Polishing solution for silicon nitride ceramic bearing ball and preparation method thereof

Abstract

The invention relates to the technical field of grinding and polishing, in particular to a polishing solution for a ceramic bearing ball and a preparation method of the polishing solution. The polishing solution mainly comprises the following components in parts by mass: 0.3-4 parts of a micro-powder grinding material, 1.0-10 parts of a lubricant, 0.5-3 parts of a friction coefficient regulator, 0.2-5 parts of a rheology regulator, 0.2-5 parts of a polymeric dispersant, 0.2-5 parts of an emulsifier, 0.3-4 parts of organic alkali and 71-95 parts of matrix oil. The polishing solution has the characteristics of high efficiency and easiness in cleaning, and the surface quality of the polished ceramic bearing ball is good.

Description

Technical Field

[0001] The invention relates to the technical field of grinding and polishing, and in particular to a polishing liquid for silicon nitride ceramic bearing balls and a preparation method thereof. Background Art

[0002] As a key technology in the equipment manufacturing industry, precision and ultra-precision machining technology has long been the focus of research and development and application in countries around the world. With the rapid development of this machining technology, its application in my country is no longer limited to a few fields such as cutting-edge defense and aerospace. It has expanded to all areas of the national economy, and its application scale has increased year by year, from single-piece small-batch production to large-scale production. With the continuous emergence of new products, the application scope of precision and ultra-precision machining will be further expanded. Precision and ultra-precision machining technology has become the foundation of the current high-tech field. In view of the rapid development of advanced manufacturing technology, the requirements for precision are getting higher and higher. Conventional processes can no longer meet the requirements of high-precision manufacturing, and precision and ultra-precision machining technology is urgently needed to support it.

[0003] With the development of science and technology, the market has higher and higher requirements for the accuracy, speed, reliability and other performance of machine tools and instruments. Compared with traditional bearing steel, silicon nitride ceramic ball bearings have better comprehensive performance such as long service life, high speed, good overall accuracy and rigidity, good thermal stability and non-magneticity, and have very broad application prospects. However, ceramic materials have high hardness and poor toughness, especially spherical materials. The production and processing technology is more complicated, and scratches and / or gnaws are easily generated during the polishing process. The surface finish and roughness of the material are difficult to reach the expected level, affecting the final use effect.

[0004] The polishing liquid for silicon nitride ceramic bearing balls in the prior art has the following disadvantages: severe scratches and gnaws, large surface roughness of ceramic bearing balls, long polishing time, and high processing costs. Compared with the defects of low polishing rate and large surface roughness of water-based polishing liquid, oil-based polishing liquid has higher polishing rate, better workpiece surface processing quality, and better performance.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] One object of the present invention is to provide a polishing liquid for silicon nitride ceramic bearing balls to solve the problems of serious scratches and gnaws, large surface roughness, long polishing time and high processing cost in the prior art. The polishing liquid of the present invention has the characteristics of high efficiency and easy cleaning.

[0007] The second purpose of the present invention is to provide a method for preparing a polishing liquid for silicon nitride ceramic bearing balls. The method is simple and easy to operate. By this method, an oily polishing liquid with high efficiency, easy cleaning, stable and uniform dispersion is obtained, and the surface quality of the ceramic bearing balls after polishing is excellent.

[0008] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted: A polishing liquid for silicon nitride ceramic bearing balls, mainly composed of the following components in parts by mass: Mix 0.3-4 parts of abrasive powder, 1.0-10 parts of lubricant, 0.5-3 parts of friction coefficient regulator, 0.2-5 parts of rheology regulator, 0.2-5 parts of polymer dispersant, 0.2-5 parts of emulsifier, 0.3-4 parts of organic base and 71-95 parts of base oil.

[0009] Preferably, the polishing liquid for silicon nitride ceramic bearing balls is mainly composed of the following components in parts by mass: 0.5-2 parts of mixed abrasive powder, 3.0-8 parts of lubricant, 1-2 parts of friction coefficient regulator, 0.3-2 parts of rheology regulator, 0.3-2 parts of polymer dispersant, 0.5-2 parts of emulsifier, 0.5-2 parts of organic base and 80-90 parts of base oil.

[0010] Preferably, the polishing liquid further comprises 0.1 to 1 part of a preservative, preferably 0.2 to 0.5 part of a preservative; Preferably, the preservative includes at least one of propylparaben, monocaprylin, disodium stannous citrate and potassium citrate.

[0011] Preferably, the mixed abrasive powder comprises spherical polycrystalline diamond powder and spherical cerium oxide powder.

[0012] Preferably, the particle size of the mixed abrasive powder is 125-500 nm.

[0013] More preferably, the mixed abrasive powder is selected from particles with a particle size of 200-300 nm.

[0014] Preferably, the sphericity of the spherical polycrystalline diamond powder and the spherical cerium oxide powder is 0.86-0.90.

[0015] Preferably, the mass ratio of the spherical polycrystalline diamond powder to the spherical cerium oxide powder is (4-9):1.

[0016] Preferably, the mass ratio of the spherical polycrystalline diamond powder to the spherical cerium oxide powder is 4:1, 5:1, 6:1, 7:1, 8:1 or 9:1; and / or the particle size of the mixed abrasive powder is 125nm, 200nm, 300nm, 400nm or 500nm.

[0017] Preferably, the lubricant includes at least one of polyethylene glycol, polyglycerol and capric triglyceride.

[0018] More preferably, the lubricant includes at least one of polyethylene glycol 400, polyethylene glycol 600, polyglycerol 800 and capric triglyceride.

[0019] Preferably, the friction coefficient adjuster includes at least one of oleic acid diethanolamine borate and polyether-modified dimethylsiloxane.

[0020] More preferably, the oleic acid diethanolamine borate B-ODEA and polyether modified dimethylsiloxane WR-653 is at least one of the following.

[0021] Preferably, the rheology modifier includes at least one of lauryl oleate, a polyurea compound and a fatty acid amide wax.

[0022] More preferably, the rheology modifier includes at least one of lauryl oleate, polyurea compound RA-4102, and fatty acid amide wax RA-2900-20X.

[0023] Preferably, the polymer dispersant includes at least one of a polymer containing an acidic group, a block polymer, a polymer polyurethane block copolymer, dispersant DP-810 and DW-403.

[0024] More preferably, the polymer dispersant includes at least one of oily acrylic dispersant YL-472A, block polymer YL-4633, polymer polyurethane block copolymer DP-810, dispersant DP-8325N and DW-403.

[0025] Preferably, the emulsifier includes at least one of polyoxyethylene cardanol ether, sucrose amino ester, coconut oil acid alkanolamide, polyoxyethylene octylphenol ether and fatty alcohol ether.

[0026] More preferably, the emulsifier includes at least one of cardanol polyoxyethylene ether BGF-9, sucrose amino ester NP-10, coconut oil acid alkanolamide (Ninal 6501), octylphenol polyoxyethylene ether OP-4 and fatty alcohol ether MOA-3B.

[0027] Preferably, the organic base includes at least one of tetramethylethylenediamine and diisopropylethylamine.

[0028] Preferably, the base oil comprises solvent oil and mineral oil with a carbon chain length of C12-16, and the mass ratio of the two is (1-4):(1-3). More preferably, the mass ratio of the solvent oil and the mineral oil with a carbon chain length of C12-16 is 4:1; more preferably, the solvent oil is D100, and the mineral oil with a carbon chain length of C12-16 is 7# white oil.

[0029] Preferably, the viscosity of the polishing liquid for silicon nitride ceramic bearing balls is controlled at 20-70 cp (25° C.), and preferably, the viscosity of the polishing liquid is controlled at 30-50 cp (25° C.).

[0030] The method for preparing the polishing liquid as described above comprises the following steps: The base oil, polymer dispersant and mixed abrasive powder are mixed, stirred electrically and dispersed ultrasonically, a friction coefficient regulator, a lubricant and an emulsifier are added, stirring and ultrasonically dispersed are continued, a rheology regulator, an organic base and a preservative are added and stirring is continued.

[0031] Preferably, the method for preparing the polishing liquid comprises the following steps: The base oil, polymer dispersant and mixed abrasive powder are mixed, and the mixture is stirred and dispersed by ultrasonic for 20-30 minutes to obtain a mixed dispersion. The temperature of the ultrasonic medium is maintained at 20-50°C, and the electric stirring speed is not less than 700 rpm. Preferably, a friction coefficient regulator, a lubricant, and an emulsifier are added, stirring and ultrasonic dispersion are continued for 10 to 20 minutes, and the temperature of the ultrasonic medium is maintained at 20 to 50° C.; Preferably, a rheology regulator, an organic base and a preservative are added to the mixed solution and stirred continuously for 10 to 15 minutes to obtain the polishing solution of the present invention.

[0032] In view of the fact that ceramic balls are easily gnawed during the polishing process, the present invention adopts a mixed abrasive of spherical polycrystalline diamond micropowder and spherical cerium oxide micropowder. Since micropowder abrasives with high sphericity are expensive, and micropowders with poor sphericity often have poor polishing performance and are easy to cause scratches, the present invention selects a mixed abrasive micropowder with moderate sphericity and economical, and its sphericity is 0.86~0.90. The present invention effectively avoids the problem of scratching and / or gnawing of ceramic bearing balls by using spherical abrasives to achieve the effect of smooth and flawless surface of ceramic balls. The present invention mixes polycrystalline diamond with strong hardness with cerium oxide micropowder with low hardness, which can achieve mutual complementarity and mutual benefit. On the one hand, it is to ensure that the polishing liquid has a strong polishing rate, and on the other hand, it is to avoid scratching and / or gnawing of ceramic balls. The mixed abrasive micropowder of the present invention still has a good polishing effect under the condition of low micropowder dosage by cooperating with other components. The present invention adopts a polymer dispersant, which not only has good anti-coarsening performance, but also has good anti-settling ability. Compared with small molecular dispersants, polymer dispersants can prolong the storage stability of the polishing liquid; the present invention adopts appropriate friction coefficient regulators, emulsifiers and rheology regulators, so that the polishing liquid has good suspension, lubricity and fluidity, and enables the abrasive powder to fully participate in the grinding and polishing, which greatly improves the polishing efficiency, so that the surface of the polished ceramic bearing ball is mirror-like, scratch-free and without gnawing. Considering that the polishing of ceramic bearing balls is a batch of materials thrown into the polishing equipment at the same time, generally hundreds or thousands of balls collide and rub against each other, it is inevitable that gnawing or biting will occur. Therefore, the present invention can effectively avoid the problem of gnawing or biting caused by mutual collision and friction by adopting appropriate lubricants. In addition, the present invention controls the viscosity of the polishing liquid within 20~70cp (25°C), the main purpose of which is: during the polishing process, the polishing liquid will not be unable to adhere well to the ceramic bearing balls due to too low viscosity, resulting in the polishing liquid not having an effective polishing effect, nor will the micropowder in the polishing liquid be unevenly dispersed and have poor fluidity due to too high viscosity. In addition, during the polishing process, the polishing liquid and grinding chips are very likely to adhere to the ceramic bearing balls and clog the grinding device, resulting in a very poor polishing effect.

[0033] Compared with the prior art, the present invention has the following beneficial effects: (1) The polishing liquid for silicon nitride ceramic bearing balls of the present invention has stronger polishing force and higher polishing rate, high polishing efficiency, can effectively avoid scratches and / or gnaws and micro cracks on the surface of the workpiece during the polishing process, and has better dispersibility, fluidity and lubrication performance.

[0034] (2) The polishing liquid used for silicon nitride ceramic bearing balls of the present invention is easier to clean than conventional oily polishing liquids. The workpiece after grinding can be directly rinsed with water without the need for other volatile solvents, while conventional oily polishing liquids must be combined with other organic solvents to be cleaned.

[0035] (3) The preparation method of the polishing liquid of the present invention is simple and easy. The polishing liquid with high efficiency, easy cleaning, stable and uniform dispersion can be obtained by the method. The surface quality of the ceramic bearing ball after polishing is excellent. The preparation method has close connection between the previous and subsequent steps, is easy to operate, and has mild operating conditions. It can realize industrial production and has very good economic benefits. DETAILED DESCRIPTION

[0036] The embodiments of the present invention will be described in detail below in conjunction with the examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. If no specific conditions are specified in the examples, the conditions are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be obtained commercially.

[0037] According to one aspect of the present invention, the present invention relates to a polishing liquid for silicon nitride ceramic bearing balls, mainly composed of the following components in parts by mass: Mix 0.3-4 parts of abrasive powder, 1-10 parts of lubricant, 0.5-3 parts of friction coefficient regulator, 0.2-5 parts of rheology regulator, 0.2-5 parts of polymer dispersant, 0.2-5 parts of emulsifier, 0.3-4 parts of organic base and 71-95 parts of base oil.

[0038] In one embodiment, the mixed abrasive powder is 0.3-4 parts, and can also be 0.5 parts, 1 parts, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts or 4 parts.

[0039] In one embodiment, the lubricant is 1.0 to 10 parts, and 1.0, 1.5, 2, 2.5, 3, 4, 5, 6, 7, 8, 9 or 10 parts can also be selected.

[0040] In one embodiment, the friction coefficient modifier is 0.5 to 3 parts, and can also be 0.5 parts, 1 part, 2 parts or 3 parts.

[0041] In one embodiment, the rheology regulator is 0.2 to 5 parts, and can also be 0.2 parts, 0.5 parts, 1 part, 2 parts, 3 parts, 4 parts or 5 parts.

[0042] In one embodiment, the polymer dispersant is 0.2 to 5 parts, and can also be 0.2 parts, 0.5 parts, 1 part, 2 parts, 3 parts, 4 parts or 5 parts.

[0043] In one embodiment, the emulsifier is 0.2 to 5 parts, and can also be 0.2 parts, 0.5 parts, 1 part, 2 parts, 3 parts, 4 parts or 5 parts.

[0044] In one embodiment, the organic base is 0.3 to 4 parts, and can also be 0.3 parts, 0.5 parts, 1 part, 2 parts, 3 parts or 4 parts.

[0045] In one embodiment, the base oil is 71-95 parts, and can also be 71 parts, 75 parts, 80 parts, 85 parts, 90 parts or 95 parts.

[0046] The invention obtains easy-to-clean and efficient polishing liquid through the coordinated cooperation of various components.

[0047] Preferably, the polishing liquid also includes 0.1 to 1 part of a preservative.

[0048] In one embodiment, the preservative is 0.1 to 1 part, and can also be 0.1 part, 0.2 part, 0.3 part, 0.4 part, 0.5 part, 0.6 part, 0.7 part, 0.8 part, 0.9 part or 1 part.

[0049] Preferably, the preservative includes at least one of propylparaben, monocaprylin, disodium stannous citrate and potassium citrate.

[0050] In one embodiment, the preservative is glyceryl monocaprylate.

[0051] In one embodiment, the preservatives are propylparaben and disodium stannous citrate.

[0052] Preferably, the polishing liquid for silicon nitride ceramic bearing balls is mainly composed of the following components in parts by mass: 0.5-2 parts of mixed abrasive powder, 3-8 parts of lubricant, 1-2 parts of friction coefficient regulator, 0.3-2 parts of rheology regulator, 0.3-2 parts of polymer dispersant, 0.5-2 parts of emulsifier, 0.5-2 parts of organic base and 80-90 parts of base oil.

[0053] The polishing liquid obtained by adopting the components and proportions of the present invention is used for polishing silicon nitride ceramic bearing balls, and the surface roughness Ra can reach 8-14nm, the surface has no gnaws, scratches, micro cracks, and the surface is a mirror surface.

[0054] Preferably, the mixed abrasive powder includes spherical polycrystalline diamond powder and spherical cerium oxide powder. The spherical abrasive powder is used to effectively avoid the problem of scratches and / or gnaws on the ceramic bearing balls, so as to achieve a smooth and flawless surface of the ceramic balls. The present invention mixes polycrystalline diamond with higher hardness with cerium oxide powder with lower hardness, which can achieve mutual complementarity and mutual benefit. On the one hand, it is to ensure that the polishing liquid has a higher polishing rate, and on the other hand, it is to avoid scratches and / or gnaws on the ceramic balls.

[0055] The mixed abrasive micropowder mainly plays a role in polishing and improving the adhesion of the polishing liquid on the ceramic ball. If the micropowder content is too high, the cost will be very high, and if the micropowder content is too low, a good polishing effect cannot be obtained. The present invention has a good polishing effect at a low micropowder dosage by cleverly combining the mixed abrasive micropowder with other components.

[0056] Preferably, the particle size of the mixed abrasive powder is 125-500 nm.

[0057] In one embodiment, the particle size of the mixed abrasive powder is 125-500 nm, and can also be 125 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm or 500 nm.

[0058] More preferably, the particle size of the mixed abrasive powder is 200-300 nm.

[0059] More preferably, the mixed abrasive powder includes spherical polycrystalline diamond powder and spherical cerium oxide powder.

[0060] Further preferably, the sphericity of the spherical polycrystalline diamond powder and the spherical cerium oxide powder is 0.86-0.90.

[0061] Further preferably, the mass ratio of the spherical polycrystalline diamond powder to the spherical cerium oxide powder is (4-9):1, and the mass ratio can also be selected to be 4:1, 5:1, 6:1, 7:1, 8:1 or 9:1.

[0062] Preferably, the lubricant includes at least one of polyethylene glycol, polyglycerol and capric triglyceride.

[0063] Further preferably, the lubricant includes at least one of polyethylene glycol 400, polyethylene glycol 600, polyglycerol 800 and capric triglyceride.

[0064] The polishing mechanism of balls is completely different from that of flat workpieces. In the polishing of flat workpieces, the workpieces are usually fixed and there is no contact between them. In the polishing of bearing balls, a batch of materials are thrown into the polishing equipment at the same time. Generally, hundreds or thousands of balls collide and rub against each other, which inevitably causes gnawing or biting. This is why the lubricant in the polishing liquid is particularly important. The present invention uses the above lubricant to reduce the gnawing or biting caused by mutual collision and friction.

[0065] Preferably, the friction coefficient adjuster includes at least one of oleic acid diethanolamine borate and polyether-modified dimethylsiloxane.

[0066] In one embodiment, the friction coefficient modifier is oleic acid diethanolamine borate B-ODEA.

[0067] In one embodiment, the friction coefficient adjuster is polyether-modified dimethylsiloxane WR-653.

[0068] In one embodiment, the friction coefficient adjuster is oleic acid diethanolamine borate B-ODEA and polyether modified dimethylsiloxane WR-653.

[0069] Preferably, the rheology modifier includes at least one of lauryl oleate, a polyurea compound and a fatty acid amide wax.

[0070] In one embodiment, the rheology modifier is lauryl oleate.

[0071] In one embodiment, the rheology modifier is a polyurea compound RA-4102.

[0072] In one embodiment, the rheology modifier is lauryl oleate and fatty acid amide wax RA-2900-20X.

[0073] Preferably, the polymer dispersant includes at least one of a polymer containing an acidic group, a block polymer, a polymer polyurethane block copolymer, dispersant DP-8325N and DW-403.

[0074] In one embodiment, the polymer dispersant is a polymer YL-472A containing an acidic group.

[0075] In one embodiment, the polymer dispersant is polymer polyurethane block copolymer DP-810.

[0076] In one embodiment, the polymer dispersant is DP-8325N.

[0077] The present invention can form a stable and uniform polishing liquid by adding the above dispersant.

[0078] Preferably, the emulsifier includes at least one of cardanol polyoxyethylene ether, sucrose amino ester, coconut oil acid alkanolamide, octylphenol polyoxyethylene ether and fatty alcohol ether; In one embodiment, the emulsifier is cardanol polyoxyethylene ether BGF-9.

[0079] In one embodiment, the emulsifier is fatty alcohol ether MOA-3B.

[0080] In one embodiment, the emulsifier is coconut oleic acid alkanolamide (Ninal 6501).

[0081] In one embodiment, the emulsifier is octylphenol polyoxyethylene ether OP-4 and sucrose amino ester NP-10.

[0082] Preferably, the organic base includes at least one of tetramethylethylenediamine and diisopropylethylamine.

[0083] In one embodiment, the organic base is tetramethylethylenediamine.

[0084] In one embodiment, the organic base is diisopropylethylamine.

[0085] Preferably, the base oil comprises solvent oil and mineral oil with a carbon chain length of C12-16, and the mass ratio of the two is (1-4):(1-3). More preferably, the mass ratio of the solvent oil and the mineral oil with a carbon chain length of C12-16 is 4:1; more preferably, the solvent oil is D100, and the mineral oil with a carbon chain length of C12-16 is 7# white oil.

[0086] In one embodiment, the mass ratio of the solvent oil to the mineral oil with a carbon chain length of C12-16 is 1:1.

[0087] In one embodiment, the mass ratio of the solvent oil and the mineral oil with a saturated alcohol carbon chain length of C12-16 is 1:3.

[0088] In one embodiment, the mass ratio of the solvent oil and the mineral oil with a saturated alcohol carbon chain length of C12-16 is 3:2.

[0089] In one embodiment, the mass ratio of D100 to 7# white oil is 4:1. According to another aspect of the present invention, the present invention also relates to a method for preparing the polishing liquid as described above, comprising the following steps: The base oil, polymer dispersant and mixed abrasive powder are mixed, stirred electrically and dispersed ultrasonically, a friction coefficient regulator, a lubricant and an emulsifier are added, stirring is continued and ultrasonic dispersion is performed, a rheology regulator, an organic base and a preservative are added and stirring is continued.

[0090] Preferably, the method for preparing the polishing liquid comprises the following steps: The base oil, polymer dispersant and mixed abrasive powder are mixed, stirred electrically and ultrasonically dispersed for 20 to 30 minutes to obtain a mixed dispersion, wherein the temperature of the ultrasonic medium is maintained at 20 to 50° C. and the speed of the electric stirring is not less than 700 rpm; In one embodiment, the base oil, polymer dispersant and mixed abrasive powder are mixed, and the dispersion time for electric stirring and ultrasonic dispersion is 20 to 30 minutes, and 20 minutes, 21 minutes, 22 minutes, 23 minutes, 24 minutes, 25 minutes, 26 minutes, 27 minutes, 28 minutes, 29 minutes or 30 minutes can also be selected.

[0091] Preferably, the friction coefficient regulator, lubricant and emulsifier are added, stirring is continued and ultrasonic dispersion is performed for 10 to 20 minutes, and the temperature of the ultrasonic medium is maintained at 20 to 50° C.; In one embodiment, the dispersion time for ultrasonic dispersion by adding friction coefficient regulator, lubricant and emulsifier is 10 to 20 minutes, and 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, 16 minutes, 17 minutes, 18 minutes, 19 minutes or 20 minutes can also be selected.

[0092] Preferably, the rheology regulator, organic base and preservative are added and stirring is continued for 10 to 15 minutes.

[0093] In one embodiment, the stirring time for adding the rheology regulator, the organic base and the preservative for stirring is 10 to 15 minutes, and can also be 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes or 15 minutes.

[0094] In a preferred embodiment, the method for preparing the polishing liquid comprises the following steps: (a) mixing the base oil, the polymer dispersant and the mixed abrasive powder, stirring electrically and dispersing by ultrasonic wave for 20 to 30 minutes to obtain a mixed dispersion, wherein the temperature of the ultrasonic medium is maintained at 20 to 50° C. and the speed of the electric stirring is not less than 700 rpm; (b) adding a friction coefficient modifier, a lubricant, and an emulsifier to the mixed dispersion, continuing to stir and ultrasonically disperse for 10 to 20 minutes, and maintaining the temperature of the ultrasonic medium at 20 to 50° C.; (c) adding a rheology regulator, an organic base and a preservative to (b) and continuing stirring for 10 to 15 minutes to obtain the polishing liquid of the present invention.

[0095] The polishing liquid of the invention can be used for grinding high-hardness, high-precision, high-value-added products such as silicon nitride, zirconium oxide, tungsten carbide, alloy balls, etc.

[0096] The present invention will be further explained below with reference to specific embodiments. In addition, all reagents used in the present invention are industrially pure. Example 1

[0097] A polishing liquid for silicon nitride ceramic bearing balls, the preparation method of which comprises the following steps: (a) 90 parts of base oil (the mass ratio of D100 and 7# white oil is 4:1), 0.3 parts of acidic group-containing polymer YL-472A and 2 parts of mixed abrasive micropowder with D50 of 300 nm and sphericity of 0.90 are mixed, wherein the mass ratio of spherical polycrystalline diamond and spherical cerium oxide micropowder in the mixed abrasive micropowder is 7:1, and the mixture is stirred electrically and dispersed by ultrasonic wave for 20-30 minutes to obtain a mixed dispersion, wherein the temperature of the ultrasonic medium is maintained at 20-50°C and the speed of the electric stirring is 700 rpm; (b) adding 1 part of oleic acid diethanolamine borate B-ODEA, 3 parts of polyethylene glycol 400 and 0.5 parts of cardanol polyoxyethylene ether BGF-9 to the above mixed dispersion, continuing to stir and ultrasonically disperse for 10-20 minutes, and maintaining the temperature of the ultrasonic medium at 20-50°C; (c) Add 2 parts of polyurea compound RA-4102, 0.5 parts of tetramethylethylenediamine and 0.2 parts of propyl p-hydroxybenzoate to (b), and continue stirring for 10 to 15 minutes to obtain the polishing liquid of the present invention. Example 2

[0098] A polishing liquid for silicon nitride ceramic bearing balls, the preparation method of which comprises the following steps: (a) 90 parts of base oil (the mass ratio of D100 and 7# white oil is 4:1), 0.3 parts of acidic group-containing polymer YL-472A and 2 parts of mixed abrasive micropowder with a median particle size D50 of 300 nm and a sphericity of 0.90 are mixed, wherein the mass ratio of spherical polycrystalline diamond and spherical cerium oxide micropowder in the mixed abrasive micropowder is 4:1, and the mixture is stirred electrically and ultrasonically dispersed for 20 to 30 minutes to obtain a mixed dispersion, wherein the temperature of the ultrasonic medium is maintained at 20 to 50° C. and the speed of the electric stirring is 700 rpm; (b) adding 1 part of oleic acid diethanolamine borate B-ODEA, 3 parts of polyethylene glycol 400 and 0.5 parts of cardanol polyoxyethylene ether BGF-9 to the above mixed dispersion, continuing to stir and ultrasonically disperse for 10-20 minutes, and maintaining the temperature of the ultrasonic medium at 20-50°C; (c) Add 2 parts of polyurea compound RA-4102, 0.5 parts of tetramethylethylenediamine and 0.2 parts of propyl p-hydroxybenzoate to (b), and continue stirring for 10 to 15 minutes to obtain the polishing liquid of the present invention. Example 3

[0099] A polishing liquid for silicon nitride ceramic bearing balls, the preparation method of which comprises the following steps: (a) 90 parts of base oil (the mass ratio of D100 and 7# white oil is 4:1), 0.3 parts of acidic group-containing polymer YL-472A and 2 parts of mixed abrasive micropowder with a median particle size D50 of 300 nm and a sphericity of 0.90 are mixed, wherein the mass ratio of spherical polycrystalline diamond and spherical cerium oxide micropowder in the mixed abrasive micropowder is 9:1, and the mixture is stirred electrically and ultrasonically dispersed for 20 to 30 minutes to obtain a mixed dispersion, wherein the temperature of the ultrasonic medium is maintained at 20 to 50° C. and the speed of the electric stirring is 700 rpm; (b) adding 1 part of oleic acid diethanolamine borate B-ODEA, 3 parts of polyethylene glycol 400 and 0.5 parts of cardanol polyoxyethylene ether BGF-9 to the above mixed dispersion, continuing to stir and ultrasonically disperse for 10-20 minutes, and maintaining the temperature of the ultrasonic medium at 20-50°C; (c) Add 2 parts of polyurea compound RA-4102, 0.5 parts of tetramethylethylenediamine and 0.2 parts of propyl p-hydroxybenzoate to (b), and continue stirring for 10 to 15 minutes to obtain the polishing liquid of the present invention. Example 4

[0100] A polishing liquid for silicon nitride ceramic bearing balls, the preparation method of which comprises the following steps: (a) 71 parts of base oil (the mass ratio of D100 and 7# white oil is 1:1), 5 parts of polymer dispersant DP-8325N and 4 parts of mixed abrasive micropowder with a median particle size D50 of 125 nm and a sphericity of 0.86 are mixed, wherein the mass ratio of spherical polycrystalline diamond and spherical cerium oxide micropowder in the mixed abrasive micropowder is 7:1, and the mixture is stirred electrically and ultrasonically dispersed for 20 to 30 minutes to obtain a mixed dispersion, wherein the temperature of the ultrasonic medium is maintained at 30° C. and the speed of the electric stirring is 800 rpm; (b) adding 1 part of oleic acid diethanolamine borate B-ODEA, 10 parts of polyethylene glycol 400 and 2 parts of fatty alcohol ether MOA-3B to the above mixed dispersion, continuing to stir and ultrasonically disperse for 10-20 minutes, and maintaining the temperature of the ultrasonic medium at 20-50°C; (c) Add 2 parts of polyurea compound RA-4102, 4 parts of diisopropylethylamine and 0.5 parts of monocaprylic glycerol to (b), and continue stirring for 10 to 15 minutes to obtain the polishing liquid of the present invention. Example 5

[0101] A polishing liquid for silicon nitride ceramic bearing balls, the preparation method of which comprises the following steps: (a) 75 parts of base oil (the mass ratio of D100 and 7# white oil is 1:3), 0.3 parts of acidic group-containing polymer YL-472A and 0.5 parts of mixed abrasive micropowder with a median particle size D50 of 200 nm and a sphericity of 0.90 are mixed, wherein the mass ratio of spherical polycrystalline diamond and spherical cerium oxide micropowder in the mixed abrasive micropowder is 7:1, and the mixture is stirred electrically and ultrasonically dispersed for 20 to 30 minutes to obtain a mixed dispersion, wherein the temperature of the ultrasonic medium is maintained at 30° C. and the speed of the electric stirring is 800 rpm; (b) adding 1 part of oleic acid diethanolamine borate B-ODEA, 8 parts of polypropylene glycol 800 and 0.2 parts of Ninal 6501 to the above mixed dispersion, continuing to stir and ultrasonically disperse for 10-20 minutes, and maintaining the temperature of the ultrasonic medium at 20-50°C; (c) Add 2 parts of polyurea compound RA-4102, 2 parts of diisopropylethylamine and 1.0 part of a mixture of propyl p-hydroxybenzoate and disodium stannous citrate (mass ratio is 1:1) to (b), and continue stirring for 10 to 15 minutes to obtain the polishing liquid of the present invention. Example 6

[0102] A polishing liquid for silicon nitride ceramic bearing balls, the preparation method of which comprises the following steps: (a) 95 parts of base oil (the mass ratio of D100 and 7# white oil is 3:2), 0.3 parts of dispersant DW-403 and 0.3 parts of mixed abrasive micropowder with a median particle size D50 of 500 nm and a sphericity of 0.90 are mixed, wherein the mass ratio of spherical polycrystalline diamond and spherical cerium oxide micropowder in the mixed abrasive micropowder is 7:1, and the mixture is stirred electrically and ultrasonically dispersed for 20 to 30 minutes to obtain a mixed dispersion, wherein the temperature of the ultrasonic medium is maintained at 40° C. and the speed of the electric stirring is 800 rpm; (b) adding 1 part of oleic acid diethanolamine borate B-ODEA, 1 part of a mixture of polyethylene glycol 600 and capric triglyceride (mass ratio of the two is 2:1), 5 parts of octylphenol polyoxyethylene ether OP-4 and amino sucrose ester NP-10 (mass ratio of the two is 3:1) to the above mixed dispersion, continuing to stir and ultrasonically disperse for 10-20 minutes, and maintaining the temperature of the ultrasonic medium at 20-50°C; (c) Add 2 parts of polyurea compound RA-4102, 0.3 parts of tetramethylethylenediamine and 0.1 parts of potassium citrate to (b), and continue stirring for 10 to 15 minutes to obtain the polishing liquid of the present invention. Example 7

[0103] A polishing liquid for silicon nitride ceramic bearing balls, the preparation method of which comprises the following steps: (a) 90 parts of base oil (the mass ratio of D100 and 7# white oil is 4:1), 0.3 parts of acidic group-containing polymer YL-472A and 2 parts of mixed abrasive micropowder with D50 of 300 nm and sphericity of 0.90 are mixed, wherein the mass ratio of spherical polycrystalline diamond and spherical cerium oxide micropowder in the mixed abrasive micropowder is 7:1, and the mixture is stirred electrically and dispersed by ultrasonic wave for 20-30 minutes to obtain a mixed dispersion, wherein the temperature of the ultrasonic medium is maintained at 20-50°C and the speed of the electric stirring is 700 rpm; (b) adding 0.5 parts of oleic acid diethanolamine borate B-ODEA, 3 parts of polyethylene glycol 400 and 0.5 parts of cardanol polyoxyethylene ether BGF-9 to the above mixed dispersion, continuing to stir and ultrasonically disperse for 10 to 20 minutes, and maintaining the temperature of the ultrasonic medium at 20 to 50°C; (c) Add 2 parts of polyurea compound RA-4102, 0.5 parts of tetramethylethylenediamine and 0.2 parts of propyl p-hydroxybenzoate to (b), and continue stirring for 10 to 15 minutes to obtain the polishing liquid of the present invention. Example 8

[0104] A polishing liquid for silicon nitride ceramic bearing balls, the preparation method of which comprises the following steps: (a) 90 parts of base oil (the mass ratio of D100 and 7# white oil is 4:1), 0.3 parts of acidic group-containing polymer YL-472A and 2 parts of mixed abrasive micropowder with D50 of 300 nm and sphericity of 0.90 are mixed, wherein the mass ratio of spherical polycrystalline diamond and spherical cerium oxide micropowder in the mixed abrasive micropowder is 7:1, and the mixture is stirred electrically and dispersed by ultrasonic wave for 20-30 minutes to obtain a mixed dispersion, wherein the temperature of the ultrasonic medium is maintained at 20-50°C and the speed of the electric stirring is 700 rpm; (b) Add 3 parts of a mixture of oleic acid diethanolamine borate B-ODEA and polyether modified dimethylsiloxane WR-653 (mass ratio is 1:2), 3 parts of polyethylene glycol 400, and 0.5 parts of cardanol polyoxyethylene ether BGF-9 to the above mixed dispersion, continue stirring and ultrasonic dispersion for 10-20 minutes, and keep the temperature of the ultrasonic medium at 20-50°C; (c) Add 2 parts of polyurea compound RA-4102, 0.5 parts of tetramethylethylenediamine and 0.2 parts of propyl p-hydroxybenzoate to (b), and continue stirring for 10 to 15 minutes to obtain the polishing liquid of the present invention. Example 9

[0105] A polishing liquid for silicon nitride ceramic bearing balls, the preparation method of which comprises the following steps: (a) 80 parts of base oil (the mass ratio of D100 and 7# white oil is 4:1), 0.2 parts of block polymer YL-4633 and 2 parts of mixed abrasive powder with D50 of 300 nm and sphericity of 0.90 are mixed, wherein the mass ratio of spherical polycrystalline diamond and spherical cerium oxide powder in the mixed abrasive powder is 7:1, and the mixture is stirred electrically and dispersed by ultrasonic wave for 20-30 minutes to obtain a mixed dispersion, wherein the temperature of the ultrasonic medium is maintained at 20-50°C, and the speed of the electric stirring is 700 rpm; (b) adding 1.0 part of oleic acid diethanolamine borate B-ODEA, 3 parts of polyethylene glycol 400 and 0.5 parts of cardanol polyoxyethylene ether BGF-9 to the above mixed dispersion, continuing to stir and ultrasonically disperse for 10-20 minutes, and maintaining the temperature of the ultrasonic medium at 20-50°C; (c) Add 2 parts of polyurea compound RA-4102, 0.5 parts of tetramethylethylenediamine and 0.2 parts of propyl p-hydroxybenzoate to (b), and continue stirring for 10 to 15 minutes to obtain the polishing liquid of the present invention. Example 10

[0106] A polishing liquid for silicon nitride ceramic bearing balls, the preparation method of which comprises the following steps: (a) 85 parts of base oil (the mass ratio of D100 and 7# white oil is 4:1), 2.0 parts of high molecular weight polyurethane block copolymer DP-810 and 2 parts of mixed abrasive micropowder with D50 of 300 nm and sphericity of 0.90 are mixed, wherein the mass ratio of spherical polycrystalline diamond and spherical cerium oxide micropowder in the mixed abrasive micropowder is 7:1, and the mixed abrasive micropowder is stirred electrically and ultrasonically dispersed for 20-30 minutes to obtain a mixed dispersion, wherein the temperature of the ultrasonic medium is maintained at 20-50° C. and the speed of the electric stirring is 700 rpm; (b) adding 1 part of oleic acid diethanolamine borate B-ODEA, 3 parts of polyethylene glycol 400 and 0.5 parts of cardanol polyoxyethylene ether BGF-9 to the above mixed dispersion, continuing to stir and ultrasonically disperse for 10-20 minutes, and maintaining the temperature of the ultrasonic medium at 20-50°C; (c) Add 2 parts of polyurea compound RA-4102, 0.5 parts of tetramethylethylenediamine and 0.2 parts of propyl p-hydroxybenzoate to (b), and continue stirring for 10 to 15 minutes to obtain the polishing liquid of the present invention. Embodiment 11

[0107] A polishing liquid for silicon nitride ceramic bearing balls, the preparation method of which comprises the following steps: (a) 90 parts of base oil (the mass ratio of D100 and 7# white oil is 4:1), 2.0 parts of high molecular weight polyurethane block copolymer DP-810 and 2 parts of mixed abrasive micropowder with D50 of 300 nm and sphericity of 0.90 are mixed, wherein the mass ratio of spherical polycrystalline diamond and spherical cerium oxide micropowder in the mixed abrasive micropowder is 7:1, and the mixed abrasive micropowder is stirred electrically and ultrasonically dispersed for 20 to 30 minutes to obtain a mixed dispersion, wherein the temperature of the ultrasonic medium is maintained at 20 to 50° C. and the speed of the electric stirring is 700 rpm; (b) adding 1.0 part of oleic acid diethanolamine borate B-ODEA, 3 parts of polyethylene glycol 400 and 0.5 parts of cardanol polyoxyethylene ether BGF-9 to the above mixed dispersion, continuing to stir and ultrasonically disperse for 10-20 minutes, and maintaining the temperature of the ultrasonic medium at 20-50°C; (c) Add 0.3 parts of tetradecanol oleate CMO, 0.5 parts of tetramethylethylenediamine and 0.2 parts of propyl p-hydroxybenzoate to (b), and continue stirring for 10 to 15 minutes to obtain the polishing liquid of the present invention. Example 12

[0108] A polishing liquid for silicon nitride ceramic bearing balls, the preparation method of which comprises the following steps: (a) 90 parts of base oil (the mass ratio of D100 and 7# white oil is 4:1), 2.0 parts of high molecular weight polyurethane block copolymer DP-810 and 2 parts of mixed abrasive micropowder with D50 of 300 nm and sphericity of 0.90 are mixed, wherein the mass ratio of spherical polycrystalline diamond and spherical cerium oxide micropowder in the mixed abrasive micropowder is 7:1, and the mixed abrasive micropowder is stirred electrically and ultrasonically dispersed for 20 to 30 minutes to obtain a mixed dispersion, wherein the temperature of the ultrasonic medium is maintained at 20 to 50° C. and the speed of the electric stirring is 700 rpm; (b) adding 1.0 part of oleic acid diethanolamine borate B-ODEA, 3 parts of polyethylene glycol 400, and 0.5 parts of cardanol polyoxyethylene ether BGF-9 to the above mixed dispersion, continuing to stir and ultrasonically disperse for 10-20 minutes, and maintaining the temperature of the ultrasonic medium at 20-50°C; (c) Add 0.2 parts of polyurea compound RA-4102, 0.5 parts of tetramethylethylenediamine and 0.2 parts of propyl p-hydroxybenzoate to (b), and continue stirring for 10 to 15 minutes to obtain the polishing liquid of the present invention. Embodiment 13

[0109] A polishing liquid for silicon nitride ceramic bearing balls, the preparation method of which comprises the following steps: (a) 90 parts of base oil (the mass ratio of D100 and 7# white oil is 4:1), 2.0 parts of high molecular weight polyurethane block copolymer DP-810 and 2 parts of mixed abrasive micropowder with D50 of 300 nm and sphericity of 0.90 are mixed, wherein the mass ratio of spherical polycrystalline diamond and spherical cerium oxide micropowder in the mixed abrasive micropowder is 7:1, and the mixed abrasive micropowder is stirred electrically and ultrasonically dispersed for 20 to 30 minutes to obtain a mixed dispersion, wherein the temperature of the ultrasonic medium is maintained at 20 to 50° C. and the speed of the electric stirring is 700 rpm; (b) adding 1.0 part of oleic acid diethanolamine borate B-ODEA, 10 parts of polyglycerol 800, and 0.5 parts of cardanol polyoxyethylene ether BGF-9 to the above mixed dispersion, continuing to stir and ultrasonically disperse for 10 to 20 minutes, and maintaining the temperature of the ultrasonic medium at 20 to 50°C; (c) Add 5 parts of a mixture of 12-tetradecyl oleate CMO and fatty acid amide wax RA-2900-20X (the mass ratio of the two is 2:3), 0.5 parts of tetramethylethylenediamine and 0.2 parts of propyl p-hydroxybenzoate to (b), and continue stirring for 10 to 15 minutes to obtain the polishing liquid of the present invention. Comparative Example 1

[0110] A polishing liquid for silicon nitride ceramic bearing balls, the preparation method of which comprises the following steps: (a) 90 parts of base oil D100, 0.1 parts of acidic group-containing polymer YL-472A and 0.2 parts of mixed abrasive micropowder with a D50 of 50 nm and a sphericity of 0.90 are mixed, wherein the mass ratio of spherical polycrystalline diamond to spherical cerium oxide micropowder in the mixed abrasive micropowder is 3:1, and the mixture is stirred and ultrasonically dispersed for 20 to 30 minutes to obtain a mixed dispersion, wherein the temperature of the ultrasonic medium is maintained at 18° C. and the speed of the electric stirring is 400 rpm; (b) adding 0.2 parts of oleic acid diethanolamine borate B-ODEA, 12.0 parts of polyethylene glycol 400, and 6.0 parts of cardanol polyoxyethylene ether BGF-9 to the above mixed dispersion, continuing to stir and ultrasonically disperse for 10 to 20 minutes, and maintaining the temperature of the ultrasonic medium at 18°C; (c) Add 0.1 parts of polyurea compound RA-4102, 0.2 parts of tetramethylethylenediamine and 2.0 parts of propyl p-hydroxybenzoate to (b), and continue stirring for 10 to 15 minutes to obtain the polishing liquid of the present invention. Comparative Example 2

[0111] A polishing liquid for silicon nitride ceramic bearing balls, the preparation method of which comprises the following steps: (a) 90 parts of base oil (the mass ratio of D100 to 7# white oil is 4:1), 0.3 parts of acidic group-containing polymer YL-472A and 2 parts of spherical polycrystalline diamond powder with a D50 of 300 nm and a sphericity of 0.90 are stirred electrically and dispersed ultrasonically for 20 to 30 minutes to obtain a mixed dispersion, wherein the temperature of the ultrasonic medium is maintained at 20 to 50° C. and the speed of the electric stirring is 700 rpm; (b) adding 1.0 part of oleic acid diethanolamine borate B-ODEA, 3 parts of polyethylene glycol 400, and 0.5 parts of cardanol polyoxyethylene ether BGF-9 to the above mixed dispersion, continuing to stir and ultrasonically disperse for 10-20 minutes, and maintaining the temperature of the ultrasonic medium at 20-50°C; (c) Add 2 parts of polyurea compound RA-4102, 0.5 parts of tetramethylethylenediamine and 0.2 parts of propyl p-hydroxybenzoate to (b), and continue stirring for 10 to 15 minutes to obtain the polishing liquid of the present invention. Comparative Example 3

[0112] A polishing liquid for silicon nitride ceramic bearing balls, the preparation method of which comprises the following steps: (a) 90 parts of base oil (the mass ratio of D100 and 7# white oil is 4:1), 0.3 parts of acidic group-containing polymer YL-472A and 2 parts of mixed abrasive micropowder with D50 of 300 nm and sphericity of 0.75 are mixed, wherein the mass ratio of spherical polycrystalline diamond and spherical cerium oxide micropowder in the mixed abrasive micropowder is 7:1, and the mixture is stirred electrically and dispersed by ultrasonic wave for 20-30 minutes to obtain a mixed dispersion, wherein the temperature of the ultrasonic medium is maintained at 20-50°C and the speed of the electric stirring is 700 rpm; (b) adding 1.0 part of oleic acid diethanolamine borate B-ODEA, 3 parts of polyethylene glycol 400, and 0.5 parts of cardanol polyoxyethylene ether BGF-9 to the above mixed dispersion, continuing to stir and ultrasonically disperse for 10-20 minutes, and maintaining the temperature of the ultrasonic medium at 20-50°C; (c) Add 2 parts of polyurea compound RA-4102, 0.5 parts of tetramethylethylenediamine and 0.2 parts of propyl p-hydroxybenzoate to (b), and continue stirring for 10 to 15 minutes to obtain the polishing liquid of the present invention.

[0113] Comparative Example 4

[0114] A polishing liquid for silicon nitride ceramic bearing balls, the preparation method of which comprises the following steps: (a) 90 parts of base oil (the mass ratio of D100 and 7# white oil is 4:1), 8 parts of dispersant DP-8325N and 2 parts of mixed abrasive micropowder with D50 of 300 nm and sphericity of 0.90 are mixed, wherein the mass ratio of spherical polycrystalline diamond and spherical cerium oxide micropowder in the mixed abrasive micropowder is 7:1, and the mixture is stirred electrically and ultrasonically dispersed for 20 to 30 minutes to obtain a mixed dispersion, wherein the temperature of the ultrasonic medium is maintained at 20 to 50° C. and the speed of the electric stirring is 700 rpm; (b) adding 1 part of oleic acid diethanolamine borate B-ODEA and 0.5 parts of cardanol polyoxyethylene ether BGF-9 to the above mixed dispersion, continuing to stir and ultrasonically disperse for 10-20 minutes, and maintaining the temperature of the ultrasonic medium at 20-50°C; (c) Add 0.5 parts of tetramethylethylenediamine and 0.2 parts of propyl p-hydroxybenzoate to (b), and continue stirring for 10 to 15 minutes to obtain the polishing liquid of the present invention.

[0115] Comparative Example 5

[0116] A polishing liquid for silicon nitride ceramic bearing balls, the preparation method of which comprises the following steps: (a) 90 parts of base oil (the mass ratio of D100 and 7# white oil is 4:1), 0.3 parts of acidic group-containing polymer YL-472A and 2 parts of mixed abrasive micropowder with D50 of 300 nm and sphericity of 0.90 are mixed, wherein the mass ratio of spherical polycrystalline diamond and spherical cerium oxide micropowder in the mixed abrasive micropowder is 7:1, and the mixture is stirred electrically and dispersed by ultrasonic wave for 20-30 minutes to obtain a mixed dispersion, wherein the temperature of the ultrasonic medium is maintained at 20-50°C and the speed of the electric stirring is 700 rpm; (b) adding 1.0 part of oleic acid diethanolamine borate B-ODEA, 15 parts of polyglycerol 800, and 0.5 parts of cardanol polyoxyethylene ether BGF-9 to the above mixed dispersion, continuing to stir and ultrasonically disperse for 10 to 20 minutes, and maintaining the temperature of the ultrasonic medium at 20 to 50°C; (c) Add 10 parts of polyurethane rheology additive WR-9263, 0.5 parts of tetramethylethylenediamine and 0.2 parts of propyl p-hydroxybenzoate to (b), and continue stirring for 10 to 15 minutes to obtain the polishing liquid of the present invention. Experimental example

[0117] The polishing performance of the polishing liquid used for silicon nitride ceramic balls in Examples 1 to 13 of the present invention and Comparative Examples 1-5 was tested. Steps for polishing silicon nitride ceramic balls: 1. Clean the upper and lower cast iron plates, especially the concentric grooves on the upper and lower plates; 2. Drop the upper plate to a certain height, pour the ceramic ball to be polished into it from the opening of the upper plate, and then add a small amount of diamond polishing liquid to keep the ball and the plate surface wet; 3. Drop the upper plate completely and adjust the pressure and speed before polishing. A conventional roughness meter is used to test the roughness of the surface of the workpiece being processed, and an electron microscope is used to observe the scratches on the surface of the ball. The specific polishing effect is shown in Table 1.

[0118] Table 1 Polishing effect Example / Comparative Example Dispersibility Cleaning performance Scratches Roughness (Ra, nm) Viscosity (cp, 25℃) Example 1 good good The surface is mirror-like, without bite marks, scratches or micro-cracks 8nm 32 Example 2 good good The surface is mirror-like, without bite marks, scratches or micro-cracks 10nm 30 Example 3 good good The surface is mirror-like, without bite marks, scratches or micro-cracks 12nm 33 Example 4 good good The surface is mirror-like, without bite marks, scratches or micro-cracks 11nm 20 Example 5 good good The surface is mirror-like, without bite marks, scratches or micro-cracks 13nm 50 Example 6 good good The surface is mirror-like, without bite marks, scratches or micro-cracks 14nm 23 Example 7 good good The surface is mirror-like, without bite marks, scratches or micro-cracks 9nm 26 Example 8 good good The surface is mirror-like, without bite marks, scratches or micro-cracks 10nm 27 Example 9 good good The surface is mirror-like, without bite marks, scratches or micro-cracks 9nm 35 Example 10 good good The surface is mirror-like, without bite marks, scratches or micro-cracks 10nm 25 Embodiment 11 good good The surface is mirror-like, without bite marks, scratches or micro-cracks 11nm 23 Example 12 good good The surface is mirror-like, without bite marks, scratches or micro-cracks 12nm 22 Embodiment 13 good good The surface is mirror-like, without bite marks, scratches or micro-cracks 10nm 70 Comparative Example 1 Very bad Poor The surface has bite marks, obvious scratches, and the surface is dull and black. 35nm 35 Comparative Example 2 good good The surface is seriously damaged, with many scratches, micro cracks, and black surface. 55nm 34 Comparative Example 3 good good The surface is seriously damaged, with many small scratches and blackened surface. 43nm 32 Comparative Example 4 good good The surface is seriously damaged, with obvious scratches and blackened surface. 45 8 Comparative Example 5 good good Surface gnawed, many obvious scratches, black surface 38 85 It can be seen from the polishing effect described in the above table that the polishing liquid obtained in Examples 1-13 of the present invention not only has good polishing effect, excellent surface polishing quality and good roughness, but also has the effects of easy cleaning, good dispersion effect and moderate viscosity, and its viscosity is controlled within the range of 20~70cp (25°C). For example, the surface roughness Ra of Example 1 is as low as 8nm, the surface has no gnaws, scratches, microcracks, and the surface is mirror-like. However, after polishing with the polishing liquid of Comparative Example 1, in which the amount of each component is not within the scope of the present invention, the polishing effect is poor, the roughness is large (Ra is 35nm), which is far greater than the roughness corresponding to Examples 1-13, and does not meet the market requirements (usually requiring Ra≤20nm), and the surface of the ceramic bearing ball has gnaws, obvious scratches, microcracks, and the surface is not bright and black. The polishing liquid described in Comparative Example 2 uses a single micropowder, i.e., polycrystalline diamond micropowder, and removes cerium oxide micropowder. Its surface polishing effect is very poor, the surface of the ceramic bearing ball is seriously gnawed, there are many scratches, there are microcracks, the surface is black, and the surface roughness is very large, reaching 55nm. The mixed abrasive micropowder used in the polishing liquid described in Comparative Example 3 has a low sphericity of only 0.75, and its surface polishing effect is also relatively poor. The surface of the ceramic bearing ball is seriously gnawed, there are many fine scratches, the surface is black, and the surface roughness is large. The viscosity of the polishing liquid obtained in Comparative Example 4 is relatively low, only 8 cp (25°C). During use, due to its too low viscosity, too little liquid adheres to the ceramic bearing ball during the polishing process, resulting in low polishing efficiency, gnawed surface of the ceramic bearing ball, obvious scratches, and black surface, which directly affects the processing efficiency. In contrast, in Comparative Example 5, the viscosity of the obtained polishing liquid is too high, as high as 85 cp (25°C), the fluidity of the polishing liquid is poor, the polishing liquid and the grinding chips are easily attached to the ceramic bearing balls, and the balls cannot be polished at all, resulting in a very poor polishing effect.

[0119] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A polishing liquid for silicon nitride ceramic bearing balls, characterized in that: It is mainly composed of the following components by mass: Mix 0.3-4 parts of abrasive powder, 1.0-10 parts of lubricant, 0.5-3 parts of friction coefficient regulator, 0.2-5 parts of rheology regulator, 0.2-5 parts of polymer dispersant, 0.2-5 parts of emulsifier, 0.3-4 parts of organic base and 71-95 parts of base oil.

2. The polishing liquid for silicon nitride ceramic bearing balls according to claim 1, characterized in that: It is mainly composed of the following components by mass: Mix 0.5-2 parts of abrasive powder, 3.0-8 parts of lubricant, 1-2 parts of friction coefficient regulator, 0.3-2 parts of rheology regulator, 0.3-2 parts of polymer dispersant, 0.5-2 parts of emulsifier, 0.5-2 parts of organic base and 80-90 parts of base oil.

3. The polishing liquid for silicon nitride ceramic bearing balls according to claim 1, characterized in that: The polishing liquid also includes 0.1 to 1 part of preservative, preferably 0.2 to 0.5 part of preservative; Preferably, the preservative includes at least one of propylparaben, monocaprylin, disodium stannous citrate and potassium citrate.

4. The polishing liquid for silicon nitride ceramic bearing balls according to claims 1-3, characterized in that: The mixed abrasive powder includes spherical polycrystalline diamond powder and spherical cerium oxide powder; the sphericity of the spherical polycrystalline diamond powder and the spherical cerium oxide powder is 0.86-0.90; the mass ratio of the spherical polycrystalline diamond powder to the spherical cerium oxide powder is (4-9):1; Preferably, the particle size of the mixed abrasive powder is 125-500 nm; More preferably, the mixed abrasive powder is selected from particles with a particle size of 200-300 nm.

5. The polishing liquid according to claim 4, characterized in that: The mass ratio of the spherical polycrystalline diamond powder to the spherical cerium oxide powder is 4:1, 5:1, 6:1, 7:1, 8:1 or 9:1; and / or the particle size of the mixed abrasive powder is 125nm, 200nm, 300nm, 400nm or 500nm.

6. The polishing liquid for silicon nitride ceramic bearing balls according to claim 1 or 2, characterized in that: The lubricant comprises at least one of polyethylene glycol, polypropylene glycol and capric triglyceride; The friction coefficient modifier includes at least one of oleic acid diethanolamine borate and polyether modified dimethylsiloxane; The rheology modifier includes at least one of lauryl oleate, a polyurea compound and a fatty acid amide wax; The polymer dispersant includes at least one of a polymer containing an acidic group, a block polymer, a polymer polyurethane block copolymer, a dispersant DP-8325N and DW-403; The emulsifier comprises at least one of polyoxyethylene cardanol ether, sucrose amino ester, coconut oil acid alkanolamide, polyoxyethylene octylphenol ether and fatty alcohol ether; The organic base includes at least one of tetramethylethylenediamine and diisopropylethylamine.

7. The polishing liquid for silicon nitride ceramic bearing balls according to claim 6, characterized in that: The lubricant comprises at least one of polyethylene glycol 400, polyethylene glycol 600, polyglycerol 800 and capric triglyceride; The friction coefficient modifier includes at least one of oleic acid diethanolamine borate B-ODEA and polyether modified dimethylsiloxane WR-653; The rheology modifier includes at least one of lauryl oleate, polyurea compound RA-4102, and fatty acid amide wax RA-2900-20X; The polymer dispersant includes at least one of oily acrylic dispersant YL-472A, block polymer YL-4633, polymer polyurethane block copolymer DP-810, dispersant DP-8325N and DW-403; The emulsifier includes at least one of cardanol polyoxyethylene ether BGF-9, sucrose amino ester NP-10, coconut oil acid alkanolamide (Ninal 6501), octylphenol polyoxyethylene ether OP-4 and fatty alcohol ether MOA-3B; The organic base includes at least one of tetramethylethylenediamine and diisopropylethylamine; The base oil includes solvent oil and mineral oil with a carbon chain length of C12-16, and the mass ratio of the two is (1-4):(1-3); more preferably, the mass ratio of the solvent oil and the mineral oil with a carbon chain length of C12-16 is 4:1; more preferably, the solvent oil is D100, and the mineral oil with a carbon chain length of C12-16 is 7# white oil.

8. The polishing liquid for silicon nitride ceramic bearing balls according to claim 1 or 2, characterized in that: The viscosity of the polishing liquid is 20-70 cp (25° C.), preferably, the viscosity of the polishing liquid is 30-50 cp (25° C.).

9. The method for preparing a polishing liquid for silicon nitride ceramic bearing balls according to claim 1, characterized in that: The following steps are involved: Mix the base oil, polymer dispersant and mixed abrasive powder, stir electrically and disperse ultrasonically, add friction coefficient regulator, lubricant and emulsifier, continue stirring and disperse ultrasonically, add rheology regulator, organic base and preservative and continue stirring.

10. The method for preparing a polishing liquid for silicon nitride ceramic bearing balls according to claim 9, characterized in that: The base oil, polymer dispersant and mixed abrasive powder are mixed, stirred electrically and ultrasonically dispersed for 20 to 30 minutes to obtain a mixed dispersion, wherein the temperature of the ultrasonic medium is maintained at 20 to 50° C. and the speed of the electric stirring is not less than 700 rpm; Preferably, the friction coefficient regulator, lubricant, and emulsifier are added, and the stirring and ultrasonic dispersion are continued for 10 to 20 minutes, and the temperature of the ultrasonic medium is maintained at 20 to 50° C.; Preferably, the rheology regulator, the organic base and the preservative are added and stirred continuously for 10 to 15 minutes to obtain the polishing liquid of the present invention.