Ceramic composite material having patterns of various colors, and manufacturing method therefor

Abstract

Disclosed are a ceramic composite material and a manufacturing method therefor, the ceramic composite material comprising at least one set of a first layer and a second layer, wherein the first layer comprises spherical zirconia particles, and the second layer comprises 60-95 wt% of spherical zirconia particles and 5-40 wt% of aluminum oxide. The ceramic composite material has superior mechanical properties and unique patterns of various colors.

Description

Ceramic composite material with patterns of various colors and method for manufacturing the same

[0001] The present invention relates to a ceramic composite material having patterns of various colors formed thereon and a method for manufacturing the same, and more particularly, to a ceramic composite material having patterns of various colors formed thereon and a method for manufacturing the same, based on a ceramic material, with a unique pattern implemented thereon.

[0002]

[0003] When ceramic materials are subjected to rapid temperature changes, internal stresses and volume changes can cause cracks on the surface, ultimately leading to failure. Therefore, for various heat-resistant or insulating devices and materials, resistance to thermal shock—that is, heat resistance—is paramount.

[0004] Therefore, among ceramic materials, zirconia, which has excellent structural properties, is widely used as a structural ceramic. Zirconium dioxide (ZrO2), also known as zirconia, is a white crystalline oxide and is the ceramic material closest to metal. It has excellent properties such as high heat resistance, low thermal conductivity, chemical stability, high strength, high hardness, and high fracture toughness, and is used as a heat-resistant material for glass melting, iron and steel making, etc. On the other hand, zirconia has limited applications due to the high brittleness inherent in ceramic materials.

[0005] However, since it was discovered that zirconia can overcome the brittleness inherent in ceramics, it has been utilized in a variety of fields. In particular, recent efforts have been actively underway to apply it to decorative items requiring superior mechanical properties, such as watch bezels, cases, and watch bands, as well as substrates for various mechanical and electronic components.

[0006] Furthermore, with the improvement of living standards, zirconia is being used not only in watches but also in jewelry, leading to an increase in demand for zirconia in various colors. Meanwhile, when coloring zirconia with various colors, it must be able to maintain its color even during high-temperature firing without affecting its excellent physical and chemical properties. The various colored zirconias developed so far have been colored by adding metallic pigments to zirconia, but this method has the disadvantage of destroying the stability of zirconia and reducing its mechanical properties. Furthermore, as zirconia undergoes structural changes from monoclinic to tetragonal to cubic depending on temperature, the volume change due to phase transition upon cooling exceeds its deformation resistance, which can lead to cracking.

[0007] Therefore, in addition to the degradation of zirconia's properties due to metallic pigments, zirconia also suffers from cracks that prevent it from retaining its original color. To complement these structural properties, active research is being conducted on composite materials that incorporate aluminum oxide (Al2O3) into zirconia.

[0008] Furthermore, when manufacturing decorative items using composite materials blending stabilized zirconia and aluminum oxide, not only color but also pattern are becoming important factors. Therefore, research is needed to improve the mechanical properties of these composites while developing ceramic composites with diverse colored patterns.

[0009]

[0010] The present invention was created in consideration of the above-mentioned points, and the purpose of the present invention is to provide a ceramic composite material having a unique pattern formed by laminating a composite material using aluminum oxide based on a ceramic material, and a method for manufacturing the same, in which patterns of various colors are formed with improved mechanical properties.

[0011]

[0012] In order to achieve the above-mentioned purpose, a ceramic composite material having patterns of various colors formed according to the present invention is characterized in that a first layer and a second layer form a set, and at least one of the sets is included, the first layer includes zirconia spherical particles, and the second layer includes 60 to 95 wt% of zirconia spherical particles and 5 to 40 wt% of aluminum oxide.

[0013] The above ceramic composite material further includes a pigment, and the pigment is characterized in that it includes at least one of magnesium oxide, zinc oxide, nickel oxide, cobalt oxide, manganese oxide, iron oxide, and copper oxide.

[0014] The above zirconia spherical particles are characterized in that they are manufactured by including a step of manufacturing a mixture by dissolving 93 to 95 wt% of partially stabilized zirconia powder, 1 to 5 wt% of a binder, 1 to 5 wt% of a dispersant, and 1 to 5 wt% of an antifoaming agent in water; and a step of spray-drying the mixture at 150 to 230°C.

[0015] The above-mentioned partially stabilized zirconia powder is a powder in which a small amount of a metal stabilizer is added to the zirconia powder, and the metal stabilizer is characterized by including at least one of yttrium oxide (Y2O3), magnesium oxide (MgO), calcium oxide (CaO), and cerium oxide (Ce2O3).

[0016] A pigment-free ceramic composite material having patterns of various colors formed thereon, characterized in that it satisfies the conditions (a) to (c) below.

[0017] (a) Breaking strength of 800 MPa or more

[0018] (b) Fracture toughness 4.4 MPa·m 1 / 2 more

[0019] (c) Hardness of 1020 MPa or more

[0020] The above various colors are characterized by at least one of white, gray, black, blue, tan, yellow-brown, red, green, and pink.

[0021] The method for manufacturing a ceramic composite material according to the present invention comprises: a first step of preparing a composite by mixing at least one of zirconia spherical particles and aluminum oxide; a second step of forming a molded body by loading the composite into an embossing mold and laminating it to form a multilayer, and applying a pressure of 700 to 1,500 kgf / cm2 to form a pattern; a third step of degreasing and heat-treating the molded body by first heating it at 155 to 175°C for 30 to 40 hours and then secondarily heating it at 650 to 850°C for 30 to 40 hours; a step 3-2 of pre-sintering the degreasing and heat-treated molded body at 1450 to 1550°C; and a sintering pre-treated molded body in a vacuum at an atmospheric pressure of 10 -1 ~ 10 -5 Torr, and the sintering temperature is 1550 to 1700℃, including the fourth step;

[0022] A method for manufacturing a ceramic composite material according to the present invention comprises: a first step of preparing a composite by mixing at least one of zirconia spherical particles and aluminum oxide; a second step of forming a multilayer by inserting the composite into an embossing mold and laminating it, and applying a pressure of 700 to 1,500 kgf / cm2 to obtain a molded body having a pattern; a third step of degreasing and heat-treating the molded body by first heating it at 155 to 175°C for 30 to 40 hours and then secondarily heating it at 650 to 850°C for 30 to 40 hours; and a fourth step of heating the degreasing and heat-treated molded body from room temperature to a sintering temperature of 1450 to 1550°C and then heating it at the sintering temperature for 1.5 to 2.5 hours to sinter it.

[0023] In the second step, the multilayer is characterized in that the first layer and the second layer form a set, and at least one of the sets is included, the first layer includes zirconia spherical particles, and the second layer includes 60 to 95 wt% of zirconia spherical particles and 5 to 40 wt% of aluminum oxide.

[0024] The above complex further comprises a pigment, and the pigment is characterized in that it comprises at least one selected from magnesium oxide, zinc oxide, nickel oxide, cobalt oxide, manganese oxide, iron oxide, and copper oxide.

[0025] The above zirconia spherical particles are characterized in that they are manufactured by including a step of manufacturing a mixture by dissolving 93 to 95 wt% of partially stabilized zirconia powder, 1 to 5 wt% of a binder, 1 to 5 wt% of a dispersant, and 1 to 5 wt% of an antifoaming agent in water; and a step of spray-drying the mixture at 150 to 230°C.

[0026] The above-mentioned partially stabilized zirconia powder is a powder in which a small amount of a metal stabilizer is added to the zirconia powder, and the metal stabilizer is characterized by including at least one of yttria (Y2O3), magnesium oxide (MgO), calcium oxide (CaO), and cerium oxide (Ce2O3).

[0027] In the second step, the molded body is obtained by using at least one of extrusion molding and injection molding of the complex.

[0028] It is characterized by ceramic parts with patterns implemented through a method of manufacturing ceramic composite materials with patterns of various colors.

[0029]

[0030] A ceramic composite material having patterns of various colors formed according to the present invention comprises a first layer and a second layer as a set, and includes at least one of the sets, wherein the first layer includes zirconia spherical particles, and the second layer includes 60 to 95 wt% of zirconia spherical particles and 5 to 40 wt% of aluminum oxide, thereby not only improving mechanical properties such as tensile strength and hardness, but also implementing patterns in various colors.

[0031] In addition, the method for manufacturing a ceramic composite material having a pattern of various colors according to the present invention comprises: a first step of preparing a composite by mixing at least one of zirconia spherical particles and aluminum oxide; a second step of loading the composite into an embossing mold to laminate the composite to form a multilayer, and applying a pressure of 700 to 1,500 kgf / cm2 to obtain a molded body having a pattern; a third step of degreasing and heat-treating the molded body by first heating it at 155 to 175°C for 30 to 40 hours and then secondarily heating it at 650 to 850°C for 30 to 40 hours; a third-second step of pre-sintering the degreasing and heat-treated molded body at 1450 to 1550°C; and a sintering pre-treated molded body in a vacuum at an atmospheric pressure of 10 -1 ~ 10 -5 Torr, and the sintering temperature is 1550 to 1700℃, which includes the fourth step; and has the effect of providing a unique pattern that is standardized.

[0032]

[0033] Figure 1 is an EDS analysis photograph of zirconia.

[0034] Figure 2 shows a laminated structure of a ceramic composite material according to an embodiment of the present invention.

[0035] Figure 3 shows a ceramic composite material having patterns of various colors formed according to an embodiment of the present invention.

[0036] Figures 4 and 5 are watch parts to which a ceramic composite material according to an embodiment of the present invention is applied.

[0037] Figure 6 is a knife to which a ceramic composite material according to an embodiment of the present invention is applied.

[0038]

[0039] All terms described in this specification are currently widely used and have been selected in consideration of the functions of the present invention. However, these terms may vary depending on the intentions of those skilled in the art, customs, or the emergence of new technologies. Furthermore, if the inventor specifies any term in the present invention, its meaning will be described in the description of the invention. Therefore, the terms used in the present invention should not be interpreted simply as names of terms, but rather based on their actual meaning and the overall content described in the description of the present invention.

[0040] Hereinafter, with reference to the attached drawings, a ceramic composite material having various colored patterns formed according to an embodiment of the present invention and a method for manufacturing the same will be described in detail. In the drawings, parts irrelevant to the description have been omitted to clearly explain the present invention, and the same reference numerals will be used throughout the specification to refer to identical or similar components.

[0041] The present invention provides a ceramic composite material having patterns of various colors formed thereon.

[0042] A ceramic composite material according to an embodiment of the present invention comprises a first layer and a second layer as a set, at least one of the sets is included, the first layer includes zirconia spherical particles, and the second layer includes 60 to 95 wt% of zirconia spherical particles and 5 to 40 wt% of aluminum oxide.

[0043] The above zirconia spherical particles are included in the ceramic composite material of the present invention.

[0044] The above zirconia spherical particles can be manufactured by including a step of manufacturing a mixture by dissolving 93 to 95 wt% of partially stabilized zirconia powder, 1 to 5 wt% of a binder, 1 to 5 wt% of a dispersant, and 1 to 5 wt% of an antifoaming agent in water; and a step of spray drying the mixture at 150 to 230°C.

[0045] The above zirconia spherical particles may include partially stabilized zirconia powder. The partially stabilized zirconia powder may be manufactured by adding a small amount of a metal stabilizer to pure zirconia powder. Zirconium dioxide (ZrO2), also known as zirconia, is a white crystalline oxide and is the ceramic material closest to metal. The zirconia has a density of 5.68 g / cm. 3 , has excellent material properties such as high heat resistance with a melting point of 2715℃ and a boiling point of 400℃, low thermal conductivity, chemical stability, high strength, high hardness, and high fracture toughness, and is used as a heat-resistant material for glass melting, iron and steel making, etc. Referring to Fig. 1, Table 1 shows the chemical composition of the above zirconia.

[0046] Chemical composition wt% wt% sigma B4.48 0.29 C5.53 0.29 O2 1.29 0.33 Zr 68.70 0.50 total 100.00

[0047] On the other hand, although zirconia has the same chemical composition, its structure can change depending on the temperature, which can change its physical properties. That is, the zirconia can be monoclinic from room temperature to 1170℃, and can change into tetragonal and cubic structures as the temperature rises. Therefore, zirconia that has been sintered at 1500℃ or higher into a tetragonal structure undergoes a phase transition to a monoclinic system when naturally cooled to 950℃ or lower. The zirconia that has undergone a phase transition is accompanied by a volume change of 3 to 5%, and the resulting stress can exceed the deformation resistance of the zirconia, which can cause cracks.

[0048] Therefore, in order to alleviate the problem of cracking during natural cooling after sintering of zirconia, in an embodiment of the present invention, a partially stabilized zirconia powder may be manufactured by adding a small amount of a metal stabilizer to the zirconia powder. The metal stabilizer may be selected from at least one of yttrium oxide (Y2O3), magnesium oxide (MgO), calcium oxide (CaO), and cerium oxide (Ce2O3). Accordingly, the yttrium oxide may be included in an amount of 2.5 to 3.5 mol% based on the total mol% of the zirconia powder. In addition, the magnesium oxide may be included in an amount of 8 to 9 mol% based on the total mol% of the zirconia powder, and the calcium oxide may be included in an amount of 8 to 9 mol% based on the total mol% of the zirconia powder. In an embodiment of the present invention, yttrium oxide may be mainly selected as the metal stabilizer. If the content of the metal stabilizer is less than the range, a volume change may occur due to a phase transition during natural cooling after sintering, which may exceed the deformation resistance, thereby causing cracking. If the content of the above metal stabilizer exceeds the range, it may be meaningless in terms of critical significance.

[0049] Thus, the density of the partially stabilized zirconia powder is 6.1 g / cm 3 As compared to zirconia powder, not only density but also hardness increases. Therefore, the partially stabilized zirconia powder can improve the density and sinterability of the ceramic composite material of the present invention. In addition, the partially stabilized zirconia powder has a square structure and exhibits high toughness at room temperature, which can mitigate cracking during natural cooling after sintering of the molded body and minimize changes in physical properties and color when coloring by pigments, which will be described later.

[0050] In addition, the zirconia spherical particles may include a binder. The binder not only binds each component but also softens the mixture, thereby increasing fluidity and filling the voids with the powder, thereby improving density. Therefore, the binder may affect the production of a molded article having a high density. Accordingly, the binder may be selected from a polyvinyl alcohol-based binder, an acrylic resin, etc. In an embodiment of the present invention, the binder may mainly be selected from a polyvinyl alcohol-based binder. The polyvinyl alcohol-based binder is water-soluble and can dissolve in water to bind the partially stabilized zirconia powder particles. Therefore, the binder may be included in an amount of 1 to 5 wt% based on the total weight of the zirconia spherical particles. In another embodiment, the binder may be included in an amount of 1 to 4 wt% based on the total weight of the zirconia spherical particles.

[0051] In addition, the zirconia spherical particles may include a dispersant. The dispersant can evenly disperse each component to make the composition of each spherical particle uniform. In other words, the dispersant can prevent the generated microparticles from re-agglomerating when large particles and aggregated particles are converted into smaller particles. Therefore, the dispersant may use an adsorbent material such as a surfactant or a polymer material. The dispersant may be selected from a polycarboxylic acid ammonium-based, alkylamine-based, or silicone-based surfactant. In an embodiment of the present invention, a polycarboxylic acid ammonium salt-based dispersant may be mainly selected. The polycarboxylic acid ammonium salt-based dispersant does not contain a sulfur component and thus may not adversely affect the molded body. Therefore, the dispersant may be included in an amount of 1 to 5 wt% based on the total weight of the zirconia spherical particles. In another embodiment, the dispersant may be included in an amount of 2 to 3 wt% based on the total weight of the zirconia spherical particles.

[0052] In addition, the zirconia spherical particles may include a defoaming agent. The defoaming agent can remove harmful bubbles and thus has an excellent foam suppression effect. Therefore, the defoaming agent may be selected from organic phosphates, alcohols, etc. In an embodiment of the present invention, a polyether-based dispersant may be mainly selected. Therefore, the defoaming agent may be included in an amount of 1 to 5 wt% based on the total weight of the zirconia spherical particles. In another embodiment, the defoaming agent may be included in an amount of 1 to 2 wt% based on the total weight of the zirconia spherical particles.

[0053] The above aluminum oxide (Al2O3) is included in the ceramic composite material of the present invention.

[0054] The above aluminum oxide, based on strong ionic bonds, has the highest strength among oxides. Furthermore, aluminum oxide is known to have excellent corrosion and chemical resistance. Therefore, to complement the structural characteristics of zirconia, adding aluminum oxide (Al2O3) to zirconia can improve its thermal shock resistance. In addition to improving thermal shock resistance, adding aluminum oxide to zirconia not only improves its physical properties but also minimizes color change upon cooling.

[0055] In addition, the average particle size of the zirconia spherical particles and the aluminum oxide may be 50 to 80 nm. When the average particle size of the zirconia spherical particles and the aluminum oxide is nanocrystalline, excellent formability is provided and the mechanical properties of the present invention can be improved. This is because the particle distribution is more uniform as the present invention is formed with a uniform nanoparticle size, thereby preventing grain growth.

[0056] Therefore, if the average particle size is less than 50 nm, shrinkage may occur during sintering. In addition, if the average particle size exceeds 80 nm, sintering may not occur properly, which may affect the mechanical properties and may cause color deterioration.

[0057] In addition, the ceramic composite material may have a structure in which the first layer is composed of zirconia spherical particles, the second layer is composed of 60 to 95 wt% of zirconia spherical particles and 5 to 40 wt% of aluminum oxide, such that the first layer and the second layer form a set and include at least one of the sets. Alternatively, the multilayer may be formed by laminating at least one or more of the first layer or the second layer. In another embodiment, the ceramic composite material may have a structure in which the first layer is composed of zirconia spherical particles, the second layer is composed of 75 to 85 wt% of zirconia spherical particles and 15 to 25 wt% of aluminum oxide, such that the first layer and the second layer form a set and include at least one or more of the sets. Alternatively, the multilayer may be formed by laminating at least one or more of the first layer or the second layer.

[0058] Therefore, in the case of the second layer, if the content of the zirconia spherical particles is less than 60 wt%, sinterability may be reduced, making it difficult to obtain sufficient strength, and if the content of the zirconia spherical particles exceeds 95 wt%, a decrease in the content of aluminum oxide may occur, which may result in changes in mechanical properties and expressed color. In addition, if the content of the aluminum oxide is less than 5 wt%, durability and wear resistance may be reduced and changes in expressed color may occur, and if only the content of the aluminum oxide is increased to exceed 25 wt% while the particle size, sintering conditions, etc. of the aluminum oxide are fixed, mechanical properties may be reduced.

[0059] The ceramic composite material according to an embodiment of the present invention may further include a pigment.

[0060] The pigment may be selected from at least one of magnesium oxide, zinc oxide, nickel oxide, cobalt oxide, manganese oxide, iron oxide, and copper oxide. The pigment may react with aluminum oxide as a pigment reaction catalyst to form a spinel structure and exhibit color. Specifically, magnesium oxide and zinc oxide may exhibit white, nickel oxide and cobalt oxide may exhibit blue, manganese oxide may exhibit yellowish brown, iron oxide may exhibit yellowish brown, and copper oxide may exhibit blue, red, green, pink, gray, black, etc. depending on the particle size. In the present invention, the "spinel structure" refers to a ceramic having a molecular structure of AB2X4 (A and B are metal elements, X is oxygen, for example, A: Mg, Zn, Ni, Co, Mn, Fe, etc., B: Al, etc.). The spinel structure is a cubic lattice having a regular octahedral shape, in which oxygen atoms are almost completely packed in a cubic close-packed manner. That is, it has a structure in which the B atom is surrounded by six oxygen atoms in an octahedral configuration between the oxygen atoms, and the A atom is surrounded by four oxygen atoms in a tetrahedral configuration. Therefore, compounds with a spinel structure are stable at high temperatures and can easily form hybrid crystals, so they can secure a variety of color development and vivid colors.

[0061] Furthermore, the structure formed by the reaction between the pigment and aluminum oxide in the present invention can not only improve the mechanical properties of zirconia, particularly its corrosion resistance, but also enhance its aesthetics. Furthermore, the spinel structure can stabilize the pigmented color by suppressing color changes after sintering.

[0062] The ceramic composite material according to an embodiment of the present invention may further include at least one of Si, Mn, Cr, Co, Mo, V, and B.

[0063] The above silicon (Si) can be included in the ceramic composite material of the present invention. Silicon is a metalloid with a melting point of 1414°C and a boiling point of 3265°C. Silicon is hard but brittle. While stable and unreactive at room temperature, it becomes highly reactive at high temperatures or in a molten state, allowing it to react with other elements such as oxygen and nitrogen. Silicon in a molten state also readily forms alloys.

[0064] Accordingly, the ceramic composite material of the present invention may contain 0.025 to 0.030 wt% of silicon. If the silicon content is less than 0.025 wt%, problems may arise in terms of strength, etc. of the ceramic composite material. In addition, if the silicon content exceeds 0.030 wt%, problems may arise in terms of physical properties, etc. of the ceramic composite material as the content of other components decreases.

[0065] The manganese (Mn) may be included in the ceramic composite material of the present invention. Manganese is a transition element with a melting point of 1245°C and a boiling point of 1962°C. Since manganese has the effect of slightly increasing toughness, it may be included in the ceramic composite material of the present invention.

[0066] Accordingly, the ceramic composite material of the present invention may contain 0.40 to 0.60 wt% of manganese. If the manganese content is less than 0.40 wt%, problems may arise in the strength, corrosion resistance, and processability of the ceramic composite material. In addition, if the manganese content exceeds 0.60 wt%, a decrease in the hardness of the ceramic composite material may occur.

[0067] The above chromium (Cr) may be included in the ceramic composite material of the present invention. The above chromium

[0068] As a transition element, it has a melting point of 1,907℃ and a boiling point of 2.671℃. In addition, chromium is hard, shiny, and resistant to corrosion, so it is mainly used in tool steels, and can affect strength, heat treatment, etc. In addition, the combination of chromium and cobalt can provide very high wear resistance.

[0069] Accordingly, the ceramic composite material of the present invention may contain 9.90 to 11.00 wt% of chromium. If the content of chromium is less than 9.90 wt%, corrosion resistance of the ceramic composite material may be impaired. In addition, if the content of chromium exceeds 11.00 wt%, the content of other components may be reduced, which may cause problems with the wear resistance and strength of the extrusion mold.

[0070] The cobalt (Co) may be included in the ceramic composite material of the present invention. Cobalt (Co) is a transition element with a melting point of 1495°C and a boiling point of 2927°C. Because cobalt has a high melting temperature, the quenching temperature can be increased. Quenching can be used not only for cooling but also to prevent changes due to temperature increases caused by rapid heating. The quenching temperature of steel is generally around 750 to 800°C, but the quenching temperature can be increased using cobalt. If the temperature is higher than the quenching temperature, the grains become coarse and large, which not only prevents sufficient strength but also may cause cracks or warping.

[0071] Therefore, the ceramic composite material of the present invention may contain 9.50 to 10.00 wt% of cobalt. If the content of cobalt is below or above the range, there is a problem in that the quenching temperature is low, making it impossible to prevent changes during molding of the ceramic composite material of the present invention.

[0072] The above molybdenum (Mo) may be included in the ceramic composite material of the present invention. Molybdenum (Mo) is a transition metal with a melting point of 2617°C and a boiling point of 4650°C. Because molybdenum does not soften or corrode even in high temperatures, it can be primarily used as an alloying element for steel. Furthermore, molybdenum can be used as an alloying element to increase strength and tensile strength.

[0073] Accordingly, the ceramic composite material of the present invention may contain 1.90 to 2.30 wt% of molybdenum. If the content of molybdenum is less than 1.90 wt%, corrosion resistance, etc. cannot be improved when manufacturing watch parts using the ceramic composite material. In addition, if the content of molybdenum exceeds 2.30 wt%, excessive strength may cause cracks at high temperatures.

[0074] The above vanadium (V) may be included in the ceramic composite material of the present invention. Vanadium is a transition element with a melting point of 1910°C and a boiling point of 3407°C. Vanadium is widely used as an additive in iron and various alloys. In particular, when added to carbon steel, vanadium combines with carbon to form highly strong carbide, resulting in extremely high wear resistance.

[0075] Accordingly, the ceramic composite material of the present invention may contain 0.15 to 0.20 wt% of vanadium. If the content of vanadium is less than 0.15 wt%, problems may arise with the wear resistance of the ceramic composite material. In addition, if the content of vanadium exceeds 0.20 wt%, the excessive strength of the ceramic composite material may cause cracks at high pressure and temperature.

[0076] The above-mentioned boron (B) may be included in the ceramic composite material of the present invention. The boron forms a boride with the chromium, molybdenum, and vanadium, forming a composite intermetallic compound. Furthermore, the boron may enhance toughness and corrosion resistance, which are higher than those of carbon at the same hardness.

[0077] Accordingly, the ceramic composite material of the present invention may contain 0.5 wt% to 1.5 wt% of boron. When the boron content is less than 0.5 wt%, the toughness is excellent, but the hardness may be reduced. In addition, when the boron content exceeds 1.5 wt%, the hardness is increased, but the toughness may be reduced.

[0078]

[0079] [Method for manufacturing ceramic composite materials with patterns of various colors]

[0080] The present invention provides a method for manufacturing a ceramic composite material having patterns of various colors formed thereon.

[0081] A method for manufacturing a ceramic composite material according to an embodiment of the present invention comprises: a first step of preparing a composite by mixing at least one of zirconia spherical particles and aluminum oxide; a second step of loading the composite into an embossing mold to laminate the composite to form a multilayer, and applying a pressure of 700 to 1,500 kgf / cm2 to obtain a molded body having a pattern; a third step of degreasing and heat-treating the molded body by first heating it at 155 to 175°C for 30 to 40 hours and then secondarily heating it at 650 to 850°C for 30 to 40 hours; and a third-2 step of pre-sintering the degreasing and heat-treated molded body at 1450 to 1550°C; and a sintering pre-treated molded body in a vacuum at an atmospheric pressure of 10 -1 ~ 10 -5 Torr, and the sintering temperature is 1550 to 1700℃, including the fourth step;

[0082] As another embodiment, a method for manufacturing a ceramic composite material includes a first step of preparing a composite by mixing at least one of zirconia spherical particles and aluminum oxide; a second step of forming a molded body by inserting and laminating the composite into an embossing mold to form multiple layers and applying a pressure of 700 to 1,500 kgf / cm2 to form a pattern; a third step of degreasing and heat-treating the molded body by first heating it at 155 to 175°C for 30 to 40 hours and then secondarily heating it at 650 to 850°C for 30 to 40 hours; and a fourth step of heating the degreasing and heat-treated molded body from room temperature to a sintering temperature of 1450 to 1550°C and then heating it at the sintering temperature for 1.5 to 2.5 hours to sinter it.

[0083]

[0084] [Step 1] - Preparation of the complex

[0085] Step 1 involves preparing a composite by mixing at least one of zirconia spherical particles and aluminum oxide. The overlapping components described in the ceramic composite material will be briefly described.

[0086] The above zirconia spherical particles can be manufactured by including a step of preparing a mixture by dissolving 93 to 95 wt% of partially stabilized zirconia powder, 1 to 5 wt% of a binder, 1 to 5 wt% of a dispersant, and 1 to 5 wt% of an antifoaming agent in water; and a step of spray drying the mixture at 150 to 230°C. The partially stabilized zirconia powder is a powder in which a small amount of a metal stabilizer is added to the zirconia powder, and the metal stabilizer may include at least one of yttrium oxide (Y2O3), magnesium oxide (MgO), calcium oxide (CaO), and cerium oxide (Ce2O3). Accordingly, the yttrium oxide may be included in an amount of 2.5 to 3.5 mol% based on the total mol% of the zirconia powder. In addition, the magnesium oxide may be included in an amount of 8 to 9 mol% based on the total mol% of the zirconia powder, and the calcium oxide may be included in an amount of 8 to 9 mol% based on the total mol% of the zirconia powder. In embodiments of the present invention, yttrium oxide may be primarily selected as the metal stabilizer. If the content of the metal stabilizer falls below the specified range, a phase transition during natural cooling after sintering may cause volume changes, exceeding the deformation resistance and potentially causing cracks. If the content of the metal stabilizer exceeds the specified range, it may be insignificant in terms of critical significance.

[0087] Aluminum oxide, based on its strong ionic bonds, possesses the highest strength among oxides. Furthermore, aluminum oxide is known to possess excellent corrosion and chemical resistance. Therefore, to complement the structural properties of zirconia, aluminum oxide (Al2O3) can be incorporated into zirconia to enhance thermal shock resistance, improve physical properties, and minimize color change upon cooling.

[0088] In addition, the average particle size of the zirconia spherical particles and the aluminum oxide may be 50 to 80 nm. When the average particle size of the zirconia spherical particles and the aluminum oxide is nanocrystalline, excellent formability is provided and the mechanical properties of the present invention can be improved. This is because the particle distribution is more uniform as the present invention is formed with a uniform nanoparticle size, thereby preventing grain growth.

[0089] Accordingly, the composite may be composed of zirconia spherical particles, or may be composed of 60 to 95 wt% of zirconia spherical particles and 5 to 40 wt% of aluminum oxide. As another example, the composite may be composed of zirconia spherical particles, or may be composed of 75 to 85 wt% of zirconia spherical particles and 15 to 25 wt% of aluminum oxide.

[0090] In addition, the complex may further include a pigment. The pigment may include at least one selected from the group consisting of magnesium oxide, zinc oxide, nickel oxide, cobalt oxide, manganese oxide, iron oxide, and copper oxide. The pigment may react with aluminum oxide, which is a pigment reaction catalyst, to form a spinel structure to exhibit color. Specifically, magnesium oxide and zinc oxide may exhibit white, nickel oxide and cobalt oxide may exhibit blue, manganese oxide may exhibit yellowish brown, iron oxide may exhibit yellowish brown, and copper oxide may exhibit blue, red, green, pink, gray, black, etc. depending on the particle size. In the present invention, "spinel structure" means a ceramic having a molecular structure of AB2X4 (A and B are metal elements, X is oxygen, for example, A: Mg, Zn, Ni, Co, Mn, Fe, etc., B: Al, etc.). The spinel structure is a cubic lattice having a regular octahedral shape, in which oxygen atoms are almost completely packed in a cubic close-packed manner. That is, it has a structure in which the B atom is surrounded by six oxygen atoms in an octahedral configuration between the oxygen atoms, and the A atom is surrounded by four oxygen atoms in a tetrahedral configuration. Therefore, compounds with a spinel structure are stable at high temperatures and can easily form hybrid crystals, so they can secure a variety of color development and vivid colors.

[0091] Accordingly, the composite may not contain a pigment, or may contain a pigment. When the ceramic composite material of the present invention includes a pigment to realize various colors, a mixture is formed by mixing 10 to 20 wt% of the pigment with respect to the total weight% of the composite, and then mixed with a liquid material. The mixing may be performed by a method widely known in the art. Specifically, the liquid material may have a predetermined viscosity and may include a solvent, a lubricant, etc. Such a liquid material may be removed during a high-temperature sintering process. The solvent may be selected from at least one of water and an organic solvent, and specifically, at least one of water, ether, acetone, and alcohol (ethanol, etc.) may be selected. The lubricant may be selected as long as it is commonly used in the art.

[0092] Accordingly, the liquid material may contain 0.5 to 15 parts by weight of lubricant per 100 parts by weight of solvent. The mixture may be mixed with the liquid material at a weight ratio of 0.1 to 0.9:1. The mixture in which the liquid material is mixed may be placed in a stirrer and stirred, sprayed in the form of droplets using a sprayer, and then dried to produce a complex in the form of granules having a uniform size.

[0093] The above granulated complex can be obtained as a powder having an average particle size of 50 to 80 nm. If the average particle size of the powder is less than 50 nm, the granules may scatter during molding, making it difficult to control the density, and may cause shrinkage during firing. In addition, if the average particle size exceeds 80 nm, many air bubbles may exist after molding due to the pores created within the granules, which may affect the mechanical properties and there is a risk of color deterioration.

[0094]

[0095] [Step 2] - Plastic surgery

[0096] The second step is a step of forming a multilayer by loading the composite of the first step into an embossing mold and laminating it, and applying a pressure of 700 to 1,500 kgf / cm2 to obtain a molded body having a pattern. The multilayer may be formed by a set of a first layer and a second layer, and may include at least one of the sets. As another example, the multilayer may be formed by laminating at least one first layer or a second layer. The first layer may include zirconia spherical particles, and the second layer may include 60 to 95 wt% of zirconia spherical particles and 5 to 40 wt% of aluminum oxide. As another example, the first layer may include zirconia spherical particles, and the second layer may be composed of 75 to 85 wt% of zirconia spherical particles and 15 to 25 wt% of aluminum oxide.

[0097] In addition, as described in the first step, when the complex including the pigment forms a multilayer, the multilayer may further include a pigment. The pigment may include at least one selected from magnesium oxide, zinc oxide, nickel oxide, cobalt oxide, manganese oxide, iron oxide, and copper oxide. That is, the first layer may include zirconia spherical particles and a pigment, and the second layer may include zirconia spherical particles, aluminum oxide, and a pigment.

[0098] Accordingly, the multilayer is formed by stacking the complex containing or not containing pigment into an embossing mold. Referring to Fig. 2, the granulated complex is shown to be stacked.

[0099] In addition, a molded body having a pattern can be obtained by applying a pressure of 700 to 1,500 kgf / cm2 to the embossing mold having multiple layers formed thereon. The molded body can have any shape as a bulk form before being processed into a finished product. That is, the molded body can have various shapes such as a ring, a circular plate, a polygonal plate, etc. As another example, the molded body can have a shape such as a finished product (watch, watch parts, cutting tools, etc.) or a semi-finished product (basel). The molding method for manufacturing the molded body is not particularly limited.

[0100] In addition, the molding method can be selected from sheet molding, extrusion molding, injection molding, press molding, etc. The press molding is a method of manufacturing a molded body by filling a mold with powder and applying pressure. Depending on the method of applying pressure, there are single-axis pressing molding, multi-axis isostatic pressing molding, etc. The molding method of the present invention is mainly single-axis pressing molding, in which a composite is loaded into an embossing mold and laminated to form a multilayer. A molded body can be obtained by applying pressure of 700 to 1,500 kgf / cm2 to the multilayer laminated in the embossing mold.

[0101] In another embodiment, the molding method of the present invention may select at least one of extrusion molding and injection molding. Extrusion molding is a method of producing a molded body having a desired shape by forcing a metal or ceramic material, etc., into the hole of an extrusion mold. It can be performed by preparing a billet of an appropriate size made of aluminum oxide, zirconia spherical particles, etc., placing it into an extruder, forcing it into an extrusion die to produce an extrudate, heat treating it, and cutting it into an appropriate size. Therefore, extrusion molding allows for a variety of product shapes, and can produce products with improved strength, structural integrity, etc. through cold or hot extrusion. Therefore, the composite of the first step is prepared as a billet of an appropriate size, sequentially placed into a hopper, and the molten and extruded composite is pushed into an extrusion die to form a multilayer, thereby producing a molded body under typical extrusion conditions. The extrusion conditions are not particularly limited and can be selected and used according to each situation. Preferably, the temperature is about 50℃ higher than the melting point of the composite but lower than the decomposition temperature. Therefore, the extrusion temperature should be within the range of 210 to 250°C. If it is lower than 210°C, complete melting is impossible, which may result in increased pressure during extrusion. Furthermore, if the extrusion temperature is higher than 250°C, significant decomposition may occur, resulting in yellowing and deterioration and foaming within the extruder.

[0102] Injection molding involves mixing and melting the above-mentioned composite, sequentially extruding the melt into pellets, and then feeding them into an injection molding machine to produce a molded article. Injection conditions are not particularly limited and can be selected and used depending on the situation. Preferably, the temperature is 210 to 250°C and the pressure is 5 to 7 MPa.

[0103] Therefore, upon completion of the above second step, a molded body with patterns of various colors can be obtained. Referring to Fig. 3, Fig. 3 shows a molded body obtained when the laminated composite has completed molding.

[0104]

[0105] [Stage 3] - Degreasing and heat treatment stage

[0106] The third step is to degrease and heat-treat the molded body. Specifically, the properties of the ceramic composite material depend on the degree of uniformity of the mixture. Therefore, the degreased and heat-treating step can minimize foreign substances and create a uniform mixture. That is, when mixing the composite material with the liquid material to produce the mixture, the organic components of the dispersant, antifoaming agent, and binder can cause pores or cracks during the sintering step described below. Therefore, the organic substances can be removed through the degreased and heat-treating step.

[0107] Therefore, the above-mentioned degreasing and heat treatment step may include first heating at 155 to 175°C for 30 to 40 hours, followed by second heating at 650 to 850°C for 30 to 40 hours. During the first heating, moisture within the molded body can be removed, and during the second heating, organic components within the molded body can be removed. This step-by-step heating can suppress thermal stress of the molded body, thereby preventing the banding phenomenon in which the molded body bends.

[0108] Meanwhile, if the temperature and time ranges are exceeded during the degreasing and heat treatment stages, residual organic matter may cause cracks to occur during the sintering stage. Furthermore, if the temperature and time ranges are exceeded during the degreasing and heat treatment stages, warping or breakage of the molded body may occur.

[0109]

[0110] [Step 3-2] - Sintering pretreatment

[0111] Step 3-2 is a step performed when a multilayer is formed with a composite that does not contain pigment. Step 3-2 is a step of pre-sintering the molded body that has undergone de-geothermal heat treatment at 1450 to 1550°C for 1 to 4.5 hours. The pre-sintering step is a process to remove impurities, moisture, and other foreign substances that were not treated in the de-geothermal heat treatment step before sintering to create a uniform mixture. In addition, the pre-sintering step is a process of applying heat at a sufficient temperature to make particles with a large specific surface area, such as powder, into a more dense mass. The pre-sintering step can be performed according to a typical ceramic sintering pre-treatment process.

[0112] Meanwhile, if the temperature and time, which are the pre-sintering conditions, fall below the range, residual foreign substances may remain, which may cause cracks and color changes during the sintering step. If the temperature and time, which are the pre-sintering conditions, fall outside the range, deformation of the molded body may occur.

[0113]

[0114] [Stage 4] - Sintering

[0115] The fourth step is the sintering step. Specifically, the sintering step can be divided into a process for sintering a composite without pigment and a process for sintering a composite with pigment.

[0116] First, the step of sintering the composite that does not contain pigment is to sinter the pre-treated molded body in a vacuum at a pressure of 10 -1 ~ 10 -5Torr, and the sintering temperature can be 1550 to 1700℃. Specifically, the sintering step refers to a process of applying sufficient temperature and pressure to make particles with a large specific surface area, such as powder, into a more dense mass. The sintering method can be classified into vacuum sintering, pressureless sintering, pressure sintering, spark plasma sintering, reaction sintering, etc., depending on the process conditions. In the present invention, it can be performed according to a conventional ceramic sintering method. That is, the sintering is performed using a high vacuum sintering furnace in a vacuum or argon (Ar) gas atmosphere at a pressure of 10 -1 ~ 10 -5 Torr, and the sintering temperature can be 1550 to 1700℃ for 1.0 to 4.5 hours. When this sintering is completed, a sintered body with excellent mechanical properties can be manufactured.

[0117] As another example, the step of sintering a composite including a pigment may be performed by heating the degreasing heat-treated molded body from room temperature to a sintering temperature of 1450 to 1550°C, and then heating at the sintering temperature for 1.5 to 2.5 hours. Upon completion of this sintering, a sintered body having excellent mechanical properties may be manufactured.

[0118] Meanwhile, if the sintering conditions (pressure, temperature, and time) fall below the specified range, sintering will not occur properly, making it impossible to manufacture the dense ceramic composite material of the present invention. Furthermore, if the sintering conditions (pressure, temperature, and time) exceed the specified range, zirconia volume expansion may occur, resulting in a deterioration in mechanical properties.

[0119] The ceramic composite material of the present invention, in which various colored patterns are formed after sintering as described above, can have at least one color among white, gray, black, blue, yellow-brown, yellow-brown, red, green, and pink.

[0120] Referring to Figure 3, Figure 3 shows ceramic composite materials of various colors after the sintering step is completed.

[0121]

[0122] [Step 5] - Processing

[0123] Step 5 may further include processing the sintered compact. If the sintered compact is a wristwatch component, the processing may involve cutting to form an actual shape. The cutting may be performed using laser processing, for example, and may be configured to form the shape of components such as a case body, bezel, and / or dial that constitute the wristwatch. Referring to FIGS. 4 and 5 , watch components with various colored patterns according to an embodiment of the present invention are illustrated. Furthermore, referring to FIG. 6 , a knife with a unique pattern according to an embodiment of the present invention is illustrated.

[0124] In this way, the uses of the ceramic composite material manufactured according to the method for manufacturing a ceramic composite material according to an embodiment of the present invention are not limited. For example, the ceramic composite material of the present invention can be applied to decorative items, electronic component substrates, household appliances, etc. Specifically, the ceramic composite material of the present invention can be applied to various ceramic parts and products that satisfy both gloss and strength as aesthetic requirements, such as decorative items such as watch cases, watch bands, watch faces, tie pins, buttons, and jewelry, kitchen knives, fruit knives, surgical knives, pocket knives, folding knives, razor knives, hairdressing knives, hairdressing nippers, hairdressing scissors, lawnmower blades, battery blades, battery scissors, or industrial cutting tools, electronic component substrates, etc.

[0125] In addition, the ceramic composite material manufactured by the method for manufacturing a ceramic composite material of the present invention can be applied to various ceramic parts, etc., by being colored in a variety of vivid colors based on ceramic, implementing a unique pattern, and providing excellent mechanical properties.

[0126]

[0127] Below, manufacturing examples and examples are provided. The following manufacturing examples and examples are provided solely to aid in understanding the present invention.

[0128]

[0129] <Manufacturing Example>

[0130] [Manufacturing Example 1] - Partially stabilized zirconia powder

[0131] Partially stabilized zirconia powder (Y-TZP, yttria-stabilized tetragonal zirconium polycrystal) was prepared by co-precipitation by adding 3 mol% of yttria, a metal stabilizer, to the total mol% of pure zirconia powder.

[0132]

[0133] [Manufacturing Example 2] - Zirconia spherical particles

[0134] 93 wt% of the partially stabilized zirconia powder manufactured according to Manufacturing Example 1, 3 wt% of a polycarboxylic acid ammonium salt-based dispersant, and 2 wt% of a polyether-based antifoaming agent were dissolved in water and first wet-mixed for 20 hours. To increase the cohesion of the first wet-mixed powder, 2 wt% of a polyvinyl alcohol-based (PVA) binder was added, and a second wet-mixing for 4 hours was performed to prepare a mixture. The second wet-mixed mixture was spray-dried at 210°C to prepare zirconia spherical particles.

[0135]

[0136] <Examples and Comparative Examples> - Manufacturing of Ceramic Composite Materials

[0137] [Example 1]

[0138] Zirconia spherical particles and aluminum oxide were prepared according to Manufacturing Example 2. The first layer was composed of only zirconia spherical particles, and the second layer was composed of a composite mixed with 60 wt% of zirconia spherical particles and 40 wt% of aluminum oxide. The first and second layers (the first and second layers constitute a set) were placed in an embossing mold, and the first and second layers were alternately laminated in three sets to constitute a multilayer structure.

[0139] A molded body was manufactured by applying a pressure of 10,000 kgf / cm2 for 2 hours to the embossing mold in which the above multilayers were formed, and then the molded body was first heated at 160°C for 30 hours, and then secondarily heated at 700°C for 30 hours to perform a degreasing heat treatment. The degreasing heat-treated molded body can be sintered at 1500°C for 2 hours. The sintered pre-treated molded body was heated in a vacuum at an atmospheric pressure of 10 -3 , the temperature was 1600℃ and sintered for 2 hours to obtain a sintered body, a ceramic composite material of the present invention.

[0140]

[0141] [Example 2]

[0142] Example 2 produced a ceramic composite material in the same manner as Example 1, except that the second layer was composed of a composite mixed with 80 wt% of zirconia spherical particles and 20 wt% of aluminum oxide.

[0143]

[0144] [Example 3]

[0145] Example 3 was performed in the same manner as Example 1 to manufacture a ceramic composite material, except that the second layer was composed of a composite mixed with 95 wt% of zirconia spherical particles and 5 wt% of aluminum oxide.

[0146]

[0147] [Example 4] - Including pigment

[0148] Zirconia spherical particles and aluminum oxide manufactured according to Manufacturing Example 2 were prepared. The first layer was composed of a composite using only zirconia spherical particles, and the second layer was composed of a composite mixing 80 wt% of zirconia spherical particles and 20 wt% of aluminum oxide. In order to further include pigment in the composite, a mixture was created by mixing 10 wt% of copper oxide in the first layer and 10 wt% of cobalt oxide in the second layer based on the total weight% of the composite, and then a liquid material containing 100 parts by weight of DI water as a solvent and 5 parts by weight of a lubricant was mixed in a ratio of 2:1 to the mixture, stirred using a ball mill to create a mixture, and then spray-dried to create a composite in the form of granules having a uniform size. The composite was placed in an embossing mold, and the first and second layers were alternately laminated in three sets to create a multilayer structure.

[0149] A molded body was manufactured by applying a pressure of 10,000 kgf / cm2 for 2 hours to the embossing mold in which the above multilayers were formed, and then the molded body was first heated at 160°C for 30 hours, and then secondarily heated at 700°C for 30 hours to perform a degreasing heat treatment. The degreasing heat-treated molded body was then heated from room temperature to 1500°C, and then sintered at the sintering temperature for 2 hours to obtain a sintered body, a ceramic composite material of the present invention. The attached Fig. 5 is a photograph showing a ceramic composite material manufactured according to Example 4.

[0150]

[0151] [Comparative Example 1]

[0152] Comparative Example 1 was performed in the same manner as Example 1, except that the second layer was composed of a composite mixed with 55 wt% of zirconia spherical particles and 45 wt% of aluminum oxide, thereby manufacturing a ceramic composite material.

[0153]

[0154] [Comparative Example 2]

[0155] Comparative Example 2 produced a ceramic composite material in the same manner as Example 1, except that the second layer was composed of a composite mixed with 97 wt% of zirconia spherical particles and 3 wt% of aluminum oxide.

[0156]

[0157] [Comparative Example 3] - Including pigment

[0158] Comparative Example 3 produced a ceramic composite material in comparison with Example 4, except that the second layer was composed of a composite mixed with 55 wt% of zirconia spherical particles and 45 wt% of aluminum oxide.

[0159]

[0160] [Comparative Example 4]

[0161] Comparative Example 4 produced a ceramic composite material in the same manner as Comparative Example 1, except that the zirconia spherical particles were replaced with zirconia when preparing the composites of the first and second layers.

[0162]

[0163] [Comparative Example 5]

[0164] Comparative Example 5 produced a ceramic composite material in the same manner as Example 2, except that the sintering temperature was set to 1500°C.

[0165]

[0166] Table 2 shows the components and contents according to examples and comparative examples of the present invention.

[0167] Examples and Comparative Examples Components and Contents 1st Layer 2nd Layer Pigment Presence or Absence Sintering Temperature (℃) Zirconia Spherical Particles (wt%) Zirconia Spherical Particles (wt%) Aluminum Oxide (wt%) Example 1 100 60 40 x 1600 Example 2 100 80 20 x 1600 Example 3 100 955 x 1600 Example 4 100 80 20 o 1500 Comparative Example 1 100 55 45 x 1600 Comparative Example 2 100 973 x 1600 Comparative Example 3 100 55 45 o 1500 Comparative Example 4 Zirconia Zirconia Aluminum Oxide x 1600 100 55 45 Comparative Example 5 100 80 20 x 1500

[0168]

[0169] <Example of an exam>

[0170] [Test Example 1] - Density of sintered body

[0171] The density of ceramic composite material specimens with patterns of various colors formed according to the examples and comparative examples of the present invention was measured by the “Archimedes method.”

[0172]

[0173] [Test Example 2] - Breaking Strength

[0174] The fracture strength of ceramic composite material specimens with various colored patterns formed according to the examples and comparative examples of the present invention was measured through a three-point bending strength test using a UTM (Universal Testing Machine, Model No. 4206, Instron, USA) with a crosshead speed of 0.5 mm / min and a span distance of 30 mm.

[0175]

[0176] [Test Example 3] - Fracture Toughness and Hardness

[0177] The fracture toughness of ceramic composite material specimens with various colored patterns formed according to the examples and comparative examples of the present invention was measured by the Vickers indentation method using a Vickers hardness tester (AVK-C2, Mitutoyo, Japan) with a load of 10 kg. In addition, the hardness was measured using a micro Vickers hardness tester with a load of 500 g.

[0178]

[0179] [Example 4] - Vivid colors and patterns

[0180] The clarity of the colors and patterns of ceramic composite material specimens with patterns of various colors formed according to the examples and comparative examples of the present invention were observed with the naked eye.

[0181]

[0182] Table 3 shows the results of property analysis according to examples and comparative examples of the present invention.

[0183] Density of sintered body (g / cm) 3 )Fracture strength (MPa)Fracture toughness (MPam) 1 / 2 ) Hardness (MPa) Color and pattern clarity Example 15.5516178.11521 Good Example 25.7816988.61598 Good Example 35.8516738.31556 Good Example 45.438324.41025 Good Comparative Example 15.5214827.31418 Good Comparative Example 25.9816208.21529 Good Comparative Example 35.217483.8982 Good Comparative Example 45.233991.4317 Average Comparative Example 55.557968.5998 Good

[0184] Referring to Table 3, it was confirmed that the examples of the present invention had better sintered body density, fracture strength, fracture toughness, and hardness than the comparative examples. That is, examples 1 to 3 that did not include pigment had a sintered body density of 5.55 g / cm. 3 Above, fracture strength is 1550 MPa or more, fracture toughness is 6.5 MPam 1 / 2Above, it was confirmed that the hardness was 1500 MPa or more. Example 4 including pigment had a sintered body density of 5.40 g / cm 3 Above, fracture strength is 800 MPa or more, fracture toughness is 4.4 MPam 1 / 2 , it was confirmed that the hardness was 1020 MPa or more. Therefore, it was confirmed that the ceramic composite material not including pigment in both the examples and comparative examples had superior mechanical properties compared to the ceramic composite material including pigment. In addition, when comparing Example 4 including pigment with Comparative Example 3, it was confirmed that Example 4, in which zirconia and aluminum oxide were appropriately mixed, had significantly improved mechanical properties compared to Comparative Example 3.

[0185] Specifically, looking at the density of the sintered body, the density of the sintered body increased within the specified content range of the zirconia spherical particles and aluminum oxide, and it was confirmed that Example 3 with the highest content of the zirconia spherical particles was the best. On the other hand, as shown in Table 3, Comparative Example 1 was outside the range of the examples, and it was confirmed that the density of the sintered body showed a tendency to decrease, but Comparative Example 2 with a high zirconia content was confirmed to have an excellent density of the sintered body. In addition, it was found that Comparative Example 3 including pigment, Comparative Example 4 composed only of zirconia instead of zirconia spherical particles, and Comparative Example 5 with a sintering temperature outside the range of the examples relatively decreased in density. Therefore, it was found that the density of the sintered body depends on the zirconia spherical particles and aluminum oxide, the presence or absence of a metal stabilizer, the presence or absence of a pigment, and the sintering temperature within the specified content range. In addition, it was found that as the content of zirconia spherical particles and aluminum increased within a certain range, the density of the sintered body improved, while the particle size decreased, so the sinterability was affected by the tetragonal / monoclinic ratio, which is a structural characteristic of zirconia.

[0186] The fracture strength and fracture toughness showed a similar trend to the density of the sintered body, and it was found that most examples were superior to the comparative examples. Specifically, it was found that examples 1 to 3 that did not include pigments had increased fracture strength and fracture toughness compared to example 4. On the other hand, in the case of the comparative examples, it was found that the mechanical properties of comparative example 3 including pigment, comparative example 4 composed of only zirconia, and comparative example 5 whose sintering temperature was outside the range of the examples were significantly lowered compared to comparative examples 1 and 2. Therefore, it was found that the fracture strength and fracture toughness depended on zirconia and aluminum oxide within a given content range, the presence or absence of a metal stabilizer, the presence or absence of a pigment, the sintering temperature, etc.

[0187] Hardness also showed a similar trend to the density of the sintered body, but as the content of zirconia spherical particles increased, the composition ratio of zirconia spherical particles, which have lower hardness than aluminum oxide, increased, resulting in microcracks in the material due to excessive grain growth. Therefore, it was found that Comparative Example 2, which had a high content of zirconia spherical particles, had a lower hardness than Example 3. Therefore, it was found that hardness depended on the content of zirconia, the presence or absence of a metal stabilizer, the presence or absence of a pigment, and the sintering temperature.

[0188] In terms of color and pattern clarity, it was observed with the naked eye that the colors and patterns were generally clear in the examples and comparative examples. On the other hand, Comparative Example 4, which used zirconia instead of zirconia spherical particles (i.e., partially stabilized zirconia powder containing a metal stabilizer), showed reduced clarity compared to the other examples and comparative examples when observed with the naked eye. Therefore, it was found that the metal stabilizer minimizes color change during natural cooling, and thus the color and pattern clarity depend on the presence or absence of a metal stabilizer.

[0189]

[0190] In this way, a ceramic composite material having a pattern of various colors formed according to an embodiment of the present invention is provided in which a composite material including at least one of zirconia spherical particles and aluminum oxide is laminated to form a unique pattern, and a ceramic composite material having a pattern of various colors formed and having excellent mechanical properties is expressed in a variety of vivid colors.

[0191] The embodiments described above are merely illustrative, and those skilled in the art will readily appreciate various modifications and equivalent alternative embodiments. Therefore, the true scope of technical protection of the present invention should be determined by the technical spirit of the invention as set forth in the claims.

Claims

1. In ceramic composite materials, The above ceramic composite material comprises a first layer and a second layer as a set, and includes at least one of the sets, The above first layer contains zirconia spherical particles, A ceramic composite material having patterns of various colors formed, characterized in that the second layer comprises 60 to 95 wt% of zirconia spherical particles and 5 to 40 wt% of aluminum oxide.

2. In paragraph 1, The above ceramic composite material further contains a pigment, A ceramic composite material having patterns of various colors formed, characterized in that the pigment comprises at least one of magnesium oxide, zinc oxide, nickel oxide, cobalt oxide, manganese oxide, iron oxide, and copper oxide.

3. In paragraph 1, The above zirconia spherical particles are, A step of preparing a mixture by dissolving 93 to 95 wt% of partially stabilized zirconia powder, 1 to 5 wt% of a binder, 1 to 5 wt% of a dispersant, and 1 to 5 wt% of a defoaming agent in water; and A ceramic composite material having patterns of various colors formed, characterized in that it is manufactured by including a step of spray drying the above mixture at 150 to 230°C.

4. In paragraph 3, The above partially stabilized zirconia powder is, As a powder with a small amount of metal stabilizer added to zirconia powder, A ceramic composite material having patterns of various colors formed, characterized in that the metal stabilizer comprises at least one of yttrium oxide (Y2O3), magnesium oxide (MgO), calcium oxide (CaO), and cerium oxide (Ce2O3).

5. In paragraph 1, A pigment-free ceramic composite material having patterns of various colors formed thereon, characterized in that it satisfies the conditions (a) to (c) below. (a) Breaking strength of 1500 MPa or more (b) Fracture toughness 6.5 MPam 1 / 2 more (c) Hardness of 1500 MPa or more 6. In paragraph 1, A ceramic composite material having a pattern of various colors formed, characterized in that the above various colors are at least one of white, gray, black, blue, yellow-brown, yellow-ochre, red, green, and pink.

7. In the method for manufacturing ceramic composite materials, A first step of preparing a composite by mixing at least one of zirconia spherical particles and aluminum oxide; A second step of forming a molded body by laminating the above complex in an embossing mold to form multiple layers and applying a pressure of 700 to 1,500 kgf / cm2 to form a pattern; A third step of heat-treating the above-mentioned molded body by first heating it at 155 to 175°C for 30 to 40 hours and then second heating it at 650 to 850°C for 30 to 40 hours; Step 3-2 of pre-sintering the above-mentioned molded body subjected to de-sintering at 1450 to 1550°C; and The above pre-sintered molded body is placed in a vacuum at a pressure of 10 -1 ~ 10 -5 A method for manufacturing colored zirconia ceramics, comprising: a fourth step of sintering at a sintering temperature of 1550 to 1700°C; 8. In the method for manufacturing ceramic composite materials, A first step of preparing a composite by mixing at least one of zirconia spherical particles and aluminum oxide; A second step of forming a molded body by laminating the above complex in an embossing mold to form multiple layers and applying a pressure of 700 to 1,500 kgf / cm2 to form a pattern; A third step of heat-treating the above-mentioned molded body by first heating it at 155 to 175°C for 30 to 40 hours and then second heating it at 650 to 850°C for 30 to 40 hours; and A method for manufacturing a ceramic composite material having patterns of various colors formed, comprising: a fourth step of heating the above-mentioned molded body, which has undergone degreasing heat treatment, from room temperature to a sintering temperature of 1450 to 1550°C, and then heating and sintering at the sintering temperature for 1.5 to 2.5 hours.

9. In paragraph 7 or 8, In the above second step, The above multilayer comprises a first layer and a second layer forming a set, and includes at least one of the sets, The above first layer contains zirconia spherical particles, A method for manufacturing a ceramic composite material having patterns of various colors formed, characterized in that the second layer comprises 60 to 95 wt% of zirconia spherical particles and 5 to 40 wt% of aluminum oxide.

10. In paragraph 8, The above complex further comprises a pigment, A method for manufacturing a ceramic composite material having patterns of various colors formed, characterized in that the pigment includes at least one of magnesium oxide, zinc oxide, nickel oxide, cobalt oxide, manganese oxide, iron oxide, and copper oxide.

11. In paragraph 7 or 8, The above zirconia spherical particles are, A step of preparing a mixture by dissolving 93 to 95 wt% of partially stabilized zirconia powder, 1 to 5 wt% of a binder, 1 to 5 wt% of a dispersant, and 1 to 5 wt% of a defoaming agent in water; and A ceramic composite material having patterns of various colors formed, characterized in that it is manufactured by including a step of spray drying the above mixture at 150 to 230°C.

12. In paragraph 11, The above partially stabilized zirconia powder is, As a powder with a small amount of metal stabilizer added to zirconia powder, A method for manufacturing a ceramic composite material having patterns of various colors, characterized in that the metal stabilizer comprises at least one of yttrium oxide (Y2O3), magnesium oxide (MgO), calcium oxide (CaO), and cerium oxide (Ce2O3).

13. In paragraph 7 or 8, In the above second step, A method for manufacturing a ceramic composite material having patterns of various colors formed, characterized in that a molded body is obtained by using at least one of extrusion molding and injection molding of the above complex.

14. A ceramic component having a pattern implemented by a method for manufacturing a ceramic composite material in which patterns of various colors are formed according to either clause 7 or 8.

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