A method for preparing an electro-magnetic-cutting three-phase CI@SiO2@ZrSiO4 composite abrasive

Abstract

The application provides a preparation method of a CI@SiO2@ZrSiO4 composite abrasive for electro-magnetic-cutting three-phase, and the CI@SiO2 nano-powder is prepared by using a sol-hot calcination method, and then the CI@SiO2@ZrSiO4 composite abrasive is prepared by using a sol-gel method; the prepared composite abrasive is composed of a ferromagnetic phase spherical carbonyl iron (CI) core with good uniformity and strong magnetism, a SiO2 ceramic layer for protecting the physical and chemical properties of the ferromagnetic phase, and a cutting phase ZrSiO4 ceramic shell with high dielectric property and high hardness; the prepared composite abrasive has high magnetic permeability, high dielectric property and high hardness, meanwhile, the spherical composite abrasive particles ensure that the workpiece is uniformly stressed during grinding, and deep scratches do not appear after grinding, and the workpiece can be precisely ground and polished by combining an electromagnetic rheological composite grinding / polishing process.

Description

Technical Field

[0001] This invention belongs to the field of surface grinding / polishing technology, specifically relating to a method for preparing CI@SiO2@ZrSiO4 composite abrasives with an electro-magnetic-cutting three-phase structure. Background Technology

[0002] The processing principle of magnetic abrasive finishing technology is that magnetic abrasives are linked along the magnetic field lines under the action of a magnetic field to form a flexible "magnetic brush". The flexible "magnetic brush" and the workpiece surface exert pressure and cutting action, thereby removing surface defects and improving surface quality. Among them, the composite grinding and polishing technology that couples multiple energy fields using magnetic composite (hybrid) abrasives is mainly the electromagnetic rheological composite grinding / polishing process. This is because electromagnetic rheological fluids not only have a fast response and high viscosity, but also have a higher yield stress under the action of electromagnetic coupling energy fields than under the action of electric or magnetic fields alone, resulting in a significant improvement in processing efficiency.

[0003] Electro-magnetic-cutting three-phase composite abrasives play a crucial role as a key tool carrier in electromagnetic rheological composite grinding / polishing processes. The core of this process lies in the preparation of high-performance electro-magnetic-cutting three-phase abrasive grains. These grains are essentially composed of two parts: a ferromagnetic core and a dielectric abrasive shell. The ferromagnetic phase acts as a flexible "magnetic brush," linking the abrasive grains along magnetic lines of force under the influence of a magnetic field, thus generating sufficient grinding pressure on the workpiece surface. The dielectric abrasive shell, under the influence of an electric field, forms particle chains, enhancing the strength of the flexible brush head. Furthermore, the high-hardness dielectric abrasive shell also performs micro-cutting grinding.

[0004] Currently, the main types of composite abrasives used in electromagnetic rheological grinding / polishing technology are as follows:

[0005] One type is abrasives that combine magnetic and dielectric properties;

[0006] Second, a single abrasive that combines dielectric and magnetic properties;

[0007] Thirdly, there are composite abrasives formed by coating, which possess both dielectric and magnetic properties.

[0008] While simply physically mixing magnetic and dielectric abrasives is a simple preparation method, the processing effect under electromagnetic synergy is not as good as that of a single abrasive possessing both dielectric and magnetic properties, or a composite abrasive with both dielectric and magnetic properties formed by coating. Furthermore, the preparation of a single abrasive with both dielectric and magnetic properties is more difficult than that of a composite abrasive with both dielectric and magnetic properties formed by coating, and the preparation efficiency is low, making it unsuitable for mass production. Therefore, from the perspective of abrasive structure design, selecting an efficient and simple method to prepare electromagnetic rheological composite abrasives that simultaneously possess strong magnetism, high dielectric properties, high surface hardness, and long lifespan is a key challenge in electromagnetic rheological grinding / polishing technology research. Summary of the Invention

[0009] In order to overcome the shortcomings of the prior art, the purpose of this invention is to provide a method for preparing a three-phase electro-magnetic-cutting CI@SiO2@ZrSiO4 composite abrasive, so as to solve the problems of short grinding life and complex preparation process of existing electromagnetic rheological composite abrasives.

[0010] This invention provides a method for preparing an electro-magnetic-cutting three-phase CI@SiO2@ZrSiO4 composite abrasive, comprising the following steps:

[0011] Step 1: Prepare a brown turbid solution by mixing iron carbonyl with anhydrous ethanol and ammonia. Then, add a colorless mixed solution of TEOS, EtOH, and H2O dropwise according to a specific volume ratio. After reacting in a constant-temperature water bath, filter and collect the precipitate, then dry it to obtain a brownish-yellow dry gel. Place it in a tube furnace for heat treatment to obtain CI@SiO2 nanoparticles.

[0012] Step 2: Weigh a 1 mol / L ZrOCl2·8H2O solution, then weigh TEOS and add it to an ethanol-water solution for ultrasonic homogenization. Mix the two solutions together, add the sintering aid LiF, and then perform pre-hydrolysis in a high-speed disperser.

[0013] Step 3: After pre-hydrolysis, ammonia is added to the precursor solution to adjust the pH to form a gel. The resulting gel is then dried to obtain a dry gel. The dry gel is prepared into a 30 wt.% ethanol suspension and mechanically activated in a ball mill to obtain a ZrSiO4 precursor sol.

[0014] Step 4: Mix CI@SiO2 nanoparticles with anhydrous ethanol, homogenize by ultrasonication, add precursor sol, and uniformly coat with a high-shear disperser.

[0015] Step 5: After drying, heat treatment is carried out in an N2+H2 atmosphere. After acid washing, water washing and drying, excess impurities are removed by magnetic separation to obtain CI@SiO2@ZrSiO4 abrasive.

[0016] The specific volume ratio of TEOS, EtOH and H2O is 54:45:1;

[0017] Preferably, the constant temperature water bath reaction temperature is 50–80 °C, and the time is 3–5 h;

[0018] Preferably, the heat treatment temperature is 400–500 °C, and the time is 1–2 h;

[0019] Preferably, the ball mill uses yttrium-stabilized zirconia beads with a diameter of 0.3~0.4 mm as the grinding media, the media volume filling rate is 70%~80%, and the stirring mill speed is 1000~2000 r / min;

[0020] Preferably, the heat treatment temperature in the N2+H2 atmosphere is 800-1000 ℃, the time is 1-2 h, and the heating rate is 5-10 ℃ / min;

[0021] Preferably, the mass ratio of the carbonyl iron to the ZrSiO4 precursor sol is 1:(2-5).

[0022] The beneficial effects of this invention are as follows:

[0023] (1) ZrSiO4 ceramics not only resist the corrosion of common acids and bases such as HCl and NaOH, and have good chemical stability, but also have good dielectric properties. They can be polarized and move along the direction of electric field lines under the action of electric field. In addition, they also have good heat resistance, wear resistance, high hardness, and high strength.

[0024] (2) The magnetic strength of CI@SiO2@ZrSiO4 abrasive grains is related to the size of the spherical carbonyl iron CI, the thickness of the SiO2 ceramic layer, and the thickness of the ZrSiO4 ceramic layer, while the dielectric strength is related to the thickness, density, and crystallinity of the ZrSiO4 ceramic layer. The electromagnetic properties of CI@SiO2@ZrSiO4 abrasive grains can be adjusted by controlling the mass ratio of each phase. Detailed Implementation

[0025] To facilitate understanding by those skilled in the art, the present invention will be described in detail below with reference to specific embodiments.

[0026] This invention provides a method for preparing an electro-magnetic-cutting three-phase CI@SiO2@ZrSiO4 composite abrasive, comprising the following steps:

[0027] Step 1: Prepare a brown turbid solution by mixing iron carbonyl with anhydrous ethanol and ammonia. Then, add a colorless mixed solution of TEOS, EtOH, and H2O dropwise according to a specific volume ratio. After reacting in a constant-temperature water bath, filter and collect the precipitate, then dry it to obtain a brownish-yellow dry gel. Place it in a tube furnace for heat treatment to obtain CI@SiO2 nanoparticles.

[0028] In this embodiment, 5g of carbonyl iron (CI) was weighed and added to 50ml of EtOH at room temperature, and ultrasonically dispersed for 60min. While vigorously stirring, 100mL of 25% ammonia was added dropwise, forming a brown turbid liquid. Then, a colorless mixed solution of TEOS, EtOH, and H2O (Vammonia:Vwater:VTEOS=54:45:1) was added dropwise. The mixture was reacted at a constant temperature of 65℃ in a water bath for 4h, and the resulting solution was allowed to stand and age at room temperature for 12h. The precipitate was collected, washed three times each with deionized water and anhydrous ethanol, and the nanoparticles were dried at 70℃ for 10h to obtain a brownish-yellow dry gel. The dry gel was finely ground and placed in a tube furnace for heat treatment at 450℃ for 1h to obtain CI@SiO2 nanoparticles.

[0029] Step 2: Weigh a 1 mol / L ZrOCl2·8H2O solution, then weigh TEOS and add it to an ethanol-water solution for ultrasonic homogenization. Mix the two solutions. Add the sintering aid LiF and perform pre-hydrolysis in a high-speed disperser. In this example, at room temperature, weigh 9.67 g of ZrOCl2·8H2O and add it to 30 mL of deionized water to form a 1 mol / L homogeneous solution. Then weigh 7.50 g of TEOS and add it to 30 mL of a 50% (w / w) ethanol-water solution for ultrasonic homogenization. Mix the two solutions to obtain the precursor solution. Weigh 0.23 g of LiF and add it to the precursor solution, then place it in a high-speed disperser and stir at 1200 r / min for 2 h for pre-hydrolysis.

[0030] Step 3: After pre-hydrolysis, ammonia is added to the precursor solution to adjust the pH to form a gel. The resulting gel is then dried to obtain a dry gel. The dry gel is prepared into a 30 wt.% ethanol suspension and mechanically activated in a ball mill to obtain a ZrSiO4 precursor sol.

[0031] In this embodiment, after pre-hydrolysis, 1 mol / L ammonia solution was added dropwise to the precursor solution to adjust the pH value until a gel was formed. The resulting gel was dried in an oven at 90°C for 12 h to obtain a dry gel. Using the dry gel as the raw material and ethanol as the solvent, a suspension with a solid content of 30% (mass fraction) was prepared. The suspension was poured into a media stirring mill, using yttrium-stabilized zirconia beads with a diameter of 0.3-0.4 mm as the grinding media, with a media volume filling rate of 80% (volume fraction), and the stirring mill speed of 1500 r / min for mechanical activation. After mechanical activation, a ZrSiO4 coated precursor was obtained.

[0032] Step 4: Mix CI@SiO2 nanoparticles with anhydrous ethanol, homogenize by ultrasonication, add precursor sol, and uniformly coat with a high-shear disperser.

[0033] In this embodiment, 6% (w / w) of CI@SiO2 powder was weighed and added to 10.00 mL of anhydrous ethanol, and sonicated for 30 min to obtain a CI@SiO2 suspension. Then, the CI@SiO2 suspension was added to 50 mL of precursor sol, and the CI@SiO2 powder was uniformly dispersed and mixed in the ZrSiO4 coated precursor gel using a high-shear homogenizing emulsifier to obtain a homogeneously dispersed and coated precursor.

[0034] Step 5: After drying, heat treatment is carried out in an N2+H2 atmosphere. After acid washing, water washing and drying, excess impurities are removed by magnetic separation to obtain CI@SiO2@ZrSiO4 abrasive.

[0035] In this embodiment, the homogeneously dispersed and coated precursor was dried at 90 °C for 10 h. The dried powder was ground in an agate mortar, poured into a ceramic crucible and pressed into a cake shape, and then heat-treated at 800 °C for 60 min (N2 + H2 mixed atmosphere, heating rate 5 °C / min). The heat-treated powder sample was then acid-washed, water-washed and dried, and impurities were removed by magnetic separation to obtain the CI@SiO2@ZrSiO4 composite material.

[0036] This invention is not limited to the specific embodiments described above. Those skilled in the art can implement this invention using various other specific embodiments based on the disclosed content of the embodiments. Therefore, any design that adopts the design structure and concept of this invention and makes some simple changes or modifications falls within the protection scope of this invention.

Claims

1. A method for preparing an electro-magnetic-cutting three-phase CI@SiO2@ZrSiO4 composite abrasive, comprising the following steps: Step 1: Weigh carbonyl iron and add it to EtOH, then add ammonia water dropwise to form a brown turbid liquid. Then, according to a specific volume ratio, add TEOS, EtOH and H2O dropwise to form a colorless mixed solution. After reacting in a constant temperature water bath, filter and collect the precipitate, and dry it to obtain a brownish-yellow dry gel. Place it in a tube furnace for heat treatment to obtain CI@SiO2 nanoparticles. Step 2: Weigh a 1 mol / L ZrOCl2·8H2O solution, then weigh TEOS and add it to an ethanol-water solution for ultrasonic homogenization. Mix the two solutions together, add the sintering aid LiF, and then perform pre-hydrolysis in a high-speed disperser. Step 3: After pre-hydrolysis, ammonia is added to the precursor solution to adjust the pH to form a gel; then the obtained gel is dried to obtain a dry gel, and the dry gel is prepared into a 30 wt.% ethanol suspension and mechanically activated in a ball mill to obtain ZrSiO4 precursor sol. Step 4: Mix CI@SiO2 nanoparticles with anhydrous ethanol, homogenize by ultrasonication, add precursor sol, and uniformly coat with a high-shear disperser. Step 5: After drying, heat treatment is carried out in N2+H2 atmosphere. After acid washing, water washing and drying, excess impurities are removed by magnetic separation to obtain CI@SiO2@ZrSiO4 abrasive. The constant temperature water bath reaction temperature is 50–80 ℃, and the time is 3–5 h; The heat treatment temperature is 400–500 ℃, and the time is 1–2 h; The ball mill uses yttrium-stabilized zirconia beads with a diameter of 0.3~0.4 mm as the grinding media, with a media volume filling rate of 70%~80%, and the stirring mill speed is 1000~2000 r / min.

2. The method for preparing the electro-magnetic-cutting three-phase CI@SiO2@ZrSiO4 composite abrasive according to claim 1, characterized in that: The specific volume ratio of TEOS, EtOH and H2O is 54:45:

1.

3. The method for preparing the electro-magnetic-cutting three-phase CI@SiO2@ZrSiO4 composite abrasive according to claim 1, characterized in that: The heat treatment in an N2+H2 atmosphere is carried out at a temperature of 800–1000 ℃ for 1–2 h, with a heating rate of 5–10 ℃ / min.

4. The method for preparing the electro-magnetic-cutting three-phase CI@SiO2@ZrSiO4 composite abrasive according to claim 1, characterized in that: The mass ratio of the carbonyl iron to the ZrSiO4 precursor sol is 1:(2-5).