Granulated diamond micro-powder for grinding fluid as well as preparation method and application of granulated diamond micro-powder

Abstract

The invention discloses granulated diamond micro-powder for grinding fluid and a preparation method of the granulated diamond micro-powder, and the granulated diamond micro-powder for the grinding fluid is prepared from the following raw materials in parts by weight: 30-60 parts of monocrystal diamond, 12-25 parts of phenolic resin, 10-30 parts of glass powder and 0.5-8 parts of an aluminum oxide separant. The granulated diamond micro-powder for the grinding fluid is relatively good in integrity, and the content of unshaped micro-powder is low; meanwhile, the process is high in efficiency and high in finished product percent of pass; the prepared granulated diamond grinding fluid has good removal efficiency and surface roughness.

Description

Technical Field

[0001] The present invention belongs to the field of abrasive materials, and particularly relates to granulated diamond micropowder for grinding fluid, a preparation method thereof, and an application thereof. Background Art

[0002] The microscopic morphology of single crystal diamond micropowder is a polyhedron with sharp edges and corners, thus having a strong chip-forming force. However, when grinding and polishing a workpiece, its irregular edges and corners are likely to scratch the surface of the workpiece, resulting in the need for more subsequent processes to repair the scratches to ensure a high flatness of the workpiece surface. Therefore, it is necessary to perform a series of treatments on the single crystal diamond micropowder to obtain particles with a particle size distribution range meeting certain requirements and regular shapes. In this way, the polishing requirements of superhard material workpieces with high precision can be met without causing surface scratches.

[0003] The prior art generally obtains uniformly mixed granulated micropowder by means such as spray drying technology. In addition to single crystal diamond, this granulated micropowder also contains dextrin, glass powder, and alumina release agent, and then the granulated micropowder is sintered to obtain the final micropowder.

[0004] The process of sintering to prepare the final micropowder can be divided into steps:

[0005] (1) As the temperature rises, dextrin decomposes and volatilizes;

[0006] (2) As the temperature further rises, glass powder melts;

[0007] (3) As the temperature drops, glass powder condenses to obtain shaped micropowder.

[0008] The decomposition and volatilization temperature of the existing dextrin used (generally below 200°C) is lower than the melting temperature of glass powder (above 500°C), and there is an obvious gap between the temperature points at which the two substances react, resulting in a low yield of the final micropowder during the preparation process. Moreover, due to this large temperature gap, the unqualified micropowder is mixed with the normal micropowder, which not only easily causes the risk of unshaped micropowder being distributed in normal particles and scratching the workpiece, but also increases the workload and cost during the separation of the two. Summary of the Invention

[0009] The technical problem to be solved by the present invention is: to provide granulated diamond micropowder for grinding fluid, a preparation method thereof, and an application thereof, which has good integrity of the diamond micropowder and a small content of unshaped micropowder; at the same time, the process has high efficiency and a high qualified rate of finished products; and the prepared granulated diamond grinding fluid has good removal efficiency and surface roughness.

[0010] The technical solution of the present invention is as follows:

[0011] A granulated diamond micropowder for abrasive liquid is prepared from the following raw materials in parts by weight:

[0012]

[0013] In the present invention, phenolic resin which decomposes and volatilizes only at a relatively high temperature is introduced to replace the existing dextrin, significantly reducing the temperature difference between the reactions of the two substances. Combined with the adjustment of the sintering process, the reaction temperatures of the two substances can be closely connected, thereby improving the production rate of the synthesized micropowder.

[0014] Preferably, the particle size of the single crystal diamond is 0.5 - 20 μm.

[0015] Preferably, the specific type of the phenolic resin is thermosetting phenolic resin. Further, the decomposition temperature of the thermosetting phenolic resin > 300°C. As a specific embodiment, the thermosetting phenolic resin is phenolic resin 1402.

[0016] Preferably, the glass powder is glass powder KS - 200.

[0017] The present invention also provides a preparation method of the granulated diamond micropowder for abrasive liquid, comprising the following steps:

[0018] (1) Mix the single crystal diamond, phenolic resin, glass powder and alumina release agent evenly by spray drying technology to obtain granulated micropowder;

[0019] (2) Sinter the granulated micropowder obtained in step (1) to obtain the diamond micropowder.

[0020] By introducing phenolic resin with a high decomposition temperature and optimizing the production process, the present invention can greatly improve the qualification rate of the final shaped micropowder, reduce the process workload, and improve the efficiency of the whole process.

[0021] Preferably, in step (1), during spray drying, the inlet temperature is 210 - 230°C, the outlet temperature is 100 - 120°C, the feeding rate is 0.2 - 0.4 L / min, and the rotational speed of the atomizer is 34000 - 36000 rpm.

[0022] Preferably, in step (2), the sintering process is as follows:

[0023] The process of sintering to prepare the final micropowder can be divided into steps:

[0024] (2.1) First, raise the temperature to 400 - 510°C at a rate of 1 - 3°C / min and keep it warm for 1 - 3 h, during which the phenolic resin decomposes and volatilizes (decomposition temperature > 300°C);

[0025] (2.2) Then, by adjusting the sintering process, the temperature is raised to 630 - 670 °C and held for 1 - 4 h to enable the glass powder to reach the melting temperature in the shortest time.

[0026] (2.3) After that, it is cooled to room temperature at a rate of 1 - 3 °C / min, and the glass powder condenses to obtain firm shaped micropowder.

[0027] The present invention also provides a grinding fluid, comprising the granulated diamond micropowder for grinding fluid, an auxiliary agent, and water. Preferably, the auxiliary agent is an organosilicon surface auxiliary agent, more preferably BYK - 348 or BYK - 017.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] (1) By innovatively introducing phenolic resin as the first organic binder in this technology, it is realized that the shaped micropowder will not disperse at low temperature, reducing the proportion of micropowder dispersion before the melting of the glass powder.

[0030] (2) By adjusting the sintering process between the two binders and coordinating with the characteristics of the two binders, it can be well connected with the glass powder to ensure the integrity of the shaped micropowder in a relay manner. Description of the Drawings

[0031] Figure 1 It is the SEM image of the shaped micropowder obtained in Example 1;

[0032] Figure 2 It is the SEM image of the shaped micropowder obtained in Comparative Example 1. Detailed Embodiments

[0033] Example 1

[0034] A kind of granulated diamond micropowder for grinding fluid, and the formula of the granulated diamond micropowder is as follows:

[0035]

[0036] The preparation method of the granulated diamond micropowder for grinding fluid in this example comprises the following steps:

[0037] S1. Mix single - crystal diamond (particle size 10 μm), phenolic resin 2402, glass powder KS - 200, and alumina isolating agent evenly by spray - drying technology (inlet temperature is 220 °C, outlet temperature is 110 °C, feeding rate is 0.3 L / min, atomizer rotation speed is 35000 rpm) to obtain granulated micropowder;

[0038] S2. Place the granulated micropowder in a muffle furnace for calcination, gradually raise the temperature to 450 °C, and hold for 3 h;

[0039] S3. Adjust the sintering process, continue to heat up to 650 °C, hold for 3.5 h. After the temperature drops, the glass powder condenses to obtain solid shaped fine powder.

[0040] Figure 1 is the scanning electron microscope image of the shaped fine powder obtained in this example. It can be seen from Figure 1 that the shaped fine powder has regular shape, and there is basically no breakage and caking.

[0041] Example 2

[0042] A kind of granulated diamond micropowder for grinding fluid, and the formula of the granulated diamond micropowder is as follows:

[0043]

[0044] The preparation method of the granulated diamond micropowder for grinding fluid in this example includes the following steps:

[0045] S1. Mix single crystal diamond (particle size 10 μm), phenolic resin 2402, glass powder KS-200 and alumina release agent evenly by spray drying technology (inlet temperature is 220 °C, outlet temperature is 110 °C, feeding rate is 0.3 L / min, atomizer rotation speed is 35000 rpm) to obtain granulated micropowder;

[0046] S2. Place the granulated micropowder in a muffle furnace for calcination, gradually heat up to 450 °C, and hold for 3 h;

[0047] S3. Adjust the sintering process, continue to heat up to 650 °C, hold for 3.5 h. After the temperature drops, the glass powder condenses to obtain solid shaped fine powder.

[0048] Example 3

[0049] A kind of granulated diamond micropowder for grinding fluid, and the formula of the granulated diamond micropowder is as follows:

[0050]

[0051] The preparation method of the granulated diamond micropowder for grinding fluid in this example includes the following steps:

[0052] S1. Mix single crystal diamond (particle size 10 μm), phenolic resin 2402, glass powder KS-200 and alumina release agent evenly by spray drying technology (inlet temperature is 220 °C, outlet temperature is 110 °C, feeding rate is 0.3 L / min, atomizer rotation speed is 35000 rpm) to obtain granulated micropowder;

[0053] S2. Place the granulated micropowder in a muffle furnace for calcination, gradually heat up to 450 °C, and hold for 2.5 h;

[0054] S3. Adjust the sintering process, continue to heat up to 650 °C, hold for 3 h. After the temperature drops, the glass powder condenses to obtain solid shaped fine powder.

[0055] Example 4

[0056] A granulated diamond fine powder for abrasive liquid, and the formula of the granulated diamond fine powder is as follows:

[0057]

[0058] The preparation method of the granulated diamond fine powder for abrasive liquid in this example includes the following steps:

[0059] S1. Mix single crystal diamond (particle size 10 μm), bisphenol A epoxy resin, glass powder KS-200 and alumina release agent evenly by spray drying technology (inlet temperature is 220 °C, outlet temperature is 110 °C, feeding rate is 0.3 L / min, atomizer rotation speed is 35000 rpm) to obtain granulated fine powder;

[0060] S2. Place the granulated fine powder in a muffle furnace for calcination, gradually heat up to 450 °C, and hold for 3 h;

[0061] S3. Adjust the sintering process, continue to heat up to 650 °C, hold for 3.5 h. After the temperature drops, the glass powder condenses to obtain solid shaped fine powder.

[0062] Example 5

[0063] A granulated diamond fine powder for abrasive liquid, and the formula of the granulated diamond fine powder is as follows:

[0064]

[0065] The preparation method of the granulated diamond fine powder for abrasive liquid in this example includes the following steps:

[0066] S1. Mix single crystal diamond (particle size 10 μm), acrylic resin P600, glass powder KS-200 and alumina release agent evenly by spray drying technology (inlet temperature is 220 °C, outlet temperature is 110 °C, feeding rate is 0.3 L / min, atomizer rotation speed is 35000 rpm) to obtain granulated fine powder;

[0067] S2. Place the granulated fine powder in a muffle furnace for calcination, gradually heat up to 450 °C, and hold for 3 h;

[0068] S3. Adjust the sintering process, continue to heat up to 650 °C, hold for 3.5 h. After the temperature drops, the glass powder condenses to obtain solid shaped fine powder.

[0069] Example 6

[0070] A granulated diamond micropowder for abrasive liquid, and the formula of the granulated diamond micropowder is as follows:

[0071]

[0072] The preparation method of the granulated diamond micropowder for abrasive liquid in this embodiment includes the following steps:

[0073] S1. Mix single crystal diamond (particle size 10 μm), phenolic resin 2402, glass powder KS-200 and alumina isolating agent evenly through spray drying technology (import temperature is 220 °C, export temperature is 110 °C, feeding rate is 0.3 L / min, atomizer rotation speed is 35000 rpm) to obtain granulated micropowder;

[0074] S2. Place the granulated micropowder in a muffle furnace for calcination, gradually heat up to 350 °C, and keep the temperature for 3.5 h;

[0075] S3. Adjust the sintering process, continue to heat up to 650 °C, keep the temperature for 3 h, after the temperature drops, the glass powder condenses to obtain firm shaped micropowder.

[0076] Example 7

[0077] A granulated diamond micropowder for abrasive liquid, and the formula of the granulated diamond micropowder is as follows:

[0078]

[0079] The preparation method of the granulated diamond micropowder for abrasive liquid in this embodiment includes the following steps:

[0080] S1. Mix single crystal diamond (particle size 10 μm), phenolic resin 2402, glass powder KS-200 and alumina isolating agent evenly through spray drying technology (import temperature is 220 °C, export temperature is 110 °C, feeding rate is 0.3 L / min, atomizer rotation speed is 35000 rpm) to obtain granulated micropowder;

[0081] S2. Place the granulated micropowder in a muffle furnace for calcination, directly heat up to 650 °C, after the temperature drops, the glass powder condenses to obtain shaped micropowder.

[0082] Comparative Example 1

[0083] The main difference from Example 1 is that dextrin is used to replace phenolic resin, and the proportions of other components are the same.

[0084] Figure 2 This is the scanning electron microscope image of the shaped micropowder obtained in this comparative example. It can be seen from Figure 2 that the shaped micropowder has a relatively regular shape, but some are damaged.

[0085] Comparative Example 2

[0086] The main difference from Example 1 is that sodium carboxymethyl cellulose is used to replace phenolic resin, and the proportions of other components are the same.

[0087] Test Example 1

[0088] The granulated diamond micropowders prepared in Examples 1 - 7 and Comparative Examples 1 - 2 were observed under a scanning electron microscope to determine whether the micropowder particles were regular, whether there were any damages or caking, etc., and the qualified rate of the finished products was counted.

[0089] Table 1 Detection results of Examples 1 - 7 and Comparative Examples 1 - 2

[0090] Integrity Qualified rate of finished products (%) Example 1 The fine powder is regular, without breakage and caking 96 Example 2 The fine powder is regular, without breakage and caking 94 Example 3 The fine powder is regular, without breakage and caking 94 Example 4 The fine powder is regular, with a small amount of breakage and caking 80 Example 5 The fine powder is regular, with a small amount of breakage and caking 77 Example 6 The fine powder is regular, with a small amount of breakage and caking 84 Example 7 The fine powder is relatively regular, with some breakage 73 Comparative Example 1 The fine powder is relatively regular, with some breakage 70 Comparative Example 2 The fine powder is relatively regular, with some breakage 72

[0091] From the above results, it can be seen that compared with the prior art, the granulated diamond micropowders of the present invention have good integrity of micropowder particles, and the optimized sintering process improves the qualified rate of shaped micropowders.

[0092] Test Example 2

[0093] The granulated diamond micropowders obtained in Examples 1 - 7 and Comparative Examples 1 - 2 and the commercially available PCD abrasives were added with 0.8% additives BYK - 348, BYK - 017 and water respectively to prepare grinding fluids with a concentration of 3%. Using sapphire as the grinding object, a grinding experiment was carried out. The grinding experiment was carried out on a surface grinder, using a copper grinding disc with a diameter of φ460mm, and the liquid addition method was pneumatic pressurized spraying through a liquid spray pipe. Grinding process parameters: the rotational speed of the grinding disc was 80r / min, the grinding pressure was 20.68kPa, the liquid addition speed was 5mL / min, and the grinding time was 10min. The removal rate ν and surface roughness Ra during the grinding process were obtained respectively, and the results are shown in Table 2.

[0094] Among them, the calculation method of the removal rate is as follows: Using a thickness gauge on a marble platform with a flatness of 0 grade, the average thickness δ1 of 5 points on the initial sapphire substrate and the average thickness δ2 of 5 points on the sapphire substrate after grinding were measured respectively. The unit of the above workpiece thickness is μm, the grinding time is t, the unit is min, and the material removal rate is ν=(δ1 - δ2) / t, the unit is μm / min.

[0095] The calculation method of the surface roughness Ra is as follows: Using an SJ - 210 type roughness gauge to measure the surface roughness value Ra of the sapphire substrate. Three points were selected at the center position and at a circumferential position 2cm away from the center respectively, and a total of 4 measurements were taken, and then the average value was taken as the surface roughness value Ra of the sapphire.

[0096] Table 2 Grinding performance of Examples 1 - 7, Comparative Examples 1 - 2 and commercially available abrasives

[0097] Removal rate ν (μm / min) Surface roughness value Ra (nm) Example 1 1.61 0.257 Example 2 1.50 0.262 Example 3 1.44 0.265 Example 4 1.23 0.326 Example 5 0.87 0.373 Example 6 1.36 0.277 Example 7 0.81 0.384 Comparative Example 1 1.05 0.387 Comparative Example 2 0.94 0.391 Commercially available PCD 0.67 0.512

[0098] It can be seen from the results that the grinding fluid made of the granulated diamond micropowder of the present invention has good removal efficiency and surface roughness; when the phenolic resin in the formula is replaced, the removal rate of the granulated diamond micropowder decreases and the surface roughness increases. Thus, it can be seen that the granulated diamond micropowder of the present invention has better grinding performance.

Claims

1. A granulated diamond micropowder for abrasive liquid, characterized in that, Prepared from the following raw materials in parts by weight:

2. The granulated diamond micropowder for abrasive liquid according to claim 1, characterized in that, The particle size of the single crystal diamond is 0.5 - 20 μm.

3. The granulated diamond micropowder for abrasive liquid according to claim 1, characterized in that, The phenolic resin is a thermosetting phenolic resin.

4. The granulated diamond micropowder for abrasive liquid according to claim 3, wherein The decomposition temperature of the phenolic resin is > 300 °C.

5. The granulated diamond micropowder for abrasive liquid according to claim 3, wherein, The phenolic resin is phenolic resin 1402.

6. The granulated diamond micropowder for abrasive liquid according to claim 1, wherein The glass powder is glass powder KS - 200.

7. A preparation method of granulated diamond micropowder for abrasive liquid according to any one of claims 1 to 6, characterized in that, Comprising the following steps: (1) Mix the single crystal diamond, phenolic resin, glass powder and alumina release agent evenly by spray drying technology to obtain granulated fine powder; (2) Sinter the granulated fine powder obtained in step (1) to obtain the diamond fine powder.

8. The preparation method of the granulated diamond micropowder for the abrasive liquid according to claim 7, characterized in that, In step (2), the sintering process is as follows: (2.1) First, heat up to 400 - 510 °C at a rate of 1 - 3 °C / min and keep warm for 1 - 3 h, and the phenolic resin decomposes and volatilizes; (2.2) Then, by adjusting the sintering process, heat up to 630 - 670 °C and keep warm for 1 - 4 h to make the glass powder reach the melting temperature in the shortest time; (2.3) After that, cool down to room temperature at a rate of 1 - 3 °C / min, and the glass powder condenses to obtain a solid integral fine powder.

9. A polishing liquid, characterized in that, Comprising the granulated diamond fine powder for abrasive liquid, an auxiliary agent and water according to any one of claims 1 - 8.

10. The abrasive liquid according to claim 9, wherein, The auxiliary agent is an organosilicon surface auxiliary agent, preferably BYK - 348 or BYK - 017.

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