanadium content of 0.035% by mass, and a terbium content of 0.075% by mass, and V It is a zirconia sintered body containing yttrium with a /Tb ratio of 0.47 and the balance being yttrium content of 3 mol%. It had a bright yellow color.

Example 14
A sintered body of this example was obtained in the same manner as in Example 1, except that the components were mixed so as to have the following composition.

_Al2O3 : _1.0 % by mass
_V2O5 : _0.035 % by mass
_Tb4O7 : _0.075 % by mass
Zirconia containing 3 mol% yttrium: balance The obtained sintered body has an aluminum content of 1.0% by mass, a vanadium content of 0.035% by mass, and a terbium content of 0.075% by mass, and V It is a zirconia sintered body containing yttrium with a /Tb ratio of 0.47 and the balance being yttrium content of 3 mol%. It had a bright yellow color.

Example 15
A sintered body of this example was obtained in the same manner as in Example 1, except that the components were mixed so as to have the following composition.

_Al2O3 : _5.0 % by mass
_V2O5 : _0.035 % by mass
_Tb4O7 : _0.075 % by mass
Zirconia containing 3 mol% yttrium: balance The obtained sintered body has an aluminum content of 5.0% by mass, a vanadium content of 0.035% by mass, and a terbium content of 0.075% by mass, and V It is a zirconia sintered body containing yttrium with a /Tb ratio of 0.47 and the balance being yttrium content of 3 mol%. It had a bright yellow color.

Comparative example 1
A sintered body of this comparative example was obtained in the same manner as in Example 1 except that the components were mixed so as to have the following composition.

_Al2O3 : _3.0 % by mass
_V2O5 : _0.045 % by mass
Zirconia containing 3 mol % yttrium: balance The sintered body of this comparative example did not contain terbium as a coloring element, and both the baked surface and the polished surface were greenish yellow when visually observed.

Comparative example 2
A sintered body of this comparative example was obtained in the same manner as in Example 1 except that the components were mixed so as to have the following composition.

_Al2O3 : _3.0 % by mass
_Tb4O7 : _0.075 % by mass
Zirconia containing 3 mol % yttrium: Balance The sintered body of this comparative example did not contain vanadium as a coloring element, and both the baked surface and the polished surface were orange when visually observed.

Comparative example 3
A sintered body of this comparative example was obtained in the same manner as in Example 1 except that the components were mixed so as to have the following composition.

_V2O5 : _0.50 % by mass
Zirconia containing 3 mol % yttrium: balance The sintered body of this comparative example did not contain terbium as a coloring element, and both the baked surface and the polished surface were greenish yellow when visually observed.

Comparative example 4
A sintered body of this comparative example was obtained in the same manner as in Example 1 except that the components were mixed so as to have the following composition.

_V2O5 : _0.030 % by mass
Zirconia containing 3 mol % yttrium: balance The sintered body of this comparative example did not contain terbium as a coloring element, and both the baked surface and the polished surface were greenish yellow when visually observed.

Comparative example 5
A sintered body of this comparative example was obtained in the same manner as in Example 1 except that the components were mixed so as to have the following composition.

_Al2O3 : 0.25% _by mass
_V2O5 : _0.045 % by mass
_Tb4O7 : _0.50 % by mass
Zirconia containing 3 mol % yttrium: balance The sintered body of this comparative example had a V/Tb ratio of 0.09, and both the fired surface and the polished surface were orange when visually observed.

Comparative example 6
A sintered body of this comparative example was obtained in the same manner as in Example 1 except that the components were mixed so as to have the following composition.

_Al2O3 : 0.25% _by mass
_V2O5 : _0.055 % by mass
_Tb4O7 : _0.50 % by mass
Zirconia containing 3 mol% yttrium: Balance The sintered body of this comparative example has a V/Tb ratio of 0.11, and both the baked surface and the polished surface have an orange-yellow color when visually observed. rice field.

Comparative example 7
A sintered body of this comparative example was obtained in the same manner as in Example 1 except that the components were mixed so as to have the following composition.

_Al2O3 : 0.50% _by mass
_V2O5 : _0.055 % by mass
_Tb4O7 : _0.50 % by mass
Zirconia containing 3 mol% yttrium: Balance The sintered body of this comparative example has a V/Tb ratio of 0.11, and both the baked surface and the polished surface have an orange-yellow color when visually observed. rice field.

Table 1 shows the evaluation results of the sintered bodies of Examples and Comparative Examples.

It can be confirmed that a sintered body having L ^* of 80 or more and 100 or less, a ^* of -3 or more and 4 or less, and b ^* of more than 30 and 50 or less can be obtained in the examples. On the other hand, all of the comparative examples exhibit a color tone such as yellowish, but from comparative examples 1, 3 and 4, when only vanadium is used as a coloring element, a ^* is -3 or less, and from comparative example 2, It can be confirmed that a ^* exceeds 4 when only terbium is used as the coloring element. Further, from Comparative Examples 5 to 7, when the V / Tb ratio is outside the range of the present embodiment, a ^* exceeds 4, so L ^* is 80 or more and 100 or less, a ^* is -3 or more and 4 or less, and , b ^* exceeding 30 and 50 or less cannot be obtained.

From Examples 7 to 9, it can be confirmed that a ^* decreases as the vanadium content increases. Also, from Examples 10 to 12, it can be confirmed that a ^* increases as the content of terbium increases. It was confirmed that when the content of vanadium is high, the color tone of the sintered body is greenish, and when the content of terbium is high, the color tone of the sintered body is reddish. From these facts, it is presumed that when vanadium and terbium are contained as coloring elements, the absorption bands of vanadium and terbium interact with each other to weaken the green and orange coloration of the sintered body.

Moreover, it can be confirmed from Examples 13 to 15 that L ^* increases as the aluminum content increases.

The three-point bending strengths of Examples 1 and 2 were 1030 MPa and 1058 MPa, respectively.

Furthermore, chroma (C ^* ) and hue angle (h) were calculated for Examples and Comparative Examples. Table 2 shows the results.

From Table 2, it can be confirmed that all the examples have a saturation of 30 or more and a hue angle of more than 83° and 96° or less. On the other hand, it can be confirmed from Comparative Example 2 that the sintered body to which only terbium was added as a coloring element had a low hue angle of 72.6°. Further, from Comparative Examples 1, 3 and 4, it can be confirmed that the sintered bodies to which only vanadium is added as a coloring element all have hue angles exceeding 96°.

It was confirmed that Examples 1 to 15, Comparative Examples 1, 2, and 4 to 7 had a chroma of 30 or more and exhibited a vivid color tone. However, since Comparative Examples 1, 2, and 4 to 7 have a hue angle of 83° or less or more than 96°, it can be confirmed that they do not exhibit a color tone visually recognized as yellow without being tinged with green or orange.

Furthermore, from Comparative Examples 5 to 7, it can be confirmed that even if vanadium and terbium are included as coloring elements, the hue angle is less than 83° when the V/Tb ratio is outside the range of the present embodiment.

Claims (17)

A sintered body containing vanadium and terbium and having a zirconia matrix, wherein the mass ratio of vanadium to terbium is 0.12 or more. The sintered body according to claim 1, wherein the vanadium content is 0.010% by mass or more and 0.20% by mass or less. The sintered body according to claim 1 or 2, wherein the terbium content is 0.050% by mass or more and 0.60% by mass or less. The sintered body according to any one of claims 1 to 3, containing aluminum. 5. The sintered body according to claim 4, wherein the aluminum content is 0.10% by mass or more and 15% by mass or less with respect to the mass of the sintered body. The sintered body according to any one of claims 1 to 5, wherein said zirconia is zirconia containing a stabilizing element. 7. The sintered body according to claim 6, wherein said stabilizing element is one or more selected from the group consisting of yttrium, magnesium and calcium. 8. The sintered body according to claim 6, wherein the content of said zirconia stabilizing element is 1.0 mol % or more and 6.0 mol % or less. The sintered body according to any one of claims 1 to 8, wherein lightness L ^* , chromaticity a ^* , and chromaticity b ^* in the L ^{* a} *b ^* color system satisfy the following.
Lightness L ^* : 80≤L ^* ≤100
Chromaticity a ^* : -3≤a ^* ≤4, and
Chromaticity b ^* : 30<b ^* ≤50 The sintered body according to any one of claims 1 to 9, ^wherein the chroma C ^{* and} the hue angle h in the L*a*b ^* color system satisfy the following.
Chroma C ^* : 28≦C*≦44, and hue angle h: 83°<h≦96° The sintered body according to any one of claims 1 to 10, having an average crystal grain size of 0.2 µm or more and 2 µm or less. The sintered body according to any one of claims 1 to 11, which has a three-point bending strength of 900 MPa or more. Zirconia containing 0.010% by mass or more and 0.20% by mass or less of vanadium, 0.050% by mass or more and 0.60% by mass or less of terbium, and having a mass ratio of vanadium to terbium of 0.12 or more 13. The method for producing a zirconia sintered body according to any one of claims 1 to 12, characterized in that a matrix composition is used. 14. The method for producing a sintered body according to claim 13, wherein the composition contains 0.10% by mass or more and 15% by mass or less of aluminum. Zirconia containing 0.010% by mass or more and 0.20% by mass or less of vanadium, 0.050% by mass or more and 0.60% by mass or less of terbium, and having a mass ratio of vanadium to terbium of 0.12 or more A composition for use as a matrix. 16. The composition according to claim 15, containing 0.10% by mass or more and 15% by mass or less of aluminum. A member comprising the sintered body according to any one of claims 1 to 12.