CN114195551A

CN114195551A - Bill zirconia ceramic and preparation method thereof

Info

Publication number: CN114195551A
Application number: CN202111380951.2A
Authority: CN
Inventors: 廖章权; 李联和; 龚斌; 刘革命; 谢楠
Original assignee: GANZHOU KOIN STRUCTURE CERAMICS CO Ltd
Current assignee: GANZHOU KOIN STRUCTURE CERAMICS CO Ltd
Priority date: 2021-11-20
Filing date: 2021-11-20
Publication date: 2022-03-18
Anticipated expiration: 2041-11-20
Also published as: CN114195551B

Abstract

The invention discloses a dark-colored zirconia ceramic and a preparation method thereof, belonging to the technical field of structural ceramics. The green zirconia ceramic is prepared by dissolving iso-octoate including nickel iso-octoate in a solvent as a colorant, laying the colorant on the surface of a zirconia ceramic blank, and sintering to obtain a green zirconia ceramic blank or a green zirconia ceramic with green appearance. The prepared jade-colored zirconia ceramic can realize uniform color on the surface, can also realize gradually-changed color from dark color to light color in a directional manner, has controllable color development depth, small using amount of pigment and reduced sintering temperature, has the general visual effect of green and semitransparent jade after being formed into ceramic at the high temperature of more than 1400 ℃, and keeps the physical properties of density, bending strength and the like basically unchanged.

Description

Bill zirconia ceramic and preparation method thereof

Technical Field

The invention relates to zirconia ceramic and a preparation method thereof, belonging to the technical field of structural ceramics. In particular to a dark-colored zirconia ceramic and a preparation method thereof.

Background

In general, most of zirconia ceramic products are white or off-white in color, and the yellow spots are easily generated after the zirconia ceramic products are used for a long time. The preparation of colored zirconia ceramics requires the addition of metal oxides for coloring.

The color zirconia ceramics have excellent performances of high toughness, high strength, high hardness, wear resistance and the like, and are widely applied to the field of structural ceramics; meanwhile, the jade-like skin-friendly effect is achieved, so that the jade-like skin-friendly decorative paint is widely applied to the fields of appearance pieces and high-grade decoration.

The Chinese patent application with publication number CN110981472A of 'a high-strength green zirconia ceramic powder and a preparation method and application thereof' (hereinafter referred to as the prior art I) 'published as 2020, 04 and 10 months, discloses' a high-strength green zirconia ceramic powder consisting of yttrium-stabilized zirconia and a green colorant; the dosage of the yttrium oxide in the yttrium-stabilized zirconia is 3.5-5.5 mol% of the zirconium oxide; the green colorant comprises the components of aluminum oxide, zinc oxide, chromium oxide, ferric oxide, titanium oxide, cobalt oxide and manganese oxide in a molar ratio of 16-50: 1.5-10: 0.8-25: 0.2-17: 0.04-2: 0.04-4: 0.04-0.4; the addition amount of the green colorant is 2-7.5 wt% of yttrium-stabilized zirconia. In addition, a preparation method and application of the high-strength green zirconia ceramic powder are also disclosed. The raw materials adopted by the green zirconia ceramic powder are green and environment-friendly, the sources are rich and easy to obtain, the obtained product has high strength, good toughness, good color development, high glossiness and few defects, and can meet the harsh use requirements in practical application; and the preparation process is simple and efficient, and is beneficial to popularization, application and development of technical effects.

The chinese patent application publication No. CN110002876A, published as number 07, 12 and 2019, discloses "a green zirconia ceramic and a preparation method thereof" (hereinafter referred to as prior art two), discloses "a green zirconia ceramic and a preparation method thereof, and belongs to the field of ceramic materials. Firstly, preparing a zirconium hydroxide precursor by adopting a coprecipitation process, then adding metal salts of vanadium, cobalt and aluminum into the precursor, drying and sintering to prepare zirconium oxide granulated powder containing vanadium pentoxide and cobalt aluminate, and forming and sintering the powder to prepare green zirconium oxide ceramic. "the green color of the zirconia ceramics can be adjusted by adjusting the content and proportion of the colorant (the vanadium pentoxide and the cobalt aluminate) in the zirconia powder. The invention solves the technical effects that the pigment can not reach the uniform dispersion state of the grain size in the traditional physical pigment mixing mode, and the metal salt can not be completely precipitated easily in the coprecipitation colorant adding mode.

The prior art adopts a method of uniformly mixing the colorant and the yttrium-stabilized zirconia or zirconium hydroxide precursor, and has the defects of large colorant consumption, low efficiency and the like.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides a jade-colored zirconia ceramic and a preparation method thereof.

The invention adopts the following technical scheme:

a preparation method of the bicolor zirconia ceramic comprises the following steps:

step one, mixing iso-octoate, an organic solvent and an auxiliary agent to prepare a color agent solution;

secondly, laying the toner solution obtained in the step one on the surface of the zirconia green body to obtain a colored zirconia green body;

step three, sintering the colored zirconia green body obtained in the step two to obtain a dark brown zirconia ceramic or a dark brown zirconia ceramic blank;

step one the isooctoate comprises nickel isooctanoate;

and step two, the zirconia blank is prepared by molding a mixture of metal oxide and zirconia and then primarily sintering.

According to one preferable scheme of the preparation method of the green zirconia ceramic, the isooctoate also comprises cobalt isooctanoate and/or chromium isooctanoate.

According to another preferable scheme of the preparation method of the green zirconia ceramic, the molar ratio of the cobalt isooctanoate, the chromium isooctanoate and the nickel isooctanoate is a: b: c, wherein a is more than 0 and less than 0.25, b is more than 0 and less than 0.25, and c is more than 0.5 and less than 0.75.

According to another preferable scheme of the preparation method of the dark colored zirconia ceramic, the metal oxide is rare earth oxide.

According to another preferable scheme of the preparation method of the dark-colored zirconia ceramic, the rare earth oxide is yttrium oxide.

According to another preferable scheme of the preparation method of the dark colored zirconia ceramic, the organic solvent is at least one of hydrocarbons, ketones and ethers; the auxiliary agent is at least one of a dispersant, a surfactant and an auxiliary penetrating agent.

In another preferable embodiment of the preparation method of the bi-colored zirconia ceramic, the hydrocarbons are aliphatic hydrocarbons and/or aromatic hydrocarbons, and halogenated hydrocarbons of the aliphatic hydrocarbons and/or aromatic hydrocarbons; the ketone is N-methylpyrrolidone (NMP).

According to another preferable scheme of the preparation method of the Bill zirconia ceramic, the aliphatic hydrocarbon is naphtha, and the ether is diethylene glycol dibutyl ether.

According to another preferable scheme of the preparation method of the bi-colored zirconia ceramic, the color agent solution is laid in the third step, and the dosage of the color agent solution is 0.01ml/cm based on the surface area of the zirconia ceramic²-0.5ml/cm²。

According to another preferable scheme of the preparation method of the bicolor zirconia ceramic, the color agent solution is laid, one end of the zirconia molded blank is erected in the color agent solution, and the color agent solution gradually extends upwards along micropores on the surface of the zirconia molded blank and permeates into the micropores on the surface of the zirconia molded blank. The concentration of the colorant solution is made to differ from one end of the zirconia green body to the other.

According to another preferable scheme of the preparation method of the dark colored zirconia ceramic, the metal oxide is at least one of calcium oxide, magnesium oxide, rare earth oxide and aluminum oxide. Among the rare earth oxides, yttrium oxide is preferred.

In still another preferable scheme of the preparation method of the dark colored zirconia ceramic of the invention,

the invention also provides the bicolor zirconia ceramic, and the bicolor zirconia ceramic is positioned on the surface and/or the light surface layer of the zirconia ceramic.

One of the preferred embodiments of the present invention relates to a bi-colored zirconia ceramic, which is prepared by the method of any one of claims 1 to 8.

According to still another preferable embodiment of the bi-colored zirconia ceramic of the present invention, the bi-color is a gradual color gradually changing from dark to light.

According to another preferable scheme of the bicolor zirconia ceramic, pretreatment liquid is laid on the surface of the zirconia blank before the second step. To control the thickness of the blue color development.

According to another preferable scheme of the invention, the white zirconia ceramic body is soaked in the pretreatment solution, taken out, dried and soaked in the coloring agent solution.

According to one preferable scheme of the bicolor zirconia ceramic, the pretreatment solution is an organic solvent for preparing a color solution or a mixture of the organic solvent and an auxiliary agent.

The invention has the beneficial effects that: the prepared jade-colored zirconia ceramic can realize uniform color on the surface, can also realize gradually-changed color from dark color to light color in a directional manner, has controllable color development depth, small using amount of pigment and reduced sintering temperature, has the general visual effect of green and semitransparent jade after being formed into ceramic at the high temperature of more than 1400 ℃, and keeps the physical properties of density, bending strength and the like basically unchanged.

Drawings

FIG. 1 is a schematic view of example 1 of the present invention, which is a top-down gray shade.

FIG. 2 is a schematic view of example 2 of the present invention, which is a top-down gray shade.

FIG. 3 is a schematic view of example 3 of the present invention, which is a top-down gray shade.

FIG. 4 is a schematic view of example 4 of the present invention, showing a uniform and dark color.

FIG. 5 is a schematic view of example 5 of the present invention, which is a uniform and dark color.

Fig. 6 is a schematic view of embodiment 6 of the present invention, wherein the top-down color is gradually darker.

FIG. 7 is a schematic view of example 7 of the present invention, showing a uniform bluish color.

FIG. 8 is a schematic representation of a comparative example of the present invention, shown in white.

FIG. 9 is a 40-fold enlarged schematic of the surface of a comparative example of the present invention.

FIG. 10 is a 40 times magnification of the surface of example 1 of the present invention.

Fig. 11 is a schematic light-transmitting view of embodiment 1 of the present invention.

FIG. 12 is a schematic cross-sectional view of example 2 of the present invention.

Fig. 13 is a schematic cross-sectional view of embodiment 3 of the present invention.

FIG. 14 is a schematic cross-sectional view of example 8 of the present invention.

Detailed Description

Comparative example

See fig. 8 and 9.

Burning the powder material obtained by uniformly mixing yttrium oxide and zirconium dioxide to prepare powder material particles with the specific surface of 9, grinding the powder material particles to obtain slurry with the D50 particle size of 0.15 mu m, drying the slurry, pressing and forming a zirconium oxide ceramic blank with the thickness of about 3mm or 10mm, and then carrying out isostatic pressing and calcining at the temperature of 650 ℃ to obtain the zirconium oxide ceramic blank.

Sintering the calcined zirconia ceramic body into ceramic at the temperature of 1480 ℃ to obtain a white zirconia ceramic body. The relevant detection data of the ceramic blank of the zirconia ceramic product are shown in the following table 1. The white zirconia ceramic blank weighed about 85 parts by weight and was 2.4 mm thick. The prepared white zirconia ceramics turns yellow or has yellow patches after long-term use, the yellow color of the surface gradually deepens along with the use time, and trace iron elements and other impurities can be detected on the yellow surface or the yellow patches after washing.

After the surface of the white zirconia ceramic is enlarged by 40 times, a plurality of pits or micropores with different sizes are formed on the surface.

Example 1

See fig. 1 and fig. 10, 11.

Step one, according to molar ratio, cobalt isooctanoate: chromium isooctanoate: preparing 45 parts by weight of nickel isooctanoate, adding 50 parts by weight of naphtha, 5 parts by weight of dispersant, 5 parts by weight of surfactant and 5 parts by weight of permeation promoter, grinding and mixing to obtain a toner solution.

Step two, the toner solution in the step one is added according to the surface area of 0.01ml/cm²Spraying the mixture on the surface of the zirconia ceramic blank to obtain the colored zirconia ceramicA green body;

and step three, sintering the colored zirconia ceramic blank at 1450 ℃ after the colored zirconia ceramic blank is dried to obtain the dark-colored gradient zirconia ceramic blank with compact surface, few micropores and small size. Further processing the ceramic into the jade color gradient zirconia ceramic. The jade color is basically unchanged after the surface of the jade color gradient zirconia ceramic is processed, the outer layer with the diameter of about 0.5mm is seen in the cross section of the jade color gradient zirconia ceramic and is in the jade color, and the middle part of the jade color gradient zirconia ceramic is in the white color. When light is transmitted from the back surface, the gradual change color is more obvious and is semitransparent, and other objects between a light source and the blue gradual change zirconia ceramic blank can be seen from the front surface. After the prepared jade color gradient zirconia ceramic is used for a long time, the jade color gradient zirconia ceramic does not change color, and no iron element is detected on the surface after conventional washing, so that the surface compactness of the jade color gradient zirconia ceramic is superior to that of the white zirconia ceramic in a comparative example. The obtained jade-colored zirconia ceramics has softer color and can show semitransparent jade feeling after the cobalt isooctanoate and the chromium isooctanoate are added into the color agent solution. The green graded zirconia ceramic green weighed about 88.7 parts by weight, calculated as about 0.005 parts by weight cobalt oxide in terms of oxides, 0.01 parts by weight chromium oxide, and about 0.06 parts by weight nickel oxide in terms of nickel oxide.

The data of the green-colored graded zirconia ceramic blank after sintering are shown in table 1.

Example 2

See fig. 2, 12.

The toner solution described in example 1 was added in an amount of 0.2ml/cm in terms of surface area²Spraying the mixture on a zirconia ceramic blank body in the comparative example, drying the zirconia ceramic blank body, and sintering the dried zirconia ceramic blank body into porcelain at 1400 ℃ to obtain the jade-color gradient zirconia ceramic blank. Further processing the ceramic into the jade color gradient zirconia ceramic. The jade color is basically unchanged after the surface of the jade color gradient zirconia ceramic is processed, the outer surface layer of the cross section is seen to be jade, and the center is white. After long-term use, the blue-color gradually-changed zirconia ceramic knife does not change color. The green color gradient zirconia ceramic blank weighs about 127.64 parts, has a thickness of about 15 mm, and has a visible color development depth of 2.5-3 mm. The color former such as nickel isooctanoate is calculated to be about 0.005 parts by weight of cobalt oxide, 0.01 parts by weight of chromium oxide,0.075 part by weight of nickel oxide.

Example 3

See fig. 3 and 13.

According to molar ratio, cobalt isooctanoate: chromium isooctanoate: preparing 45 parts by weight of nickel isooctanoate (0.24: 0.24: 0.52), adding 50 parts by weight of naphtha, 5 parts by weight of dispersant, 5 parts by weight of surfactant and 5 parts by weight of permeation promoter, grinding and mixing to obtain a toner solution.

The toner solution was measured at a surface area of 0.1ml/cm²Spraying the mixture on a zirconia ceramic blank body in the comparative example, drying, and sintering at 1480 ℃ to obtain the jade-color gradient zirconia ceramic blank. Further processing the ceramic into the jade color gradient zirconia ceramic. The jade color is basically unchanged after the surface of the jade color gradient zirconia ceramic blank is processed, the outer layer of the cross section is seen to be jade, and the center of the cross section is white. After long-term use, the blue-color gradually-changed zirconia ceramic knife does not change color. The green gradient zirconia ceramic blank weighs about 129.31 parts by weight and has a thickness of 15 mm. Calculated by the weight of nickel isooctanoate and so on calculated as oxide about cobalt oxide 0.01 parts, chromium oxide 0.01 parts, nickel oxide 0.03 parts.

Example 4

See fig. 4.

According to molar ratio, cobalt isooctanoate: chromium isooctanoate: preparing 30 parts by weight of nickel isooctanoate with the weight ratio of 0.15:0.11:0.74, adding 70 parts by weight of naphtha, 5 parts by weight of surfactant and 5 parts by weight of permeation promoter, grinding and mixing to obtain a toner solution; the toner solution was measured at a surface area of 0.4ml/cm²The mixture is coated on the zirconia ceramic blank body of the comparative example, and sintered into porcelain under the condition of 1450 ℃ after being dried, so that the jade uniform zirconia ceramic blank is obtained. Further processed into the jade-colored zirconia ceramics. After the surface of the zirconium oxide ceramic blank with uniform dark color is added, the dark color is unchanged, the cross section of the zirconium oxide ceramic blank is dark color, and the dark color in the center is slightly weak. After long-term use, the blue zirconia ceramics do not change color. The green gradient zirconia ceramic blank weighs about 87.13 parts by weight and has a thickness of 6 mm. Calculated, the nickel isooctanoate is 0.007 weight portions of cobalt oxide, 0.005 weight portions of chromium oxide and 0.072 weight portions of nickel oxide in terms of oxides.

Example 5

See fig. 5.

According to molar ratio, cobalt isooctanoate: chromium isooctanoate: 5 parts by weight of nickel isooctanoate is prepared according to the proportion of 0.15:0.24:0.61, 90 parts by weight of naphtha and 10 parts by weight of surfactant are added for grinding and mixing for 2 hours to prepare a toner solution; soaking the zirconia ceramic body in the toner solution to obtain a colored ceramic body, wherein the usage amount of the toner solution is about 0.5ml/cm²And drying and sintering the mixture into porcelain at 1500 ℃ to obtain the jade uniform zirconia ceramic blank. Further processed into the jade-colored zirconia ceramics. The green gradient zirconia ceramic blank weighs about 89.49 parts by weight and has a thickness of 2.8 mm. Calculated, the cobalt oxide 0.008 weight portion, the chromium oxide 0.012 weight portion, the nickel oxide 0.055 weight portion are counted by nickel isooctanoate and the like.

The data of the green-colored zirconia ceramic green body measured after sintering are detailed in table 1 below.

Example 6

See fig. 6.

Adding 35 parts by weight of nickel isooctanoate into 55 parts by weight of naphtha and 10 parts by weight of surfactant, grinding and mixing for 2 hours to prepare a toner solution;

the toner solution was applied at a surface area of about 0.05ml/cm²The powder is sprayed on the surface of a zirconia ceramic blank in the comparative example, dried and sintered into porcelain at the temperature of 1480 ℃ to obtain the jade gradual change zirconia ceramic blank. The green graded zirconia ceramic blank weighed about 87.83 parts by weight, calculated as nickel isooctanoate, about 0.11 parts by weight calculated as nickel oxide.

Example 7

See fig. 7.

According to molar ratio, cobalt isooctanoate: preparing 8 parts by weight of nickel isooctanoate with the ratio of 0.15:0.85, adding 82 parts by weight of naphtha, 5 parts by weight of surfactant and 5 parts by weight of permeation promoter, grinding and mixing for 3 hours to prepare a toner solution;

preparing the slurry in the comparative example into a zirconia ceramic knife blank with the thickness of 1.8mm, and calcining the blank at 950 ℃ after isostatic pressing to obtain a calcined white zirconia ceramic knife blank; then, the toner solution was added to the mixture in such a manner that the surface area of the toner solution was 0.1ml/cm²And coating the mixture on a calcined ceramic knife blank, drying, and sintering at 1450 ℃ to obtain the jade uniform zirconia ceramic knife.

The color of the obtained jade uniform zirconia ceramics is softer after the cobalt iso-octoate is added into the color agent solution.

The green gradient zirconia ceramic blank weighs about 84.87 parts by weight and has a thickness of 2.5 mm. The calculated amount of nickel isooctanoate is about 0.01 weight part of cobalt oxide and 0.07 weight part of nickel oxide calculated by oxide.

Example 8

See fig. 14.

50 parts by weight of naphtha, 5 parts by weight of a dispersant, 5 parts by weight of a surfactant and 5 parts by weight of a permeation promoter are mixed to prepare a pretreatment solution.

The white zirconia ceramic ball blank with the diameter of about 10mm prepared in the comparative example is soaked in the pretreatment solution, taken out, dried and soaked in the color agent solution described in the example 3 (the dosage of the color agent solution is less than 0.1ml/cm based on the surface area of the white zirconia ceramic ball blank)²) Obtaining a colored zirconia ceramic ball blank, drying the blank, and sintering the blank into ceramic at the temperature of 1480 ℃ to obtain the zirconia ceramic ball blank with uniform and jade color on the surface. And further processing the mixture into the zirconium oxide ceramic balls with the jade uniform surface. The cross section of the zirconia ceramic ball with the uniformly dark color on the surface is a dark color ring with the outermost ring of about 0.2mm and the inside is white.

The zirconia ceramic balls with the uniformly dark-colored surfaces are used as grinding media for a long time, and when the dark-colored rings are worn and the parts of the dark-colored rings are exposed to be white, the grinding media are prompted to be replaced. Therefore, the surface jade color uniform zirconia ceramic ball can be mixed with a white zirconia ceramic ball for use, and the surface jade color uniform zirconia ceramic ball is used as a marker for replacing a grinding medium.

The white zirconia ceramic body is soaked in the pretreatment liquid, the pretreatment liquid left in the micropores after the surface is dried occupies the deeper part of the micropores on the surface of the white zirconia ceramic body, and the pigment solution is prevented from penetrating into the deeper part of the inside of the white zirconia ceramic body along the micropores, so that the pigment solution can only penetrate to the shallower part of the surface of the white zirconia ceramic body along the micropores. During sintering, the pretreatment liquid escapes along the micropores, and meanwhile, the toner solution is brought to the surface of the zirconia ceramic ball blank, and finally, a thin blue ring is formed on the surface of the blue zirconia ceramic ball blank.

The amount of the pretreatment liquid left in the micropores after the surface is dried and the amount of the color solution laid on the surface of the zirconia ceramic blank can be controlled to control the color development depth of the bi-color zirconia ceramic blank and the bi-color zirconia ceramic surface. The amount of the colorant solution can be reduced, and the color development efficiency of the colorant can be improved.

After the above examples are used for a long time, no trace iron element impurities are detected on the surface after washing.

TABLE 1

Table 1 three test value test positions in each example: the gradual change of the gray color is three points at different positions on a straight line in the gradual change direction; the uniform and dark color is any different position.

As can be seen from table 1, the bicolor zirconia ceramic product ceramics prepared in the embodiments realize various situations of different shades of different colors, different color thicknesses, gradual change of the bicolor colors, uniform bicolor colors and the like under different parameter conditions, and simultaneously satisfy the condition that the zirconia ceramics forms porcelain at a temperature of above 1400 ℃, and the main physical property indexes of the ceramics are closer than those of a white zirconia ceramic knife. Because substances such as nickel isooctanoate, cobalt isooctanoate, chromium isooctanoate and the like in the color agent solution penetrate into micropores on the surface of the zirconium oxide ceramic blank and are converted into other substances after sintering, most of gaps in the zirconium oxide ceramic are filled, the density and the compactness of the surface of the zirconium oxide are improved, and the penetration of other substances in the using process can be prevented.

The components in the above embodiments may be combined and adjusted according to actual situations, and for brevity of description, all possible combinations of the technical features in the above embodiments are not described, however, as long as there is no contradiction between the combinations of the technical features, the combinations should be considered as being within the scope of the description in the present specification.

Finally, the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all of them should be covered in the claims of the present invention.

Claims

1. The preparation method of the bicolor zirconia ceramic is characterized by comprising the following steps:

secondly, laying the toner solution obtained in the step one on the surface of the zirconia ceramic blank to obtain a colored zirconia ceramic blank;

step three, sintering the colored zirconia green body obtained in the step two to obtain a dark brown zirconia ceramic blank or a dark brown zirconia ceramic;

step one the isooctoate comprises nickel isooctanoate;

and step two, the zirconia ceramic body is prepared by molding a mixture of metal oxide and zirconia and then primarily sintering.

2. The method of claim 1, wherein the isooctoate further comprises cobalt isooctanoate and/or chromium isooctanoate.

3. The method of claim 2, wherein the cobalt isooctanoate, chromium isooctanoate and nickel isooctanoate are present in a molar ratio a: b: c, wherein 0 < a < 0.25, 0 < b < 0.25, 0.5 < c < 0.75.

4. The method for preparing a bicolor zirconia ceramic according to claims 1, 2 and 3, wherein the metal is oxidized to a rare earth oxide. The rare earth oxide is preferably yttria.

5. The peccant zirconia ceramic of claim 4, wherein the organic solvent is at least one of a hydrocarbon, a ketone, an ether; the auxiliary agent is at least one of a dispersant, a surfactant and an auxiliary penetrating agent.

6. The method for preparing the bi-colored zirconia ceramic according to claim 5, wherein the hydrocarbon is aliphatic hydrocarbon and/or aromatic hydrocarbon, and halogenated hydrocarbon of the aliphatic hydrocarbon and/or aromatic hydrocarbon; the ketone is N-methylpyrrolidone (NMP).

7. The method of preparing the peclet-colored zirconia ceramic of claim 6, wherein the aliphatic hydrocarbon is naphtha and the ether is diethylene glycol dibutyl ether.

8. The bicolor zirconia ceramic is characterized in that the bicolor color is positioned on the surface and/or a shallow surface layer of the zirconia ceramic.

9. The pecan zirconia ceramic of claim 8, prepared by the method of any one of claims 1 to 8.

10. The bi-colored zirconia ceramic of claim 8 or 9, wherein the bi-color is a gradual color that gradually lightens from dark to dark from one end to the other.