JP2008050246A - Zirconia powder for colored zirconia sintered compact and sintered compact - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a zirconia powder for a colored zirconia sintered compact, with which variation in coloration and strength in the colored zirconia sintered compact is suppressed and the concern of the contamination caused by color migration in a production process is made unnecessary, and from which the zirconia sintered compact having uniform coloration and strength can be obtained; and to provide the zirconia sintered compact obtained by using the same. <P>SOLUTION: When a zirconia powder containing an Fe-Y multiple oxide as coloring agent is used, the problem of color migration in the production process of the sintered compact is avoided, and the coloration of the final sintered compact becomes uniform and the strength of the sintered compact is maintained. The zirconia powder containing 1.5-6.0 wt.% Y<SB>2</SB>O<SB>3</SB>and 0.0-1.0 wt.% Al<SB>2</SB>O<SB>3</SB>and the coloring agent containing 0.01-10 wt.% Fe-Y multiple oxide are preferably used, and preferable Fe-Y multiple oxide is FeYO<SB>3</SB>. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a zirconia powder for producing a zirconia sintered body which has developed a color from light yellow to dark color by sintering, and in particular, the coloring is uniform and the sintered body strength after sintering is uniform and high strength. Zirconia powder to be used, and a sintered body using the same.

  Since the zirconia sintered body using the zirconia powder of the present invention is uniformly colored, there is no variation in strength and durability, and in particular, in a light yellow colored zirconia, it has a natural and uniform color tone. It is suitable for use in ceramic decorative parts, electronic parts, dentures and dental materials (such as crowns and bridges) that require aesthetics.

  Since zirconia ceramics can be colored unlike metals, for example, when used for decorative parts, electronic parts, dentures and dental materials, zirconia ceramics are superior in aesthetics compared to the case of using metals. In addition, zirconia ceramics have characteristics such as higher tissue adaptability, lower thermal conductivity, and no metal allergy compared to metals, and are sufficient in strength. It is expected as a material to replace dentures.

  Conventionally, oxides of Pr, Er, Fe, Co, Ni, Ti, V, Cr, Cu, and Mn have been known as colorants for coloring zirconia sintered bodies (for example, Patent Document 1). .

As a result of detailed studies by the present inventors, when Fe ₂ O ₃ is used as a colorant, it is not Fe ₂ O ₃ alone that causes the zirconia sintered body to develop color, but zirconia as a stabilizer. It has been found that the contained Y ₂ O ₃ is a Fe—Y complex oxide (FeYO ₃ or the like) produced by reacting with Fe ₂ O ₃ at a high temperature of 1000 ° C. or higher.

Furthermore, when an iron compound as a colorant, particularly Fe ₂ O ₃ is used, Fe ₂ O ₃ reacts with Y ₂ O ₃ during the sintering process, and the reacted Y ₂ O ₃ is no longer a crystal of the zirconia sintered body. There is a problem that the sintered body strength is partially reduced because it does not work as a stabilizer.

In addition, Fe ₂ O ₃ has a unique reddish color and has a problem of color transfer in the manufacturing process. The color tone is completely different from the final product, and such a color transfer has a problem in terms of product contamination.

Furthermore, when the reaction of Fe ₂ O ₃ and Y ₂ O ₃ does not proceed sufficiently due to the mixing state of raw materials and the amount of coloring components added, uneven coloring occurs in large-sized sintered bodies, and coloring for each product occurs in small ceramic parts. There has been a problem of variation in product yield, and there has been a problem of reduction in product yield in a field where uniformity of color tone is required.

Special table 2003-506309 gazette

  The present invention provides a colored zirconia sintered body that has no variation in coloring and sintered body strength, does not bother the contamination of color transfer in the production process, and can provide zirconia with uniform coloring and strength. The object is to provide a powder for zirconia and a zirconia sintered body using the powder.

As a result of intensive studies on color development and strength in zirconia containing an iron compound as a coloring component, the present inventors have determined that coloring of the sintered body is not iron oxide alone but iron oxide and yttria, which is a crystal stabilizing component. It has been found that complex oxides, particularly FeYO ₃ , exhibit the desired coloring only, and zirconia powder using such an Fe—Y complex oxide as a colorant from the beginning has coloring of the sintered body obtained. It was found to be uniform, free from color transfer problems during the manufacturing process, and without variations from product to product. Furthermore, since the coloring component iron has previously reacted with yttria, the yttria added from the beginning for stabilizing the crystal of zirconia is not consumed in the sintering process, so finally The present inventors have found that the obtained colored zirconia sintered body has no reduction in strength and that there is no variation in strength, and has completed the present invention.

  The present invention is described in detail below.

  The zirconia powder of the present invention is a zirconia powder containing an Fe—Y composite oxide as a colorant.

Conventionally known as a coloring component of zirconia, Fe ₂ O ₃ is red, reddish brown, or black when baked at high temperature in air. Therefore, when Fe ₂ O ₃ is added to a zirconia powder not containing Y ₂ O ₃ and sintered, Fe ₂ O ₃ aggregates and is scattered, and it is difficult to obtain a uniform color.

On the other hand, Fe-Y composite oxide obtained by heat-treating a mixture of _Fe 2 _{O 3} and _Y 2 _{O 3} is mainly formed of a Feyo _3, the color is colored orange-brown. The zirconia powder of the present invention contains the Fe-Y composite oxide in the zirconia powder, so that the manufacturing process is not contaminated with different color shifts, and is further uniformly colored during sintering. be able to.

  The zirconia powder of the present invention preferably contains other components such as a stabilizer. Yttria, ceria, calcia, magnesia, alumina and the like are known as stabilizers.

A zirconia sintered body is most commonly added with Y ₂ O ₃ as a stabilizer in order to maintain strength and improve hot water resistance, and such a zirconia sintered body is generally called partially stabilized zirconia. Y ₂ O ₃ can be used in the range of 1.5 to 6.0 wt%, and the range of ₃ to 6 wt% is preferable because the strength of the sintered body is improved, and more preferably 4.8 to 5.7 wt%. The range is more preferable because durability is improved in addition to strength. With partially stabilized zirconia, a certain strength can be obtained without including Al ₂ O ₃ , but the strength can be further increased by including Al ₂ O ₃ . The content of Al ₂ O ₃ is preferably 0.0~1.0wt%.

Conventionally, when Fe ₂ O ₃ is used as a colorant, a part of the stabilizer Y ₂ O ₃ is partially oxidized by the formation of Fe—Y composite oxide when formed into a sintered body. The content of Y ₂ O ₃ as a stabilizer contained in the zirconia sintered body is reduced from the set value, and this compositional deviation reduces the strength, toughness and durability of the zirconia sintered body. There was a problem of doing.

In the present invention, by using an Fe—Y composite oxide obtained by reacting Fe ₂ O ₃ and Y ₂ O ₃ in advance as a colorant, a part of Y ₂ O ₃ added as a stabilizer is Fe— It is not consumed for the production of the Y composite oxide, and the content of the stabilizer Y ₂ O ₃ can be left in the zirconia sintered body as set, and the strength of the zirconia sintered body The problem that the toughness and the durability are lowered does not occur.

  In the present invention, an Fe—Y composite oxide is used as the colorant, and the amount added is preferably 0.01 to 10 wt%, particularly preferably 0.1 to 5 wt%. If the Fe-Y composite oxide is less than 0.01 wt%, it is difficult to uniformly color the target, and if it is more than 10 wt%, the strength of the sintered body tends to decrease.

The method for producing the zirconia powder of the present invention is not particularly limited. For example, the zirconia powder can be produced by mixing Al ₂ O ₃ and Fe—Y composite oxide with zirconia powder containing Y ₂ O _3. is there. You may heat-process at the temperature of 800-1000 degreeC after mixing.

As the zirconia powder containing Y ₂ O ₃ , for example, a hydrated zirconia sol having an average particle diameter of 0.05 to 0.3 μm obtained by hydrolysis of a zirconium salt aqueous solution of a zirconia powder containing Y ₂ O ₃ is used. Examples include zirconia powder having a BET specific surface area of ² to 35 m ² / g obtained by calcination, a crystallite diameter of 10 to 70 nm, a tetragonal zirconia ratio of 50% or more, and an average particle diameter of 0.1 to 50 μm. Is done.

The zirconia sintered body obtained by sintering the zirconia powder of the present invention containing, for example, about 0.2 wt% of Fe—Y composite oxide at a temperature of 1300 to 1500 ° C. has a color tone defined in JISZ8729. In the L ^* a ^* b ^* color system, lightness L ^* , color coordinates a ^* , b ^* are in the range of 85 ≧ L ^* ≧ 65, 15 ≧ a ^* ≧ −5, 30 ≧ b ^* ≧ 10 It becomes a system zirconia sintered body. Such a color tone becomes a color similar to human teeth, is excellent in strength, toughness, and durability, and becomes a zirconia sintered body that is optimal as a denture or a dental material.

  Needless to say, the Fe—Y composite oxide in the present invention alone has value as a colorant for a zirconia sintered body.

As the Fe-Y composite oxide, FeYO ₃ is the most typical, but iron, yttria, and oxygen are deviated from stoichiometric amounts, for example, those having oxygen defects, and metal components deviate from the stoichiometric composition. Can also be used. Moreover, you may use what was partially substituted with the 3rd component etc. in the range which does not lose the effect of this invention.

  The zirconia powder according to the present invention can achieve uniform coloring by sintering, does not contaminate the manufacturing process of the sintered body due to different color transfer, and there is no variation in coloring and strength for each product. A zirconia sintered body can be obtained.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited at all by these Examples. In addition, the zirconia powder manufactured by the hydrolysis method was used for the starting material used in the Example.

Example 1
To the zirconia powder obtained by hydrolysis of zirconium oxychloride with a Y ₂ O ₃ concentration of 3.60 wt% and an Al ₂ O ₃ concentration of 0.25 wt%, 0.24 wt% of FeYO ₃ was added as an Fe—Y composite oxide. The powder was obtained by wet mixing with a ball mill and drying. The powder was pressure-molded and sintered in air at 1350 ° C. for 2 hours to obtain a colored zirconia sintered body. The sintered body was yellow with transparency.

The colored zirconia sintered body was evaluated for bending strength, K _IC value indicating toughness, and monoclinic ratio on the surface of the sintered body after hydrothermal treatment at 140 ° C. for 24 hours in an autoclave. The results are shown in Table 1.

  The strength and toughness were good values, and there was no variation in the color tone of each sintered body, and a sintered body of uniform quality was obtained.

Example 2
To the zirconia powder obtained by hydrolysis of zirconium oxychloride with a Y ₂ O ₃ concentration of 5.20 wt% and an Al ₂ O ₃ concentration of 0.25 wt%, 0.24 wt% of FeYO ₃ was added as an Fe—Y composite oxide. The powder was obtained by wet mixing with a ball mill and drying. The powder was pressure-molded and sintered in air at 1350 ° C. for 2 hours to obtain a colored zirconia sintered body. The sintered body was yellow with transparency.

Table 1 shows the bending strength of the colored zirconia sintered body, the K _IC value indicating toughness, and the monoclinic ratio of the sintered body surface after hydrothermal treatment at 140 ° C. for 24 hours in an autoclave as a durability test. .

  The strength, toughness, and durability were all good values, and there was no variation in the color tone of each sintered body, and a sintered body with uniform quality was obtained.

Example 3
To the zirconia powder obtained by hydrolysis of zirconium oxychloride with a Y ₂ O ₃ concentration of 5.20 wt% and an Al ₂ O ₃ concentration of 0.25 wt%, 1.20 wt% of FeYO ₃ was added as an Fe—Y composite oxide. The powder was obtained by wet mixing with a ball mill and drying. The powder was pressure-molded and sintered in air at 1350 ° C. for 2 hours to obtain a colored zirconia sintered body. The sintered body was yellow with transparency.

Table 1 shows the bending strength of the colored zirconia sintered body, the K _IC value indicating toughness, and the monoclinic ratio of the sintered body surface after hydrothermal treatment at 140 ° C. for 24 hours in an autoclave as a durability test. .

  The strength, toughness, and durability were all good values, and there was no variation in the color tone of each sintered body, and a sintered body with uniform quality was obtained.

Example 4
To a zirconia powder having a Y ₂ O ₃ concentration of 5.20 wt% and an Al ₂ O ₃ concentration of 0.25 wt% obtained by hydrolysis of zirconium oxychloride, 2.40 wt% of FeYO ₃ was added as an Fe—Y composite oxide. The powder was obtained by wet mixing with a ball mill and drying. The powder was pressure-molded and sintered in air at 1350 ° C. for 2 hours to obtain a colored zirconia sintered body. The sintered body was yellow with transparency.

Table 1 shows the bending strength of the colored zirconia sintered body, the K _IC value indicating toughness, and the monoclinic ratio of the sintered body surface after hydrothermal treatment at 140 ° C. for 24 hours in an autoclave as a durability test. .

  The strength, toughness, and durability were all good values, and there was no variation in the color tone of each sintered body, and a sintered body with uniform quality was obtained.

Example 5
To the zirconia powder obtained by hydrolysis of zirconium oxychloride with a Y ₂ O ₃ concentration of 4.80 wt% and an Al ₂ O ₃ concentration of 0.25 wt%, 0.24 wt% of FeYO ₃ was added as an Fe—Y composite oxide. The powder was obtained by wet mixing with a ball mill and drying. The powder was pressure-molded and sintered in air at 1350 ° C. for 2 hours to obtain a colored zirconia sintered body. The sintered body was yellow with transparency.

Table 1 shows the bending strength of the colored zirconia sintered body, the K _IC value indicating toughness, and the monoclinic ratio of the sintered body surface after hydrothermal treatment at 140 ° C. for 24 hours in an autoclave as a durability test. .

  The strength, toughness, and durability were all good values, and there was no variation in the color tone of each sintered body, and a sintered body with uniform quality was obtained.

Example 6
To the zirconia powder having a Y ₂ O ₃ concentration of 5.00 wt% and an Al ₂ O ₃ concentration of 0.25 wt% obtained by hydrolysis of zirconium oxychloride, 0.24 wt% of FeYO ₃ was added as an Fe—Y composite oxide. The powder was obtained by wet mixing with a ball mill and drying. The powder was pressure-molded and sintered in the atmosphere at 1350 ° C. for 2 hours to obtain a colored zirconia sintered body. The sintered body was yellow with transparency.

Table 1 shows the bending strength of the colored zirconia sintered body, the K _IC value indicating toughness, and the monoclinic ratio of the sintered body surface after hydrothermal treatment at 140 ° C. for 24 hours in an autoclave as a durability test. .

  The strength, toughness, and durability were all good values, and there was no variation in the color tone of each sintered body, and a sintered body with uniform quality was obtained.

Example 7
To the zirconia powder obtained by hydrolysis of zirconium oxychloride with a Y ₂ O ₃ concentration of 5.50 wt% and an Al ₂ O ₃ concentration of 0.25 wt%, 0.24 wt% of FeYO ₃ was added as an Fe—Y composite oxide. The powder was obtained by wet mixing with a ball mill and drying. The powder was pressure-molded and sintered in air at 1350 ° C. for 2 hours to obtain a colored zirconia sintered body. The sintered body was yellow with transparency.

Table 1 shows the bending strength of the colored zirconia sintered body, the K _IC value indicating toughness, and the monoclinic ratio of the sintered body surface after hydrothermal treatment at 140 ° C. for 24 hours in an autoclave as a durability test. .

  The strength, toughness, and durability were all good values, and there was no variation in the color tone of each sintered body, and a sintered body with uniform quality was obtained.

Example 8
To the zirconia powder obtained by hydrolysis of zirconium oxychloride with a Y ₂ O ₃ concentration of 5.60 wt% and an Al ₂ O ₃ concentration of 0.25 wt%, 0.24 wt% of FeYO ₃ was added as an Fe—Y composite oxide. The powder was obtained by wet mixing with a ball mill and drying. The powder was pressure-molded and sintered in air at 1350 ° C. for 2 hours to obtain a colored zirconia sintered body. The sintered body was yellow with transparency.

Table 1 shows the bending strength of the colored zirconia sintered body, the K _IC value indicating toughness, and the monoclinic ratio of the sintered body surface after hydrothermal treatment at 140 ° C. for 24 hours in an autoclave as a durability test. .

  The strength, toughness, and durability were all good values, and there was no variation in the color tone of each sintered body, and a sintered body with uniform quality was obtained.

Example 9
To the zirconia powder obtained by hydrolysis of zirconium oxychloride with a Y ₂ O ₃ concentration of 5.70 wt% and an Al ₂ O ₃ concentration of 0.25 wt%, 0.24 wt% of FeYO ₃ was added as an Fe—Y composite oxide. The powder was obtained by wet mixing with a ball mill and drying. The powder was pressure-molded and sintered in air at 1350 ° C. for 2 hours to obtain a colored zirconia sintered body. The sintered body was yellow with transparency.

Table 1 shows the bending strength of the colored zirconia sintered body, the K _IC value indicating toughness, and the monoclinic ratio of the sintered body surface after hydrothermal treatment at 140 ° C. for 24 hours in an autoclave as a durability test. .

  The strength, toughness, and durability were all good values, and there was no variation in the color tone of each sintered body, and a sintered body with uniform quality was obtained.

Comparative Example 1
Oxy _Y 2 _{O 3} concentration 3.60Wt% obtained by hydrolysis of zirconium chloride, the concentration of _Al 2 _{O 3} 0.25 wt% of zirconia powder, a _Fe 2 _{O 3} was added 0.1 wt%, wet mixed by a ball mill And dried to obtain a powder. The powder was pressure-molded and sintered in air at 1350 ° C. for 2 hours to obtain a colored zirconia sintered body.

  The color tone of the sintered body was the same as that of Example 1, but the color tone varied among the sintered bodies. Moreover, since the color tone of the mixed powder of zirconia and iron oxide and the final product are greatly different, the manufacturing process was contaminated by a reddish color transfer.

Table 1 shows the bending strength, the K _IC value indicating toughness, and the monoclinic ratio of the sintered body surface after hydrothermal treatment at 140 ° C. for 24 hours in an autoclave as a durability test.

  The obtained sintered body showed a variation for each sintered body, resulting in a decrease in strength and toughness as compared with Example 1.

Comparative Example 2
Oxy _Y 2 _{O 3} concentration 5.20Wt% obtained by hydrolysis of zirconium chloride, the concentration of _Al 2 _{O 3} 0.25 wt% of zirconia powder, a _Fe 2 _{O 3} was added 0.1 wt%, wet mixed by a ball mill And dried to obtain a powder. The powder was pressure-molded and sintered in air at 1350 ° C. for 2 hours to obtain a colored zirconia sintered body.

Flexural strength of the sintered body, K _IC value indicating the toughness, and sintering showing 140 ° C. in an autoclave in a durability test, the percentage of monoclinic crystals of the sintered body surface after the hydrothermal treatment for 24 hours in Table 1 Although the color tone of the body was the same as in Example 2, there was a variation in coloring, resulting in a decrease in strength and durability as compared with Example 2.

Comparative Example 3
0.5% by weight of Fe ₂ O ₃ is added to zirconia powder having a Y ₂ O ₃ concentration of 5.20 wt% and Al ₂ O ₃ concentration of 0.25 wt% obtained by hydrolysis of zirconium oxychloride, and wet-mixed with a ball mill And dried to obtain a powder. The powder was pressure-molded and sintered in air at 1350 ° C. for 2 hours to obtain a colored zirconia sintered body.

Flexural strength of the sintered body, K _IC value indicating the toughness, and sintering showing 140 ° C. in an autoclave in a durability test, the percentage of monoclinic crystals of the sintered body surface after the hydrothermal treatment for 24 hours in Table 1 The color tone of the body was the same as in Example 3, but there was variation in coloring, and the strength and durability were reduced compared to Example 3.

Comparative Example 4
Oxy _Y 2 _{O 3} concentration 5.20Wt% obtained by hydrolysis of zirconium chloride, the concentration of _Al 2 _{O 3} 0.25 wt% of zirconia powder, a _Fe 2 _{O 3} was added 1.0 wt%, wet mixed by a ball mill And dried to obtain a powder. The powder was pressure-molded and sintered in air at 1350 ° C. for 2 hours to obtain a colored zirconia sintered body.

Flexural strength of the sintered body, K _IC value indicating the toughness, and 140 ° C. in an autoclave in a durability test, sintered body showing the percentage of monoclinic crystals of the sintered body surface after the hydrothermal treatment for 24 hours in Table 1 The color tone was the same as that of Example 4, but there was variation in coloring, and the strength and durability were reduced as compared with Example 4.

  The brightness and color coordinate values of the zirconia sintered bodies obtained in Examples 1 to 4 and Comparative Examples 1 to 4 are shown in Table 2 below.

Claims (6)

Zirconia powder containing Fe-Y composite oxide as a colorant. Y ₂ O ₃ and 1.5~6.0wt%, zirconia powder of claim 1, further comprising a 0.0～1.0Wt% of _Al 2 _{O 3.} The zirconia powder according to claim 1, wherein the content of the Fe—Y composite oxide is 0.01 to 10 wt%. A coloring agent for a zirconia sintered body, wherein the Fe—Y composite oxide contains FeYO ₃ . A colorant powder comprising a Fe—Y composite oxide comprising FeYO _{3 of} claim 4. The sintered compact obtained by sintering the zirconia powder of Claims 1-3.