Preparation method and application of ceramic powder

Abstract

The invention belongs to the field of ceramic materials, and particularly discloses a preparation method and application of ceramic powder. The preparation method comprises the following steps: S1, respectively grinding mixed slurry A and mixed slurry B to obtain modified aluminum oxide and modified zirconium oxide; s2, grinding raw materials including modified aluminum oxide and modified zirconium oxide to obtain mixed slurry C, and drying the mixed slurry C to obtain the ceramic powder, the mixed slurry A contains aluminum oxide and a cationic modifier; the mixed slurry B contains zirconium oxide and an anionic modifier. According to the preparation method disclosed by the invention, Zeta potentials on the surfaces of aluminum oxide and zirconium oxide particles are respectively regulated and controlled through the cationic modifier and the anionic modifier, so that the surfaces of the prepared modified aluminum oxide and modified zirconium oxide respectively present different electrical properties, and the dispersibility between the modified aluminum oxide powder and the modified zirconium oxide powder is improved by utilizing electrostatic interaction; and agglomeration among particles is avoided.

Description

Technical Field

[0001] The invention belongs to the field of ceramic materials, and in particular relates to a preparation method of ceramic powder and application thereof. Background Art

[0002] As a precision ceramic structural part, the ceramic splitter has a relatively complex internal structure. It is made of alumina and zirconia as the main materials. The blank is made through injection molding, dry pressing or isostatic pressing, and finally processed through machining and surface treatment. It has the advantages of high hardness, high strength and excellent wear resistance. In the field of semiconductor packaging, it acts as a "bridge" for precise connection and signal transmission between chips and chips, and between chips and substrates.

[0003] In the existing preparation process, the injection molding process can achieve stable mass production of products while meeting the high dimensional accuracy requirements of the product and reducing the amount of machining wear. Therefore, ceramic splitters are generally prepared by injection molding. The injection molding process of ceramic splitters generally uses zirconia toughened alumina (ZTA) powder as the main material, and prepares injection feed by adding additives such as binders, lubricants and promoters during the mixing process, and then obtains green bodies through injection molding, and obtains finished products through processes such as debinding sintering, machining and surface treatment. In the process of preparing zirconia toughened alumina (ZTA) powder, due to the influence of intermolecular forces and electrostatic forces, there is a problem that the ZTA powder particles have poor dispersion and are prone to agglomeration, which affects the uniformity of the feed, sintering density and strength of the finished product. Summary of the invention

[0004] In order to overcome at least one technical problem existing in the above-mentioned prior art, one of the objectives of the present invention is to provide a method for preparing ceramic powder.

[0005] A second object of the present invention is to provide an application of the above-mentioned method for preparing ceramic powder in preparing ceramic splitting knife products.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A first aspect of the present invention provides a method for preparing a ceramic powder, comprising the following steps:

[0008] S1: Grinding the mixed slurry A and the mixed slurry B separately to obtain modified alumina and modified zirconia;

[0009] S2: grinding the raw materials including modified alumina and modified zirconia to obtain a mixed slurry C, and drying the mixed slurry C to obtain the ceramic powder;

[0010] The mixed slurry A contains aluminum oxide and a cationic modifier;

[0011] The mixed slurry B contains zirconium oxide and an anion modifier;

[0012] The cationic modifier is selected from at least one of magnesium salt, aluminum salt, calcium salt and ammonium salt;

[0013] The anion modifier is selected from at least one of polyacrylate, citrate and dodecylbenzene sulfonate.

[0014] The anionic modifier and cationic modifier used in the present invention have good modification effects, are easy to implement, and can achieve mass production. The modification of the cationic modifier and the anionic modifier will not have an adverse effect on the mechanical properties of the product made from the ceramic powder, etc., wherein the cationic modifier can also play a role in sintering aid during the sintering process, such as the magnesium chloride cationic modifier, which can act as a sintering aid during the sintering process by introducing magnesium ions to reduce the sintering temperature and prevent abnormal grain growth. The present invention also tried to use polyethyleneimine as a cationic modifier and ammonium polymethacrylate as an anionic modifier during research and development, but polyethyleneimine and ammonium polymethacrylate are both high molecular polymers, which will affect the viscosity of the modified system, the viscosity is large, the modification effect is not ideal, and the excess cationic and anionic modifiers are difficult to remove, which affects the density and strength of the ceramic splitter made from the ceramic powder, and is not suitable for large-scale production and application.

[0015] In some embodiments of the present invention, the magnesium salt includes at least one of magnesium chloride, magnesium nitrate, and magnesium sulfate.

[0016] In some embodiments of the present invention, the aluminum salt includes at least one of aluminum chloride, aluminum sulfate, and aluminum nitrate.

[0017] In some embodiments of the present invention, the calcium salt comprises at least one of calcium chloride and calcium citrate.

[0018] In some embodiments of the present invention, the polyacrylate salt includes at least one of sodium polyacrylate and potassium polyacrylate.

[0019] In some embodiments of the present invention, the citrate comprises at least one of sodium citrate and potassium citrate.

[0020] In some embodiments of the present invention, the dodecylbenzene sulfonate comprises at least one of sodium dodecylbenzene sulfonate and potassium dodecylbenzene sulfonate.

[0021] In some embodiments of the present invention, the ammonium salt includes at least one of cetyltrimethylammonium bromide (CTAB) and tetraethylammonium salt.

[0022] In the present invention, during the grinding process of mixed slurry A and mixed slurry B, the surface electrical properties of alumina and zirconia powders are respectively regulated by using a cationic modifier and an anionic modifier, so that the surface of the modified alumina powder presents positive charge, and the surface of the modified zirconia powder presents negative charge, and the principle that particles of the same kind of powders with the same charge repel each other is utilized to improve the dispersibility of alumina particles and zirconia particles, and avoid agglomeration of the same kind of powders; then, the two powders with opposite electrical properties on the surface after modification are mixed and ground, and the modified zirconia with a smaller particle size wraps the modified alumina with a larger particle size by using the electrostatic attraction effect, so as to form mixed large particles with the same electrical properties on the surface, and the large particles repel each other due to the electrostatic effect, so as to achieve uniform mixing and dispersion of the two powders, thereby obtaining a ceramic powder with good dispersibility and not easy to agglomerate, namely, ZTA powder.

[0023] In an acidic or weakly neutral environment, some hydroxyl groups on the surface of alumina will be deprotonated to form negatively charged Al-O-, which provides a reaction site for the adsorption of cations. The cationic modifier can form a complex-like structure by electrostatic adsorption or ion exchange with the hydroxyl groups on the surface of the alumina particles, thereby achieving the regulation of the electrical properties of the alumina surface and making the surface of the modified alumina particles positively charged. For example, when the cationic modifier is magnesium chloride, the reaction form to the alumina powder with hydroxyl groups is:

[0024] Al-OH+Mg 2+ →Al-O-Mg + +H +

[0025] The surface Zeta potential of alumina powder before modification is +10mV to +20mV. The surface Zeta potential of alumina powder can be adjusted within the range of +20mV to +50mV by using cationic modifier, which can achieve the best electrical control effect.

[0026] In a weakly alkaline or neutral environment, the hydroxyl groups on the surface of zirconium oxide are in a state of equilibrium between protonation and non-protonation (i.e., Zr–OH 2 + and Zr–OH), the positively charged sites on the surface (Zr–OH 2 + ) more, and can react with the negatively charged groups of anionic modifiers (such as carboxyl (–COO - ), sulfonic acid (–SO 3 - ) etc.) to produce electrostatic adsorption and hydrogen bonding, thereby achieving the regulation of the surface electrical properties of zirconium oxide, making its surface negatively charged. The surface Zeta potential of zirconium oxide powder before modification is +10mV to +20mV. The surface Zeta potential of zirconium oxide powder is regulated within the range of -20mV to -50mV by using anionic modifiers, which can achieve the best electrical regulation effect.

[0027] The zeta potential of the aluminum oxide and zirconium oxide in the present invention before and after modification with a specific modifier is shown in Table 1 below.

[0028] Table 1 Zeta potential of alumina and zirconia before and after modification

[0029]

[0030] After modification by the modifier, the surface of alumina is positively charged and the surface of zirconia is negatively charged. Through electrostatic action, the modified alumina and modified zirconia can be evenly dispersed to avoid particle agglomeration.

[0031] In some embodiments of the present invention, the pH of the mixed slurry A is 5 to 8; in some embodiments of the present invention, the pH of the mixed slurry A can be any one of 5, 5.5, 6, 6.5, 7, 7.5, 8, or a range formed by any two of them. In the grinding process of the present invention, the pH of the mixed slurry A is regulated by a cationic modifier to achieve an ideal modification effect. When the pH value of the mixed slurry A is less than 5, all the hydroxyl groups on the surface of the alumina particles are protonated to positively charged (Al–OH 2 + ), reducing the adsorption capacity of the cationic modifier and resulting in poor modification effect; when the pH value of the mixed slurry A is greater than 8, the cationic modifier such as magnesium chloride is hydrolyzed to generate magnesium hydroxide precipitate (Mg(OH) 2 ), affecting the modification effect.

[0032] In some embodiments of the present invention, the pH of the mixed slurry B is 6 to 9; in some embodiments of the present invention, the pH of the mixed slurry B can be any one of 6, 6.5, 7, 7.5, 8, 8.5, 9, or a range formed by any two of them. In the grinding process of the present invention, the pH value of the mixed slurry B is regulated by an anionic modifier to achieve an ideal modification effect. When the pH value of the mixed slurry B is less than 6, some functional groups (such as carboxyl groups) in the anionic modifier are hydrolyzed, resulting in changes in the modified molecular structure, and if the pH value is too low, the viscosity of the system will increase, affecting the modification effect; when the pH value of the mixed slurry B is greater than 9, the hydroxyl groups on the surface of zirconium oxide are deprotonated (Zr–OH→Zr–O-), the surface is negatively charged, and the electrostatic adsorption force with the anionic modifier is significantly weakened, and the modification effect will deteriorate.

[0033] In some embodiments of the present invention, the Zeta potential of the modified alumina is +20mV to +50mV; in some embodiments of the present invention, the Zeta potential of the modified alumina is +20mV, +25mV, +30mV, +30.4mV, +32.9mV, +33.7mV, +39.5mV, +48.9mV, +50mV, or any value in the range formed by any two of them; in some preferred embodiments of the present invention, the Zeta potential of the modified alumina is +30mV to +50mV.

[0034] In some embodiments of the present invention, the Zeta potential of the modified zirconia is -20mV to -50mV; in some embodiments of the present invention, the Zeta potential of the modified zirconia is any value among -20mV, -25mV, -30mV, -34.1mV, -37.1mV, -35.1mV, -37.2mV, -48.9mV, and -50mV, or a range formed by any two of them; in some embodiments of the present invention, the Zeta potential of the modified zirconia is -30mV to -50mV.

[0035] In some embodiments of the present invention, in the mixed slurry A, the mass ratio of aluminum oxide to the cationic modifier is (20-400):1; in some embodiments of the present invention, in the mixed slurry A, the mass ratio of aluminum oxide to the cationic modifier is 20:1, 40:1, 60:1, 80:1, 100:1, 120:1, 140:1, 160:1, 180:1, 200:1, 220:1, 240:1, 260:1, 280:1, 300:1, 320:1, 340:1, 360:1, 380:1, 400:1, any one of the values ​​or a range formed by any two of them.

[0036] In the present invention, when the amount of cationic modifier is insufficient, the surface of the alumina powder cannot be covered by enough cationic modifier, the electrical regulation effect is limited, only part of the surface of the alumina particles is covered and wrapped by the cationic modifier, there is insufficient electrical properties on the particle surface, and the van der Waals force between the particles is dominant, resulting in agglomeration of the alumina particles; when the amount of cationic modifier is too much, the surface of the alumina powder has reached a "saturated adsorption" state, and the excess cationic modifier molecules will be free in the dispersion medium, increasing the concentration of free ions in the system and the viscosity of the solution system, and the free ions will compress the double electric layer on the surface of the alumina particles, reduce the Zeta potential of the alumina particles (ie, the "shielding effect"), and weaken the electrostatic repulsion between the alumina particles, and the alumina powder particles may re-agglomerate or settle. In addition, too much cationic modifier may cause the product made from ceramic powder as a raw material to produce more holes during the debinding process, resulting in more holes in the blank after the product is sintered, affecting the density, hardness and strength of the product.

[0037] In some embodiments of the present invention, the mixed slurry A comprises the following materials in mass percentage: 20-40% aluminum oxide, 0.1-1% cationic modifier, 15-30% solvent, and 29-64.9% grinding balls; In some embodiments of the present invention, the mixed slurry A is composed of the following materials in mass percentage: 20-40% aluminum oxide, 0.1-1% cationic modifier, 15-30% solvent, and grinding balls as the balance.

[0038] In some embodiments of the present invention, in the mixed slurry A, the mass percentage of aluminum oxide can be any value of 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, 40% or a range formed by any two of them.

[0039] In some embodiments of the present invention, in the mixed slurry A, the mass percentage of the cationic modifier can be any value among 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1% or a range formed by any two of them.

[0040] In some embodiments of the present invention, in the mixed slurry A, the mass percentage of the solvent is any one of 15%, 17%, 20%, 22%, 24%, 26%, 28%, 30% or a range formed by any two of them.

[0041] In some embodiments of the present invention, in the mixed slurry A, the mass percentage of grinding balls is any one of 29%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 62%, 64.9% or a range formed by any two of them.

[0042] In some embodiments of the present invention, the grinding balls in the mixed slurry A are alumina ball milling beads.

[0043] In some embodiments of the present invention, in the mixed slurry B, the mass ratio of zirconium oxide to anionic modifier is (12.5-200):1; in some embodiments of the present invention, in the mixed slurry B, the mass ratio of zirconium oxide to anionic modifier is any value of 12.5:1, 25:1, 30:1, 50:1, 75:1, 100:1, 125:1, 150:1, 175:1, 200:1 or a range formed by any two of them. In some preferred embodiments of the present invention, in the mixed slurry B, the mass ratio of zirconium oxide to anionic modifier is (25-100):1.

[0044] In the present invention, when the amount of anionic modifier is insufficient, the surface of the zirconium oxide powder cannot be covered by enough anionic modifier, the electrical property regulation effect is limited, only part of the surface of the zirconium oxide particles is covered and wrapped by the anionic modifier, and there is insufficient electrical property on the surface of the zirconium oxide particles, and the van der Waals force between the particles is dominant, resulting in agglomeration of the zirconium oxide particles; when the amount of anionic modifier is too much, the surface of the zirconium oxide powder has reached a "saturated adsorption" state, and the excess anionic modifier molecules will be free in the dispersion medium, increasing the concentration of free ions in the system and the viscosity of the solution system, and the free ions will compress the double electric layer on the surface of the zirconium oxide particles, reduce the Zeta potential of the zirconium oxide particles (ie, the "shielding effect"), and weaken the electrostatic repulsion between the zirconium oxide particles. The zirconium oxide powder particles may re-agglomerate or settle. In addition, too much anionic modifier may cause the product made from the ceramic powder of the present invention to produce more holes during the debinding process, resulting in more holes in the blank after sintering, affecting the density, hardness and strength of the product.

[0045] In some embodiments of the present invention, the mixed slurry B comprises the following materials in mass percentage: 20-40% zirconium oxide, 0.2-1.6% anion modifier, 15-30% solvent, and 28.4-64.8% grinding balls; In some embodiments of the present invention, the mixed slurry B is composed of the following materials in mass percentage: 20-40% zirconium oxide, 0.2-1.6% anion modifier, 15-30% solvent, and grinding balls as the balance.

[0046] In some embodiments of the present invention, in the mixed slurry B, the mass percentage of zirconium oxide can be any value of 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, 40% or a range formed by any two of them.

[0047] In some embodiments of the present invention, in the mixed slurry B, the mass percentage of the anionic modifier may be any one of 0.2%, 0.4%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.6% or a range formed by any two of them.

[0048] In some embodiments of the present invention, in the mixed slurry B, the mass percentage of the solvent may be any one of 15%, 17%, 20%, 22%, 24%, 26%, 28%, 30% or a range formed by any two of them.

[0049] In some embodiments of the present invention, in the mixed slurry B, the mass percentage of grinding balls can be any value among 28.4%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 62%, 64.8% or a range formed by any two of them.

[0050] In some embodiments of the present invention, the grinding balls in the mixed slurry B are zirconia ball milling beads.

[0051] In some embodiments of the present invention, the mixed slurry C comprises the following materials in mass percentage: 20-40% mixed powder, 15-30% solvent, and 30-65% grinding balls; the mixed powder is modified alumina and modified zirconia; in some embodiments of the present invention, the mixed slurry C is composed of the following materials in mass percentage: 20-40% mixed powder, 15-30% solvent, and grinding balls as the balance.

[0052] In some embodiments of the present invention, in the mixed slurry C, the mass percentage of the mixed powder can be any value of 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, 40% or a range formed by any two of them.

[0053] In some embodiments of the present invention, in the mixed slurry C, the mass percentage of the solvent may be any one of 15%, 17%, 20%, 22%, 24%, 26%, 28%, 30% or a range formed by any two of them.

[0054] In some embodiments of the present invention, in the mixed slurry C, the mass percentage of grinding balls can be any value of 30%, 35%, 40%, 45%, 50%, 55%, 60%, 62%, 65% or a range formed by any two of them.

[0055] In some embodiments of the present invention, the grinding balls in the mixed slurry C are zirconia ball milling beads.

[0056] In some embodiments of the present invention, step S1 is specifically: mixing and ball-milling alumina powder, a cationic modifier, a solvent, and alumina ball milling beads to obtain a mixed slurry A, and after drying, obtaining modified alumina; mixing and ball-milling zirconium oxide powder, anionic modifier, solvent, and zirconium oxide ball milling beads to obtain a mixed slurry B, and after drying, obtaining modified zirconium oxide.

[0057] In some embodiments of the present invention, the drying temperature is 120-160°C.

[0058] In some embodiments of the present invention, the drying time is 3 to 5 hours.

[0059] In some embodiments of the present invention, the grinding balls are selected from at least one of alumina ball milling beads and zirconia ball milling beads.

[0060] In some embodiments of the present invention, the particle size of the grinding ball is 5 to 15 mm; in some embodiments of the present invention, the particle size of the grinding ball is any one of 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, and 15 mm, or a range formed by any two of them. The smaller the particle size of the grinding ball, the better the grinding effect, and the smaller the particle size of the powder after grinding. However, too small a grinding ball may cause the system viscosity to be too large, and the modification effect becomes worse. Therefore, it is necessary to control the particle size of the grinding ball within the range of 5 to 15 mm. Within this range, both the grinding effect and the modification effect are good.

[0061] In some embodiments of the present invention, the solvent is selected from at least one of water, ethanol and methanol.

[0062] In some embodiments of the present invention, in the mixed slurry C, the mass ratio of modified alumina to modified zirconia is (3-19):1; in some embodiments of the present invention, in the mixed slurry C, the mass ratio of modified alumina to modified zirconia is 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, or any range formed by any two of them. If the amount of modified alumina is too much and the amount of modified zirconia is too little, the ceramic splitting knife product made from ceramic powder has high strength, but insufficient toughness, high brittleness, and is easy to break during processing and use; if the amount of modified alumina is too little and the amount of modified zirconia is too much, the ceramic splitting knife product made from ceramic powder has low strength, is easy to deform and break, and affects the service life.

[0063] In some embodiments of the present invention, the grinding in step S1 and / or step S2 is performed by ball milling.

[0064] In some embodiments of the present invention, the ball mill has a rotation speed of 120 to 400 rpm; in some embodiments of the present invention, the ball mill has a rotation speed of 120 rpm, 150 rpm, 180 rpm, 200 rpm, 220 rpm, 250 rpm, 280 rpm, 300 rpm, 320 rpm, 350 rpm, 380 rpm, 400 rpm, or a range formed by any two of the values.

[0065] In some embodiments of the present invention, the slurry temperature during ball milling is 40-50°C; in some embodiments of the present invention, the slurry temperature during ball milling is 40°C, 41°C, 42°C, 43°C, 44°C, 45°C, 46°C, 47°C, 48°C, 49°C, 50°C, any one of the values ​​or a range formed by any two of them.

[0066] In some embodiments of the present invention, the ball milling time is 15 to 30 hours; in some embodiments of the present invention, the ball milling time is any one of 15 hours, 18 hours, 20 hours, 22 hours, 24 hours, 26 hours, 28 hours, and 30 hours, or a range formed by any two of them.

[0067] The present invention also regulates the rotation speed and temperature of the ball mill, mainly because if the ball mill rotation speed is too slow, the modification effect and the ball milling effect are both poor; if the ball mill rotation speed is too fast and the slurry temperature during ball milling is too high, the system viscosity will be too high and the slurry will stick to the wall, which will also lead to poor ball milling effect and affect the dispersion effect.

[0068] The second aspect of the present invention provides the use of the method for preparing the ceramic powder according to the first aspect of the present invention in preparing a ceramic splitting knife product.

[0069] The beneficial effects of the present invention are as follows: the preparation method of the present invention regulates the Zeta potential of the surface of alumina and zirconia particles respectively by using a cationic modifier and an anionic modifier, so that the surfaces of the prepared modified alumina and modified zirconia present different electrical properties respectively, and utilizes electrostatic action to improve the dispersibility between the modified alumina and modified zirconia powders, avoid agglomeration between particles, and promote uniform mixing between the two different powders, thereby obtaining a ceramic powder in which alumina and zirconia are uniformly dispersed, and the ceramic powder is subjected to mixing, molding, debinding sintering and other processes to obtain a ceramic splitter with high hardness, high strength and high density, that is, the ceramic splitter prepared by using the ceramic powder prepared by the preparation method of the present invention as a raw material can have a nanoindentation hardness of 25-30GPa and a bending strength of 800-850MPa. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 This is a scanning electron microscope image of the ceramic powder prepared in Example 1.

[0071] Figure 2 This is a scanning electron microscope image of the ceramic powder prepared in Comparative Example 1. DETAILED DESCRIPTION

[0072] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples, but the implementation and protection of the present invention are not limited thereto. It should be noted that if there are processes that are not particularly described in detail below, they can be implemented or understood by those skilled in the art with reference to the prior art. The reagents or instruments used that do not indicate the manufacturer are all conventional products that can be purchased commercially.

[0073] Example 1

[0074] This example provides a method for preparing ceramic powder, comprising the following steps:

[0075] Step 1: Modification of alumina powder and zirconia powder:

[0076] Alumina powder, cationic modifier (i.e., magnesium chloride), solvent (i.e., deionized water), and alumina ball milling beads are sequentially added to a ball mill for ball milling. After ball milling, mixed slurry A is obtained, and mixed slurry A is dried to obtain modified alumina powder; wherein, the ball milling speed is 200 rpm, circulating cooling water is used to ensure that the temperature in the ball mill is maintained at 40°C, the ball milling time is 20 hours, the drying temperature is 140°C, and the drying time is 3 hours; mixed slurry A is composed of the following materials in mass percentage: 20% alumina powder, 1% magnesium chloride, 30% solvent, 49% alumina ball milling beads, and the pH of mixed slurry A is 6, as shown in the formula numbered A1 in Table 2. The particle size of the alumina ball milling beads is 5 mm.

[0077] Zirconia powder, anion modifier (sodium citrate), solvent (deionized water), and zirconium oxide ball milling beads are sequentially added to a ball mill for ball milling. After ball milling, mixed slurry B is obtained, and mixed slurry B is dried to obtain modified zirconium oxide powder; wherein, the ball milling speed is 200 rpm, circulating cooling water is used to ensure that the temperature in the ball mill is maintained at 40°C, the ball milling time is 20 hours, the drying temperature is 140°C, and the drying time is 3 hours; mixed slurry B is composed of the following materials in mass percentage: 20% zirconium oxide powder, 0.2% sodium citrate, 30% solvent, and 49.8% zirconium oxide ball milling beads; the pH of mixed slurry B is 8, as shown in the formula numbered G1 in Table 3. The particle size of the zirconium oxide ball milling beads is 5 mm.

[0078] Step 2: Preparation of ZTA powder:

[0079] The modified alumina powder and modified zirconia powder obtained in step 1 are mixed to obtain a mixed powder, which is then added to a ball mill, and then a solvent (i.e., deionized water) and zirconia ball milling beads are added in sequence for ball milling. After the ball milling is completed, a mixed slurry C is obtained, and the mixed slurry C is dried to obtain the ceramic powder in this example, i.e., ZTA powder; wherein, the ball milling speed is 200 rpm, and circulating cooling water is used to ensure that the temperature in the ball mill is maintained at 40°C, the ball milling time is 20 hours, the drying temperature is 140°C, and the drying time is 3 hours; the mixed slurry C is composed of the following materials in mass percentage: 19% modified alumina powder, 1% modified zirconia powder, 30% solvent, and 50% zirconia ball milling beads, as shown in Table 4.

[0080] Example 2

[0081] The preparation method of the ceramic powder in this example is different from that in Example 1 only in that this example adopts the formula of the mixed slurry A numbered A2 in Table 2 to prepare the modified alumina powder.

[0082] Example 3

[0083] The preparation method of the ceramic powder in this example is different from that in Example 1 only in that this example adopts the formula of the mixed slurry A numbered A3 in Table 2 to prepare the modified alumina powder.

[0084] Example 4

[0085] The preparation method of the ceramic powder in this example is different from that in Example 1 only in that this example adopts the formula of the mixed slurry A numbered A4 in Table 2 to prepare the modified alumina powder.

[0086] Example 5

[0087] The preparation method of the ceramic powder in this example is different from that in Example 1 only in that this example adopts the formula of the mixed slurry A numbered A5 in Table 2 to prepare the modified alumina powder.

[0088] Example 6

[0089] The preparation method of the ceramic powder in this example is different from that in Example 2 only in that this example adopts the formula of the mixed slurry B numbered G1 in Table 3 to prepare the modified zirconia powder.

[0090] Example 7

[0091] The preparation method of the ceramic powder in this example is different from that in Example 2 only in that this example adopts the formula of the mixed slurry B numbered G3 in Table 3 to prepare the modified zirconia powder.

[0092] Example 8

[0093] The preparation method of the ceramic powder in this example is different from that in Example 2 only in that this example adopts the formula of the mixed slurry B numbered G4 in Table 3 to prepare the modified zirconia powder.

[0094] Example 9

[0095] The preparation method of the ceramic powder in this example is different from that in Example 2 only in that this example adopts the formula of the mixed slurry B numbered G5 in Table 3 to prepare the modified zirconia powder.

[0096] Example 10

[0097] The preparation method of the ceramic powder in this example is different from that in Example 2 only in that the mass percentages of the modified alumina powder, modified zirconia powder and zirconia ball milling beads in the mixed slurry C in this example are different.

[0098] Embodiment 11

[0099] The preparation method of the ceramic powder in this example is different from that in Example 2 only in that the mass percentages of the modified alumina powder, modified zirconia powder and zirconia ball milling beads in the mixed slurry C in this example are different.

[0100] The surface grain morphology of the ceramic powders prepared in Examples 1 to 11 was tested by scanning electron microscopy. The test results showed that the alumina grains and zirconium oxide grains in the ceramic powders prepared in Examples 1 to 11 were uniformly dispersed without grain agglomeration. The scanning electron microscope image of the ceramic powder in Example 1 is as follows: Figure 1 shown.

[0101] Comparative Example 1

[0102] The preparation method of the ceramic powder in this example is different from that in Example 2 only in that: this example adopts the formula of the mixed slurry A numbered AS1 in Table 2 to prepare the modified alumina powder.

[0103] Comparative Example 2

[0104] The preparation method of the ceramic powder in this example is different from that in Example 2 only in that this example uses the formula of the mixed slurry A numbered AS2 in Table 2 to prepare the modified alumina powder.

[0105] Comparative Example 3

[0106] The preparation method of the ceramic powder in this example is different from that in Example 2 only in that: this example adopts the formula of the mixed slurry A numbered AS3 in Table 2 to prepare the modified alumina powder.

[0107] Comparative Example 4

[0108] The preparation method of the ceramic powder in this example is different from that in Example 2 only in that: this example adopts the formula of the mixed slurry A numbered AS4 in Table 2 to prepare the modified alumina powder.

[0109] Comparative Example 5

[0110] The preparation method of the ceramic powder in this example is different from that in Example 2 only in that this example adopts the formula of the mixed slurry B numbered GS1 in Table 3 to prepare the modified zirconia powder.

[0111] Comparative Example 6

[0112] The preparation method of the ceramic powder in this example is different from that in Example 2 only in that this example adopts the formula of the mixed slurry B numbered GS2 in Table 3 to prepare the modified zirconia powder.

[0113] Comparative Example 7

[0114] The preparation method of the ceramic powder in this example is different from that in Example 2 only in that this example adopts the formula of the mixed slurry B numbered GS3 in Table 3 to prepare the modified zirconia powder.

[0115] Comparative Example 8

[0116] The preparation method of the ceramic powder in this example is different from that in Example 2 only in that this example adopts the formula of the mixed slurry B numbered GS4 in Table 3 to prepare the modified zirconia powder.

[0117] Comparative Example 9

[0118] The preparation method of the ceramic powder in this example is different from that in Example 2 only in that the mass percentages of the modified alumina powder, modified zirconium oxide powder and solvent used in this example are different.

[0119] Comparative Example 10

[0120] The preparation method of the ceramic powder in this example is different from that in Example 2 only in that the mass percentages of the modified alumina powder, modified zirconium oxide powder and solvent used in this example are different.

[0121] Comparative Example 11

[0122] The only difference between the preparation method of ceramic powder in this example and Example 2 is that: this example uses the formula of mixed slurry A numbered AS3 in Table 2 to prepare modified alumina powder, and uses mixed slurry B numbered GS3 in Table 3 to prepare modified zirconia powder, and the mass percentages of solvent and zirconia ball milling beads in mixed slurry C are different.

[0123] Comparative Example 12

[0124] The preparation method of the ceramic powder in this example is different from that in Example 2 only in that: this example uses the formula of mixed slurry A numbered AS5 in Table 2 to prepare modified alumina powder, and uses mixed slurry B numbered GS5 in Table 3 to prepare modified zirconia powder.

[0125] Comparative Example 13

[0126] The preparation method of the ceramic powder in this example is different from that in Example 2 only in that: this example adopts the formula of the mixed slurry A numbered AS6 in Table 2 to prepare the modified alumina powder.

[0127] Comparative Example 14

[0128] The preparation method of the ceramic powder in this example is different from that in Example 2 only in that this example uses mixed slurry B numbered GS6 in Table 3 to prepare modified zirconia powder.

[0129] Comparative Example 15

[0130] The only difference between the preparation method of ceramic powder in this example and Example 2 is that this example uses the formula of mixed slurry A numbered AS6 in Table 2 to prepare modified alumina powder, and uses mixed slurry B numbered GS6 in Table 3 to prepare modified zirconia powder.

[0131] The surface grain morphology of the ceramic powders prepared in Comparative Examples 1 to 15 was tested by scanning electron microscopy. The test results showed that the zirconium oxide grains in the ceramic powders prepared in Comparative Examples 1 to 15 all showed grain agglomeration. The scanning electron microscope image of the ceramic powder in Comparative Example 1 is as follows: Figure 2 As shown, Figure 2 There are zirconium oxide agglomerates with a length of about 3.52 μm.

[0132] The formulas of mixed slurry A, mixed slurry B, and mixed slurry C in the preparation methods of Examples 1 to 11 and Comparative Examples 1 to 15 are shown in Tables 2 to 4, respectively. The Zeta potentials of the alumina powder and the zirconia powder before modification were tested to be +10 mV and +12 mV, respectively. Then, the Zeta potentials of the modified alumina powder and the modified zirconia powder prepared from the mixed slurry A and the mixed slurry B in each embodiment and comparative example were tested, and the test results are shown in Tables 2 and 3, respectively.

[0133] Table 2 Formula of mixed slurry A and Zeta potential of modified alumina powder

[0134]

[0135] Table 3 Formula of mixed slurry B and Zeta potential of modified zirconia powder

[0136]

[0137] Table 4 Formula of mixed slurry C

[0138]

[0139] Application Examples

[0140] This example provides a method for preparing a ceramic splitter, and the specific steps are as follows:

[0141] 1. Preparation of feed: 15% by mass of binder and 85% by mass of ceramic powder are mixed in a mixer at 180°C for 8 hours to prepare feed;

[0142] 2. Injection molding: injecting the feed obtained in step 1 to obtain a splitter green body;

[0143] 3. Debinding: Debinding the splitter green body obtained in step 2, with the highest debinding temperature being 450° C. to obtain a splitter pre-sintered body;

[0144] 4. Sintering: Sinter the splitter pre-sintered body obtained in step 3 at a sintering temperature of 1570° C. for a holding time of 4 h to obtain a splitter sintered body;

[0145] 5. Grinding: The splitting knife sintered body obtained in step 4 is processed and ground to obtain the ceramic splitting knife.

[0146] The ceramic powders prepared in Examples 1 to 11 and Comparative Examples 1 to 15 were respectively prepared into ceramic splitting knife products according to the above-mentioned preparation methods.

[0147] Performance Testing

[0148] The nanoindentation hardness and flexural strength of the ceramic splitters made from the ceramic powders in Examples 1 to 11 and Comparative Examples 1 to 15 were tested respectively, and the specific test methods are shown in Table 5 below. The splitter sintered body is a hollow structure and is not suitable for direct density testing. Therefore, the sample tested in the density test of the present invention is a blank frame of the splitter sintered body. When the ceramic splitter is prepared using the ceramic powders in Examples 1 to 11 and Comparative Examples 1 to 15, after sintering, the splitter sintered body is removed from the blank frame for subsequent finished product processing. However, since the splitter sintered body is a hollow structure, it is not suitable for density testing, and the material of the blank frame is the same as that of the ceramic splitter sintered body and is not a hollow structure, therefore, the test sample in the density test of the present invention is the blank frame, and the measured density can represent the density of the ceramic splitter. The specific test method is shown in Table 5 below.

[0149] Table 5 Performance test methods

[0150]

[0151] The performance test results obtained according to the above test method are shown in Table 6 below.

[0152] Table 6 Performance test results

[0153]

[0154]

[0155] As can be seen from Table 6, Examples 1 to 11 use a method in which a specific type and amount of cationic modifier and anionic modifier are used to regulate the surface electrical properties of alumina and zirconia particles, respectively, so that the surfaces of the modified alumina powder and modified zirconia powder obtained present different electrical properties, respectively. The electrostatic effect is used to improve the dispersibility between the same powders, avoid agglomeration between particles, and promote uniform mixing between different powders, thereby obtaining a uniformly distributed injection feed precursor. Finally, a high-hardness, high-strength and high-density ceramic splitter is obtained through mixing, molding, debinding sintering and other processes. Specifically, the nanoindentation hardness of the obtained ceramic splitter is 25.3 to 28.5 GPa, and the flexural strength is 810 to 850 MPa; the density of the obtained splitter sintered body is 4.128 to 4.299 g / cm 3 Comparative Examples 1 to 11 respectively changed the amount of the cationic modifier or the anionic modifier, the pH of the ceramic slurry A or the ceramic slurry B and other conditions, while Comparative Examples 12 to 15 did not modify the alumina powder and the zirconia powder, or used cationic modifiers and anionic modifiers not specified in the present invention for modification. The ceramic splitters obtained in Comparative Examples 1 to 15 had poor strength, low density and reduced hardness.

[0156] The above is a detailed description of the embodiments of the present invention, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A method for preparing ceramic powder, characterized in that: The following steps are involved: S1: Grinding the mixed slurry A and the mixed slurry B separately to obtain modified alumina and modified zirconia; S2: grinding the raw materials including modified alumina and modified zirconia to obtain a mixed slurry C, and drying the mixed slurry C to obtain the ceramic powder; The mixed slurry A contains aluminum oxide and a cationic modifier; The mixed slurry B contains zirconium oxide and an anion modifier; The cationic modifier is selected from at least one of magnesium salt, aluminum salt, calcium salt and ammonium salt; The anion modifier is selected from at least one of polyacrylate, citrate and dodecylbenzene sulfonate.

2. The method for preparing ceramic powder according to claim 1, characterized in that: The pH of the mixed slurry A is 5 to 8; And / or, the pH of the mixed slurry B is 6-9.

3. The method for preparing ceramic powder according to claim 1, characterized in that: The Zeta potential of the modified alumina is +20mV to +50mV; And / or, the Zeta potential of the modified zirconium oxide is -20 mV to -50 mV.

4. The method for preparing ceramic powder according to claim 1, characterized in that: The mixed slurry A comprises the following materials in percentage by mass: 20-40% of aluminum oxide, 0.1-1% of a cationic modifier, 15-30% of a solvent, and 29-64.9% of grinding balls.

5. The method for preparing ceramic powder according to claim 1, characterized in that: The mixed slurry B comprises the following materials in percentage by mass: 20-40% zirconium oxide, 0.2-1.6% anion modifier, 15-30% solvent, and 28.4-64.8% grinding balls.

6. The method for preparing ceramic powder according to claim 1, characterized in that: The mixed slurry C comprises the following materials in percentage by mass: 20-40% of mixed powder, 15-30% of solvent, and 30-65% of grinding balls; the mixed powder is modified alumina and modified zirconia.

7. The method for preparing ceramic powder according to any one of claims 4 to 6, characterized in that: The grinding balls are selected from at least one of alumina ball milling beads and zirconia ball milling beads; And / or, the particle size of the grinding balls is 5 to 15 mm; And / or, the solvent is selected from at least one of water, ethanol and methanol.

8. The method for preparing ceramic powder according to claim 1 or 6, characterized in that: In the mixed slurry C, the mass ratio of modified alumina to modified zirconia is (3-19):

1.

9. The method for preparing ceramic powder according to claim 1, characterized in that: The grinding in step S1 and / or step S2 is performed by ball milling, and the ball milling meets at least one of the following characteristics: (a) The ball milling speed is 120-400 rpm; (b) The slurry temperature during ball milling is 40-50°C; (c) The ball milling time is 15 to 30 hours.

10. Use of the method for preparing ceramic powder according to any one of claims 1 to 9 in preparing ceramic splitting knife products.

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